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HomeMy WebLinkAbout2007-12-13 Council Packet - Work Session lJ I IV THl1 A, 1 , P.. I IL H ~~ ~_/ ~~ t/~eu~°h~~ KENA~ SI(A ME ND TO: Mayor/Council FRO1VIa Carol L. Freas, City erk DATE: December 4, 2007 RE: SCHEDULING OF WORK SESSION --Bluff Erosion Project City Manager Koch has requested a work session be held to hear a status report of and discuss the bluff erosion project with representatives of the Corps of Engineers. The work session would be held on Thursday, December 13, 2007, beginning at 6:30 p.m. in the Kenai City Council Chambers. Does council agree to schedule a work session for Thursday, December 13, 2007 at 6x30 p. m. for the purpose of hearing a status report of and discussing the bluff erosion project with representatives of the Corps of Engineers? DEPARTMENT OF THE ARMY U.S. ARMY ENGINEER DISTRICT, ALASKA P.O. 60X 6898 ELMENDORF AFB, ALASKA 99506.0898 Project Formulation Section 30 November 2007 The City of Kenai, working with the engineering consultant PN&D developed preliminary plans to provide bank stabilization along the bluff at the lower reach of the Kenai River. A design concept report was completed in January 2000. Several resource agencies reviewed these design plans in the report, provided concerns and comments on the plans, and requested additional information to fully evaluate the impacts of the project. Technical studies were completed by the U.S. Army Corps of Engineers and Alaska Department of Fish and Game to evaluate the mechanisms} contributing to the bluff erosion and to determine potential effects of bluff stabilization. These studies address many of the agency concems and requests for additional information. A summary of the agency concerns and Corps responses are enclosed. The technical studies are presented in the Corps' Kenai River Technical Report, May 2006. The report can be found on the Internet at http a/www.poa.usaee.armv.mi]/en/cw/reports.htm The Corps is presently conducting field investigations, technical analyses, and designs of bank stabilizatian alternatives. These alternatives include consideration of factors such as environmental impacts, real estate acquisition, cost, constructability, and reliability. It is requested. that you review the May 2006 report and enclosed summary of agency comments. We would like to meet with you to discuss our report findings, present the current design alternatives, and discuss any concerns or comments you may have on the project. A meeting is schedule for December 13, 2007 from 1:00 to 4:00 pm and will be held at the Cook Inlet Aquaculture Association office at 40610 Kalifornsky Road in Kenai. I look forward to meeting with you and discussing this project. Please contact me at 907-753- 5638 if you need additional information. -- Patrick Fitzgerald, P.E. Project Formulation Section G ~+ O. •$ ~ G O ~ 4+ U CE 'Q ~ y ~ H a y o c a ~, m o a~ v a y x O. 0 U d U u v b0 U ~ Q x x x x ~ ~ ~ ~ ~ d~' d d¢ c {. x y ~ ~, ^a^ ~s ,~ mommy ~~ p~v ,~~bA~ C id ~~ '~' .Y O .~ 'y U '~ U '~' i' ~ `' S O N ~ O ~ w "~ cV E aU+ ~ .~ ~ O i+ O N y,, U U N O u 'O Q+ y N~ F O ~ itl .~ U .~ ~ m ~ .p .~ N ~~>yy ~ p ~ ~ .C~~+ ~ ~ •i3 ~ icy y ,~ 'p ~p O a ''~'' 009 C 3 q w G O ..p.. ^~ O N 'p b axi ~ bA y U '~ ~ ,~.. y O U ,p U ~ U o ~~ ° ~b o ~ api~ ~ G ~ ~^ ~° a~~ ~ ~ aw ~yF o U ~ o :5 '° ~ a ~ Y ~ ° '° ~ o~n o 3 > m U ~ P p~ 3 0 0.h'" ~ o is >, ~~ c b q'~ ~° y d y p o w .c ~i y Y ~y~v aogY m^°~'c'i 'W°w'~ro.G ~Y~ooroo ' ^ qtr ~' ,A °~ 3 ^4 ~~"-+ O ~ O U ~ y •n p ~ t. 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Spur dewy Cook Inlet Aquaculture Association 40610 Kalifornsky Road 907-283-5761 Two blocks east of Bridge Access Road 1 r = y~ _.. -. ...acc PUBLlC NOTICE ~, nr CfM ~ SNC The Kenai City Council will meet in a work session on Thursday, December 13, 2007 with representatives of the Corps of Engineers for the purpose of hearing a status report and discussing of the City's bluff erosion project. The work session will be held in the Kenai City Council Chambers located at 210 Fidalgo Avenue, Kenai, beginning of 6:30 p.m. The work session is open to the public. Contact the Kenai City Clerk's office at 210 Fidalgo Avenue, Kenai, 283.7535, extension 231, with questions. Carol L. Freas, City Clerk D/211 i.