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HomeMy WebLinkAbout2005-09-12 Harbor Commission PacketKENAI HARBOR COMMISSION MEETING SEPTEMBER 12, 2005 CITY COUNCIL CHAMBERS 7:00 P.M. AGENDA ITEM 1: CALL TO ORDER/h ROLL CALL ITEM 2: AGENDA APPROVAL ITEM 3: APPROVAL OF MEETING SUMMARY -- July 11, 2005 ITEM 4: PERSONS SCHEDULED TO BE HEARD ITEM 5: OLD BUSINESS ao Discussion -- Kenai River Bank Erosion Project - Corps of Engineers Technical Report. ITEM 6: NEW BUSINESS a° Discussion-- Meeting Schedule Recommendation -- Tideland Application for Shore Fishery -- Ted J. Crookston ITEM 7: a° REPORTS Director Dock Foreman City Council Liaison ITEM 8: COMMISSIONER COMMENTS/QUESTIONS ITEM 9: PERSONS NOT SCHEDULED TO BE HEARD ITEM 10: INFORMATION ao Kenai City Council Action Agendas of August 3 and 17, 2005. 8/23 / 05 Kenai City Dock Fuel Schedule 8/31/05 KK memorandum related to FY 2006 Alaska Designated Legislative Grants. ITEM 11: ADJOURNMENT PLEASE CONTACT US ]:F YOU WILL NOT BE ABLE TO ATTEND THE MEET'lNG: CAROL -- KE:I:TH -- 283-8231 O~, Z83-8232 KENAI HARBOR COMMISSION MEETING JULY 11, 2005 CITY COUNCIL CHAMBERS 7:00 P.M. AGENDA ITEM 1. ITEM 2' ITEM 3. ITEM 4: ITEM 5: ITEM 6: a. ITEM 7: ae ITEM 8: ITEM 9: ITEM 10: ae C, ITEM 11: CALL TO ORDER/h ROLL CALL AGENDA APPROVAL APPROVAL OF MEETING SUMMARY May 9, 2005 June 6, 2005 PERSONS SCHEDULED TO BE HEARD OLD BUSINESS Discussion -- Kenai River Bluff Erosion Control Project/Update NEW BUSINESS Discussion -- Dock Boat Exit Road/Land Trade with Conservation Fund. REPORTS Director Dock Foreman City Council Liaison COMMISSIONER COMMENTS/QUESTIONS PERSONS NOT SCHEDULED TO BE HEARD INFORMATION Kenai City Council Action Agendas of June 1 and 15, 2005. 6 / 8 / 05 DNR letter regarding Kenai River Mile 3.5, Mooting Buoy/Final Consistency Response. 6/24/05 City of Kenai/Dock Rate Schedule. 6/15/05 Kenai River Center Project Tracking Sheet/Floating Facilities/Floating Docks -- Gary Foster, Applicant. ADJOURNMENT KENAI HARBOR COMMISSION MEETING JULY 11, 2005 CITY COUNCIL CHAMBERS 7:00 P.M. CHAIR TOM THOMPSON, PRESIDING MEETING SUMMARY ITEM 1: CALL TO ORDER/h ROLL CALL Chair Thompson called the meeting to order at approximately 7'14 p.m. confn'med as follows: Roll was Commissioners present: Commissioners absent: Others present' d. Foster, J. Barrett, S. Romain, T. Thompson B. Eldridge, P. Barrett Public Works Manager K. Komelis and Council Member Massie ITEM 2: AGENDA APPROVAL Public Works Manager Komelis requested the following additions to the packet: · 7/8/05 email message from B. Meiklejohn, The Conservation Fund. · Kenai River Personal Use Fishery, General Information Brochure MOTION: Commissioner J. Barrett MOVED to approve the meeting agenda as presented with the additional back-up information and Commissioner Romain SECONDED the motion. There were no objections. SO ORDERED. ITEM 3: APPROVAL OF MEETING SUMMARY 3-a. May 9, 2005 3-b, June 6~ 2005 MOTION: Commissioner d. Barrett MOVED for approval of the meeting summaries of the May 9 and June 6, 2005 Harbor Commission meetings and Commissioner Romain SECONDED the motion. There were no objections. SO ORDERED. ITEM 4: PERSONS SCHEDULED TO BE HEARD -- None. ITEM 5: OLD BUSINESS Discussion -- Kenai River Bluff Erosion Control Project/Update Public Works Manager Komelis reviewed correspondence from the Corps of Engineers to City Manager Snow which was included in the packet. Comments made during the Commission's discussion of the issue included' · If there's any way to lean on the Corps, it should be done. · A suggestion the City Manager contact Senator Stevens' office related to the progress of the project with copies to Senator Murkowski and Representative Don Young. · An actual completion date for the report should be requested and acquired. · ITEM 6: NEW BUSINESS Discussion -- Dock Boat Exit Road/Land Trade with Conservation Fund. Komelis reviewed his June 9,205 memorandum to Linda Snow and its attachments, which were included in the packet. Upon discussion of the issue, comments of the Commission were positive and it was suggested the trade go forward in order to realize the goal of development of the exit road to the boating facility. MOTION: Commissioner J. Barrett MOVED the Harbor Commission recommend to council the city swap Parcel 7 wetlands for The Conservation Fund's land and the city pursue the sale of Parcels 1-6 with exception of Parcel 3 to The Conservation Fund. Commissioner Foster SECONDED the motion. There were no objections. SO ORDERED. A second motion was suggested to consider sale of Lot 3 to The Conservation Fund if the Fund is interested in purchasing it, however it did not go forward. ITEM 7: REPORTS 7-a. Director-- Komelis distributed the Personal Use Fishery brochure and reviewed it with the Commission. Dock Foreman -- No report. 7-c. City Council Liaison -- Council Member Massie noted the following: · The Commission is a member short. Commissioner Foster stated he had spoken with Rick Mullowny, owner of Alaska Chinook Lodge, located on Anger Drive. · The Council will be beginning the process of searching for a new city manager. · A special Council Meeting will be held on Friday, July 15, 2005 to appoint an acting city manager. ITEM 8: COMMISSIONER COMMENTS/QUESTIONS Commissioners stated their appreciation of the personal use fishery brochure. HARBOR COMMISSION MEETING JULY 11, 2005 PAGE 2 J. Barrett -- Reported he would be absent from the August meeting. A brief discussion took place related to the personal use fishery. Comments included' · Questions of the area allowed for dip netting should be referred to the Alaska Department of Fish & Game regulations. · The city should consider requesting a "no wake zone" especially at the mouth of the River as the Kenai River Special Management Area Board (KRSMA) is considering one above the bridge. MOTION: Commissioner Foster MOVED to recommend the city council investigate a "no wake zone" being placed at the mouth of the Kenai River up to the Pacific Star Cannery. Commissioner J. Barrett SECONDED the motion. There were no objections. ~O ORDERED. ITEM 9: PERSONS NOT SCHEDULED TO BE HEARD -- None. ITEM 10: INFORMATION 10-a. 10-b. 10-c. 10-d. Kenai City Council Action Agendas of June 1 and 15, 2005. 6 / 8/05 DNR letter regarding Kenai River Mile 3.5, Mooring Buoy/Final Consistency Response. 6/24/05 City of Kenai/Dock Rate Schedule. 6/15/05 Kenai River Center Project Tracking Sheet/Floating Facilities/Floating Docks -- Gary Foster, Applicant. ITEM 11: ADJOURNMENT MOTION: Commissioner J. Barrett MOVED to adjourn and Commissioner Roma_in SECONDED the motion. There were no objections. SO ORDERED. The meeting adjourned at approximately 8:20 p.m. Meeting Summary prepared by: Carol L. Freas, City Clerk HARBOR COMMISSION MEETING JULY 11, 2005 PAGE 3 TO' FROM: DATE: RE' 210 Fidalgo Avenue, Kenai, Alaska 99611-7794 Telephone: 907-283-7535 / FAX: 907-283-3014 www.ci.kenai.ak, us KENAI. ALASKA MEMORANDUM COMMISSION/COMMITTEE/BOARD MEMBERS Carol L. Freas, City C~/~~ August 24, 2005 MEETING SCHEDULES Because of problems in achieving quorums for commission/committee or board meetings over the years, the Kenai City Council, at its Strategic Planning Session held on August 20, 2005, discussed how participation might be improved. Council and Administration recognize the value of commission/committee or board members and that as volunteers, you have determined to give up personal time in order to participate because of your commitment to the community. However, it is also recognized that lack of attendance by a few can result in: · A lack of quorum -- no business may be conducted without a quorum of the whole being represented {a seven-member commission must have four members present in order to conduct business). · Loss of valuable time for those of the membership who do attend. · Costs in staff time in preparing meeting packets, attending meetings, preparing meeting summaries/minutes, copying packets, postage for mailing packets, and meeting advertising, which average at approximately $300.00/meeting (Planning & Zoning, approximately $500/meeting or $1,000/month). In addition, the KMC 1.90.050(b) (a copy of which is provided to all appointees) states, If the commission, committee or board member shall be absent from more than one-half of all the meetings of his/her committee, commission or board, regular and special, held within any period of three (3) consecutive calendar months, he/she shall thereupon cease to hold the seat. It was Council's suggestion the members of our commissions/committees and boards be asked to discuss this issue and offer recommendations for encouraging better meeting participation. Keeping in mind the standard meeting day, time and place will remain as it is currently, please consider the following: 1. Would you prefer the commission/committee or board meeting to return to a bi- monthly schedule? 2. Would you prefer meeting only during summer months? If so, which months? 3. Would you prefer meeting only during winter months? If so, which months? 4. Do you, as a group, have other recommendations for Council to consider related to commission/committee and board participation, i.e. combine commissions and responsibilities, increase membership, etc.? Thanks for your help! CITY OF KENAI "Oil Capital of Alaska~ 210 FIDALGO .AVE., SUITE 200 KENAI, ALASKA 99611-7794 TELEPHONE: 907-28,.3-7535 FAX: 907-283-~14 MEMO TOe From: Subject: Phone: I)~te: Harbor Commission Keith Kornelis, Kenai Public Works Manager ~ Corp Draft Report- Kenai River Bank Erosion (907) 283-8232 Fo~x: (907) 283-3014 September 6, 2005 I have received the Corps of Engineers Kenai River Bank Erosion Technical Report, Kenai, Alaska. It is a draft techniml report. I have attached the main parts of the draft report.. Them are many additional tables, drawings, figures, and spreadsheets that are part of this draft report. The full draft report is available in my office for anyone to review. ~/REPLY TO ATTENTION OF: DEPARTMENT OF THE ARMY U.S. ARMY ENGINEER DISTRICT, ALASKA P.O. BOX 6898 ANCHORAGE, ALASKA 99506-6898 Project Formulation Section Mr. Keith Kornelis Public Works Director 210 Fidal~o Avenue, Suite Kenai, AK 99611-7794 Dear Mr. Kornelis- 200 Enclosed is the draft technical report' of bank erosion along the Kenai River at Kenai, Alaska. Please review the draft report and provide comments, if any, by October 3, 2005. If you have questions please call me at (907) 753-5638. Enclosure Since · . · Pat. rick Fitzgerald, PE Study Manager DEPARTMENT OF THE ARMY U.S. ARMY ENGINEER DISTRICT, ALASKA P.O. BOX 6898 ELMENDORF AFB, AK 99506-6898 KENAI RIVER BANK EROSION RECEIVED TECHNICAL REPORT KENAI, ALASKA .',':~~~' July 2005 PUBLIC WORKS DEPARTME_~_NT.. SUMMARY This report presents the findings of a technical investigation of bank.erosion along the Kenai River at the city of Kenai, Alaska. The Secretary of the Army was directed in the Energy and Water Development Appropriations Act of 2002, Senate Report 107-039, to expend up to $500,000 to conduct a "special technical evaluation of bank stabilization needs along the lower Kenai River." '~ The city of Kenai and the lower reach of the Kenai River are located on the Kenai Peninsula, approximately 65 air miles and 155 highway miles southwest of Anchorage via the Sterling Highway. The section of riverbank being studied is along the north bank of the river, between the mouth of the river and the city. Erosion of the bank along the Kenai. River at Kenai has continued to encroach upon city, commercial, and private, utilities and structures at an average rate of 1 to 3 feet per year. The citY has had to relocate utilities and roads, and cannot move forward with planning and development of the area along the bluff. Erosion has also resUlted in properties and structures being abandoned or condemned. The steep and unstable bank is a safety risk to residents and visitors to Kenai. The city and residents currently incur an average annual loss of $151,000 due to reduced value of lands and buildings and relocation of buildings and utilities. A number of forces contribute to the bank erosion such as wind, waVes, foot traffic, overland drainage, groundwater seepage, and fiver currents. The primary contributor of erosion is groundwater seepage out of the bank face, which causes the piping of f'me sand material from the upper bank and weakening of the lower silt/clay layer. Further studies and bank stabilization project designs should first ad&ess groundwater seepage, To estimate the impacts of a stabilized bank it was assumed that the bank stabilization conceptual design by Peratrovich, Nottingham, and Drage, Inc. (PND) in their February 2002 report was the with-project condition. Primary features of this concept would consist of an armor stone layer along the lower bank with the upper bank cut to a shallower grade and 'revegetated. Groundwater seepage out of the bank face would be routed through a collector drain and discharged to the fiver. Although it is recognized that the PND design was at a conceptual level, additional analysis and design should first focus on groundwater seepage and collection. There is the potential for direct and indirect loss of habitat from stabilization of the bank. Direct habitat loss would occur from project construction in the intertidal area and also result inca loss of potential, nesting habitat for swallows if the bank grade is altered. Change of the bank grade would remove numerous spruce trees from the top of the bank. Bald eagles commonly use these trees to perch and overlook the river and associated wetlands. If the' bank is cut back to a more shallow, stable slope and subsequently revegetated, it is likely that the new vegetation will provide some bird habitat. There will likely be disturbance and displacement of birds during some phases of construction. The timing of construction will be important since construction impacts to many birds can be avoided. Hydraulic modeling was performed to compare the existing and with-project conditions. Results of the modeling indicate that the project would have minimal encroachment on the river flow path and would have an insignificant impact on river currents. Kenai River Bank Erosion Technical Report- Kenai, Alaska Indirect impacts would encompass effects of the erosion control project that are encountered outside the project footprint. Of particular concern are the sand dunes' and the large intertidal area in front of the dunes and the sewage treatment plant. According to the sediment impact analysis, see Appendix C, the impacts to the dunes from an erosion control project are expected to be minor. Although armoring the bank would decrease, the amount of sediment entering the system, this quantity is small in comparison to the overall amount of sediment contributed from other s6urces in the river. Although the bluff is' receding, geotechnical analyses indicate that the slope is stable and that massive slope failures are not contributing factors to the erosion.' Both the sand and clay slOpe faces, however, are susceptible to surface raveling, sloughing, and wind and water erosion. Well flow tests were also conducted along the bluff. The tests indicate that the sand layer of the bluff is highly permeable. However, the number of tests performed was insufficient to adequately map groundwater flow patterns suitable for detailed design of a bluff stabilization project. Kenai River Bank Erosion Technical Report - Kenai, Alaska CONTENTS 1.0 2.0 3.0 4.0 5.0 6.0 7.0 6.1 '6.2 6.3 6.4 6.5 ii STUDY AUTHORITY .................. --~ ...... - ..... ~=--- ...................... --~- 2 STUDY PURPOSE AND LOCATION ....................... - ..................... ~-- 3 2.1 Purpose and Lpgation ................................ ' ' - .................. 3 2.2 Study Scope ........................................................... : ................. 3 PREVIOUS STUDIES ................................................ - ............................. 5 EXISTING CONDITIONS ........ - .................................... 6 4.1 Community Description ........................ ...... 6 4.2 Physical Environment .......................................................................... 6 4.3 Environmental Resources ..................................................................... 7 PROBLEMS AND OPPORTUNITIES ....................... ~ .........8 5.1 Problem statement .................................................................. 8 5.2 Opportunities ........... ' 8 EVALUATION OF BANK EROSION AND STABILIZATION .................. 9 Bank Erosion Process .............................................................. 9 Sedimentation ..................................................................... 9 Riverine Characteristics .................................................................... 9 Geotechnical Investigation ...................................................................... 10 Environmental Evaluation ................ : ................................................ 10 6.5.1 Cultural Resources .............................................................. 10 6.5.2 Environmental Impacts.- ........................ 10 6.6 Economic Impacts ............................................................... 11 6.6.1 Current without project Conditions ..... 11 6.6.2 Future without-project conditions ................................................. .---- 13 6.6.3 Future with-project conditions ............................................................... 14 CONCLUSION ................... - ............................................... 15 7.1 Bank Stabilization Design Considerations ................................................ 15 7.:2 Additional Study Requirements .............................................................. t5 7.3 Conclusion .................................................................................. 15 FIGURES Figure 1. Figure 2. Figure 3. Figure 4. Location Map ' ' 3 Lower Kenai River ........................................................................ 4 Kenai Bank Lots and Existing Bank Line, Used by permission of the city of Kenai. ........... 12 Kenai Utility Locations and Existing Bank Line, Used by permission of the city of Kenai.---- 13 APPENDICES Appendix A Appendix B Appendix C Appendix D Environmental Studies Hydraulics and Hydrology Sediment Impact Assessment Geotechnical Investigation Kenai River Bank Erosion Technical Report- Kenak Alaska 1.0 STUDY AUTHORITY This study is in partial response to the Rivers and Harbors in Alaska resolution, adopted by the U.S. House of Representatives Committee on Public Works on 2 December 1970. This resolution reads in part: Resolved by the Committee on Public Workx of the House of Representatives, United States, that the Board of Engineers for Rivers and Harbors is hereby requested to review the reports of the Chief of Engineers on Rivers and Harbors in Alaska, published as House Document Numbered 414, 83ra Congress, 2~a Session;...and other pertinent reports, with a view to determining whether any modifications of the recommendations contained herein are advisable at the present time. The Secretary of the Army was directed in the Energy and Water Development Appropriations Act of 2002, Senate Report 107-039, to expend up to $500,000 to conduct a "special technical evaluation of bank stabilization needs along the lower Kenai River." Kenai River Bank Erosion Technical Report- Kenai, Alaska 2.0 STUDY PURPOSE AND LOCATION 2.1. Purpose and Location The purpose of this study is to.conduct a technical investigation of bank erosion and stabilization along the lower Kenai River at Kenai, Alaska. The city of Kenai and the lower reach of the.Kenai River is approximately 65 air miles and 155 highway miles Southwest of Anchorage via the Sterling Highway. The bank is along the north bank of the river, between the river and the city. The location of Kenai is shown on Figure 1. A detailed photograph of the lower Kenai River is shown on Figure 2. 2.2 Study Scope · The scope of this investigation includes identification of the mechanisms for bank erosion, analysis of bank stability, measurements' of groundwater flow, and impacts to the environmental resources and the river and coastal environment from a bank stabilization · project. · 20Qq, t~hpO, ue~t.~m; Ino,; O 2004 Figure 1. Location Map Kenai River Bank Erosion Technical Report- Kenai, Alaska Figure 2. Lower Kenai River Kenai River Bank Erosion Technical Report- Kenai, Alaska 3.0 PREVIOUS STUDIES Section 905(b) (WRDA 86) Analysis, Kenai River Bluff Erosion, U.S. Army Corps of Engineers, July 2005. This report provides a reconnaissance level analysis to determine if there is Federal interest in a cost-shared feasibility study. "Kenai Coastal Tail and Erosion Control Project", Peratrovich, Nottingham, and Drage, Inc., February 2002. This report provides a design concept of bank stabilization and a pedestrian trail along the bank. "Erosion at the Mouth of the Kenai River, Alaska", Orson Smith, William Lee, and Heike Merkel, April 2001. Report contains a sediment budget analysis with regard to the proposed "Kenai Coastal Trail and Erosion Control Project:', PND Feb 2002. Draft "Bluff Erosion Study, Kenai River Sedimentation Study", TAMS Engineers, November 1982. This report identified groundwater seepage from the bank face as the primary mechanism of bank erosion and recommended control of this seepage as the first order of work towards bank stabilization. "Erosion and Sedimentation in the Kenai River, Alaska", U.S. Geological Survey, 1982. This report presented an assessment of erosion and sedimentation of the entire Kenai River. Kenai River Bank Erosion Technical Report- Kenai, Alaska 4.0 EXISTING CONDITIONS 4.1 Community Description .History. Prior to Russian settlement, Kenai was a Dena'ina Athabascan Indian village. Russian fur traders first arrived in 1741. At that time, about 1,000 Dena'ina lived in the village of Shk'imk't, near the river. The traders called the people "Kenaitze," or "Kenai people." In 1791, a fortified Russian trading post, Fort St. Nicholas, was constructed for fur and fish trading. In 1869 the U.S. military established a post for the Dena'ina Indians in the area, called Fort Kenay, which was abandoned in 1870 after Alaska was purchased by the U.S. A post office was established in 1899. Through the 1920s, commercial fishing was the primary activity. In 1940, homesteading enabled the area to develop. The first dirt road from Anchorage was constructed in 1951. In 1957, oil was discovered at Swanson River, 20 miles northeast of Kenai - the first major Alaska oil strike. The City was incorporated in 1960. In 1965, offshore oil discoveries in Cook Inlet fueled a period of rapid growth.. Kenai-has been a growing center for oil exploration, production and services since that time. Culture. The Kenai River is a major sport fishing location for Anchorage residents and tourists. The fiver is world renown for trophy king and silver salmon. The Kenaitze (Tanaina Athabascans) live borough-wide and utilize the rich resources of Cook Inlet. Economy. The City is the center of the oil and gas industry for the Kenai Peninsula, providing services and supplies for Cook Inlet's oil and natural gas drilling and exploration. Tesoro Alaska's oil refining operations and Unocal's urea plant are located in North Kenai. Both in-state and out-of-state visitors provide a significant industry on the Peninsula. Other important economic sectors include sport, subsistence and commercial fishing, fish processing, timber and lumber, agriculture, transportation services, construction and retail trade. 234 area residents hold commercial fishing permits. The largest employers are the Borough School District, Unocal, Peak Oilfield Services, the Borough, and Central Peninsula General. Hospital. The Challenger Learning Center of Alaska was completed in Spring 2000. Logging of spruce bark beetle-killed timber also occurs in the area. Facilities. Water is supplied by three deep wells and is piped to 75% of households. Sewage is piped and receives secondary treatment. The remaining 25% of households use individual water wells and septic systems. Natural gas is primarily used for home heating purposes. Homer Electric Assoc. operates the Bradley Lake Hydroelectric Project and is part owner of !he Alaska Electric Generation & Transmission Cooperative.. The Borough landfill is located tn nearby Soldotna. 4.2 Physical Environment The City of Kenai is located on the Nikishka Lowland geomorphological subdivision of the Kenai Lowland. This region is characterized by a modified morainal topography, which is separated by an interlacing pattem of swamps and muskegs developed in abandoned drainage 'channels and broad depressions. The topography and surficial deposits of the region are primarily the products of repeated glaciations, which advanced from ice centers in the surrounding mountain ranges. Near the City of Kenai, the glacial moraines are fronted by a Kenai River Bank Erosion Technical Report- Kenai, Alaska broad coastal plain consisting of terraced and channeled sand and gravel deposits, which terminate as steep sea bluffs above a series of raised tidal flats. The .topography in the area of the Kenai River mouth consists of a bank approximately 70 feet high opposite a low-lying wetland and tide flat area. The topography indicates that the fiver valley historically has experienced much higher flows during periods of glacial retreat. Both the bed material-and the channel pattern reflect previous glacial discharges and, except for the lower 12 miles the fiver, is undersized. The bank at the mouth of the river is composed of three distinct material types. An organic mat top layer approximately. 2 feet thick, a fine sand layer approximately 37 feet thick, and a silt/clay layer that varies from 35 to 45 feet thick. A more detailed description of the physical environment of the project area is provided in Appendices B, C, and D. 4.3 Environmental Resources Surveys in the project area to inventory birds, mammals, fish and invertebrates were conducted. The Kenai River estuary is a very biologically productive area noted for its abundant fishery resources including all 5 species of salmon. Other species include, stickleback, lamprey, eulachon, rainbow trout, Dolly Varden, juvenile marine species such as walleye pollock, Pacific cod, tom cod, sole, Pacific herring, sand lance, Pacific sandfish, sculpins, snail fish, and shrimp species. Fish and maeroinvertebrates were sampled, stomach content analysis, and partial food webs were constructed for the estuary. Time series temperature and salinity indicated a highly dyn~c nature of the physical environment in the estuary. Invertebrate species sampled in the project footprint area were limited due to the hard substrates. Uncompacted substrates on the south shore provided habitat for small clams (Telina sp.) and marine worms, which are prey for many bird species. The shoreline and wetland in the area are used seasonally for nesting, foraging and staging by a variety of gulls, waterfowl, and bald eagles. Along the face of the bank, the most common birds were ravens, magpies, hemng gulls and swallows. Harbor seals are routinely observed near the fiver mouth. Beluga whales were also observed. There are the remains of 3 archaeological sites and at least 25 structures in the general project area. Of the approximately 25 structures, 7 are eligible for the National Register of Historic Places and the remainder must be evaluated for the Register. In addition, a portion of the project is within the boundaries of a locally designated historic district. A more detailed description of the environmental and cultural resources is provided in Appendix A. Kenai River Bank Erosion Technical Report- Kenai, Alaska 5.0 PROBLEMS AND OPPORTUNITIES 5.1 Problem statement The town of Kenai is located along the bank of the Kenai River at its mouth in Cook Inlet. Erosion of the north fiver..bank has continued to encroach upon city, commercial, and private utilities and structures at an average rate of 1 to 3 feet per year. The city has had to relocate utilities and roads and cannot move forward with planning and development of the area. Erosion has also resulted in properties and structures being abandoned or condemned. The steep and unstable bank is a safety risk to residents and visitors to Kenai. This erosion rate is considered conservative (faster) than that presented by the UAA. A more conservative rate was used to bracket the maximum extent of damages under the without- project condition. 5.2 Opportunities Reduce repair and relocation costs of public utilities · Reduce relocation cost of public, commercial, and private structures Reduce repair and relocation cost of public roads Allow for long-term planning and development of lands adjacent to the banks Reduce safety riSk to individuals walking along the bluff Kenai River Bank Erosion Technical Report- Kenai, Alaska 6.0 EVALUATION OF BANK EROSION AND STABILIZATION 6.1 Bank Erosion Process Bank erosion along the Kenai River mouth is a product of several conditions, with varying degrees of contribution. The erosion mechanisms are discussed in detail in Appendix B. The mechanisms acting on the bank include: Wind - Erosion due to winds along the bank is common. However, this volume of material is minimal and does not contribute significantly to the total erosion along the bank face. Waves - Wave action at the base of the bank is an infrequent occurrence and requires a combination of storm surge and high tide for the bank to be impacted since the wetland and shoal at the mouth of the river create a natural barrier by limit!rig the wave height that can reach the bank. Groundwater Seepage - Groundwater seepage out of the bank face at the sand and silt/clay layer interface transmits sand particles, which weakens the upper layer. Also, water running down the face weakens the lower silt/clay layer. Overland Flow - The upper banks along the Kenai are susceptible to erosion from overland flow. Flow over the top of the bank, if left uncontrolled will readily erode the sand in the upper bank: 6.2 Sedimentation ' Erosion from the bluff at Kenai contributes an estimated 21,300 tons of sediment to the Kenai estuary annually. Sediments from the bank consist of a mixture of gravels, sands, silts and clays, with most of the noncohesive soils in the horizon comprising the.upper half of the bank. About 50 percent of these upper horizon soils are sands in the size classes found in the Kenai Dunes. Thus, the bank contributes an average of 10,600 tons of noncohesive sediments to the system each year. This represents about 7 percent of the sand flux into the system. About 60,000 tons are delivered annually by the Kenai River from upland and streambank erosion upstream of the estuary, and about 100,000 tons are delivered by longshore transport ia Cook Inlet. Most of these sediments pass through the estuary, but some are deposited on the tidal flats and the Kenai Dunes. · StabiliZation of the bank would affect the sediment dynamics in the estuary. The overall impact of the reduction in sediment load if the bank is stabilized would be very minor, however, as the system is aggradational and the reduction in sediment volume slight. Changes in the morphology of the tidal flats and dunes are not expected given the net surplus of sediment in the reach, and the coastal morpholOgy indicates that the dunes are primarily fed by longshore transport and wave action. Detailed information on the sediment assessment is provided in Appendix C. 6.3 Riverine Characteristics · The general effect of a bank stabilization project'was evaluated using the Hydrologic Engineering Center River Analysis System (HEC-RAS). The model was run to determine potential changes to the river velocities for the existing and with-project condition. Results Kenai River Bank Erosion Technical Report- Kenai, Alaska I of the analysis indicate that the project would cause an insignificant (0.1 feet per second) to the river velocity. This. is due to the limited amount of encroachment into the river's flow path by the project. More detailed information on the geotechnical investigation is provided in Appendix B. 6.4 Geotechnical Inyestigation The purpose of the geotechnical investigation was to determine if slope stability was contributing to the recession of the bank. In additiOn to the stability investigation, a well flow test was conducted to estimate soil permeability. The well flow test indicated that the sand layer of the bank is highly permeable. Although the bank is receding, the collected soil data, laboratory testing, and analysis indicate that the slope is stable and that massive slope failures are not contributing factors to the erosion. Both the sand and clay slope faces, however, are susceptible to surface raveling, sloughing, and wind and water erosion. More detailed information on the geotechnical investigation is provided in Appendix D. 6.5 Environmental Evaluation 6.5.1 Cultural Resources There are the remains of two archaeological sites and four structures eligible for the National Register of Historic Places that could be impacted by continued erosion during the project's period of analysis. There are about 14 additional structures that could be impacted. The historical significance of these structures is unknown. 6.5.2 Environmental Impacts There is the potential for direct and indirect loss of habitat from stabilization of the bank. Direct habitat loss would occur by placing riprap in the intertidal area and also result in a loss of potential nesting habitat for swallows if the bank grade is altered. Changing the slope of the bank would require numerous spruce trees to be removed from the top of the bank. Bald eagles commonly use these trees to perch and overlook the fiver and associated wetlands. Indirect impacts would encompass effects of the erosion control project that are encountered outside the project footprint. Of particular concern are the sand dunes and the large intertidal area in front of the dunes and the sewage treatment plant. According to the recent sediment impact analysis, the results of the proposed erosion control project are expected to be minor. Although armoring the bank would decrease the mount of sediment entering the system, this quantity is small in comparison to the overall mount of sediment contributed fi'om other sources in the fiver. . · If the bank is cut back to form a more gentle, stable slope and subsequently.revegetated, it is likely that the new vegetation will provide some bird habitat. For instance, eagles could perch in the trees once they grow to an adequate size. Vegetation selected for planting should be similar to existing vegetation, in the area. There will likely be disturbance and displacement of birds during some phases of construction. The timing of construction will be important since construction impacts to many birds can be avoided. Gulls nest in large numbers on the inside bend wetlands near the mouth of the fiver across from the bank and it is unknown how they might react to Kenai River Bank Erosion Technical Report- Kenai, Alaska construction disturbance. Shorebirds use the intertidal areas in the project vicinity to forage for prey to fuel their migration to breeding grounds. Impacts could be avoided if construction was timed to avoid the weeks that they are present. Eagles often perch along the bank of the inside bend wetlands and could also be disturbed by construction activities. At low tides, gulls, eagles, shorebirds and ducks forage on the intertidal mudflats. This intertidal area is much closer to the bank than the inside bend wetlands that are only periodically covered ~t high tides in the spring and fall. It is difficult to predict the degree of disturbance that may arise from construction. In the summer months.', there is always a large mount of boat traffic near the mouth of the Kenai from both .commercial and recreational boaters. The degree of disturbance from construction may be a factor of the type and duration of the noise produced from construction.' · Seals foraging in the fiver mouth may be disturbed by construction activities such as excavation and placement of fiprap. Since the riprap will'be above the water line except for high tides, the effects after construction are likely to be minimal. Summa~. Since most bird usage occurs Outside the project footprint and the project is not expected to.affect the dunes and mudflats down-river, it is unlikely that birds will be negatively affected in the long-term due to the proposed erosion control project. However, short-term impacts are likely for several species due to construction activities. These effects could be minimized if construction was timed properly. Further consultation will be necessary to determine the construction timing to minimize affects to birds and marine mammalS. 6.6 Economic Impacts 6.6.1 Currant without-project Conditions The bank at Kenai has experienced severe erosion over the past 48 years. Thc erosion rate of three feet per year as used to bracket the maximum extent of damages under the without- project condition. The bank averages a loss of approximately a half-acre per year to erosion. The average value of this lost land is approximately $42,000 per year over the past 48 years (2 Million). An average value per acre was taken of lots near the bank that are unaffected by erosion and used to calculate the lost value caused by erosion. Twenty-nine lots have lost some or their entire footprint to erosion. The following figure shows the lots in relation to the existing bank line. Kenai River Bank Erosion Technical Report- KenaL Alaska Figure 3. Kenai Bank Lots and Exis{ing Bank Line, Used by permission of the city of Kenai. At the current rate of erosion, the bank will continue to lose approximately a half-acre per year and land will continue to lose value. Once land becomes eroded to a certain point, the resale value decreases. It can be reasonably assumed that once the erosion reaches a certain percentage (i.e .... 50%) of the land, that even if the land is assessed at a value, no buyer is Willing to take the risk of purchasing the lot. Twenty-six lots adjacent to the bluff are approaching a loss of 50% due to erosion. The existing value of these lots is $540,000 according to the city,s tax assessment records. This existing value is considered a. lost value since the land has close to no resale worth. Utility locations are also a concern for the city of Kenai. A sewer line was mOved away from the bank in 2002. Approximately 500 feet was moved at a cost of $135,000. It was recognized 4-5 years prior to the work that the sewer line was at risk of damage due to the bank eroding. The street (Mission Avenue) adjacent to the Se~er line also had to be moved at a cost of approximately $125,000. A total of $260,000 was spent to make these relocations. Figure 4 shows the abandoned section of sewer line that had to be relocated as well as the sections of line that are closest to the bank line that will have to be relocated if the erosion problems are not addressed. Kenai River Bank Erosion Technical Report- Kenai, Alaska 13 Figure 4. Kenai Utility Locations and Existing Bank Line, Used by permission of the city of Kenai. In addition to the land eroding, the buildings that reside on those lots are at risk of bank erosion. Currently there are two buildings that'are at immediate risk of falling into the 'fiver. One of the buildings has part of the foundation hanging off the edge of the bank, while the other building is on the border. In order to move the buildings out of harms way, the buildings must be pulled off their foundations, placed on beams and transported to another location. It is estimated that it would cost on average approximately $50,000 per stmcture to complete a move to another location. A total cost of $100,000 is anticipated for the immediate movement and relocation of these structures. A total cost of 2.9 Million dollars has been incurred by the city over the past 48 years due to the erosion of the bank. This is an annual cost of $60,000, with the majority of the costs taking place within the last 20 years. 6.6.2 Future without-project conditions The erosion is anticipated to continue at the current high-end estimate of 3 feet per year.. This erosion will continue to lead to lost value in land at the current 2004 cost of $42,000 per year. Utilities and street relocations will also continue. It is estimated that at least an additional 1,000 feet of road and utility lines are at risk of erosion. These roads and lines are anywhere from 40 to 100 feet from the bank. At the current pace of erosion, additional streets and sewer lines will need to be replaced within the next 20 years. It can be estimated that replacing 1,500 feet of utility lines would cost $405,000 and the roads, $375,000. A total cost of $780,000 in 2004 dollars can be estimated for the relocation of roads and lines in the next 20 years. An annual cost of $39,000 is anticipated for the movement of utility lines. Kenai River Bank Erosion Technical .Report- Kenai, Alaska There are approximately another 20 structures that will be at risk of the erosion of the bank within the next 20 years. It is estimated that'movement of these buildings will cost in the , range of $50,000 to $90,000 per structure. It is assumed that at least 1 building will need to be relocated each year at a cost of $70,000. The annual cost for the furore without-project condition is $151,000. ,, 6.6.3 Future with.projeCt conditions Though it is difficult to predict the value of land in the with-project condition, there is no doubt that the attractiveness of the land will increase dramatically resulting in additional value and added benefits to the project. The current benefits are calculated on current values of property nearby the bank. The benefits from a project that stops the existing erosion problems are/he increased value of land and resale ability and the end to the relocation of buildings and utility lines. Total annual benefit of the project is estimated to be $151,000. o Kenai River Bank Erosion Technical Report- Kenai, Alaska 7.0 CONCLUSION 7.1 Bank Stabilization Design Considerations Further study and design of bank stabilization measures should first address groundwater seeping out the bank .face. Any solution that does not address the groundwater will not solve a major source of erosion. Options that may be considered to address the groundwater include: a cutoff wall and pump system to intercept the groundwater, draw down wells to reduce the water table along the bank face, a horizontal drain system into the face of the bank to collect and divert the water, a free draining retaining system to hold back the bank material and still allow free drainage of water from the face of the bank, or creation of drainage channels to alter the groundwater gradient. 7.2 Additional Study Requirements The findings of the Corps' 905(b) report indicate that bluff stabilization may be feasible from a technical engineering perspective. However, the amount of national economic development benefits available would not support Federal participation in a cost-shared feasibility study under existing shore protection authorities until changes in the socioeconomic or physical environment warrant a restudy of the area. If the local interest desires additional technical assistance it couid be requested through the Corps' Planning Assistance to States Program. Technical assistance it could also be pursued through additional congressional legislation. If Federal participation in a feasibility'level study of bank stabilization is conducted, evaluation would be required under the Clean Water Act, National Historic Preservation Act, National Environmental Policy Act, Coastal Zone Management Act, Essential Fish habitat, Endangered Species Act, and Fish and Wildlife Coordination Act. 7.3 Conclusion StabilizatiOn is technically possible, and would likely not have a significant affect on the environment. Additional studies should focus on field data collection to address erosion . from groundwater seepage, identification of cultural resources, and analysis and design of bank stabilization measures. Groundwater studies, such as groundwater mapping, should be performed to better define the seepage patterns and flow rates to ensure a sound design for a stabilization project. Date Timothy J. Gallagher Colonel, Corps of Engineers District Engineer Kenai River Bank Erosion Technical Report- KenaL Alaska APPENDIX A" ENVIRONMENTAL RESOURCES KENAl BLUFF'EROSION TECHNICAL REPORT KENA!, ALASKA Environmental DOCuments Invertebrate samPling Bird and Marine Mammal Survey Cultural ResoUrCes· . ADF&G BaSeline Fisheries AssesSment · .. .. .. .. ... · · , -.. CEPOA-EN-CW-ER (1105-2-1 Ob) MEMORANDUM FOR RECORD SUBJECT: Kenai Blu. ff Erosion Project Benthic Invertebrate Sampling 1. Introduction. Intertidal habitat near the mouth of the Kenai River was sampled for benthic invertebrates on 3 April 2003. Chris Hoffman and Ashley Reed, biologists, U. S. Army Corps of Engineers, Alaska District, conducted the surveys. Mark Willette, fisheries biologist, Alaska Department of Fish and Game, operated the skiff and provided assistance with attempts to obtain subtidal samples on 4 April 2003. This sampling effort was performed as part of a study to investigate existing habitat and potential impacts from bluff stabilization and trail creation near the mouth of the Kenai River. With the exception of one site (R3 lower, see figure 1) on the bank opposite the buff, no benthic invertebrates were detected. Sample locations are depicted in figure 1 and sample site details and results are presented in table 1. 2. Methods. Seven sample sites were selected along the bluff, each approximately 200 meters apart. Two samples were taken at each site; an upper intertidal (U l-U7) sample 10 meters from the toe of the bluff and a lower intertidal (L l-L7) sample 40 meters from the toe of the bluff. Additional samples were taken from the opposite bank (samples R1-R3, see figure 1). Samples R1-R3 were taken at various distances from the vegetation line (see table 1) because the distances used on the bluff side were not appropriate due to a different bank profile. All samples were taken during the period surrounding a low tide. Samples were collected from shore with a trowel and a rectangular template to yield a 0.1-meter3 sample (10 cm sample depth). Samples were placed in a labeled bucket for analysis. a. All samples were washed on the same day they were collected using a two-tiered sieve and a garden hose with very low water pressure. The' coarse sieve contained ---1- centimeter mesh and was placed---20 centimeters above the fine sieve, which was made from ~-l-milimeter mesh. Much of the substrate was composed of fine silt, so care was taken to gently dissolve all clumps so invertebrates were not damaged or °verlooked. Samples were preserved in 10% neutral-buffered formalin and then transferred to isopropyl alcohol for preservation and subsequent identification. 3. Results and Discussion. Invertebrates were only found in one (R3 lower) of the 20 samples. This sample contained 21 small clams (Tellina nuculoides) ranging in size from 0.4 to 1.3 centimeters. Ice was present below the silt at both R3 sample sites, but not at any other site. a. We attempted to Collect subtidal samples but'were unsuccessful. We used a 0.1 meter3 Van Veen. dredge, but the tide and current were too strong to obtain a valid sample CEPOA-EN-CW-ER SUBJECT: Kenai Bluff Erosion Project Benthic Invertebrate Sampling despite working at sl~ii:k tide and on an incoming tide immediately after slack tide. Another attempt to obtain subtidal samples was made in May 2003 with a heavier sampling device. This attempt was also unsuccessful due to a combination of current, tide and the fact that the bottom is highly compacted. Some samples were obtained for sediment analysis from the large shoal located offshore of R3, but a cursory investigation of the sample revealed only Tellina spp. clams. The material on the shoal is composed of coarse sand and therefore probably provides good habitat for these small clams. The highly compacted nature of the river bottom likely makes it unsuitable benthic invertebrate habitat. Additional studies are planned to survey the epibenthic invertebrates in the river. b. On 17 April we obtained some sediment samples from R3 for pan of a grain size analysis. Although we did not sieve for benthic invertebrates, we noticed one Tellina spp. clam and 2 marine polychaetes, which we collected, preserved and analyzed. These marine polychaetes were identified as Neris spp. and are most likely Neris vexillosa. Encl Christopher Hoffman Biologist I ~ I · Benthic invertebrate sample site 500 rn 1000 m Note.' Red dots am approximate sample sites. An upper intertidal and lower intertidal sample were taken at each dot. Exact locations are presented in table 1. Figure 1. :1:: I-.- z CEPOA-EN-CW-ER (1105-2-1 Ob) MEMORANDUM FOR RECO~ SUBJECT: Kenai Blu. ff Erosion Project Bird and Marine Mammal Survey 1. introduction'. Bird and marine mammal surveys were conducted near Kenai, Alaska from April 2003 through March 2004. These surveys were conduct ' · determine the abundance and local distribution of bird ,a ,,. · ___ ed to. a,,,., ,-anne mammal species to address the impacts of potential erosion control measures along the Kenai Bluff. Chris Hoffman, biologist, Army Corps of Engineers, Alaska District Conducted the surveys. 