®.i US Army Cor08 of Engineers Alaska Ois~rict ¢, % J ®(F 7`he ur®se ®f this meeting is t® discusso ® Need for bank stabilization of the bluff at FGenai ® study History (previous studies and concerns) ® Current studies and design concepts ® Identify further concerns and considerations of bank stabilization ;..,~ US Army Corps O~EOB~neers A,asw°,s~°~° nvius tuies Pertinent Technical Studies ® PN&D Concept Report, January 2000 ® Corps Technical Report, May 2006 ® Corps Design Alternatives Report -Ongoing 4 ;,®,. US Armv COlPS [ OePI /~~b C OI EOBIneers Alaska Olslrlcl Jnua ~' _Mrr -- ~,®.; US Army Corps Of Enplaears Alaska Olatrfcl IV nc t ~ ® ®eveloped by Peratrovich, Nottingham, and ®rage Engineers, inc for City of Kenai ® Presented a bank stabilization concept ® Submitted to agencies for preliminary permit application ® Study ended evithout resolution of comments and concerns 6 ;,.,; US Army Corps Alaska Distrfd e`Eee'peBfS nce~at i°f Summary of Agency Comments -EPA, Sep 10, 2001 ® Conduct sediment transport study to reduce the uncertainty and verify conclusions of pervious work ® Conduct hydrologic analysis of impacts of the structure with emphasis on potential for induced erosion upstream and downstream and channel changes ® Establish baseline survey of current bird and fish use of the portion of the mud shore of the river which is the site of the proposed project better understand extent of habitat loss which would occur as a resul4 of the replacement with a hard structure ® Evaluate impact of physical changes to biota of this system ®, US Army Corps of Engineers A® ®®LIi ~®® 6 Alaska DlsViq Summary of Agency Comments - ADF~G, Sep 7, 2001 ® Complete ecosystem analysis of structure and function of the estuary ® Analyze how project well change hydrolagic patterns at and upstream of project area, including impact So wetlands on south shore and anticipated successional changes 4o the river channel • Evaluate changes 4o physical and chemical productivity of river mouth as natural erosive process is altered ® Evaluate how changes in water depth, velocity, and predation patterns will affect acclimating and outmigrating salmon and smolt ® Evaluate marine wildlife use, including where and what they feed on, and how projec4 will impact food resources and use of the area s Provide info on projec4 design life and potential impacts to river if the channel undercuts and destabilizes the toe of the rock fill ® Analyze project function at 100-year flood event during max high tide ® Evaluate alternatives including cost versus benefits and impacts to fish and wildlife resources with consideration of real estate purchase, easements, removal of structures, and trail along top of bluff to minimize tidal footprint ;,®,; us Armr corps of Engineers pyO~ syq ,r( pyp p{aT/, Alaska Distntt IIV6 6Jl 6 Summary of Agency Comments ~ USFVVS Sep 10, 2001 ® ®emonstrate that there are no practicable alternatives involving less adverse impact on the aquatic environment such as locating the trail at the top of the bluff or purchasing bluff easements to reduce the need for stabilization ® ®emonstrate that practicable measures have been taken to minimize impacts to the aquatic environment ® Identify mitigation for potential negative effects to fish and wildlife habitat and wetland hydrological functions ;,®,; Us Anny Cor05 of Engineers ,eryp ,p~yd..pe Alaska 0isfrid III.V Summary of Agency Comments - NM~S, Sep 6, 2001 ® explore alternatives to providing for a trail and stabilizing the failing banks, such as to incorporate bioengineering techniques ® Provide design alternatives that would minimize or avoid impacts ® Provide adequate mitigation for a project of this size ,o ;,®.; oSAtiny i:Otps ®r/J~ ®f ngineer~' A~ sxa~o~st3ct liter®Itseent Directed by Congress beginning in 2002 to conduct technical study of bluff erosion at Kenai Study iS not a f®rmal NEpt4 aCti®n (National Environmental Policy Act) Corps is following its planning process ® Existing conditions e Without project conditions s Develop alternatives ® Evaluate alternatives ® Compare alternatives ~~ ® Select recommended plan ~,®~~ USAtmY COtGS r S Technical a rt Ol Enyine0rs Alaska District ®® a I Report focused on environmental issues associated with stabilization of the bluff Studies tailored to address agency concerns from PN~D concept Did not develop bank stabilization designs Report available at: http://www.poa. usace.army.mi I/en/cwlreports. htm ,z ;,®~; US Army Cops O(EM131peff~3 q® ++~~ y 66 Alaska Ois~~ict ®1 r$V • ~11'Y n,~' ®gppT Report Components ® Environmental baseline data collection - Benthic infaunal invertebrates survey - Annual bird and marine mammal surveys - Fisheries data collection (ADF&G) ® Erosion and Sediment Transport - Evaluated bluff erosion mechanisms - Sediment Budget -relationship of bluff erosion to stability of beach dunes - Sediment analysis performed by Corps research 13 lab in Vicksburg, Mississippi ®,~ herd and marine mammal survey sectors 3} ~ ~ ~ ,~ ,r~ ~~ ~ .. ~I. .. ;~ °F :1 la .,.