2. ethodolog¥. Surveys were conducted from five locations along the bluff. Survey observation points and sectors are depicted in figure 1. An aerial photograph mosaic with bird survey boundaries is included in figure 2 to provide greater resolution than the topographic map. The survey area was divided into six sectors in order to describe bird and marine mammal distribution. The sectors were typically dictated by terrain except for two reference stakes used to delineate the limits of sector 3 due to lack of recognizable boundaries. The survey area included the face of the bluff as well as the shoreline and the water. Marine mammals were counted in each of the six sectors. In sector MM, all marine mammals are included, but shorebirds and waterfowl were only included when they were within range to allow identification. The MM sector is too large and the distances are too .great to allow a complete bird survey. Therefore, bird numbers in sector MM are not indicative of the total number of birds using this sector. a. The goal of the survey is to provide a "snap shot" of bird and marine mammal distribution. This is in contrast to a survey with equal-sized sectors and a discrete time spent on station. Enough time is spent at each observation point to allow a thorough count of all birds and marine mammals present. Ample time is allocated to allow diving birds and mammals'to complete a few dive cycles. Since much of the habitat use is dependent on tide stage, the survey is designed to be completed in a short time span so all sectors can be observed with minimal tidal fluctuation. The survey protocol was designed assuming that it would be more advantageous to complete two surveys per day at different tide levels than one survey lasting for several hours. Additionally, gulls, eagles, and seals move frequently and it would be difficult to avoid double counting the same animal if the survey lasted a long time in one. area. 3. Biological Observations. A list of species observed a~d their four-letter abbreviation code is included in table 1. Bird and marine mammal sightings are included in tables 2 through 24. These tables include the general conditions of the survey, species observed, and numbers in each of the six sectors. Graphs of selected species abundance over time are presented in figures 3 through 6. The spatial distributions of predominant species observed during each survey are shown in figures 7 through 22. CEPOA-EN-CW-ER SUBJECT: Kenai Bluff Erosion and Marine Mammal Survey Trip Report. a. The majority of bird observations occurred on the opposite side of the river from the bluff. One reason for this might be that the sediment is more loosely compacted and therefore is better suited for aquatic invertebrate prey species for birds. An invertebrate survey conducted in May 2003 found small clams (Telina species) located throughout these uncompacted areas. Another reason for bird location might be because the slope of the bank is much less steep and a greater surface area exists to feed on and for sediment to accumulate upon. The large sand/gravel bars that are exposed at relatively low tides are evident in Sectors 2 through 5 of the aerial photograph (figure 2). These sand/gravel bars are exposed to varying degrees as the tide goes out, thus probably explaining some of the large daily fluctuation in bird numbers in a particular sector at different times of the day. b. Gulls were the most abundant birds observed on an annual basis. The majority of these gulls were herring gulls, although some mew gulls and glaucous-winged gulls were also observed. Herring gull numbers peaked in July and large numbers of these gulls were observed breeding on the wetlands across from the bluff. These wetlands have been termed the "inside bend wetlands" for the purpose of this survey and are depicted in figure 1. Breeding is possible on these wetlands in the summer months because the tides are not high enough during this time of year to inundate the wetlands. During the spring and fall, high tides routinely flood the inside bend wetlands. While walking these wetlands to collect sediments samples on 14 May 2003, I noticed that approximately 20% of the herring gull nests contained one egg. On 21 August 2003 I returned to the wetlands and observed.that most (-90%) of the.herring gulls had fledged. Accordingly, peak habitat use of the inside bend wetlands by herring gulls is from about early May until the end of August. Gulls are routinely present on ponds in this area in the spring and fall and along the perimeter of the inside bend wetlands all year long unless the river is frozen. c. Bald eagles were most abundant in April and May and were practically absent in the summer. It is likely that eagles leave the mouth of the Kenai River in summer to breed and feed elsewhere since salmon are present in abundant quantities throughOut many areas of south-central Alaska. Eagles would typically move onto the flats on the opposite side of the bluff and at the mouth of the river at low tide and then perch along the bank of the inside bend wetlands during higher tides. d. Common goldeneye were present during February through April. Most goldeneye were observed in sector 5 in the area between the fish processing plant and upstream to the city dock. When these sectors were filled with ice, goldeneye were observed further downstream. CEPOA-EN-CW-ER SUBJECT: Kenai Bluff Erosion and Marine Mammal Survey Trip Report. e. Along the face of the bluff and the shoreline below the bluff the most common birds observed were '/'avens, magpies and small numbers of hemng gulls. Swallows were sometimes observed flying along the bluff, and while some holes along the banks (in sector 3) were seen, there was no indication of nesting. Eagles would often perch in spruce tress along the face of the bluff, presumably because it served as an excellent vantage point to observe the wetlands and the fiver. In June and July, gulls were commonly observed in sector 1 on both sides of the fiver, probably in part due to the presence of salmon carcasses from people who were d/p-netting. f. Harbor seals were routinely observed near the mouth of the Kenai River in small numbers. At low tide, seals were typically hauled out on large boulders in Cook Inlet near the mouth of the Kenai River. When not hauled out on the rocks, seals were sometimes observed in the fiver in each of the survey sectors A beluga whale was observed in sector MM in April. ' Christopher Ho ffman Biologist Kenai River Estuary Baseline Fisheries Assessment T. M. Willette J. M. Edmundson R. D. DeCino Regional Information Report No. 2A04-13 Alaska Department of Fish and Game Commercial Fisheries Division 333 Raspberry Rd. Anchorage, Alaska 99518-1599 March 2004 ~The Regional Information Report Series was established in 1987 to provide an information access system for all unpublished divisional reports. These reports fi'equently serve diverse ad hoc informational purposes or archive basic uninterpreted data. To accommodate timely reporting of recently collected information, reports in this series undergo only limited internal review and may contain preliminary data; this information may be subsequently finalized and published in the formal literature. Consequently, these reports should not be cited without prior approval of the author or of the Commercial Fisheries Division. The Alaska Department of Fish and Game administers all programs and activities free from discrimination on the basis of race, color, national origin, age, sex, religion, marital stares, pregnancy, parenthood or disability. The department administers all programs and activities in compliance with Title VI of the Civil Kights Act of 1964, Section 504 of the Rehabilitation Act of 1973, Title II of the Americans with Disabilities Act of 1990, the Age Discrimination Act of 1975, and Title IX of the Education Amendments of 1972. If you believe you have been discriminated against in any program, activity, or facility, or if you desire further information please write to ADF&G, P.O. Box 25526, Juneau, AK 99802-5526; U.S. Fish and Wildlife Service, 4040 N. Fairfield Drive, Suite 300, Arlington, VA 22203; or O.E.O., U.S. Department of the Interior, Washington DC 20240. For information on alternative formats available for this and other Department publications, please contact the department ADA Coordinator at (voice) 907-465-4120, (TDD) 907-465-3646; or (FAX 907-465-2440. AUTHORS T. Mark Willette is the Research Project Leader for the Alaska Department ofFish and Game, Commercial Fisheries Division, Region Il, Upper Cook Inlet, 43961 Kalifornsky Beach Road, Suite B, Soldoma, AK 99669, John M. Edmundson is a Research Biologist for the Alaska Department ofFish and Game, Commercial Fisheries Division, Central Region Limnology, 43961 Kalifomsky Beach Road, Suite' B, Soldoma, AK 99669. Robert D. DeCino is a Research Biologist for the Alaska Department ofFish and Game, Commercial Fisheries Division, Region Il, Upper Cook Inlet, 43961 Kalifomsky Beach Road, Suite B, Soldotna, AK 99669. ACKNOWLEGEMENTS The authors would like to thank the following ADF&G staff that assisted in sample collection, laboratory analysis, and database management for this project: Bill Glick, Jim Lazar, Stan Walker, Jennifer Brarmen-Nelson, Richard Dietrich, and Marsha Spafard. We also appreciate the logistical support provided by the City of Kenai, Pacific Star Seafoods and Salamatof Seafoods that made our field sampling efforts possible. Technical assistance and equipment provided by the Kachemak Bay Research Reserve supported our collection of physical data'in the estuary. Support for this project was provided by the U.S Army Corp of Engineers through a contract with the ADF&G. ' iii TABLE OF CONTENTS LIST OF TABLES .............................................................................................................................. v LIST OF FIGURES ............................................................................................................................ vi ABSTRACT .................................................................................................................................... viii INTRODUCTION .............................................................................................................................. 1 OBJECTIVES ................................................................. ............................................................... 2 METHODS ......................................................................................................................................... 2 Species composition, relative abundance and size of fishes ................................................. 2 Diet composition of fishes and partial food webs ................................................................. 3 Density and species composition of zooplankton .................................................................. 4 Feasibility study examining alongshore fish distribution ....................... ' ...................... 5 Temperature and salinity distributions and time series .......................................................... 5 RESETS ........................................................................................................................................... 7 Species compOsition, relative abundance and size of fishes ................................................. 7 Diet composition of fishes and partial food webs ............................................................... 16 Density and species composition of zooplankton ................................................................ 16 · Feasibility study examining alongshore fish distribution ..................................................... 17 Temperature and salinity distributions and time series ....................................................... 17 DISCUSSION ................................ · .......................................................................................... 32 LITERAT~ CITED ..................................................................................................................... 34 iv Table . . . . , LIST OF TABLES Thirty-one taxonomic groups of animals captured in the Kenai River estuary during April, June, September and December .............................................................................. 8 Frequency of occurrence and geometric mean catch per net set for 15 taxonomic groups of animals captured using 4 gear types during April ............................................. 9 Frequency of occurrence and geometric mean catch per net set for 23 taxonomic groups of animals captured using 4 gear types during June ............................................. 10 Frequency of occurrence and geometric mean catch per net set for 26 taxonomic groups of animals captured using 4 gear types during September ................................... 11 Geometric mean catch per net set for taxonomic groups of animals that exhibited statistically significant differences in relative abundance among sampling periods ....... 12 · Percent frequency of occurrence for finfishes in three stages of maturity during three sampling periods .............. 0'°*' 0'°°"'""'°'°" °° '""'° '"'"°'° °° ' '" ' °'""*°'°'"" °°'° °''" °'" °''" o,.o-o. · o..... 18 Diet composition (% of stomach content weight) and stomach fullness (% of body weight) for several taxonomic groups of finfishes captured during three sampling periods ............. · .. e... ,.,,,,.,,.,,..oo.. o.,,..o., .o...,.,. o, o,.~o,..,· Mean density and biomass (wet weight) of zooplankton collected in the Kenai River estuary during three sampling periods ............................................................................. 25 LIST OF FIGURES e Page Location of Kenai bluff study site (bold line) and sample stations (solid squares) in the Kenai River estuary ............................................................................................................... 6 Length frequency distributions for 13 taxonomic groups of animals captured during April .................................................................................................................................. 13 ge Length frequency distributions for 20 taxonomic groups of animals captured during June ...................................................................................................................... 14 e Length frequency distributions for 20 taxonomic groups of animals captured during September ............................................................................................................. 15 o Partial food web for aquatic organisms in the Kenai River estuary during April. Percent of total biomass consumed from each prey class is indicated adjacent to each prey taxonomic group. Percent of total biomass consumed from each prey class by each predator class is indicated on arrows ......................................................... 21 e Partial food web for aquatic organisms in the Kenai River estuary during June. Percent of total biomass consumed from each prey class is indicated adjacent to each prey taxonomic group. Percent of total biomass consumed from each prey class by each predator class is indicated on arrows ......................................................... 22 '7. Partial food web for aquatic organisms in the Kenai River estuary during September. Percent of total biomass consumed from each prey class is indicated adjacent to each prey taxonomic group. Percent of total biomass consumed from each prey class by each predator class is indicated on arrows ......................................... 23 ,, Length frequency distributions for prey fish consumed by 11 taxonomic groups of finfishes in the Kenai River estuary .................................................................................. 24 . Profiles of temperature, salinity, and turbidity measured in mid channel at station two on April 8 (heavy solid line) and April 11 (thin solid line) ...................................... 27 10. Time series of water depth, temperature, and salinity measured 2 rn above the bottom in mid channel at station two, April 8-14 ............................................................ 28 11. Time series of water depth, temperature, and salinity measured 2 rn above the bottom in mid channel at station two, May 15-21 ........................................................... 29 12. Time series of water depth, temperature, and salinity measured 2 m above the bottom in mid channel at station two, June 19-25 ............................................................ 30 vi 13. LIST OF FIGURES (continued) Time series of water depth, temperature, and salinity measured 2 rn above the bottom in mid channel at station two, September 11-18 .................... ....................... , ...... 31 vii ABSTRACT This report describes a baseline fisheries assessment focused on documenting the fish assemblage and some predator-prey interactions occurring in the Kenai River estuary. We sampled fishes and macroinvertebrates using five gear types during four sampling periods, and we conducted stomach x:~ntent analyses and constructed partial food webs for finfishes. We also collected zooplankton samples and continuous measurements of water temperature and salinity during each sampling period. We documented the occurrence of 31 taxonomic groups of animals in the estuary, 19 of which are marine, 8 are anadromous, and 4 typically occur in estuaries but. also in freshwater or coastal marine habitats. Epibenthic invertebrates (mostly Crangon spp., Neomysis spp., and Saduria spp.) dominated the fauna sampled in April. Eulachon dominated the fauna sampled in the water column in June and September. Six taxonomic groups of finfish were significantly more numerous in our catches in September than in previous sampling periods. Zooplankton densities in the estuary were lOw. The brackish water genera Eurytemora and the epibenthic genera Harpacticus occurred in zooplankton samples during every period. A partial food web for the estuary during April was based primarily upon benthic invertebrate prey, mostly amphipods. The complexity of the partial food web in June increased dramatically. Thirty-three percent of the finfishes sampled in June were benthic invertebrate feeders, while 40% were primarily piscivores, 13% planlaivores, and 13% insectivores. The complexity of the partial food web decreased in September. While the total number of finfish taxonomic groups increased, the number of piscivores declined. Infaunal prey (primarily polychaetes and bivalves) were not important in these partial food webs during any sampling period. Coho salmon, chinook salmon, Pacific staghom sculpin, Pacific tomcod, and starry flounder consumed juvenile salmon, but salmon were not a dominant prey in the diet of these fishes. Time series of temperature and salinity revealed the highly dynamic nature of the physical environment in the estuary. During all months except April, salinities near the bottom of the estuary dropped from greater than 20 ppt to near 0 ppt within 2-3 hours of high tide. KEYWORDS' Crangon spp., Neomysis spp., Eurytemora spp., Harpacticus spp., Pacific salmon, Oncorhynchus spp., Eulachon, Thaleichthys pacificus, zooplankton, food webs. viii INTRODUCTION The City of Kenai has proposed an erosion control project to stabilize a one-mile section of the bluffs fronting the city along the Kenai River. The proposed project plans received numerous comments from various agencies and local residents raising concerns regarding potential impacts to marine mammals, birds, and fishes that inhabit this area. The U.S. Army Corps of Engineers will be conducting studies designed to predict changes to the hydrology and sediment transport in the estuary that may result from the proposed project. These studies are expected to be complete by the spring of 2004. An interagency review team has determined that studies of the biological effects of the proposed project should be limited to baseline resource assessments until results from hydrology and sediment transport studies are available to help focus agency concerns regarding effects of the project. This report describes baseline studies focused on documenting the fish assemblage and some predator\prey interactions occurring in the Kenai River estuary. The study was limited to the area immediately adjacent to the bluffs fronting the City of Kenai, because this area will be most directly affected by the proposed bluff stabilization project. Three fisheries studies have documented the occurrence of 6 freshwater species, 11 anadromous species, and. 14 marine species of fish in the Kenai Pdver estuary. Bendock and Bingham (I 988a) sampled fishes using minnow traps, beach seines, and a substrate sampler between October 1986 and March 1987. They documented the presence of juvenile chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O. nerka), coho salmon (O. kitsutch), slimy sculpin (Cottus cognatus), Pacific staghom sculpin (Leptocottus armatus), threespine stickleback (Gasterosteus aculeautus), ninespine stickleback (Pungitius pungitius), l~)ngfin smelt (Spirinchus thaleichthys), Pacific herring (Clupea harengus pallasi), starry flounder (Platichthys stellatus), Pacific tomcod (Microgadus proximus), and snailfish (Liparus spp.) in the estuarine habitat. Bendock and Bingham (1988b) used these same gear types to sample fishes in the estuary between July and October, 1987. They documented the presence of these same 12 species, but also found pink salmon (O. gorbuscha), rainbow trout (Oncorhynchus mykiss), dolly varden (Salvelinus malma), round whitefish (Prosopium cylindraceum), Bering cisco (Coregonus laurettae), eulachon (Thaleichthys pacificus), and slender eelblenny (Lumpenus fabricii). Bendock and Bingham (1988b) concluded that juvenile salmonids increased and marine fishes decreased in abundance with distance upstream from the fiver mouth. In 1995 and 199fi, the Alaska Department of Fish and Game (ADFG) sampled fishes in the Kenai River estuary using rotary screw traps and beach seines (Jeff Breakfield, ADF&G, personal communication). Sampling was conducted from June 28 - September 2 I, 1995 and from May 9 through September 7, 1996. In addition to the species previously documented in the estuary, they also found Pacific lamprey (Lampetra tridentate), Arctic lamprey (L. japonica), chum salmon (O. keta), Pacific cod (Gadus macrocephalus), walleye pollock (Theragra chalcogramma), Pacific sandfish (Trichodon trichodon), Pacific sandlance (Ammodytes hexapterus), rock greenling (Hexagrammus lagocephalus), coastrange sculpin (Cottus aleuticus), sturgeon poacher (Agonus acipenserinus), rex sole (Glyptocephalus zachirus), and rock sole (Lepidopsetta bilineata). Juvenile sockeye salmon catches peaked in late June and early July, while juvenile chinook catches were highest in early August. Juvenile coho salmon comprised less than 5% of the total catch in both years. Although, a wide variety of fishes' were captured during these early studies in the Kenai River estuary, each of them utilized gear types that were designed primarily to capture juvenile salmon, and only one of the sampling stations was immediately adjacent to the bluffs fronting the City-of Kenai. We utilized gear types designed to capture juvenile fishes, but also species and sizes of fish that may not have been vulnerable to the gears used previously. We sampled during late winter (April), the salmon smolt migration (June), aumnm (September), and during the longfin smelt.migration (December). We conducted stomach content analyses on finfishes and constructed partial food webs to aid in evaluating potential effects of habitat changes in the estuary. We focused on the salmon smolt migration in June (Jeff Breakfield, ADFG, personal communication), because the transition from freshwater to marine habitats is a critical period in the life history of salmon. During this period, juveniles must develop the capability to osmoregulate in seawater, recognize and capture new prey items, and avoid new predator species that often aggregate near fiver mouths to prey on them (Beamish et al. 1992, Dobrynina et al. 1988). Since, several fish species known to prey on juvenile salmon have been found in the Kenai River estuary (Khorevin et al. 1981, Dobrynina et al. 1988, Thorsteinson 1962), we conducted limited food habits studies as a first step toward identifying potential predators on juvenile salmon as well as the salmon's prey in the estuary. OBJECTIVES 1. Estimate species composition, relative abundance, and size of fishes inhabiting the area immediately below the Kenai bluff each season. 2. Estimate the maturity, mean stomach fullness, and diet composition of fishes and conslxuct partial food webs for the area immediately below the Kenai bluff each season. . Estimate the density and species composition of the zooplankton in the Kenai River estuary immediately below the Kenai bluff each season. 4. Determine the feasibility of us. ing split-beam sonar to examine the distributions of salmon smolt along the Kenai bluff. . Continuously record temperature, salinity, and water depth in the area immediately below the Kenai bluff by tide cycle each season. METHODS Objective 1' Species composition, relative abundance, and size of fishes During 2003, the study site for this project was limited to the approximately 1-mile area of the estuary immediately adjacent to the bluffs fronting the City of Kenai with one additional station approximately 0.5 miles upstream (Figure 1). The maximum depth of the estuary in this area was about 6 tn at mean low water. Fishes were sampled in this area during approximately one week in April, June, September, and December. A stratified-systematic sampling design was employed to estimate relative abundance and species composition of fishes in the study site during each sampling event. As much as possible, sampling was stratified by stage of tide. Sampling was generally conducted during daylight hours. But in June, sampling was conducted during the 12 hours spanning the night, because juvenile salmon abundance and predation on salmon may be greatest at night (Dobrynina et al. 1988). Five gear types were used tO sample juvenile and adult fishes within each stratum during each week of sampling. Juvenile fish in the water column were sampled using a townet in mid channel and fishes along the shore were sampled using a small-mesh beach seine The townet had a 3 x 6 m opening. The beach seine deployed in April was 30 x 2 m, while th~ seine deployed in June and September was 50 x 6 m. Adult fishes were sampled using longlines and variable-mesh (2, 4, 6, and 8 cm stretch mesh) monofilament sinking gillnets. Longlines were baited with herring. Gillnets deployed in April were 30 x 2 m, while those deployed in June and September were 70 x 5 m. Beach seine and variable-mesh gillnet sampling was conducted at 5 stations in the estuary (Figure 1). Tow net and longline sampling was conducted along transects in mid channel and variable-mesh gillnets were also drifted along the north shore. A screw trap was used to sample fishes in the water column in June, because this gear type had been used successfully during earlier studies to sample salmon smolt. The screw trap had a 2.5 m diameter opening and was moored near station 3. All fish were identified to the lowest possible taxonomic level. If a large number of fish are caught, species composition was estimated from a random sample of about 200 individuals. Length was measured for a randomly selected subsample (up to n=20) from each species in each net set. Several analyses of variance (ANOVA) were conducted to test whether mean catch per net set differed among sampling periods. Separate analyses were conducted for each taxonomic group and gear type. The dependent variable in each analysis was the natural-logarithm transformed catch per net set and the independent variable was sampling period. Catches in the townet, screw trap and variable mesh gillnets were expressed as catch per hour. Several ANOVAs were also conducted to test whether mean catch per net set in beach seines and variable mesh gillnets differed among sampling stations. Separate analyses were conducted for each taxonomic group, and the data from all sampling periods were pooled. Only beach seine and variable mesh gillnet · catches from June and September were included in these analyses, because the configuration of these gears in April was different. Length frequency distributions were constructed for each taxonomic group for which data were available during each sampling period. Objective 2: Diet composition of fishes and partial food webs A stratified-systematic sampling design was employed to estimate diet composition of fishes in the study site during each sampling event. Sampling was stratified by stage of tide. Processing of fish samples from each net set occurred in two stages following procedures oUtlined by Livingston (1989) and E}wyer et al. (1987). Samples (n= 10) for stomach content analysis were randomly selected from each species in each stratum. In cases where distinct size classes occur within species, samples (n=l 0) were collected from each size class. Size related shifts in diet toward piscivory have been noted in Pacific cod (Livingston 1989) and walleye pollock (Dwyer et al. 1987). Juvenile fishes selected for stomach analysis were preserved whole in 10% formalin. The stomachs of larger fishes were removed, placed in cloth bags, and preserved in 10% formalin. Each specimen was labeled regarding location of capture, length, weight, sex, and sexual maturity (immature, mature, spent). Fish showing evidence of regurgitation were not included in the sample. Stomach contents analysis were conducted later in the laboratory. In the laboratory, stomach contents wet weight was measured to the nearest gram for large fish and to the nearest milligram for juvenile fish. Invertebrate preys were generally identified to the family level. Fish in the gut were identified to the lowest possible taxonomic level and measured to the nearest millimeter. Diet composition was visually estimated as a proportion of total stomach content volume (Pearcy et al. 1984). The Fisher Exact Tests were conducted to test whether the frequency of occurrence of individuals in three stages of maturity differed among sampling periods. Separate tests were Conducted for each taxonomic group of fishes. Several ANOVA's were conducted to test whether mean stomach fullness (% body weight) differed among sampling periods. Separate analyses were conducted for each taxonomic group of fishes. The dependent variable in each analysis was the arcsin square-root transformed ratio of total stomach content weight to body weight and the independent variable was sampling period. . Partial food webs were constructed to examine mass flux among taxonomic groups during each sampling period. Food webs were not complete, since only finfishes sampled in this project were included. Diet composition of each fmfish was calculated as the percent of total stomach contents weight in each of four prey classes (benthic invertebrates, insects, fishes, and zooplankton). Finfish taxonomic groups were then ag~egated into four classes (benthic invertebrate feeders, insectivores, piscivores, and planktivores) dependent on the dominant prey in their diet. Preys were ranked within each class by the percent of total mass consumed by all fmfish classes from each taxonomic group of prey. Mass flux within the food web was expressed as the percent of total mass consumed from each preY class by each finfish class. These food webs were based upon mass of prey sampled and do not account for total daily food consumption (gastric evacuation rate) or the biomass of each finfish group which was unknown. Mass flux in the actual system probably differed, but these food webs provide some insight into how the system was structured. Length frequency distributions of prey fishes were constructed for each taxonomic group of predator fishes for which data were available. Data from all sampling periods were aggregated. Objective 3: Density and species composition of zooplankton Zooplankton density and species composition was estimated from samples collected from two horizontal tows made offshore of station 2 (Figure 1). Samples were collected with a 0.5 m diameter ring net (I 53 um mesh) towed just below the surface at a speed of 1 m s¢¢'~ through tha water. The net was equipped with a flowmetcr. Samples were preserved in 10% formalin. All samples were collected within 0.5 hours of high tide, except the sample collected on April 11 was taken 1.5 hours after low tide. In the laboratory, each sample was rinsed into a graduated beaker, well mixed, and subsampled with a Stemple pipette. Zooplankton in each sample was generally identified to the family or 'genus level and enumerated. The density of animals in each taxonomic group was estimated from the ratio of abundance and volume of water filtered. 0 Objective 4: Feasibility study examining alongshore fish distribution We evaluated the feasibility of using split-beam sonar to examine the alongshore distribution of salmon smolt on June 13. A Biosonics model DT6000 scientific 200 kHz echosounder was used to examine relative fish densities along a transect running perpendicular to the north shore at station two. A 6.6° circular split-beam transducer was mounted in a side-looking orientation on a 2.0-m long sled. The sled was moved up and down the beach as the water level changed with the tide. Sampling was conducted over a 12-hour period spanning the night (8:00 pm - 8'00 am). Fish were acoustically sampled at 6 pings sec'', at ranges from 0-65 m, using a pulse width of 0.4 msec, and a-55 dB threshold. Data were stored on a laptop computer. Objective 5: Temperature and salinity distributions and time series A continuously recording conductivity-temperature-depth profiler (CTD) was moored about 2 tn above the bottom offshore of station two in the deepest part of the channel. The CTD was operated continuously during each week of sampling. A CTD was also occasionally used to measure the vertical distribution of temperature, salinity, and turbidity fi'om the surface to the bottom. City. of Kenai Figure 1. Location of Kenai bluff study site (bold line) and sample stations (solid squares) in the Kenai River estuary. RESULTS Objective 1' Species composition, relative abundance, and size of fishes Thirty-one taxonomic groups of animals were captured using five gear types in the Kenai River estuary during April, June, September, and December sampling Periods (Table 1). Fifteen taxonomic groups were captured in April, 23 in June, and 27 in September. Epibenthic invertebrates (Crangon spp., Neomysis spp. and Saduria spp.) were the most frequently encountered and numerous animals in our catches during April (Table 2). Finfish were relatively rare in April, but of these, longfin smelt were the most numerous in townet catches. In June, finfish (particularly eulachon, sockeye salmon, coho salmon, and chinook salmon) were the most frequently encountered and numerous animals in the screw trap; whereas, Pacific staghom sculpin, eulachon, snake prickleback, starry flounder were most numerous in seine and gillnet catches (Table 3). In September, finfish were again the most frequently encountered and numerous animals in our catches (Table 4). Six taxonomic groups of finfish were significantly more abundant in September than in previous sampling periods, while snake prickleback and the invertebrates Neomysis spp. and Saduria spp were less abundant (Table 5). Longlines captured spiny dogfish and starry flounder in June and September. Catch per net set in seines and gillnets were not significantly different among sampling stations. Only 3 townet sets were completed during December. The City of Kenai boat launch was blocked by ice during this time, so a crane at Salamatof Seafoods was used to lift a skiff into the estuary. But, after the first day of operations, the crane froze and ice moved downstream in fi'ont of it preventing further sampling efforts. Three taxonomic groups were captured in December. Mean catch per net set and frequency of occurrence for these groups were: Crangon spp. (0.26, 1), Gammarus spp. (1.88, 2), and longfin smelt (0.26, 1). Only catches of juvenile salmon were recorded since abundances of adult salmon in the estuary are well known. Adult salmon were captured in June and September and juvenile salmon were captured during all sampling periods except December. Eulachon smelt captured in April were adults greater than 150 mm in length, ' whi le those captured in June and September were mostly immature fish less than 150 mm (Figures 2-4). Starry flounder and Pacific staghom scuplin exhibited the greatest range in sizes. A big skate captured in June was 3.9 m in length, whereas 14 spiny dogfish captured in June and September ranged in length from about 1.1-1.2 m. Objective 2: Diet composition of fishes and partial food webs Maturity of fishes was determined for specimens collected for stomach content analysis. All specimens examined in 12 taxonomic groups of fishes were immature (Table 6). Stages of maturity differed significantly among sampling periods for eulachon and starry flounder but not other taxonomic groups:. More eulachon were mature in September than June, while more starry flounder were mature in June than September. Mean stomach fullness of eulachon and Pacific tomcod declined significantly from June to September, but differences in mean stomach fullness were not significant for other taxonomic groups (Table 7). A partial food web for the estuary during April was based primarily upon benthic invertebrate prey, mostly amphipods (Figure 5). The complexity of the partial food web in June increased dramatically. Thirty-three percent of the fmfish taxonomic groups in June were benthic invertebrate feeders, while 40% were primarily piscivores, 13% planktivores, and 13% insectivores (Figure 6). Isopods were the dominant invertebrate prey, Trichoptera the dominant insect prey, eulachon the dominant fish prey, and large calanoid copepods (mostly Eurytemora spp.) the dominant zooplankton prey. Piscivorous fishes also consumed a significant mass of insects and benthic invertebrates. A fourth class called 'Other Prey' (not shown in the figure) was dominated by fish processor waste (72%). These prey were consumed primarily (96%) by piscivores. The complexity of the partial food web decreased in September. While the total number of finfish taxonomic groups increased, the number of piscivores declined (Fi~e 7). Chinook and coho salmon switched from primarily piscivory to insectivory, while Pacific staghom sculpin and eulachon switched to consuming mostly benthic invertebrates. Pacific staghom sculpin consumed primarily shrimp, while eulachon consumed primarily Neomysis spp. and amphipods. Benthic invertebrate feeders also consumed a significant mass of zooplankton. The 'Other Prey' class was now dominated by vegetation and rocks, which were consumed entirely by benthic invertebrate feeders. Infaunal prey (primarily polychaetes and bivalves) were not important in these partial food webs during any sampling period, comprising less than 3% of the mass of benthic invertebrates consumed. Coho salmon, chinook salmon, Pacific staghom sculpin, Pacific tomcod, and starry flounder consumed juvenile salmon, but salmon were not a dominant prey in the diet of these fishes. Juvenile salmon comprised 32% of the diet of coho salmon in June, and 48% and 20% of the diets of chinook and coho salmon in September. Salmon comprised less than 10% of the diets of the other fishes that fed on them. Pacific staghom sculpin and starry flounder consumed the greatest range of sizes of.fish prey (Figure 8). Most predator taxonomic groups consumed fish ' less than 100 mm in length. Objective 3: Density and species composition of zooplankton Zooplankton densities in the estuary were low (Table 8). The brackish water genera Eurytemora and the epibenthic genera Harpacticus occurred during every sampling period. In June, the zooplankton was dominated by species typically found in freshwater. Attempts to collect samples at low tide were generally not successful, because silt clogged the net. However, samples were successfully collected 1.5 hours after low tide on April 11. The species 16 composition and densities of animals collected near high tide on April 9 and near low tide on April 11 were not substantially different (Table 8).. Objective 4: Feasibility study examining alongshore fish distribution During our 12-hour acoustic study along the north shore of the estuary, no targets were seen that appeared to be salmon smolt, but targets that were likely larger fishes were observed. The 6.6° acoustic beam used in this study fit well within the water column at this location, and the sled- system towed by a 4-wheeler was able to move the transducer up and down the beach with few difficulties as water level changed. However, we concluded that the limited range of the acoustic beam was not sufficient to effectively study the distribution of salmon smolt in the estuary, since large numbers of smolt could have been present beyond the range of our acoustic beam. Further studies were not conducted due to lack of available staff and time. Objective 5: Temperature and salinity distributions and time series The vertical distributions of water temperature and salinity measured at station two in April were clearly affected by tide stage. A profile measured near high tide on April 8 exhibited little vertical structure, while another measured on April 11 three hours after low tide showed a relatively warm, low salinity layer above 2 rn depth (Figure 9). On both dates turbidity was relatively high and increased with depth. Time .series of temperature and salinity measured 2 m above the bottom at station two revealed the highly dynamic nature of the physical environment in the estuary. During all months except April, salinities dropped from greater than 20 ppt to near 0 ppt within 2-3 hours of high tide (Figures 10-13). In April, salinities also changed rapidly, but often remained above 10 ppt even at low tide. At this time, water temperatures at low tide were 1-2° C warmer than at high tide, indicating that Kenai River was warmer than Cook Inlet. By June, this pattern was reversed, and water temperatures in the estuary were warmer at high tide than low tide. 17 DISCUSSION We documented the occurrence of 13 taxonomic groups of animals in the Kenai River estuary that had not previously been reported in the literature (Bendock and Bingham 1988a, 1988b): arrowtooth flounder, big skate, Crangon spp., Gammarus spp., Neomysis spp., Pandalusjordani, Saduria spp., sand sole,.~awback poacher, silvergray rockfish, smooth lumpsucker, snake prickleback, and spiny dogfish (Table 1). Of the 31 taxonomic groups of animals found in the estuary, 19 typically occur in marine habitats, 8 are anadromous, and 4 typically occur in estuaries, but are also found in fi'eshwater or coastal marine habitats (Mecklenburg et al. 2002). The Bering cisco commonly overwinters in salt or brackish water near river mouths (Mecklenburg et al. 2002). Catch per net set provides a general indication of relative abundance of various taxonomic groups of animals and changes in relative abundance among sampling periods within the habitat sampled by each gear type. The townet and screw trap primarily sampled smaller animals in the water column. But, the catch per net set from these two gears cannot be directly compared, because the volumes of water they sampled differed, and screw trap catchability changed with current speed. The beach seine sampled a broader size range of animals occurring on the bottom and in the water column along shore. Variable-mesh gillaets sampled larger animals occurring from the bottom to near the surface, except when strong tidal currents caused the nets to submerge. Longlines sampled the largest animals occurring near the bottom. Our highest longline catches occurred when the gear was deployed overnight. Our data (Tables 2-5) support the following conclusions regarding the faunal assemblage sampled by these gears- (1) epibenthic invertebrates dominated the fauna sampled in April, (2) eulachon dominated the fauna sampled in the water column in June and September, and.(3) six taxonomic groups of fmfish were significantly more numerous in our catches in September than in previous sampling periods, while snake prickleback and the invertebrates Neomysis spp. and Saduria spp were less numerous in September. Our April data suggest that epibenthic invertebrates may dominate the faunal assemblage in the estuary during winter. Bendock and Bingham (1988a) previously observed 11 species of finfish in the lower 10 km of the Kenai River during winter. We found only 5 of these species and 3 others they did not find. These differences may have resulted in part, because Bendock and Bingham (1988a) initiated sampling in early October, they sampled with minnow traps and substrate samplers in addition to beach seines, and they found about 10% of the juvenile salmon in inter-gravel or inter-rabble substrates, which we did not sample. However, they also did not report catches of invertebrates. The physical conditions we observed in the estuary in April were still winter like with water temperatures initially near 1 °C at low tide and river discharge very low. Further sampling should be conducted to better describe the faunal assemblage in the estuary during winter. The species composition of the zooplankton sampled in the estuary on June 20 (Table 8) was very similar to that found in lakes in the Kenai River watershed, but the density of Cyclops spp. was an order of magnitude lower than typically observed in Skilak Lake (Edmundson et al. 2003). The dominance of Cyclops spp. in these samples was not reflected in the diets of planktivores, which largely consumed Eurytemora spp. in June (Figure 6). Although, the 32 zooplankton samples we collected in June were taken near high tide, it is possible that a freshwater layer containing primarily freshwater species persisted. A shallow freshwater layer was evident on April 11 three hours after low tide (Figure 9). In June, when river discharge was greater, a shallow freshwater layer may have persisted even at high tide. Oblique tows may provide a more representative sample of zooplankton in the estuary when the water colum is stratified. Between June and September, eulachon relative abundance increased (Table 5), eulachon switched from feeding primarily on zooplankton to benthic invertebrates (mostly Neomysis spp. and amphipods), and their stomach fullness declined (Table 7). Their shift in feeding strategy was not related to a measured decline in zooplankton density (Table 8), but our samples may not have adequately described the zooplankton available.in the estuary at that time. The decline in eulachon stomach fullness may have been related to their increase in relative abundance in the estuary and/or a decline in relative abundance ofNeomysis spp. (Table 5). During this same period, Pacific staghom sculpin switched from feeding primarily on fish to epibenthic invertebrates (mostly Crangon spp.), which were more numerous in seine and gillnet catches in September than June (Table 5). Further sampling should be conducted in the estuary using gears better designed to capture benthic invertebrates. Burrowing invertebrates (e.g. Crangon spp.) were likely under represented in our catches. The Kenai River estuary can be classified as a vertically homogenous estuary in which tidal flow is great relative to river discharge and vertical salinity gradients often disappear (Kennish 2000). A general lack of vertical salinity gradients was evident in our data fi'om the drop in salinity to near 0 Ppt 2 m above the bottom at low tide during most sampling periods (FigUres 10-13). Our data indicate that the Kenai River estuary supports a detritus food web in winter and a combination of detritus and grazing food webs in summer and fall. The epibenthic invertebrates that appeared to dominate the food web in April are'typically suspension-feeding detritivores (Kennish 2000). Autotrophic production at this time of year is probably very low due to low. light levels, high turbidity, and cold temperatures. The appearance of finfish that consumed mostly zooplankton, insects and other fishes in June indicates development of a grazing food web but detritivory was still important. The grazing food web was likely supported in large part by allochthonous inputs of organisms from nearby freshwater and marine habitats, because high turbidity in the estuary limited autotrophic production. One exception may be the marginal vascular plants that supported invertebrate grazers. This was evident from the occurrence of vegetation in the stomachs of some benthic invertebrate feeding fishes sampled in September. 33 LITERATU~ CITED Beamish, R.J., B.L. Thomson, and G.A. McFarlane. 1992. Spiny dogfish predation on chinook salmon and the potential effects on hatchery-produced salmon. Trans. Amer. Fish. Soc. 121' 444-455. Bendock, T. and A.E. Bingham. 1988a. Feasibility of estimating winter distribution and habitat preference for juvenile salmonids in the mainstem Kenai River, Alaska. AK Dept. offish and Game, Division of Sport Fish, Fishery data series no. 38, 33p. Bendock, T. and A.E. Bingham. 1988b. Juvenile salmon seasonal abundance and habitat preference in selected reaches of the Kenai River, Alaska, 1987-1988. AK Dept. offish and Game, Division of Sport Fish, Fishery data series no. 70, 55p. Coyle, K.O., A.J. Paul and D.A. Ziemann. 1990. Copepod populations during the spring bloom in an Alaskan subarctic embayment. J. Plankton Res. 12(4): 759-797. Dobrynina, M.V., S.A. Gorshkov, and N.M Kinas. 1988. Effect of density ofjuvenile pink salmon, Oncorhynchus gorbuscha, on their vulnerability to predators in the Utka River (Kamchatka). J. Ichthyol. 29' 148-155. Dwyer, D.A., K.M. Bailey, P.A. Livingston. 1987. Feeding habits and daily ration of walleye pollock (Theragra chalcogramma) in the eastern Bering Sea, with special reference to cannibalism. Can. J. Fish. Aquat. Sci. 44: 1972-1984. Edmundson, J.A., T.M. Willette, J.M. Edmundson, D.C. Schmidt, S.R. Carlson, B.G. Bue, and K.E. Tarbox. 2003. Sockeye salmon overescapement (Kenai River component). Exxon Valdez oil spill restoration final report project 96258A-1, 49p. Kermish, M.J. 2000. Ecology of Estuaries. CRC Press, Inc. Boca Raton, Florida. Khorevin, L.D., V.A. Rudnev, and A.P. Shershnev. 1981. Predation on juvenile pink salmon by predatory fishes during the period of their seaward migration on Sakhalin Island. J. lchthyol. 21(6): 47-53. Livingston, P.A. 1989. Interannual trends in Pacific Cod, Gadus macrocephalus, predation on three commercially important crab species in the eastern Bering Sea. Fish. bull. 87' 807- 827. Mecklenburg, C.W., T.A. Mecklenburg, and L. K. Thorsteinson. 2002. American Fisheries Society, Bethesda, Maryland. Fishes of Alaska. Pearcy, W., T. Nishiyama, T. Fujii, and K. Masuda. 1984. Diel variations in the feeding habits of Pacific salmon caught in gill nets during a 24-hour period in the Gulf of Alaska. Fish. Bull. 82: 391-399. 34 Thorsteinson, F.V. 1962. Herring predation on pink salmon fry in a southeastern Alaska estuary. Trans. Am. Fish. Soc. 9 l' 321-323. 35 APPENDIX B HYDRAULICS AND HYDROLOGY KENAI BLUFF EROSION TECHNICAL REPORT KENAI' ALASKA Kenai River Bluffs Project The City of Kenai has proposed construction of bank stabilization project along the north bank of the Kenai River near the mouth. Details of the conceptual design are presemed in the report "Kenai Coastal Tail and Erosion Control Project", Peratrovich, Nottingham, and Drage, Inc., February 2002. The project would stabilize the bluff along a one-mile reach of riverbank from erosion by water currents, wind, and waves (figure 1). This analysis looks at the area of the proposed revetment, the revetment's effect on river currents, and areas needing consideration in the construction of revetment along the bluff. This analysis is not an evaluation of the current revetment design. E T Figure 1. Extent of proposed project Topography The City of K~/nai is located on the Nikishka Lowland geomorphological subdivisiOn of the Kenai Lowland. This region is characterized by a modified morainal topography, which is separated by art interlacing pattern of swamps and muskegs developed in abandoned drainage channels and broad depressions. The topography and surficial deposits of the region are primarily the products of repeated Pleistocene glacialtions, which advanced from ice centers in · the surrounding mountain ranges. Near the City of Kcnai, the Naptowne glacial moraines are fronted by a broad coastal plain consisting of terraced and channeled sand and gravel deposits, which terminate as steep sea bluffs above a series of raised tidal flats. (Tippetts-Abbett- McCarthy-Stratton (TAMS) 1982) The topography in the area of the Kenai River mouth consists of a bluff approximately 70 feet high opposite a low-lying wetland and tide fiat area with a dendridic drainage pattern (figure 2). The topography indicates that the river valley historically has experienced much higher flows (figure 3). Two drainage channels west of the city of Kenai which extend from the south and southwest end of the airport to their confluence behind the dunes at the mouth of the river, could be remnant drainage channels associated with the historical higher flows. These drainage channels appear to play a major part in the local bank stability (figure 4). The bluff at the mouth of the river is composed of three distinct material types. An organic mat top layer that is approximately 2 feet thick, a fine sand layer that is approximately 37 feet thick, and a lower marine deposit layer that can vary from 35 to 45 feet thick. According to Dick Reger, retired geologist with the Alaska Division of Geological and Geophysical .Surveys, the lower material is composed of marine deposits that were compacted by.a tidewater glacier. Sand and gravel were deposited above the compacted marine deposits through sediment charged effiux jets coming from beneath the approaching glacier. Dropstones fi'om melting icebergs and fine material rained onto the sandy bottom from turbid plumes in front of the glacier (figures 6 and 7). These features can be seen in the bluff face today. Figure 2. Kenai River Bluffs and wetland opposite the bluffs. o Ol ' ' ..: -. .- .~.