•...~, .~. ~ ~ ,. ~. i _~-+~ H ~. ~ ~ ~ ~ ~ ~'W. ~„~.tY ~a ~~Qi 4~,~.x ] k,d ~ i~ ~i )'d5¢nai z ~j ~ 1. ~ ' ~ ~<~ ~~~a lia °iy~,'`~p''"iS* ~ f~~' y4~x• n.. ~ ~~~ i„> , ~ .~ ~ ~,3 ~`~l yr r I 1 ~ 4~ e' ~ MM ~ _~~~ ;ll r _ ,(, ~ ~; I ~ ~' ~ I t` ~~;G„ ~,. ~'O ' + ~ ~ ~~~~ ~ ,Inside Bend ~ ~~ j ~ .n,a ~ ~ We9ands f> >,. W I Z ~ ~ ~ L/: ~ ~ ~rf i ~I I/. +~ . ' V~.. ~ ;,,,; US Army Corps Alaska DisVlct pf Enginaera rS T"chnrce~l a ®rt Report Components (cont'd) ® Hydraulics -Evaluated hydraulic impacts of PN&D concept design - Wave influence on south shore - HEC-RAS model to evaluate riverine characteristics -depth, velocity, flow patterns ® Ceotechnical Investigations - Subsurface exploration -four test borings drilled to depths ranging from 37 to 100 feet - Determine if slope stability was contributing to bluff erosion - Well flow test to estimate soil permeability ,6 I I~~~I US Ariny Corps al Engineers Y/q~ `~/~p~qa /q yp/ ~/.pe Alaska Diskicl I N O VP'4~1~®6-0MI M Report Components (cont'd) ® Economics and socio-economics - Cursory economic evaluation - Analysis limited to National Economics ® Cuiturai Resources - Limited assessment - Historical properties and archeological sites along bluff 16 ®~; us army cores Aldskd Disfnct „£~gl~dard ®rps Technical eprt Findings and Conclusions 13iuff erosion due to several contributing factors - 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 ,~ .,®~, us army torus Aidskd oism~t o,E~,gi~derd ®rps Technical Rep®rt Findings and Conciusions (cont'd) Project footprint of PN~® Concept - Rock revetment above river water level -50% of time - Cross-section area of project is insignificant relative to area of river at half-tide level or higher No changes to hydraulics of river -velocity, depth, flow patterns - Would not redirect wave energy to south shore ,A ;,,,; us Army corns Alaska Dlstac~ °`E°a'118Bf5 rp~ Technical eprt Findings and Conclusions Environmental Footprint of PN&D Concept - Low-value tidal area - Likely not to alter bird and fish use of the river 19 I ®~~ OS Atmy Corps Alaska DisVicl o,Ep9ipaar= rF3~ Technical er Findings and Conc{unions (cont'd) Bluff and Beach Dunes Material - Bluff erosion provides minor contribution to beach dunes - Bluff erosion contributes about 7% of sediment to river's sediment load - Major source of dune nourishment is material transported along Cook Inlet shoreline from the north 20 engineering Consultant Tetra Tech, Inc and subconsultants to perform: - Geotechnical Investigations - Bank Stabilization Design Alternatives - Cost Estimating - Surveying and Mapping Corps to perform: - Economic analyses - Environmental evaluations -Not NEPA - Plan formulation - Other work? To be determined during scoping 2, meetings like this one oS ArmY COrPS / Sl / ® I ~/ ~ a~I Y C+ 1 EnBinnors Alaska DisUitl 1°t ® -? 111 Report Components 22 LEFfF9 p4P31JF-< H e3,b2f--liP,vaY•NVnw~i ~FlP-Gi2 ~~ ~~~ SP~' <P~6 »in.ev- nslxA'KtEG'WUyµE ~~®~~ cUS Army Carps r LS- 11 ltrat-v~ (Engineers glaska District ~/.1®l't ® 11 ®111 Report Components (cont'd) dank Stabilization ®esign Alternatives 25 :,~,; IEnBi^ea,s glaska DisVlct 1't ® 11 111 What's Next? ®eveiop 13raft Report Conduct in~house review Release report to public for comment tioid public meeting to discuss report and comments 25 ;,,,; asA~,y~°,ps tab®lezatl®n r®ject renvmoors Alaska Dislriq G'M/~{®~?l11 ~I1 t Currently no Corps authority or funding to construct a project Should Corps be authorized to construct, then NEPA process wouid occur Should City of Kenai pursue construction, then per mit$ing pr OCesS ilJtiiiid o%%iir z~ ;~®~~ US Amry Corps d envi~+eers Aiasez Dismcr 6~' tJS Army Engineer ®istrict, Aiaska Patrick Fitzgerald P.C. Eox 6898 Elmendorf AFi3, AK 99506-6898 Phone:907-753-5638 Fax: 907-753-2625 E-Mail: patrick.s.fitzgerald@usace.army.mil 2a