--~-.,... .. % Fibre 3. Low-l~g ~e~ ~cat~g ~tofic flows. Figure 4. Drainage Channels. Figure 5. Bluff face with three distinct material types: Marine deposit, sand, and organic mat. Figure 6. Dropstone embedded in bluff face. . Figure 7. Dropstone. Climatology Temperatures range from an average low of 4°F to an average high of 62°F. Average annual precipitation is 20 inches. Tides The portion of the Kcnai River being considered for erosion protection is along a section of the Kcnai River that influenced by semi-diurnal tides, with two high waters and two low waters each lunar day. The predicted tidal parameters for the Kenai River entrance are based on the tidal benchmark at Seldovia, Alaska. The extreme tidal parameters in table 1 were determined by searching predicted tides at Kenai from 1985 to present. TABLE 1. Predicted Tidal Parameters- Kenai River Entrance Parameter Highest Predicted Tide (10/16/1993) Mean Higher High Water (MHHW) Mean Tide Mean Lower Low Water (MLLTM) Lowest Predicted Tide (6/14/1995) Elevation (ft MLLW) 26.0 20.7 11.0 0.00 -5.4 River Flow Kcnai River discharge records at Soldotna from 1965 to 2001 show th~ highest daily mean discharge was 41,400 cubic feet per second (cfs) on September 24, 1995 and thc lowest daily mean discharge was 770 els on April 1, 1966. Discharge is typically between 1,300 and 15,000 cubic feet per second with average discharges in July, August, and September around 13,000 els. Although the flow at the mouth of thc Kcnai will differ from thc flow measured at Soldotna, the flow records at Soldotna arc th~ best historical record availabl~ near th~ mouth of th~ K~nai and are considered to representative of th~ freshwater flow that could b~ experienced at thc mouth of the <¢nai. Waves The bluff at the mouth of the Kenai River is'generally not impacted by wave action. Infrequent occurrences of storms from the west and southwest that occur during extreme high tides create conditions for waves to impact the bluff. A shoal at approximately-1 to -2 feet MLLW, the tidelands flanking the mouth of the river, and the low-lying wetland across the river breaks waves before they get to the toe of the bluff. Erosion History According to an analysis of aerial photos from 1976 to 1999 performed by the University of Alaska Anchorage, the average volume of material lost from the bluff is approximately 32,150 cubic yards per year. A rough evaluation of the bluff lines drawn in the report indicates that on average the bluff is eroding at a rate of 2.5 feet per year. Erosion Mechanisms Blufferosion along the Kenai River mouth is a prOduct of several conditions, with varying degrees of contribution. The mechanisms acting on the bluff include: · Wind scour on the face of the bluff · Wave action at the toe of the bluff '. Groundwater seepage and piping from the upper sand layer · Groundwater seepage, piping, and hydrostatic pressure build up in the lower clay layer · Runoff draining Over. the bluff · Freeze thaw effects weakening the bluff · Wind Isolated occurrences of wind erosion on the upper sandy portion of the bluff were noted during an April 2003 sit~ visit. Wind erosion is minor relative to the total erosion along the bluff face. Wind does play a role in the transport of the fine sediment. This is evidenced by the build up of sand on the face of the dunes and along fence lines after a dry windy period. While the volume of sediment transported appears minor when viewed as a yearly volume, over time this could account for a large quantity of material transported. Waves Wave action at the base of the bluff is an infrequent oceu~ence. There must be the fight combination of storm surge and tide for the bluff to be impacted bywave action since the wetland and shoal at the mouth of the fiver create a natural bamer to waves by limiting the wave height that can reach the bluff. A brief analysis was performed to determine the wave height that could impact the bluff. This analysis looked at only one wave direction and did not consider the effects of refraction. A more detailed analysis would require the~use of pressure charts to accurately define the wind fields that could generate waves in Cook Inlet. The wave that could impact the bluff was evaluated by examining two wave conditions: the unbroken wave height that coUld travel past the shoal and the wetland, and the wave potential to reform after being broken. A wave traveling towards the bluff would have to travel over the shoal and wetland in order to impact the bluff. Survey of the wetland'area across the fiver indicates that it has an elevation of up to 23 feet MLLW so the water level needs to be greater than 23 feet to even begin to support a wave climate. Mean higher high water is 20.7 feet, which would not overtop the wetland, so a surge event coupled with a high tide would be needed for the wetland to be capable of supporting a wave. While tide data at Kenai is available, storm surge data is not available. To approximate a storm, surge at Kenai a list of storm surge observations compiled by the National Ocean Service and listed in table 3-6 of the Shore Protection Manual was consulted. Kodiak is the closest suitable station to Kenai. The extreme high water level recorded for Kodiak is 3.7 feet above mean high water. When combined with the mean higher high water elevation for Kenai, a highest water level of 24.4 feet MLLW (20.7 feet + 3.7 feet) is obtained. This will be the water level over the wetland while the tide is at the mean higher high water elevation,' once the tide tums this water level will begin to fall. A 24.4-foot water level leaves 1.4 feet of water over the wetland. 'Typically waves break in a water' depth that is 0.78 times the wave height, applying this to the wetland results an unbroken kvave of one foot that could be supported in 1.4 feet. Waves broken on the wetland would have the potential to reform after they are broken if there is sufficient wind and fetch to support wave growth. Wind records from the Keriai Municipal Airport have recorded sustained 30-knot winds. While this is an infrequent occurrence, this wind was used to determine the potential for wave reformation after correction for measurement height and land effect. The fetch used for wave growth after being broken was °ne-half mile. With these conditions a conservative estimate of the potential wave generation is a one-foot or smaller wave being able to reform and impact the bluff. ? / ."2 '~ ", J ' , "' ""~' "I"-):' ";', !"-'"'",,i;.i~"') ~,....::'~'"" ~' ,,,, , · ~ '.. i '~: ,", '~... ... % .:~. ; ~- ~ '; J ! '..' .~ ..,. .,...; '... ', ~, ': ~' '.i ~, ", ! ...-."" ~ \ ,. :' ~. , '"" ."i"';~'~ .,~ .'"' ~' "' '", ~ ~ , T", .; ',. '., ~ i .~ ', . · .' 3~' ~. ,' ,'-~ .,( ~,~' ..... .- . ..' , ~. .. .~ .. 'j i~ ~ g~. -...' '..I. ,'~ % ~, '-- ~, /ii. '~. ', -.. ~. ~ t, t,," ~, ~ .: ~, j · ,, . ,, ,,, ,/, -, . .?" *, i :' ":~, -':~"' & ~ '2 .... -: , ~' ,2~", /2, i, 'ii ~' "' i ~ !~"/') J; i .... ~,,,,, ,")'.... .- ,, ~, Figure 8. Bathymetry at the K. er~ai River mouth. L% Mi. / Figure 9. Topography affecting wave behavior at the mouth and 'along the bluffs. Figure 10. Breaking wave in front of the bluffS. Groundwater Seepage At the interface of the sandy material and the marine deposit, groundwater seeps out of the b luffface. The water source for the seepage appears to be the wetland area behind the airport. This area contains a large volume of water that can supply a constant source of recharge for the unconfined aquifer that is exposed at the l~luff face. The upper sand layer is very porous and really transmits surface water to the .impermeable marine deposit layer. Once the- impermeable layer is contacted, the groundwater flows along this surface, and out of the bluff face. · · Two areas east of the proposed project site appear to interrupt the groundwater flow with a natural channel (figure 12). These areas appear to provide a gradient away from the bluff face and towards two channels that meet behind the dunes at the mouth of the fiver. In this local drainage the bluffs are more stable and seepage out the bluff face is not observed (figure 13). Figure 14 shows a transition area between the bluff where the groundwater is channelized away from the bluff face and where seepage is observed out of the bluff face. ,) 10 Figure 12. view of the two drainages behind the dunes Figure 13. Stable bluff in the area behind the drainage. ll Figure 14. Transition area to seepage out of the bluff face Bluff damage due to seepage is evident by the piping holes along the face of the bluff. At the interface between the sand layer and the marine deposit, piping holes are visible along the entire length of the proposed project area (figures 15 and 16). This indicates that the water is seeping along preferential flow paths and removing material from the sand layer. As the material is removed, the support for the material above weakens until it collapses and localized failure is experienced on the upper bluff (figure 17). The failed material covers the lower bluff and then is washed away by high tides, storms, and rain. The cycle of piping out the lower material and subsequent failure then begins again. The bluff damage from the groundwater seepage is not limited to impacts seen on the upper bluff sand layer. The water seeping out of the bluff face travels over and sometimes through fractures in the marine deposit. The water traveling over the marine deposit eventually erodes channels into the deposits. Ia areas Where the water travels through the marine deposit, the water pressure appears to build up and pipes out of the bluff'base (figure 18). This was observed along the bluff after the heavy rainfall events in the fall of 2002 where blocks of marine deposit material had piped out and left large voids in the'bluffbase. The failed material was gone the following year having been washed away or scoured away by ice over the winter, In other areas the water seeps to the base of the bluff resulting in areas of high pore pressure making a traverse of the bluff'base very soupy. The seepage pathway through the marine deposit is also susceptible to deterioration from freeze thaw effects.. The water freezing in the fractures in the bluffwill expand to increase the fracture and weaken and or fail the bluff material. High tides, waves, or high flows at the base of the bluff remove the failed material that accumulates 12 and the erosion process starts over. The groundwater seepage frOm the bluff face is a major contributor of erosion of the bluff face. Figure 15. Piping hole in the bluff face. Figure 16. Series of piping holes in bluff face. 13 Figure 17. Eroded upper bank.material at the base of the bluff and channels cut in more impermeable marine deposit. Figure 18. Piping at the bluff base. 14 Overland Flow Uncontrolled flow over the top of the bluff would erode the sand in the'upper bluff. It appears that in some areas along the bluff an effort has been made to control overland flow. A drainage swale has been put in place along Mission Avenue (figure 19). This has helped to control the overland flow in this area, but the bluff is still affected by the action of the other erosional forces previously discussed. · .- ... Figure 19. Drainage swale for overland flow. Geotechnical Evaluation Soil borings were advanced at four locations (figure 20) in support of a slope stability and groundwater flow analysis. Soil samples collected during the drilling effort indicated that the sand layer was approximately 37 feet and was underlain by a clay layer that was 36 to 45 feet 'thick. Piezometers were installed in each of the borings to allow groundwater elevation measurements to be taken periodically. Groundwater measurements taken in October 2003 and April 2004 did not indicate much variation in the water level elevation (table 1). 15 Figure 20. Location of soil borings Table 1. Water level .elevation for October 2003 and April 2004 . TB 1 Water TB2 Water I TB3 Water Elevation [ft] Elevation [ft] I Elevation [ft] October 2003 62.74 60.57 I 58.23 April 2004 62..4 60.26 ! Plugged TB4 Water Elevation [ft] 61.24 60.95 Gradient lines constructed from the water elevation measurements confirmed the water flow is towards the bluff. The gradient calculated for the flow in October and April was 0.01 foot per foot. A pump test was performed on TB2 in October 2003. Using the Hvorslev Method, the hydraulic conductivity of the aquifer was determined to be 3.08 x 10-3 feet per second. This is in the range of the hydraulic conductivities for well-sorted sands, glacial outwash cited in C.W. Fetter's Applied Hydrogeology.. The pump used for the test had difficulty achieving a large draw down, and the recovery was very rapid, so the test results are approximate only. The calculated hydraulic conductivity was used in the Dupuit equation to determine the aquifer's unit flow of 2.5 x 10-3 ft3 per second for the October and April measurements. Assuming the upper soil layer is uniform with no impermeable lenses channeling flow from the face of the bluff, and a proposed protection length of 4,500 feet, then the amount of water moving through or behind the bluff proposed for protection is 972,000 ft3 per day or 7.3 million gallons per day. 16 As a check on the flow, the volume of water available for transport from the wetland (figure 21) was estimated. The area of the wetland was estimated to be 11 square miles. All precipitation that occurs was assumed to be made available to the aquifer and not stored since the wetland is already is a saturated condition. The reported average annual precipitation is 20 inches, which results in 511 million cu.bic feet of water over the wetland. This precipitation was then divided evenly over a year and resulted in 10'.5 million gallons a day moving through the aquifer. This is just the flow potential, the effects of local drainage were not been considered and the validity of distributing the flow evenly throughout the year was not tested; however, it provides a check on the calculated flow through and behind the bluff which appears to be reasonable. · Figure 21. Wetland supplying aquifer Proposed Project Effects Concems raised regarding the proposed project include: · Effect of revetment placement on river flow · Effect of the revetment on the dune stability Effect of Revetment on River Flow 'The general effect of the proposed project on the flow of the fiver was evaluated using the Hydrologic Engineering Center River Analysis System (HEC-RAS). The basic computational procedure is based on the solution of the one-dimensional energy equation. Energy losses are evaluated by friction (Manning's equation) and contraction/expansion (coefficient multiplied by the change in velocity head). 17 To perform the HEC-RAS analysis, five depth profile cross sections were collected along the lower reach, of the Kenai River. The data from the cross sections were input into the HEC-RAS program to describe the river reach. One cross section was located above the proposed bank stabilization project and one cross section was located below the proposed project. Three cross sections represented the river length that was to be included in the stabilization project. The model was mn to evaluate the velocities for different discharge and tide level conditions for the with- and without-proje& condition. The river flow was input using the Soldotna data for maximum flow, minimum flow and average summer flow. The tide conditions were selected by looking up the high and low tide conditions for the days that experienced the maximum and minimum flow. The highest and lowest predicted tide for the years 1985 to 2003 was used for evaluation of the average summer flow condition. The tide elevation was the starting water surface elevation. No flow measurements were made as part of this study. The following scenarios were analyzed: RUN NUMBER 1 2 3 4 5 6 7 8 9 10 11 12 RIVER FLOW 770 77O 77O 770 13,000 13,000 13,000 13,000 41,400 41,4O0 41,400 41,400 TIDE 0.5 18.5 0.5 18.5 -5.4 26.0 -5.4 26.0 -0.3 23.2 -0.3 23.2 PROJECT CONDITION Without project Without project With project With project - Without project - Without project With project With project - Without project Without project With project - With project Model results indicate very low velocities during high tide conditions with an average velocity in the main channel less than 1.5 feet per second (fps). Channel velocities during low tide conditions ranged from slack water to 6.6 fps. Model results indicate that the project would have minimal effect on the average river velocity. At low tide, the project would not change the average river velocity. Under high tide conditions the project would have minimal effect on the average velocity. The maximum increase by the project is 0.1 fps; an increase from 0.9 foot per second to 1.0 foot per second. 18 Results of the HEC-RAS analysis follow: River Tide Project Condition Average Velocity In Project Area Flow [ft] . [cfs] Overbank by Main Overbank Wetland Channel by Bluff _ -. [ft/s1' [fusI , Irt/s] I 770 0.5 Without project 0.01 0.16 No water 2 770 18.5 Without project 0.01 0.03 0.02' , , 3 770 0.5 With project 0.01 0.16 No water 4 770 18.5 With project 0.01 0.03 0.02 5 13,000 -5.4. Without project No water 4.67 No water 6 13,000 26.0 Without project . 0.16 0.41 0.25 7 13,000 -.5.4 With project No water 4.67 . No water 8 13,000 26.0 With project 0.16 0.41 0.25 9 41,400 ' -0.3 Without project 0.85 6.60 No water 10 41,400 23.2 Without project 0.55 1.48 0.82 . 11 41,400 -0.3 With project 0.85 6.60 No water 12 41,400 23.2 With project 0.55 1.49 0.88 It is estimated from the current project drawings, that the lowest elevation of the project will be at 10 feet MLLW. This was arrived at by overlaying the proposed project drawings on the survey data (Figure 22). Using 10 feet MLLW as the lowest project point, an evaluation was performed to determine the percent time that the project will be in the river. An analysis of the predicted tides for 2003 indicates that a portion of the project will be in the fiver approximately 55% of the time. This assumes that the water surface elevation is governed by the tides. The average flows along the revetment, when wetted, will be relatively slow. Observation of the material indicates that it is very stiff and would likely be unaffected by minor, temporary turbulence from slow moving water. During the time that the structure is not wetted, the toe will be available for periodic inspection for scour. 19 Effect of Revetment on Dunes The dunes at the mouth of the Kenai River are an ephemeral feature that owes its existence to wind blown sand, beach grass, and a favorable littoral transport system. The orientation of the dune and the channel behind the dune could be an indication of a west to east littoral transport or it could also be an indication of the best hydraulic gradient to the Kenai River. The dune appears to be nourished by wind blown sand, which is trapped in the beach grass, allowing the dune to grow until a storm event. The wind blown sand is sacrificed during storm events and the grass remains to capture more sand and renourish the dunes. The key to dune preservation is the preservation of the dune grasses. Figures 23 and 24 show the dune before and after a storm event. While the mechanism for dune renourishment appear to be wind blow sand transport, the source of sand is uncertain since the coastal bluffs and upper layer of bluff along at the mouth both contain sand similar to the dune material. This results in the follow potential SOUrC(~Si Sand that is transported along the coastal beach from northwest to southeast at the fiver mouth ~ Sand moved from the fiver system, deposited on the shoal at the mouth, and moved back to shore during storm events · Sand moved from the base of the bluffs along the shore and deposited on the beach at the mouth by tidal currents Figure.23. Kenai Dune during heavy use 21 · Figure 24. Scarped face of the Kenai dune after a storm Coastal Sand The shoreline exposure and orientation to Cook Inlet indicate a dominant northwest to southeast littoral transport system for the north fiver bank. Evidence for this transport is found northwest of the mouth of the fiver in a headland area with numerous boulders lying on the tide fiat. The headland and boulder field act like a large groin. The oblique aerial photograph at the Kenai Airport offers an excellent view of the groin effect of the headland (figure 25 and 26). The headland is indented in its lea and fine sand is evident at this site where the "groin" starves the beach of coarser sediment and allows f'me material to deposit in the eddy formed behind the groin. Further to the southeast in the direction of the dune the coarser material rejoins the beach and is carried along the base of the bluff. The material is continuous from where it rejoins the shoreline to the dune zone. The sand sediment along this stretch of beach appears to be a thin mantel of eroded bluff material with a maximum layer thickness of a few feet underlain by marine deposit material similar to the lower half of the river bank bluff. Numerous pockets along this beach show areas of high pore pressure characteristic of the saturated marine deposit material under the surface sediment.. It is suspected that most of the surface sediment is lost to offshore of the tide flat during major storms and only minor amounts are transported southeast for windblown transport to the dune face. 22 Figure 25. View of the Kenai River and indicator of sediment transport direction · ." '.' ' ...." ~ ' '"" .... .i'.".. ' ' '~'; ': .... ,.. · .-&.'.". :.'-.. -.: ..' --~i' · ". ":'~-" - " ' ' ' ;. "'.::;:'"')';':;;'"',"": ~' ?::):'~:" i ..'!'-.',:: ' '-:~ :'. ,.2:'.' '? ' ~" :::.,:..i::-;,i:.;:'¢~.'., :' ,: :.;"',':: :.'.-i':,::,;'i.i,},i;:: i.':" '..' """ -. ..,,- ,? .. Figure 26. Ground view of the'headland acting as a groin 23 River Bluff Sand An estimate of the sediment contribution from the bluff proposed for revetment is 5 to 7 percent of the sediment load in the river according to Sediment Impact Assessment conducted by the Engineering Research and Development Center (see Appendix C). Two alternatives exist to make the bluff sand available for dune nourishment. First, bluff sediment must be transport down river and drop out at the shoal at the fiver mouth. Sediment at the shoal would be available for wave transport to the beach in front of the dune, then blown by wind to the dune face. Survey data is not available to determine if the shoal is growing and it is unclear if the shoal is composed of sand similar to the bluff sand. This scenario requires a storm to transport the eroded bluff material to the beach. The storm that have that potential are infrequent and are of short duration.' A second alternative is transport of the eroded bluff sand along the river's edge by tidal currents during high tide events. The sediment would not move a long distance but t · would move close tot the mouth of the river and would be available for wind blow transport to the dune face during low tide events. To be made available for dune nourishment, bluff sediment would first be transported down the fiver to the mouth, where, if it were to stay in the system, it would drop out at the shoal at the mouth. Survey data is not available to determine if the shoal is growing and it is unclear if the shoal is composed of sand similar to the bluff sand. The material that would accumulate on the shoal would then be available for wave transport to the beach in front of the dune, and then windblown transport to the dune face. This scenario requires a storm to transport the eroded bluff material to the beach. The storms that have that potential are infrequent and are of short duration. Most Likely Sediment Source.. While the source of the dune nourishment source is likely a combination of all of the sources discussed, geographical features provide the most compelling evidence that the major source of dune nourishment is the material from the north around the headland and not river buff material. Further Studies/Recommendations For Design Work. If the City pursues the revetment project it is strongly recommended that the issue of the groundwater seeping out the bluff face be~addressed as the first order of work. Any solution.that does not address the groundwater will not solve a major source of erosion. Options that may be considered t° ad&ess the groundwater include: a cutoff wall and pump system to intercept the groundwater, draw down wells to reduce, the water table along the bluff face, a horizontal drain system into the face of the bluff to collect and divert the water, a free draining retaining system to hold back the bank material and still allow free drainage of water from the face of the bluff, or creation of drainage channels to alter the groundwater gradient. Additional information can be found at the web site: http://www.montauklighthouse.com/., erosion.htm to see' how another community with similar soi1 and groundwater issues, and a more Severe wave climate approached their erosion control. 24 APPENDIX C SEDI.MENT IMPACT ASSESSMENT KENAI BLUFF EROSION TECHNICAL REPORT KENAI, ALASKA' Kenai River Bluff Erosion Project Sediment Impact Assessment Prepared by J. Craig Fischenich, PhD, PE ERDC Environmental Laboratory For US Army Engineer District, Alaska August 23, 2004 EXECUTIVE SUMMARY Erosion of the Kenai Bluffs contributes an estimated 21,300 tons of sediment to the Kenai estuary annually. Sediments from the bluffs consist of a mixture of gravels, sands, silts and clays, with most of the noncohesive soils in the horizon comprising the upper half of the bank. About 50 percent of these upper horizon soils are sands in the size classes found in the Kenai Dunes. Thus, the bluffs contribute an average of 10,600 tons of noncohesive sediments to the system each year. This represents about 7 percent of the sand flux into the system. About 60,000 tons are delivered annually by the Kenai River from upland and streambank erosion upstream of the estuary, and about 100,000 tons are delivered by longshore transport in Cook Inlet. Most of these sediments pass through the estuary, but some are deposited on the tidal flats and the Kenai Dunes. Stabilization of the Kenai Bluffs would affect the sediment dynamics in the estuary. The overall impact of the reduction in sediment load is likely to be very minor, however, as the system is aggradational and the reduction in sediment volume slight. Local impacts of note include the alteration of the substrate along the stabilized portion of the bank (although this will generally be above the waterline), and local scour at the toe of the structure. Some coarsening of the sediments at the toe can be expected over time through sorting processes associated with the increased energy environment. Changes in the morphology of the tidal flats and dunes is not expected given the net surplus of sediment in the reach. TABLE OF CONTENTS APPENDIX C ................................................................................................................... EXECUTIVE SUMMARY '''' '"'''' °"'"''"'" '''''''''''''''"'"'''''''*"''' ""* '*'"'''*" ° °"° °*°* °*° ° °o**o**o*o-...~e co. 2 BACKGROUND ......................................................................................... 4 5 EROSION ASSESSMENT ..................... '"""'"""'"'"---'"-..--.---.---..---.--.-........................... 7 Mechanisms of Bank Failure ~~~~~~~.~~~~~~.~~~~..~~~~..~~.~~~.~~..~~.~~.~~.~~~~~.~~..~~~~~~~~~.~~~~~~~.~~~~~~~...~.~~. 7 Extent of Existing Erosion .............................................................................................. 9 SEDIMENT ANALYSES ................................................................................................ 12 Sediment Sources and Processes .................................................................................. 12 Sediment Characteristics ............................................................................................... 12 Sediment Budget ........................................................................................................... 1 $ Kenai River Erosion and Transport .............................................................................. 19 DISCUSSION AND CONCLUSIONS ............................................................................ 26 REFERZNCES ................................................................................................................. 27 APPENDIX A ................................................................................................................... 29 Sediment Impact Assessment Model ................................................................................ 29 Introduction ................................................................................................................... 29 SIAM Overview ............................................................................................................ 29 Annual Transport Capacity ....................................................................................... 30 Reach to Reach Sediment Connectivity ..................................................................... 30 Wash Load Material Supply ..................................................................................... 30 'Bed Material Supply ..................................................................................................... 31 Input Description .......................................................................................................... 32 Grain-size Class Records ........................ S~diment Reaches and Network Topology ............................................................... 32 Bed Material Records ............................................................................................... 34 Sediment Property Records ....................................................................................... 34 Hydrology Records ..................... ''e'eeee.ooo.eooeeee,eeoeoeeoe.ooee.oee.o.ooeoe.ooeee...ee..oooeoee,..oooeoeeee 34 Hydraulic Records .................................................................................................... 34 Local Sediment Sources and Sediment Loading Records ........................................ 34 Output Description ......................................................................................................... 35 Summary ........................................................................................................................ 36 References ..................................................................................................................... 36 APPENDIX B ................................................................................................................... 37 45 BACKGROUND The city of Kenai, AK is pursuing an erosion protection project along a one-mile portion of a 55- to 70-foot high bluff fronting the city and the Kenai River (Figure 1). The bluff is subject to a numbe/"of erosion and failure mechanisms, and is receding at an estimated average rate of one to three feet per year. The Alaska District (CEP©A) is developing a Project Study Plan (PSP) for the Kenai Bluff Erosion Reduction Project, and has been tasked to study the Kenai bluffs. Environmental Agencies reviewing a report submitted by the city of Kenai on the bluff erosion expressed concerns regarding the impacts of stabilizing the bluff, including the fate of the Kenai dunes (see Figure 2) if sediment input from the bluff erosion is removed from the system. The CEPOA sought assistance from the Engineer Research and Development Center (ERDC) in investigating existing and potential future sediment conditions on the Kenai River and at the confluence of the Kenai and Cook Inlet. Specifically, the ERDC Team was tasked with a detailed analysis of the sediment sources and transport rates on the Kenai River, with a focus on the sediment sizes found in the sand dunes and tidelands on the north side of the mouth of the Kenai River, to ascertain the impacts of stabilizing the Kenai Bluff upon the dunes. Figure 1. Photo of the Kenai Bluffs where stabilization efforts are. proposed. · Figure 2. 'Aerial photograph of the area of conceTM (from Smith, et al. 2001). STUDY AREA DESCRIPTION The Kenai River is a large proglacial stream draining the Kenai Mountains and portions of the Kenai Penninsula lowlands in south-central Alaska (Figure 3). The watershed includes 2,200 mi2 of diverse topography, extending from the Kenai Mountain icefields to Cook Inlet. The river's origin is at Kenai Lake, from which it flows generally westerly for 69 miles to Cook Inlet. The average gradient is 0.0012, and the substrates are generally coarse gravels and cobbles, except in the lower 12 miles, where sands and silts predominate due to the lower gradient and tidal influence. Glacial landforms dominate the Kenai, influencing the character-of the fiver and its' streamflow. Four stades during the Naptowne glaciation created morainal features such as Kenai and Skilak Lakes, as well as high terraces from' glacial lake deposits interspersed with coarse strata from fluvial outwash. Both the bed material and the channel pattern reflect previous glacial discharges (Scott 1982) and, except for the lower 12 miles the fiver, is considered "underfit". Mean annual discharge at Soldotna is about 5,400 cfs, but flow regulation by the lakes and glacial melt water create a unique seasonal variability with Iow fall and winter discharges and sustained high discharges throughout late spring and summer. Figure 3. Kenai River Watershed. The 45-mile long Cook Inlet is known for its extreme tidal rang~ (up to 36 feet at Anchorage, and about 32 feet at Kenai), and strong currents. The effect of the Coriolis force is pronounced at this latitude, and strong currents and considerable turbulence are produced during times of peak flow (Sharma and Burrell 1970). Flow is generally inland along the southeast coast, and seaward' along the northwest coast (Patchen, et. al. 1981). A constriction in the inlet known as the Forelands just north of Kenai creates increased tidal velocities and currents, so the size of sediments in the inlet tend to be a function of distance from the Forelands with coarse gravels in the region of the constriction trending to sands and silts with distance (Sharma and' Burrell 1970). The Kenai River is world-renowned for its fishery, drawing hundreds of thousands of visitors annually and contributing about $40.million to the annual economy (Dorava and Liepitz 1996). Recreation includes considerable use of motorized watercraft in the project reach. Much of the recreation is related to the fisheries of the Kenai system. The Kenai River supports 34 fish species representing 16 taxonomic families. Thirty species are native to the Kenai River and four are introduced species. Twelve species are residents of the fiver, 11 are anadr0mous, including all 5 species of Pacific salmon, and 11 species found mainly in the lower fiver are associated with the marine or brackish water environment. There are several marine mammal species present, at least seasonally, in the study area. The more common species are the sea otter, Steller sea lion, harbor seal, beluga whale and dali and harbor porpoises (Kenai Peninsula Borough 1990). EROSION ASSESSMENT The primary emphasis of this study was an assessment of the influence of stabilizing the Kenai Bluffs upon the morphology of the lower Kenai River and the adjacent sand dunes. This assessment requires the development of a sediment budget, with a focus upon the sediment sizes found in the areas of concern. The sediment budget must consider fluxes into and our of the shady area, including soils eroded from the Kenai Bluffs, sediments delivered from upstream by the Kenai River, longshore transport in Cook Inlet, and local transport by wind and waves (see Figure 4). The contribution of sediments from upstream streambank erosion to the overall sediment load in the lower reaches had not been previously quantified, and was a key component of the analysis presented in this report. Figure 4. Area of study and factors contributing to sediment flux. Mechanisms of Bank Failure Several previoUs studies haVe reported upon mechanisms of bank erosion and failure along the Kenai River upstream of the study area. Scott (1982) suggested that the retreat of Iow banks is triggered by freeze-thaw, and that flows erode non-cohesive soil lenses of sediments at the toe of high banks, which triggers upper bank failures. Scott pointed to the loss of bank vegetation and streamside use as significant contributing factors. Bamck (1984) documented erosion rates and suggested that the loss of vegetation, boat wakes, and improperly designed erosion control practices were the primary factors associated with rates of retreat. Inghram (1985) updated Scott's study by assessing subsequent rates of erosion, and concluded that rates had remained constant except at a few locations where erosion rates were exacerbated by development. Reckendorf (1989) and Reckendorf and Saele (1993) documented erosion along the Kenai River and determined that erosion rates were related.to both natural and anthropogenic factors. Freeze-thaw, panicle entrainment by flows and boat wakes, and vegetation loss through removal and trampling were listed as primary triggers of the observed erosion. We conducted an assessment of the erosion in the lower 22 miles of the Kenai River in July, 2003. Bank erosion and failures along the lower Kenai River are common, and we found indicators of each of the factors identified by previous investigators. The predominant causes of bank retreat appear to be related to the bank materials and conditions, and the lower river can be roughly separated into two reaches based upon these characteristics. With exceptions at River Mile (RM) 8, 6.5, and 3.8, where the fiver contacts high terraces of till and glacial lake deposits, the banks are relatively low and consist of sands, silts and clays downstream of RM 13 (see Figure 5). Boat wakes, freeze-thaw, and piping are the predominant mechanisms of bank loss in this reach. Material loss in the lower or middle zones of the banks is often followed by translational failure of the upper bank or, where low cohesive banks are found, cantilevered failure of the upper banks. Figure 5. Typical low eroding bank downstream of RM 13, where boat wakes, freeze- thaw, and piping are predominant failure causes. From RM 13 to RM 22, the banks are generally higher and more likely to consist of till with a coarse talus at the toe of the bank (see Figure 6). The banks in this reach are less susceptible to wake-induced erosion due to this coarse material. Fluvial entrainment during high floods followed by upper slope failures and dry soil fall are the predominant mechanisms of failm'e. Banks that are well vegetated are relatively stable, but disturbed segments of the bank are generally retreating. Other contributing factors in this reach include freeze-thaw, piping, ice scour, and trampling. Figure 6. Typical high terrace bank upstream of RM 13, where fluvial entrainment and dry soil fall are predominant mechanisms of failure. Extent of Existing Erosion During the site investigation, the extent of erosion was documented along the lower 22 miles of the river (see Figure 7). Table I presents a summary of the observed erosion sites. The location of the starting and ending points of the erosion sites was determined using a GPS unit, with coordinates converted to an equivalent River Mile along the river centerline. Length of eroding bank was determined using a laser rangefinder. Bank heights of less than 15 feet were directly measured; those in excess of this height were determined with a clinometer and laser rangefinder. The percentage ofbankline actively eroding between the starting and ending points was a visual estimate. Rates of bank retreat were determined by comparing bankline positions in 1965 and 1995 aerial photography. The table presents the average annual rate of retreat over this period. The values compare favorably with those presented by Scott (1982) and Inghram (1985), and are slightly less than those presented by Barrick (1984). · Figure 7, Erosion assessment limits (River Mile in yellow, sediment sample site in red). 10 ooo ooooo oOoO oo~o oo~o ooooo w~' 0 00 0 0 0 0 0 0 0 0 0 In addition to the 29 specific erosion sites identified in the table, numerous other locations were observed where erosion was active, but the extent of an individual erosion unit was not sufficient to merit specific note. It was estimated that about five percent of the banks in the study reach were experiencing this intermittent erosion, and that the associated rate of recession was 0.4 ft/yr from RM 13 - 22, and 0.6 ftJyr from RM 0- 13. Overall, about 22 pe~:cent of the banks in the study reach are eroding (25 percent from RM 0- 13, and 18 percent from RM 13 - 22). The average weighted recession rate is 0.77 feet per year, and is somewhat higher in the upstream reach (0.89 ft/yr) than in the lower reach (0.71 ft/yr). SEDIMENT ANALYSES To assess the effect of stabilizing the Kenai Bluffs, a sediment budget was developed for the Kenai River. Concerns regarding the fate of the Kenai Dunes as a consequence of limiting sediment supply were the focus of this effort, so those sediment sizes found in the dunes were central to the analysis. We conducted an assessment of the sediment processes in the lower 22 miles of the Kenai River in order to document the nature and extent of bank erosion, characterize the sediments, and develop a sediment budget. Sediment Sources and Processes Sediments found in and around the confluence of the Kenai River and Cook Inlet are delivered by three principal processes; 1) littoral transport of sediments along the shore of Cook Inlet, 2) sediments transported by the Kenai River as suspended and bed load, and 3) sediments derived locally through wave and overland erosion and eolian processes. These sediments originate from a wide variety of sources, including upland, streambank and coastal erosion. The relative contribution of sediments from these sources is not known, and not all of the sediments delivered to the area deposit on the tidal flats or on the Kenai Dunes. Finer sediments transported by the Kenai River pass through the estuary and further into Cook Inlet, and many of the fine sediments transported in the bay by longshore processes bypass the inlet. Some of the deposited sediments are resuspended and later transported through the study area, or are removed by winds during Iow tides. Thus, not all sediments are important in determining the impacts of stabilizing the bluffs; only those that historically deposit and remain in the dunes and tidal flats need be considered (see grain size distributions in Appendix B. Sediment Characteristics Sediments in the Kenai Dunes are very uniform fine sands (the ds0 is 0.21 mm), with only about one percent of the sediments in the silt and clay size range, and no sediments iarger than 0.5 mm. Observation of the dunes (Figure 8) suggests that energy conditions are not sufficient to transport the coarser panicles onto the dunes, or that this occurs only rarely; and when this occurs, the coarse panicles are subsequently covered by sands. A larger fraction of silts and clays likely deposits temporarily on the dunes, but is eroded when winds sort the sediments. The prevailing winds appear to be limited to the local transport of fine and medium sands, and are capable of removing silts and clays. 12 Figure 8. Photo of the Kenai Dunes with the eroding bluff in the background. Sediments found in the tidal flats in the Kenai estuary are finer than those in the dunes. An average of 8 samples collected in the tidelands suggest that the sediments are about 30 percent sands, 48 percent silts, and 22 percent clays (Kinetic Laboratories 1998). This data also shows that sediment deposits in the tidelands are less uniform than those in the dunes. Individual samples contained sand fractions ranging from 1.51 percent to 98.09 percent. The tidelands are subject to a wide range of forces, including wind, tidal currents, river currents, waves, and ice, and these act to varying degrees with time and location to sort and distribute sediments. Sediments found in the banks along the lower Kenai River are diverse, consisting primarily of poorly sorted glacial till on high bank terraces, and deposits of fine sands, silts and clays on lower banks below RM 13. Sediments in the upper horizon of the Kenai Bluffs are typical of the till deposits that form the terraces along the Kenai River. The dso based upon sieve analyses of collected samples (see Appendix B for grain size distributions) is about 0.45 mm, but sediments r .ange in size from silts to large gravels. The lower horizon of the bluff consists of consolidated clays, silts, and fine sands, most likely former deposits from glacial damming. The dso of this material is about 0.03 mm. Between these two deposits is a thin (3 -6 inch) layer of relatively impermeable till with a distinct seepage horizon along the upper surface. A high terrace on the left bank of the river at about RM 8.5 has a similar sediment size distribution to those found in the upper horizon of the Kenai Bluffs. 13 Downstream of RM 13, the banks of the Kenai River are generally low in height, and consist primarily of clays and silts, with some fine sands. Samples obtained July 8 - 10, 2003 at RM 9.6 and 11.3 are representative. The maximum sediment size found in the banks passes a 0.25 mm sieve. The dso of these sediments is about 0.02 mm. Samples collected upstream (at RM 13:2, 15.9, 18.3, 19.5 and 20.2) demonstrate a coarser and more poorly sorted gr.ain size distribution. The average dso of these samples, is just under 2 mm, and about 2/3 of the sediments in the banks fall within the.sand classes, with the remainder consisting mostly of gravels. Sediments on the bed of the Kenai River grade from coarse to fine with distance downstream. Wolman pebble counts of bar sediments obtained under low flow conditions (3800 cfs at Soldotna) on May 24- 25, 2003 show that the dso upstream of RM 13 is about 2 in., and a larger fraction of coarse sediments are found with distance upstream. Figure 9 presents an example grain size distribution, and Table 2 provides an average of bar samples collected upstream of RM 13. Pebble counts were not conducted downstream of RM 13 because the sediment is too fine. However, a study by Kinetic Laboratories (1998) included samples at RM 2, 3, 5, 10, and 13. The precise location of these samples is not noted in the report, but they demonstrate a dso in the fine sand/coarse silt range.. Lenses of gravel are present on the bed in this lower reach, particularly adjacent to high terrace/bluff features, but the bed material appears to be primarily sands. GSD, Bar Sample, Kenai River near Big Eddy 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0.01 I It I III t't-tt*'f II It I Iil F. - F!. ~*.-~,.I..I.I I Ii I Itl .... t' [...L..,L.I.I L I. I I Il ,. }..i I tl I I I II I I '1I I ..... i'~ ..... ~i' · I I II '1 '1 I I I I il I '1- I ! I i II t-I.-f.H I I III l.. I..I, ..I. I I..I.. I I I III I I'"''~'~ '' ~ 0.1 I I I I I III t I II I I!1 I I I I !11 I .I ..... ,--~. ~ r-~-I .~ ....~~- ~ ~.~, - I- ~ ~.~.,H,~..I .-.~.~--t I..- I. ..I. 1. t.t.~I ..... I II.-I 111 .... I.~.1.1.44.1~ ! I Iil IilI II I I tI I I t III . 1 I I1 [11 ........... L..t..t.l ttt.t ~.~ .i ~: .~-I'1--- ~...I.. .I ~'~ ~sl~l ~ t ~ ~f'~l iI t ~ ~1I I ,. I ~11 f '.L .I.I ,~ ~ ~ t t f~l! . ~ J.~.'~l ~..L...~ t. ........... i I''i I I1'1 "1' i Il illI' ~'~ ~i~I 'i "~'[-i iii I , I I iii i ii i iiiI ~1 i i i~lI I 1.I I Ii! " 'i'-'l' ' I I III .... I' 'l:fl illl'" /I I It ~tl[ " i I I I III I I I I III I II I litI ~ I ~ t IIII I t I I III r' .-r ~.t'~,',- · ~ ~ ~"r'rrt'! "~- ;'~ 'r~t' '~ .... r--~-r-, I i I i Iii I i ;I~~ I I I I lilt I I I I I III . ,.,. ,,.,.,., . L ~ff , ,,,,~. ,..,...,_.,.,.,,~ , , , ~,i.~~~,,_~,! ' ' "~'~ ~ ' '" . I ...... [ I ~K t ._. I... i, .L L. 1.1 ~ I. i . ~ IAL ~ iii L ~ ~... I. I .[..l~i. _ , ,~~,~' , ,~,~,,,I.~, ~'~,,l~t,-~ ,,,,, 1 10 100 I I IIIt I F I.,I t I! ..... I I I I I · . I. I I I ' I' -! ~ I · - I - I I · I I ll.I ~ 4~ I I ,,1 i ~t~ i i 1000 10000 Particle Size (n-m) ~ ~--I-- CumJlative Percent · Percent Item / Figure 9. Grain size distribution of bar sediments - Kenai River near Big Eddy (RM 16). ,Table 2. Av, er~ ,,,~%~ .?¥....,..~.~ .... :...~-'~i!~',.--..,' ...... Il' D 6'! D35. Il 3.117 l' 24.22 e of bar 46.1 collected upstream of RM 13, Kenai River. ~-..'.,~g'~-,.. ,~.-~,~.~ .:~.~i~....w~:,~.~ .' ~pt:~! ~j~?t~;:r ..... ~ .- .... :.,,.:.-..:,..,::.~,. ..~.,.:,--. ~ ..' ,.....:.,.,...,-.,~. ~,..--,-~,,.~:~-. ,., .... ,..,.,,, ~,,.~. ,~,_:..,,~~,.,,~" ,,...-..~. .- ,::,OS ll"' ' c'avl ! II 0% ! ! 43% 34% 14 Sediment Budget The University of Alaska Anchorage (UAA) conducted an assessment of the sediment budget at the mouth of the Kenai River (Smith et al. 2001). This study focused on the sand budget for the beach adjacent to the proposed project in the Kenai Dunes vicinity. The UAA study addressed wave-induced longshore transport at the dunes, northward longshore transport along Kalifomsky beach, direct contribution of sediments from the erosion of the Kenai Bluffs, and sediment delivery through riverine transport on the lower Kenai River. A summary of the study results is presented in Table3; Figure 10 shows the control volume used in the analysis. Table 3. of sediment loads in UAA Smith et al. 2001). Kenai River 690,000 363,000 Kenai Bluffs 51,120 - Wave-Induced 39,8 O0 39,8 O0 _. Longshore 67,700 67,700 Bluff shoreline of lower Kenai River at Kenai 1-2 Ill fid® with ~orm COl#al wkld-klduced iedimeflt trmlport (1.'t or on be~ch end bluIf~ ~ failure ~ ~torm erosion ~nd wtorm wage, tidal, arid river currents induce sediment transport runoff imbedded boulder bemch (11:1) lower be#h (100.1) ¢olrle ~nd, Or#el, medium.~ne smd and shinglel wive.induced ~edknent transport dominde, beech , fic~Jre bv C,~=c~'~ Sm~. PE Figure 10. Control volume schematic for UAA study (Smith, et al. 2001) The UAA study concluded that, because of a large surplus of sediment delivery to the study reach, and because the bluff erosion contributed only 7 percent to the total load from the fiver, the proposed stabilization effort would not adversely affect the Kenai Dunes. The UAA sediment budget was refined based upon the data we collected in the field. Sediment sources downstream of Soldotna were included in the total sediment load from the Kenai River by documenting existing erosion and projecting the erosion rates into the furore. The sediment loads were then separated into the wash and bed material components, so that the final sediment budget reflected only those sediments important to" the morphology of the project area. Readers are referred to ASCE Manual 54 "Sedimentation Engineering" (ASCE 1975) for a description of terminology used in this report. 15 Sediment yield from sources upstream of Soldotna was determined by integrating a flow duration curve for the USGS gage at Soldotna (Figure 11) with a sediment rating curve for this site based upon suspended sediment samples obtained by the USGS between 1967 and 2001 (Figure 12). The USGS suspended sediment data showed an average concentration of fines (less than 0.063 mm) of about 67 percent. The bed material load shown in Figure 12 w.a.s determined by adjusting the total load to eliminate the fines, and an inCrement of 10 percent of the load was added to account for the unmeasured (bed) load, following standard convention (ASCE 1975). The UAA report assumed 53 percent of the load was bed load, but we feel this to be an unrealistic estimate upstream of RM 13, so the more conservative estimate of 10 percent was adopted. Integrating the flow duration curve with the sediment rating curves yields an estimated annual total load of 138,000 tons. The bed material component of this is about 55,200 tons. These estimates do not include coarse substrates entrained from the bed by high flows, but these substrates are not likely significant in volume, nor do they contribute to the formation and maintenance of the dunes or tidelands near Kenai. This measured load is significantly less than that reported in the UAA study, which based its estimate on a projection of mean flow conditions and an average sediment concentration. Flow Duration Analysis Kenai River at Soldotna ':t:.Y~.',z; .- ,,,-'~. ~ :}'7.: ;-.-.:..-;' ~'~ · .;.,~- . .- ~.~ ~.' .-..~:-" .t~,E-. "-'.'":'--~,.'.~' -!: ~h ~~.....:,e:~ ~;! ...... ~'~ .d~i~.~.~;--. :... ~,,~' .... ..*. ~ ,g~.._~c35~~~,..~~..,~_.. r.~,_,.,, a...,.. .-.¢-..[ :20000 25000 Dbeharge, cfa Figure 11. Flow duration curve, mean daily discharge 1965 - 2002, Kenai River at Soldotna, AK. 16 10000 1000 lO0 1000 Sediment Rating Curve Kenai River at Soldotna = 0.0001x ' ,.. . ~~:~ · Total Load ~.'.:~--.,~'~-~-~,--.~.~:~,,.'-.~?:.,',~'~..~:.~ Bed Material Load 1000O 1OO00O Discharge (cfs) Figure 12. Sediment Rating Curve, Kenai River at Soldotna. Total sediment yield from bank erosion downstream of the USGS gage was assessed by determining the average annual volumetric yield from the sources listed in Table 1 and assuming a specific weight of 2.7 and 30 percent porosity (1.6 tons/cubic yard). The contribution of bank erosion to the bed material load was determined by adjusting the total load to eliminate the fraction of sediments in the banks finer than 0.063 mm. Table 4 presents a summary of the sediment contribution from each of the erosion sites. Table 5 presents a revision of the UAA sediment budget incorporating these new figures. The total bed material (sands) load into the control volume is about 210,000 tons/year. Of this, about half is derived from coastal processes, one-fourth from watershed sources above Soldotna, and the remainder is fi'om bank erosion downstream of Soldotna. We estimated the total contribution of sediments fi'om the Kenai Bluffs to be 21,300 tons/year, as opposed to the UAA study, which estimated 51,000 tons/year. The difference is likely attributable to a variation in estimated annual recession rates; we assumed 1.2 feet/year based on 1965 - 1995 Conditions, whereas the UAA estimates were based upon recession rates between 1976 and 1999, a period that may have experienced higher than normal erosion. The volume of sediments delivered by erosion and failure of the Kenai Bluffs was adjusted to eliminate fmcs by reducing the volume by the percent fmcs in sim in the bank based upon our sampling. The retreat of the bluffs contributes about 10,600 tons of sand-sized sediment per year to the system. This constitutes approximately 5 percent of the sand load of the system. The UAA study estimated the contribution to be 7 percent. The preceding assessment assumes that all of the sediments passing the gage at Soldotna and those eroded from the downstream banks are delivered to the project area. Over the long term, this may be a reasonable assessment, as there is little evidence of significant morphologic change in the lower reaches of the channel in recent history. However, long-term aggradation of 17 this reach is almost certain, and a more detailed assessment that considers sediment transport capacity and deposition is wananted. The following section of the report presents a sediment budget that accounts for deposition and erosion through, tmnspo~ and continuity analyses. This additional analysis accounts for aggradation upstream of the project site and effectively overcomes the limitations of the general budget presented in the UAA study and refined above. Table 4. Sediment cor~t~bution fi'om erosion sites downstream of Soldoma. 22.0 13.02 99.2. 1408 2253 1397 2235 20.8 20.8 100.0 89 142 89 142 20.6 20.6 100.0 71 114 -. 71 114 20.1 19.8 100.0 667 1067 666 1066 19.3 19.3 99.7 213 341 213 340 19.1 19.0 99.7 80 128 80 128 18.9 18.1 99.6 6222 9956 6197 9916 18.3 18.1) 99.6 622 996 620 992 17.7 17.6 99.6 178 284 177 283 16.2 15.9 99.7 2111 3378 2105 3368 15.7 15.4 99.7 3200 5120 3190 5105 14.0 14.0 99.7 782 1252 780 1248 13.5 13.3 99.7 480 768 479 766 13.0 13.0 99.7 89. 142 89 142 13.0 0.02 50.0 1525 2441 763 1220 11.5 11.0 6.3 222 356 14 22 11.2 10.8 6.3 200 320 13 20 11.2 10.7 6.3 156 249 10 16 10.8 10.3 6.3 389 ° 622 '25 39 10.7 10.1 6.3 320 512 20 32 10.1. 10.1 17.5 44 71 8 12 10.0 9.9 17.5 74 119 13 21 9.8 9.2 17.5 53 85 9 15 9.3 9.1 17.5 64 102 11 18 9.2 9.6 17.5 22 36 4 6 9.2 9.2 17.5 33 53 6 9 8.7 7.5 99.2 7778 12444 7716' 12345 7.7' 7.2 6.3 240 384 15 24 6'8 6.2 99.2 237 379 235 376 4.0 3.7 49.8 667 1067 332 531 1.0 0.0 49.8 13333 21333 6640 10624 Total 41571 66513 31984 51175 1 -Overlap'in fiver miles occurs in some instances because erosion sites on the left and right banks were treated separately. 2 - These "sites" represent small-scale, intermittent erosion occurring throughout the reach but not designated as a separate site because of scale. 18 Table 5. Summ~ of sediment loads in the area. Kenai River 204,500 106,200 Wave-Induced* 39, 800 39,800 Longshore* 67,700 67,700 Kenai River Erosion and Transport An analysis of sediment transport and deposition on the lower Kenai River (downstream of RM 22) was conducted using the Sediment Impact Assessment Model (SIAM), a sediment budget model developed by the ERDC Coastal and Hydraulics Laboratory under the Regional Sediment.Management Research Program. A description of SIAM is presented in Appendix A. The version of SIAM used for this assessment is a testing and evaluation compilation incorporated into HEC-RAS Beta Version 3.2. Cross sections used to represent channel geometry were developed from an existing HEC-RAS model furnished by UAA, augmented with cross sections obtained by C£POA for a flood insurance study. The cross sections extend from RM 0 to RM 22, at the USGS gage in Soldotna, AK. The model was calibrated by UAA (Smith, personal communication, 2003) and no additional calibrations were performed. The study reach was divided into four subreaches for analysis: RM 0- 7; RM 7- 13' RM 13 - 19; and RiM 19-22. ' Hydrology for the model analysis was determined using a flow duration curve developed from data for the period of record at the USGS gage at Soldotna, AK (Figure 8). The distribution of flows were represented in the model analysis by a series of five steady discharges and associated durations (Table 6), representing an average annual series of flows. The downstream boundary condition is defined by the tide, which varies semi- diurnally over a mean range of 17.7 feet at the Kenai confluence. Variations in the tidal range were represented in the model by the geometric means of the high and low tides, which were 8.6 ft msl and-9.2 ft msl, respectively. The flow durations were divided equally for these two boundary conditions, with one day per year eliminated from the flow duration series to permit full-day analyses. Table 6. Disch 'es and durations used in the assessment to represent annual hydrology. 4,000 224 9,000 76 14,000 50 19,000 14. 26,000 2 Samples from the bed of the channel were used to define the bed material size distribution as well as the diameter of the largest panicle moving as wash load (set at the d~0 of the bed material). Upstream of RM 13, the bed material was determined from bar 19 sampling using Wolman pebble counts. This data is shown in Appendix B. Bed material gradations downstream of RM 13 were determined from samples collected during a study by Kinetic Laboratories (1998), augmented with a sample collected at the Pillars (RM 12.5). Table 7 presents the bed material gradations used for each of the four subreaches in the study. The demarcation of the wash and bed material loads was established as the d l 6 of the bed material, and are shown in Table 7. Table 7. Bed material reach. silt/clay very fine sand fine sand medium sand coarse sand very coarse sand very fine gravel fine gravel fine gravel medium gravel medium gravel coarse gravel coarse gravel very coarse gravel very coarse gravel small cobble medium cobble large cobble very large cobble small boulder small boulder medium boulder large boulder very large boulder bedrock Wash Load (mm) 0 0.062 0.062 0.13 0.13 0.25 ...... 0.25 0.5 0.5 1 1 2 2 4 4 6 6 8 8 11 11 16 16 22 22 32 32 45 45 64 64 90 90 128 128 180 180 256 256 362 362 512 512 1024 1024 2048 2048 4096 76.0 0.0 0.0 0.0 7.0 2.1 1,2 0.0 6.0 4.2 0.0 3.2 5.0 6.3 6.0 6.4 4.0 5.2 6.0 3.2 2.0 3.1 1.2 2.1 0.0 6.3 2.4 6.4 0.0 5.2 3.6 3.2 0.0 3.1 1.2 2. i 0.0 2.1 1.2 1.1 0.0 6.3 3.6 6.4 0.0 6.3 6.0 7.4 0.0 8.3 9.6 6.4 0.0 5.2 7.2' 6.4 0.0 7.3 8.4 7.4' 0.0 9.4 16.9 11.7 0.0 5.2 6.0 4.3 0.0 4.2 3.6 4.3 0.0 6.3 7.2 7.4 0.0 3.1 3.6 3.2 0.0 1.0 1.2 3.2 0.0 0.0 2.4 2.1 0.0 0.0 1.2 2.1 o.o o.o o.o o.o 0.0 0.0 0.0 0.0 0.004 0.8 3.1 2.3 Local sediment sources include the inflowing sediment load at RM 22, and the bank 'erosion documented in Tables 1 and 4. The inflowing sediment load was determined using USGS data as discussed in the preceding section. To account for the load from bank sources in the SIAM model, it is necessary to categorize the types of erosion and the associated average sediment delivery by grain size. Five categories of bank loss were identified for the lower reach of the Kenai River, and are summarized below. T~,pe 1 erosion was assigned to the bank along the Kenai Bluffs where stabilization is proposed. Figure 13 shows the bank, which consists of a 30-foot layer of stiff clay 20 overlain by a 30 to 40-foot layer of till soils..Several mechanisms of bank loss were noted at this location, and occur over varying scales. The lower horizon is subject to retreat by wave erosion at the toe, freeze/thaw, and block failures associated with poor internal drainage. Each of these phenomena leads to shallow translational failures and soil fall of the upper till layer. Other mechanisms influencing bank loss of the upper horizon include dry soil fall, eolain transport, freeze/thaw, filling and piping. Failure of the upper horizon is more rapid than the lower horizon, but is limited by the angle of repose of the materials. This type of bank is found only in the lower one-mile of the study area, the mean recession rate is 1.2 feet/year, and Type 1 erosion is affecting 5000 linear feet of bank in the study reach. Figure 13. Photo of Type 1 Erosion. ~ erosion involves high till banks with cobble material at the toe that are failing in an intermittent manner, generally from causes other than boat wakes. Included are banks experiencing limited erosion, localized rotational failures, and damage from foot traffic. Figure 14 shows an example of Type 2 erosion. This type of erosion is limited to areas upstream of RM 13, and affects about 5600 feet of bank. Average bank height is 38 feet, and the average rate of recession is 1.2 feet/year. 21 Figure 14. Photo of Type 2 Erosion. Type 3 erosion involves relatively high terraces of predominately till material that are failing systemically- mainly from erosion of the toe by boat wakes followed by upper bank failures. The average bank height for these features is 35 feet, and the average rate of recession is 1.1 feet/year. These banks typically lack the coarse material-at the toe found on Type 2 banks. With the exception of sites at RM 4 and 8, Type 3 erosion is limited to the reach upstream of RM '15.4. The 'length of eroding bank is about 15,400 feet. Figure 15 shows an example of this type of erosion. T~,pe 4 erosion involves erosion of relatively low banks where the material is a coarse alluvium. The primary failure mechanisms are erosion during high flow events and ice scour. The banks are not generally susceptible to wake erosion. Average bank height is 7 feet, and the average rate of recession is 0.9 feet/year. Figure 16 shows an example of Type 4 erosion. Type 4 erosion is found at three locations between RM 6.2 and 19.1, and totals about 2400 feet. 22¸ Figure 15. Photo of Type 3 Erosion. Figure 16. Photo of Type 4 Erosion. 23 T_vpe 5 erosiOn is found exclusively downstream of RM 13. Relatively low banks of silts, clays and sands that recede from erosion, boat wakes, freeze/thaw, piping, and cantilever failures are a common feature in the lower reach of the river. Type 5 erosion involves an average recession rate of 0.6 feet/year on banks that average less than 6 feet in height. The total length of Type 5 failures is 23,519. Figure 17 shows an example of Type 5 erosion. The contribution of sediments from each type of erosion feature was determined by applying an average grain size distribution to the average height and recession rate. Table 8 presents a summary of the loading tables for the five types of erosion. Loads are determined by size fraction of sediments for use in the SIAM model, with sediments larger than very fine gravels excluded from the analysis because they do not contribute to the formation and maintenance of macroforrns in the Kenai estuary. Figure 17. Photo showing an example of type 5 erosion. Table 8. Sediment loads bank failure Type .. Clay Silt VFS FS MS CS VCS. VFG '/ 2.133 0.021 0.060 0.363 0.981 0.213 0.213 0.213 · 2 0.005 0.005 0.019 0.127 ~ 0.459 0.432 0.419 0.649 3 0.298 0.046 0.038 0.122 0.392 0.325 0.523. 0.350 4 0.001 0.002 0.006 0.024 0.101 0.064 0.045 0.045 5 0.183 0.021 0.003 0.000 0.000 0.000 0.000 0.000 24 HEC-RAS analyses were conducted for a high and low tide condition, using the five steady discharge values presented in Table 6. Summary output from the HEC-RAS runs for the mean conditions are presented in Appendix C. HydraUlic design functions for SIAM analyses were run for a variety of conditions, using Yang's transport function exclusively for the lower two reaches, and a combination ofYang's and Meyer-Peter and Muller's function for the upper two reaches. Both existing conditions and with-project conditions were assessed. The 3.2 Beta version of HEC-RAS does not permit the display of sediment transport and' deposition by grain size fraction when the SIAM module is utilized, and only repons the total aggradation or degradation by reach. However, the module was mn for this study so as to exclude sediments not found in the bed material in the vicinity of the project area, so the values reported are predominately in the sand size range. The results of the SIAM analysis are summarized in Table 9, and account for the aggradation occumng upstream of the area of concern. The inflowing bed material sediment loads to each of the study reaches are presented in the second column. The third and fourth columns show the average annual aggradation (or degradation, if negative) in the indicated reach. The load into the next reach downstream is determined by summing the inflowing load with the bank erosion in that reach, and subtracting aggradation (or adding degradation) in that reach. The model suggests that only the reach from RM 22 to 19 is degradational; the remaining reaches are aggradational. The model also indicates that transport capacity is not sufficient to move the sand and larger classes of sediments through the most downstream reach, and that the entire bed material load would deposit in this reach except for the influence of tidal currents and longshore transport. The only difference in the model analyses between the existing and with-project conditions are the 10,600 tons/year of bed material sediment yielded directly from the Kenai Bluffs. This constitutes an 18 percent reduction in the river-derived sediments depositing in the area, or about 7 percent of the total sand load. These results are in close agreement with the sediment budget presented earlier in the report, and with the estimates in the UAA study. Table 9. Summ of SIAM results. 22-19' 55,200 -3,780 -3,780 19-13 57,700 12,400 12,400 13- 7 68,500 34,900 34,900 7 - 0 46,700 58,700 48,100 25 DISCUSSION AND CONCLUSIONS The proposed project consists of constructing a revetment of varying cross-section with geotextile and rock erosion protection on its seaward slope. The construction will protect the subject one-mile stretch of bluffs along the north bank of the Kenai River fi'om erosion by extreme high water and waves. The lowest extent of the proposed erosion protection will lie in the upper half of the tidal zone; above the water most of the time. The upper eroding bluff will be graded to a shallower, more stable sloPe and planted to prevent wind- and runoff- induced erosion. River currents apparently have little affect upon the stability of the bluff, and only affect sediments on the .riverbank below the toe of the construction. Sediment lost from ~e bluff is carried only a short distance downstream, where wave-induced longshore transport becomes dominant. The UAA study of the sediment dynamics in the vicinity of the project concluded that the reduction of sediment load would be minor (about 7 percent), and would be offset by the sediment surplus in the reach. We used two alternate analyses to assess the sediment budget of the system and, while we arrived at a lower overall sediment load, we found the impact of stabilizing the Kenai Bluffs to be of the same order as the UAA study. Our ref'mement of the UAA budget to account for bank erosion and to separate sediments into bed material and wash components suggests a 5 percent reduction in load, whereas our continuity analysis that accounts for aggradation upstream of the project site suggests a 7 percent reduction in sand load. REFERENCES ASCE (1975). "Sedimentation Engineering". ASCE Manuals and Repons on Engineering Practice- No. 54. American Society of Civil Engineers, New York, NY. 745pp. Bailey P., (1985). "?eriglacial landforms and processes in the southern Kenai Mountains, Alaska," Cold Regions Research and Engineering Laboratory. Barrick L., (1984). "Kenai Riverbank Erosion Study," Alaska Department ofFish and Game Division of Fisheries Rehabilitation, Enhancement and Development. Carlson P., Janda R., Conomos T., Barnes P., Reimnitz E., Wright F., Sharma G., Burbank D., Anderson D., Gat-to L., McKim H., Petrone A., Hunter R., (1973). "Symposium on Significant Results Obtained from ERTS-I," Goddard Space Flight Center. Dorava, J., Liepitz, G., (1996). "Balancing the Three R's (Regulation, Research, and Restoration) On the Kenai River, Alaska," U.S. Department of the Interior. Dorava J., Moore G., (1997). "Effects of Boatwakes on Streambank Erosion Kenai River Alaska," U.S. Geological Survey. Finch W., (1972). "Earth Resources Technology Satellite-1 Symposium Proceedings," Goddard Space Flight Center. Gatto L., (1976). "Baseline data on the oceanography of Cook Inlet, Alaska," 76-25, Hanover, New Hampshire. Inghram M. W., (1985). "Erosion Along the Kenai River," Alaskan Division Of Geological and Geophysical Surveys." Kenai Peninsula Borough, (1990). "Kenai Peninsula Borough Costal Management Program". Resource Planning Dept., Kenai Peninsula Borough, Soldotna, AK. Kinetic Laboratories Incorporated, (1998). "1997 Kenai River Estuary Sediment Characterization Study," Prepared for the Cook Inlet RCAC. The Geochemical and Environmental Research Group Texas A and M. Loshbaugh, S. 2002. "Past grabs interest, heart of geologist". Kenai Peninsula Online. May 19, 2002. http://peninsulaclarion.com Patchen, R.C., Bruce, J.T., Connolly, M.J., U.S. (1981). "Cook Inlet circulatory survey: 1973-75". National' Oceanic and Atmospheric Administration. National Ocean Survey. NOS oceanographic circulatory survey report, 'June 1981, No.4, 89p Reckendorf F., (1989). "Kenai River Steambank Erosion Special Report," Alaska Resources Library and Information Services. Reckendorf F., (1991). "Kenai River Bank Inventory Report," Soil Conservation Service U.S. Department of Agriculture. Reckndorf F., Saele L., (1993). "Streambank Inventory and Protection Soldotna Reach, Kenai River, Alaska," Coastal Zone '93. Scott K., (1981). "Erosion and Sedimentation in the Kenai River, Alaska," U.S. Department of the Interior Geological Survey. Scott K., (1982). "Erosion and Sedimentation in the Kenai River, Alaska," Washington D.C. Smith O., Lee W., Merkel H., 2001.."Analysis of Sediment Budget With regard to the proposed Kenai Coastal Trail and Erosion Control Project," Erosion at the Mouth of the Kenai River, Alaska. University of Alaska Anchorage, School of Engineering. 27 Smith O., Smith J., Cialone M., Pope J., and Walton T., (1985). "Engineering Analysis of Beach Erosion at Homer Spit, Alaska," Department of the Army. United States U.S. Army Corps of Engineers Alaska District, (1967). "Flood Plain Information: Kenai River, Kenai-Soldonta, Alaska." United States U.S. Army Corps of Engineers Alaska District, (1973). "Flood Plain Information: Ke.~nai River, Phase 1' Kenai Peninsula BorOugh, Alaska." U.S. Army Engineer District, Alaska Corps of Engineers, (1978). "Kenai River Review". "Flood Plain Information' Kenai River, Phase 2, Kenai Penisula Borough," Alaska. 28 APPENDIX D GEOTECHNICAL INVESTIGATION KENAI BLUFF EROSION TECHNICAL REPORT KENAI, AL~SK~ Geotechnical Findings Report Kenai River Bluff Erosion Project Slope Stability Analysis Kenai, Alaska October 2004 1. Introduction The results of a geotechnical investigation performed for the Kenai River Bluff Erosion project in Kenai, Alaska are presented in this report. The purpose of the investigation was to determine if slope stability was contributing to the recession of a steep bluff along the north shore of the Kenai River adjacent to the City of Kenai. In addition to the stability investigation, a .well flow test was incorporated to collect data for to estimate soil permeability. This report presents a summary of the findings based on site observations and the results of a field exploration, laboratory testing program, and engineering computations. 2. Project Description and Location The City of Kenai has proposed constructing a revetment and bike trail along the north bank of the Kenai RiVer near its mouth at Cook Inlet. The details of the proposal are described in a report by Peratrovich, Nottingham and Drage (PN&D). According to the report, the primary intent of the project is to protect a one-mile reach of riverbank, along the toe of a steep bluff, from erosion by water currents, rain, wind, and waves. Photograph 1 is typical of the erosion that is taking place. The site of the eiPloration is shown on the Location and Vicinity Map, Figure 1. 3. Field Exploration The subsurface exploration for the project was conducted from 15 to 18 September 2003. A total of four test borings were drilled. One was drilled to 37.5 feet and three to 100 feet. The borings have been designated AP- 604-P, AP-605-MW, AP-606-P and AP-607-P. The shallower boring, AP- 605-MW, was finished as a monitor well using 2-inch diameter PVC casing. In the deeper borings, one-inch diameter PVC casing, slotted with a hack saw, was installed to facilitate future groundwater measurements. Kenai River Bluff Erosion Study Kenai, Alaska .... C ::~,er 2004 Photograph 1- Kenai River Bluff Erosion; looking west Hughes Drilling, under contract with the U.S. Army Corps of Engineers - Alaska District (USACE-AD), drilled the test borings using a truck mounted CME 75 drill rig. The drill rig was fitted with an 8-inch outside diameter, continuous flight, hollow-stem auger. An engineer with the Corps suPervised the drilling and logged the test borings in accordance with ASTM D-2488, "Description and Identification of Soils (Visual- Manual Procedurel. Collected samples were screened with a photo- ionization detector (PID) to scan for volatile organic compounds (VOC's). The test boring locations were determined using standard survey techniques. McLane Surveying, under 'contract with USACE-AD, performed the survey. Horizontal coordinates are based on NAD83, Alaska State Plane, Zone 4. Elevations are based on Mean Lower Low Water. Boring locations are shown on the Boring Location Map, Figure 2. Generally, grab samples were procured from the surface and split-spoon samples were taken below the surface at 2.5 feet, five feet, and at 5-foot intervals, thereafter. The split-spoon samples were collected using a 2.5-inch inside diameter split spoon driven with a 340-pound auto-hammer falling 30 inches. The sampler was typically driven to 18 inches ahead of the auger. The number of blows required to drive each 6-inch increment is recorded on the exploration logs. The blow count is an indication of the relative density or consistency of the soil. -2- Kenai River Bluff Erosion Study Kenai, Alaska October 200~ 4. Laboratory Testing and Soil Classification A laboratory testing program was established to classify and determine physical and engineering properties of the encountered soils. These tests and classifications were performed in accordance with the latest version of the following methods' ASTM D 422, "Standard Test Method for Particle Size Analysis of Soils." ASTM D 2216, "Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass." ASTM D 2487, "Standard Practice for Classification of Soils for Engineering Purposes (Uniform Soil Classification System)." ASTM D 4318, "Determining the Plastic Limit and Plasticity Index of Soils." · ASTM D 4767, "Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils." · Multi-Stage Consolidated-Drained Triaxial Compression Test The soil descriptions and classifica~ons contained in this report and presented on the exploration logs are the project engineer's interpretation of the field logs and the results of the laboratory testing program. The stratification lines represent approximate boundaries between soil types; the transitions are often gradual or not discernible by drill action. The exploration logs are enclosed as Appendix A, the grain size distribution curves and other laboratory test results are enclosed as Appendix B. 5. Regional Geology The City of Kenai is located on the Nikishka Lowland geomorphological subdivision of the Kenai Lowland. This region is characterized by a modified morainal topography,' which is separated by an interlacing pattern of swamps and muskegs developed in abandoned drainage channels and broad depressions. The topography and surficial deposits of the region are primarily the products of repeated Pleistocene glaciations, which advanced from ice centers in the surrounding mountain ranges. Near the City of Kenai, the Naptowne glacial moraines are fronted by a broad coastal plain consisting of terraced and channeled sand and gravel deposits, which terminate as steep sea bluffs above a series of raised tidal flats. (Tippetts-Abbett-McCarthy-Stratton (TAMS), 1982.) The topography in the area of the Kenai RiVer mouth consists of a bluff approximately 70 feet high on the north side of the river opposite a low lying wetland and tide flat area with a dendridic drainage pattern. The topography indicates the river valley has historically experienced much -3- Kenai River Bluff Erosion Study Kenai, Alaska , , , ,, Oclober2004 higher flows. Two drainage channels west of the City of Kenai, which extend from the south and southwest end of the airport to their confluence behind the dunes at the mouth of the river, could be remnant drainage channels associated with the historical higher flows. According to Dick Reger, retired geologist with the Alaska Division of Geological and Geophysical Surveys, the bluff at the mouth of the River is composed of three distinct material layers; an organic mat top layer that is approximately two feet thick, a layer of fine sand to sand and gravel with erratics that is approximately 35 feet thick, and a lower' marine deposit layer that can vary from 35 to 45 feet thick. This layering is readily visible in the bluff face. 6. Site Conditions Surface: The site is within an established residential neighborhood with paved streets, curb and gutters, and overhead and underground utilities. The topography of the area is relatively flat with little vertical relief. Vegetation consists of manicured yards and mature trees. The neighborhood is located on a steep bluff paralleling the Kenai River along an east-west alignment. The bluff is very steep, over 45 degrees in some areas. There is very little vegetation on the slope. Subsurface: The test borings indicate the surficial soils are comprised of brown, moist, poorly graded fine sand (SP). A single instance of brown, moist, silty sand (SM)was also encountered. In general, the frost classification of these soils is non-frost susceptible (NFS). Blow counts indicate the sand is in a very loose to medium dense state. These surficial sandy soils extend to an average depth of 38 feet. Photograph 2 shows a typical soil sample collected within the surficial sand layer. The soils underlying the surficial sands consist predominately of an impermeable layer of dark gray, moist, sandy lean clay (CL). Interlayed with the clay are seams of brown, moist, poorly graded sand (SP) from a few inches to several feet thick. These sand seams are loose and very permeable. Photograph 3 shows a representative seam of sand within the clay. Blow counts indicate the sandy lean clay is stiff to very stiff. Poorly graded sand (SP) and poorly graded sand with silt (SP-SM)were encountered below the clay layer at depths of 75 to 86 feet. Groundwater was encountered from 27 to 30 feet below the ground surface in the four borings. Although, groundwater may be present in the sand seams, its presence could not be determined conclusively. Ground water elevations measured while drilling and subsequently are tabulated below. -4- Kenai River Bluff Erosion Study Kenai, Alaska Table 1 - Groundwater Elevations Boring No. Ap-604-P AP-605-MW AP-606-P 31.12' AP-607-P 27.62' ~ 1. AP-606-P was obstructed at 0.71 feet; 2. Water elevations are MLLW October 30, 2003 Water Depth Water Below PVC 'Elevation 26.68' 62.94' .29.15' 60.57' Date April 16 Water Depth Below PVC 27.23' 29.46' 57.23 ObstrL~cted 61.24 27.91' ice is suspected. October 200'~ ,2004 Water Elevation 62.39' 60.26' na 60.95' 7. Engineering Analysis' Slope Stability Analysis- The Corps' slope analysis software, UTEXAS4, was used to perform the slope stability analysis. The UTEXAS program has been the Corp's primary slope stability software since the late 1980%. The software performs an auto-search for the critical surface and is capable of performing static and dynamic analyses. Photograph 2-Surficial Sand Laboratory determined soil parameters were used in the analysis and are tabulated below. These parameters are assumed to be isotropic and constant within the soil layers. The laboratory analyses are attached as Appendix B. -5- Kenai River Bluff Erosion Study Kenai, Alaska October 200~ Photograph 3- Small 2-inch sand seam within lean sandy clay Soil Type Poorly graded Sand (SP) Sandy Lean Clay (CL) Unit Weight (pcf) 99 116 Cohesion (psf) 0 2,196 Friction Angle (deg) '37 27 Water measurements taken on April 16, 2004 were used as the seasonal high groundwater elevation for modeling the groundwater profile within the surficial sand layer. The ground profile was taken from a 2003 cross sectioning effort. Undertaken by McLane Surveying of Kenai, Alaska. Section 3, which closely coincides with the alignment of ^P's 604-P, 605-MW, and 606-P was used in the analysis. Well Flow Test - Well flow test for collecting information to be used for estimating' the permeability of the surficial sand layer was also performed. Because the screened section extended above the water elevation, it was only possible to obtain water level recovery rates after pumping. Since the scope was limited to the collection of data no calculations or interpretations of the data are presented. The well was pumped at six gallons per 'minute; the maximum rate of the Grundfos pump and the recovery was recorded over time. Due to the very permeable nature of the sand, the maximum capable draw down of the -6- Kenai River Bluff Erosion Study Kenai, Alaska October 200~ pump was no more than 1.23 feet. This combination of very permeable soil and limited draw down allowed the collection of only three recovery measurements. The recovery rates for the various draw-down levels are tabulated below. Water Level Below Top of PVC 29.15 29.35 29.8 30.0 30.38 Draw Down 0 .2 .65 0.85 1.23 Recovery (seconds) na 0* 1 4 6 * Recovery was too quick to record accurately. 8. Conclusions Although the Kenai River bluff is receding, .the collected soil data, laboratory testing, and analysis indicate the slope is stable and massive slope failures are not contributing factors. The computed factor of safety for the sand/clay layer is 1.3 and for the clay layer alone, where the sand layer was modeled as a surcharge, is 3.2. Both the sand and clay slope faces, however, are susceptible to surface raveling, sloughing, and wind and water erosion. The critical surfaces for the sand/clay layers and the clay layer are presented in Figures 3 and 4, respectively. Undercutting of existing structure by receding bluff; -7- Kenai River Bluff Erosion Study Kenai, Alaska Oczob,er 20q~ Attachments· 1. Figure 1 - Location/Vicinity Map 2. Figure 2 - Test Boring Location Map 3.' Figure 3 - UTEXAS4 Output- Critical Circle; Sand and Clay 4. Figure 4- .UTEXAS4 Output - Critical Circle; Clay Only 5. Appendix A- Exploration Logs 6. Appendix B - Laboratory Analysis Data Sheets -8- '~ CORPS ~F ENGINEERS ----- · KENAI ~ · 'PRDJECT LFICATIDN HAP iO^T~ oCT 2~ I [": ;--- ~ %-' ,, SOILsAND GEOLOGY ] i,.A~~ ~/m~I = t FIGURE 1 CORPS OF ENGINEERS U.S. ARMY S& ALASKA DISTRICT CORPS OF ENGINEERS SOILS AND GEOLOGY KENAI RIVER BLUFF EROSION TEST BORING LOCATION MAP KENAI, ALASKA I$CALE: NONE ATE: OCT 2004. DRAWN/RVW: SCH/CRWJ FIGURE 2 CORPS OF ENGINEERS O I{~^== °c~' :~oo~ I FIGURE 3 CORPS OF ENGINEERS U.S. ARMY I °"^~,e~ sC"/c.~ i · [ FIGU'RE 4 ' · 210 Fidalgo Avenue, Kenai, Alaska 99611-7794 Telephone: (907) 283-7535 / Fax: (907) 283-3014 www. ci.kenai.ak.us KENAI, ALASKA MemoranClum Date: September 2, 2005 To.' From: Kenai Harbor Commission Kenai Planning and Zoning Commission (.~ Kim Howard, Assistant to City Manager ~' Tideland Application for Shore Fishery The City has received a letter from Ted J. Crookston asldng the City to begin the process to allow for a shore fishery lease. The approximate area is shown on the attached map and is within the boundary of Alaska Tidelands Survey 272 (ATS 272) on the north and west. The patent from the State of Alaska for ATS 272 deeded these tidelands to the City. Mr. Crookston is working with a surveyor to provide a survey of the land. KMC 11.20.040, Classification Prior to Lease Required provides- Before accepting applications to lease tidelands, the area involved shall have first been classified for leasing by the City Council with the approval of the Planning and Harbor Commissions, and their availability advertised in a newspaper of general circulation in the area once each week for two (2) successive weeks not less than thirty (30) days prior to the time set for the closing of the acceptance of applications, and that all applications are available for public inspection at City Hall offices. At this time, approval of the concept of leasing these tidelands is requested, not approval of any specific application. Applications will be provided to the commissions at a later date for a review. KMC 11.20.070(c) states, "The City Council shall make the final determ/nafion of the selection of the applicant based upon the Commission's recommendation and approve or reject the choice of application made." Do the Harbor Commission and Planning and Zoning Commission recommend the described tidelands be made available for lease? Attachments Cc: Ted Crookston /kh Kenai City Limits lllIIillF1 August 17, 2005 City of Kenai Kim Howard Assistant to the City Manager 210 Fidaigo Ave, Suite 200 Kcnai, Alaska 99611-7794 Ted J. Crookston 42321 N. Cook Inlet, REM Kenai, Alaska 99611 R'ECEivED ~ III Ctrv o~ ADMINIST, RATION Subject: Tideland Lease Application for Shore Fishery Dea~ Kim; This letter serves as formal notification to the City of Kenai of my desire and intern to obtain a Tideland Lease as set forth in KMC 11.20 for the purpose of a shore fishery. I hereby request the City of Kenai to initiate all neeessm3r procedures in order to process my application as soon as possible. My contact information is as follows: Ted Crookston 42321 N. Cook Inlet, REM Kenai, Alaska 99611 Primary business cell phone: 801-502-822 Email: tederookston(~jnac.com Local telephone: 907-283-6480 Attached is a portion of a survey, labeled as "Attachment A," depicting the "Subject Area" which identifies the area intended for the lease. Thank you for your consideration and assistance. I look forward to working with you to 07~ this process. Ted J. Ct~kston L 300' S ?0~44' ~ ~'" W 300' 300' 300' 210' ~ .N. ET FISHING AREA ...~.... ~i~b" 'L~'~' ...................... ~ ~ ' ~7 .NET FiSHiNG . .............. ~'~Y*'L~a'a' '/'.~.~ .... / SFP NO. 71 TRACT I , AGENDA KENAI CITY COUNCrL --REG~ MEETING AUGUST 3, 2005 7:00 P.M. ' KENAI CITY COUNCr~ CHAMBEI~ http: / / www.ci.kenai.ak.us ITEM A: CALL TO ORDER 1. Pledge of Allegiance 2. Roll Call 3. Agenda Approval 4. Consent Agenda *Ail items listed with an asterisk (*) are considered to be routine and non- controversial by the council and will be approved by one motion. There will be no separate discussion of these items unless a council member so requests, in which case the item will be removed from the consent agenda and considered in its normal sequence on the agenda as part of the General Orders. ITEM B: SCHEDULED PUBLIC COMMENTS (10 minutes) ITEM C: ITEM D: UNSCHEDULED PUBLIC COM2MENTS (3 minutes) REPORTS OF KPB ASSEMBLY~ LEGISLATORS AND COUNC~ ITEM E: REPORTS OF KENAI CONVENTION/h VISITORS BUREAU BOARD AND KENAI CHAMBER OF COMMERCE ITEM F: PUBLIC ltF_ARINGS . Ordinance No. 2107-2005 -- Increasing Estimated Revenues and Appropriations in the Semor Citizen Special Revenue Fund and the Semor Center Kitchen Capital Project Fund for Kitchen Remodel. (Clerk's Note: Ordinance No. 2107-2005 was substituted and postponed at the July 20, 2005 council meeting. A motion to adopt the ordinance is on the table.} . Ordinance No. 2109-2005 -- Increasing Estimated Revenues and Appropriations by $51,491 in the General Fund for a Juvenile Justice Grant From the State of Alaska to be Passed Through to the Boys and Girls Club of the Kenai Peninsula. e Ordinance No. 2110-2005 -- Finding that Certain Foreclosed Property, Described as Lot 1, Block 1, Thompson Park Subdivision Addition No. 1, 3920 Togiak Street, (Parcel No. 049-130-14} is Not Needed for Public Purpose and May be Sold. Resolution No. 2005-36 -- Approving a Contract to Blazy Construction, Inc. for the Project Entitled Kenai Semor Center Kitchen Addition/Renovation - 2005 for the Total Amount of $361,000. (Clerk's Note: Resolution No. 2005-36 was postponed from July 20, 2005 council meeting. A motion to approve the resolution is on the table.) Resolution No. 2005-37 -- Authorizing the Exchange of 93.13 Acres of Property Owned by the City of Kenai and Valued at $90,000 for $10,000 Plus a 6.42-Acre Parcel Owned by The Conservation Fund and Valued at $8o,ooo. ITEM G: MINUTES o *Regular City Council Meeting of July 20, 2005. *Special Council Meeting of July 15, 2005. ITEM H: ITEM I: OLD BUSINESS Discussion -- Conoco/Phillips Multipurpose FaciliW Naming Proposal. NEW BUSINF~S o Bills to be Ratified Approval of Purchase Orders Exceeding $2,500 *Ordinance No. 2111-2005 -- Increasing Estimated Revenues and Appropriations by $6,512.22 in the General Fund for Donations Made to the Officer John Watson Memorial Fund to be Used for the Town Clock. o *Ordinance No. 2112-2005 -- Amending KMC 14.22.010 to Allow Seasonal and Temporary Food Service as an Allowed Use. Footnote Attachment . *Ordinance No. 2113-2005 -- Amending the Land Use Table at KMC 14.22.010 to Allow Retail Businesses Such as Gift Shops and Coffee Shops in the Education Zone as a Secondary Use. Footnote Attachment e *Ordinance No. 2114-2005 -- Amending the Kenai Municipal Code by Adding 22.05.105 Entitled ~I'emporary Airport Land Sale Moratorium" to Impose a Temporary Moratorium on the Sale of City Lands Within a Proposed Airport Reserve Zone, With the Exception That This Moratorium Shall Not Apply to Lands Already Leased With a Right of Purchase. Attachment Approval -- Special Use Permit/Kenai Rotary -- Big Tonka Toy Event/Industry Appreciation Picnic -- Soccer Field Improvements Discussion -- FY 2006 Designated Legislative Grants (Clerk's Note: This item was postponed from the July 20, 2005 counc/l meeting.) zF~~/24 9. Discussion -- Schedule Strategic Planning Session f/~/o~ ~2-,v~z~/ (Clerk's Note: This item w~ postponed from the July 20, 2005 coundl mee~ng.) ITEM J: COMMISSION/COMMITTEE REPORTS o 2. 3. 4. 5. 6. 7. Council on Aging Airport Commission Harbor Commission Library Commission Parks & Recreation Commission Planning & Zoning Commission Miscellaneous Commissions and Committees a. Beautification Committee b. Alaska Municipal League Report c. Arctic Winter Games d. Stranded Gas Committee ITEM K: REPORT OF THE MAYOR ITEM L: ADMINISTRATION REPORTS 1. City Manager 2. Attorney 3. City Clerk ITEM M: DISCUSSION 1. Citizens (five minutes) 2. Council .EXECUTIVE SESSION -- Personnel Matter/Separation Agreement of Former City Manager. ITEM N: ...ADJOURNMENT AGENDA KENAI CITY COUNCIL- RF~ULAR MEETING AUGUST 17, 2005 7:00 P.M. . KENAI CITY COUNCIL CHAMBERS http://www, ci.kenai.ak.us 6:00 P.M., Board of Adjustment Hearing-- Appeal of Planning & Zoning Commission PZ05-35 -- An application to amend a Conditional Use Permit for Surface Extraction of Natural Resources to allow excavation below the water table for the property known as Tract Al, Beaver Loop Acres Add No. I (2369 Beaver Loop Road), Kenai, Alaska. Application submitted by Patrick J. Doyle, Beaver Loop Sand & Gravel, 49785 Island Lake Road, Kenai, Alaska. Appeal submitted by James A. Krein. ITEM A: CALL TO ORDER 1. Pledge of Allegiance 2. Roll Call 3. Agenda Approval 4. Consent Agenda *All items listed with an asterisk (*) are considered to be routine and non- controversial by the council and will be approved by one motion. There will be no separate discussion of these items unless a council member so requests, in which case the item will be removed from the consent agenda and considered in its nomal sequence on the agenda as part of the General Orders. ITEM B: SCHEDULED PUBLIC COMMENTS (10 minutes) ITEM C: UNSCHEDULED PUBLIC COMMENTS (3 minutes) ITEM D: ,,, REPORTS OF KPB ASSEMBLY, LEGISLATORS AND COUNCILS ITEM E: REPORTS OF KENAI CONVE~ION/k VISITORS BUREAU BOARD AND KENAI CHAMBER OF COMMERCE ITEM F: PUBLIC HEARINGS lo 0 o Ordinance No. 2111-2005 -- Increasing Estimated Revenues and Appropriations by $6,512.22 in the General Fund for Donations Made to the Officer John Watson Memorial Fund to be Used for the Town Clocl~ Ordinance No. 2112-2005 -- Amending KMC- 14.22.010 to Allow Seasonal and Temporary Food Service as an Allowed Use. Ordinance No. 2113-2005 -- Amending the Land Use Table at KMC 14.22.010 to Allow Retail Businesses Such as Gift Shops and Coffee Shops in the Education Zone as a Secondary Use. . e Ordinance No. 2114-2005 -- Amending thc Kenai Municipal Code by Adding 22.05.105 Entitled ~l'emporm~ Airport Land Sale Moratorium~ to Impose a Temporary Moratorium on the Sale of City Lands Within a Proposed Airport Reserve Zone, With the Exception That This Moratorium Shall Not Apply to Lands Already Leased With a Right of Purchase. Resolution No. 2005-38 -- Transferring $15,000 in the General Fund to Purchase Fuel. e Resolution No. 2005-39 -- Awarding the Bids for an Airport Pickup for the Total Amount of $26,791.31 and Two Police Sedans for the Total Amount of $47,096.60 to Great Bear Ford and the Bids for a Building Maintenance Van for the Total Amount of $22,487.00 and a Water & Sewer Cab and Chassis for the Total Amount of $36,321.00 to Hutchings Chevrolet Cadillac, Inc. . ITEM G: Resolution No. 2005-40 -- Awarding the Bid to ACCEL Fire Systems, Inc. for Multipurpose Facility Arctic Winter G':.unes Fire Standpipe Installation - 2005 for the Total Amount of .,.~.334.00. Resolution No. 2005-41 -- Supporting the City's Application to the Alaska Department of Environmental Conservation FY 07 Capital Municipal Matching Grant Program for Arsenic Water Treatment Upgrades. esolution No. 2005-42 -- Transferring $7,000 in the Airport Land ystem Special Revenue Fund for Improvements at the Airport Operations Facility Requested by the Arctic Winter Games Host Sbciety. MINUTES _ . *Regular City Council Meeting of August 3, 2005. ITEM H: OLD BUSINESS ,~~~ 1. Discussion -- Conoco/Phillips Multipurpose Facility Naming Proposal. 2 .... Discussion -- Sale of City ~~~~~. ,A~~ Wetlands to The Conservation Fund. · NEW BUS~S lo Bills to be Ratified 0 e , Approval of Purchase Orders Exceeding $2,500 Approval -- Assignments of Leases From Capital Crossing Bank to MITAK, LLC/Lots 1 and l-A, Aleyeska Subdivision, Part 3. Approval-- Eagle Bluff Subdivision Plat Se Discussion -- Scheduling Board of Adjustment Hearing/Appeal of Denial of PZ05-46 filed by Jay T & Williams A. Snow. , e Discussion -- Set Net Drive L.I.D./City Manager Report to City Council. Discussion -- City Manager Search Proposal. ITEM J: COMMISSION/COMMITTEE REPORTS lo 2. 3. 4. 5. 6. 7. Council on Aging Airport Commission Harbor Commission Library Commission Parks & Recreation Commission Planning & Zoning Commission Miscellaneous Commissions and Committees a. Beautification Commi~ee b. Alaska Municipal League Report c. Arctic Winter Games d. Stranded Gas Committee ITEM K: REPORT OF THE MAYOR ITEM L: ADMINISTRATION REPORTS 1. City Manager 2.' Attorney 3. City Clerk ITEM M: DISCUSSION 1. Citizens (five minutes} 2. Council EXECUTIVE SESSION- None Scheduled ITEM N: ADJOURNMENT KENAI. ALASKA TO' FROM: 210 Fidalgo Avenue, Kenai, Alaska 9961 -' Telephone: (907) 283-7535, Ext. 236 / FAX: (907) 283-3014 1992 Charles Kopp, Acting City Manager Keith Kornelis, Public Works Manager MEMORANDUM DATE: August 31, 2005 SUBJECT: FY 2006 Alaska Designated Legislative Grants City Council met August 16, 2005 in a work session to discuss the FY 2006 Designated Legislative Grants that we received. This is what was decided: Kenai Public Im $125,000 72,000 50,000 33,000 10,000 $290,000 $290,000 Park New Water Wells Lief Hansen Park S rinkler -Well in VIP Skateboard Park lot~l Kenai ~oad & Sewer Im $640,000 I LID's 100,000 Parkin 50,000 I New Street $790,000 I oral Lots ~hts ents $790,000 The appropriating ordinance for these grants should be before Council on September 7, 2005 for introduction. Attached are project narratives for each improvement. CITY OF KENAI; ALASKA CAPITAL IMPROVEMENT PROJECT NARRATIVF PROJECT NAME: Municipal Park Improvement ESTIMATED PROJCECT COSTS' ,,,.,,,,~,,,,,, (includes 12% State Admin. Costs). Estimated annual operations and maintenance costs upon completion are estimated at $2,000. This would primarily include routine operational costs such as mowing, irrigation, facility cleaning, trail grooming and non-murine maintenance expenses. POTENTIAL FUNDING SOURCES: Land and Water Conservation Funding (50/50 matching grant) and City General Fund. PROJECT DESCRIPTION' A portion of Kenai Municipal Park formally served as a tent campground. Since another use has been designated, funds are needed to upgrade property to match its proposed use. Kenai Municipal Park covers approximately 43 acres and is one of the oldest parks in the City's park system. Original development dates back to the early 1970's. Although portions of.the park have been upgraded throughout the years, the interior portion of the property once containing a tent campground has not except for tree and brush cleadng and a 350 L.F. trail addition along with 3 picnic pads (with grills and tables) completed this summer. Last season's addition of the paved parking lot and beach access trail upgrade was a tremendous park upgrade. Most of the park ama, however, is still void of any site amenities, and consequently, underused. Besides being one of the oldest parks in Kenai, it is also one of the more heavily used parks (shelter and play area) and most visible to the public. This is particularly true during the personal use fishery during the month of July due to its close proximity to the mouth of the Kenai River. Additionally, this park is adjacent to one of the largest residential areas in Kenai and in close proximity to Seam Elementarg, making it a very convenient and accessible park. The goal of the park improvement project is to enhance outdoor recreational opportunities and protect significant natural and cultural resources. The plan includes an additional pavilion, kiosk/signs (including interpretive signs); 20 picnic sites (to include tables and grills), 3,600 L.F. of trail upgrades, benches and trash receptacles, general landscaping, and a vehicle parking lot with approximately 20 spaces. crrY OF KENAI CAPITAL IMPROVEMENT PROJECT PROJECT NAME: NEW LOCAL WATER WELLS FOR PUBLIC FACILITIES ESTIMATXD PROJECT COSTS: $72,000 POTKNTIAL FUDING SOtFRCES: State DEC: 50% = S36,000 City: 50% = S36,000 PROJECT DESCRilvrlON: There are many areas uound the city that use a large quanuty of city potable (ctri~8) water for non=cirinkin$ water purposes. The city is about to start tre~.8 our municipal water system by removinl~ arsenic., m_ -n~n~ and iron from our water at three of our wells. The water treatment plants will be expensive to operate and maintain. We should not be using our expensive uuted water for lae~d_er~_~e ~mng or ~luipm~n~ roofing. This project would be to drill six individual on-site wazer wells to provide non-potable w&tet to each facility. The Kenai Muiti-Pumose Facitit_v uses municipal water tbr coolin.8 equipment to freeze the water for the ice rink when on-site water could be used. The ~tv Cemetery needs e watering system and the munidpal water system is not ~v~il~le ~ ~s siie. Th~ K~i Little l.~~e. ~ ~d S~/Footb~ll fields ~d MuniciOal Park could ~11 be watered ~rom an on-site well. These on. site water wells could save the city money in the long run since the water would not have to be treated nor pumped through miles of line before it is used. The General Fund is payin$ the Water a: Sewer Rind for water use at these areas so over time this could be a Gen~ Fund savings. Keith Komelis Page I December 2, 2004' CITY OF .KENAI~ ALASKA CAPIT..AL IMPROVEMENT PROJECT NARRATIV~ PROJECT NAME: Leif Hansen Park Improvements - ESTIMATED PROJECT COSTS: $50,000 Engineering anti design is estimated at $10,000. Estimated annual Ol=erations and maintenanc~ mst~ upon completion are estimated at $800.00. POTENTIAL FUNDING SOURCES= City General Funcl, smaii gran~s. PROJECT DESCRIPTION: $1gnffic~nt msource~ am expended (pdmadly latmr) ea~ summer in order to water this 2-acre pa~ comprising of turf areas, flowemeds, trees and shrubs. Installing an unde~rounel sprinkler system would save time, money, and effort. Currently, them is only one water outlet stationed at the center of the park in which to pull from. As new plantings ar~ added, it is hemming mor~ difficult to sufficiently water all areas in addition to providing evenly measured amounts of water. Currant watedng prances is labor intensive and inefficient from a water conservation standpoint. The project is relatively simple, involving the installation of a central control panel, trenching and installation of plastic pipes, sprinkler heads, and wiring. The number of sprinkler heads, type, and location are all engineered prior to installation. Yearly maintenance c~sts involve re-adjusting the sprinkler heads, replacing heads as necessary, general troubleshooting, and winterizing the system. The advantages of this type of system include: 1. Allows more time dedicated toward other tasks since you don't have labor Involved in moving hose~, setting and monitoring sprinklers. 2. Lower water usage (mom. efficient). 3. Lawn and plantings recerve evenly measured amounts of water. 4. Protects landscape investment. CITY OF KENAI CAPITAL IMPROVEMENT PROJECT PROJECT NAME: FIRE PROTECTION, VIP SUBDIVISION ESTIMATED PROJECT COST: "~"" ,,,'"- ~ : POTENTIAL FUNDING SOURCES' STATE CAPITAL BUDGET CITY OF KENAI PROJECT DESCRIPTION: This project would provide a dependable water supply for tim protection in the VIP Subdivision, which is located across the Kenai River estuary over the Bridge Access road. The VIP subdivision is not connected to city water and, therefore, fire protection is now provided by shuttling water from hydrants located on the opposite side of the Bridge. Providing a reliable non-potable water supply could include a well and possibly a building, fire pump, and a hydrant. C,ITY OF K. ENAI, ALASKA CAPITAL IMPROVEMENT PR. OJr=CT NARRATIVE PROJECT NAME: Skateboard Park Improvements ~ ESTIMATED PROJECT COSTS: ~.=2,'~0 ,- Estimated annual operations and maintenance costs upon completion are estimatecl at $500. POTENTIAL FUNDING SOURCES: Tony Hawk FouncJation [$25,000) and Daubenspeck Fund ($57,000) or Oenemt Fund. PROJECT DESCRIPTION: The skate park at some time in the future could be upgraded to include different tames an~l site amenities, namely a half. pipe. New and appealing featumso su~ as the half-pipe, would ensure long-term use anti interest in the pa~. The present site was constructed large enough (120' x 90') so that it could som~ay ae2.ommodate add~onal f~atums. SPECIAL ASSESSMENT DISTRICT I1TFORMATION L.I.D. UESTS IN PROGRF.~S: le Set Net Drive -- VIP Country Estates Subdivision Part 3 & 4, Set Net Dr/ye (that portion east of VIP Drive) to Water§ate Way. L.I.D. PETITIONS OUT: _ . Thompson Park Subdivision (Eisenhower Lane, Iowa Street, Wildrose Avenue., Primrose Place, Nevada Street, Togiak Street, Parkside Drive, Fern Street, Fireweed Lane, Lupine Drive, North Fern Street) 2. Angler Drive INTEREST EXp~~l~._n TO FOI~__M L.I.P. o o McCollum/Allak (petition received October 21, 2002 and process began, however funds were no longer ava/lable from the state and the McCollum/Al/ak residents were not/fled in June, 2003 the project would not §o forward}. South Ames Road crrY OF KENAI CAPITAL IMPROVEMENT PRO,FE~ PROJE~ NAME: CITY PARKING LOT IMPROVEMENTS . ESTIMA'rED PROJECT COSTS: POTENTIA~ FUDING SOURCES: State Capital Budget City of Kenai PRO3'igC~ DESCRIPTION: Many ot'the citT. parking lots are old and in the need of repairs or replacement. There are also dmnage pro0iems in some of the parking lots. The Kenai City Library, Kenai Police a~d lqte Depamnent, Kenai City Hall Kenai Senior Cent=, Kenei Recreation Center, Kenai Cemetery and others need work. This could be mmplete ~pl~lt remowl ~nd r~l~o~ment, p~chwork, or chip ~ad ~1~[ Keith Komelis Page I Deceu~er 2, 2004 CITY OF KENAI CAPITAL IMPROVEMENT PROJECT PROJECT NAME: NEW CITY STREET LIGHTS ESTIMATED PROJECT COSTS: $50,000 POTENTIAL FUDING SOURCES' State Capital Budget City of Kenai PROJECT DESCRIPTION' There are at least 20 areas that need streetlights to help curtail crime and vandalism, and provide safer conditions for the public. This includes bus stops for children's safety and intersections for traffic safety. 1/18/05 CITY OF KENAI-DOCK -I ,ATE SCHEDULE'T ..___ Charles M. Kopp, Acting City Manager August 23, 2005 KENAI HARBOR RATE SCHEDULE The City Manager shall establish the fees, rates, and charges for the billing and collections for the support of the harbor. The City Manager reserves the right to change the rate schedule at any time. There is a 5% sales tax added to the total invoico (3% City and 2% Borough). RATE SCHEDULE SUMMARY 1. Product wharfage (w/crane; w/o forklift) ' $ 0.07lib Non-product wharfage (ice, nets, staples, etc.) 0.04lib. Purchases Purchases Purchases ,, . . Under 500 500 gal. _2000 gal. Gallons or more or more 2. Fuel Gasoline Regular 2.356 2.306 - State Marine Tax .050 .050 , . Federal Tax .184 .184 , Total S/gal. 2.59 2.54 , , , , Diesel #2 2.54 2.49' 2.37 , State Marine Tax .05 .05 .05 Total S/gal. 2.59 2.54 _2.42' 3. Used Oil Dumping $1.00/gal. 4. Boat Launch Ramp 0-10 min. = $15.00 Includes Parking with Trailer Each min. over 10 min. - $1.00/min. , Seasonal pass per boat = $150/season 5. Parking Only (If with trailer, must pay launch fee) $10.00/da¥ Seasonal Pass for Parking $100.00/Season , 6. ~ie Up Fee A. Skiffs tied to land side of concrete dock ' $7.00/day Seasonal Pass per boat $150/season , _ B. Boats tied to buoy in river $10.00/day_ Seasonal Pass per boat $150/season 7. Forklift w/Operator (1/2-hr. minimum) $50.00/hr. 8. City Labor Char~es for call out (2-hr. min.) $40.00/h'r, ,, 9. I Other Items ! See Dock Manager Prior to Use ~ Finance ,~~