Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System

Lake Union/Lake Washington Ship Canal System The following write-up relies heavily on the Lake Union/Lake Washington Ship Canal Subarea Chapter by Douglas Houck (with substantial contributions by Deb Lester and Scott Brewer) of the Draft Reconnaissance Assessment – Habitat Factors that Contribute to the Decline of Salmonids by the Greater Lake Washington Technical Committee (2001).

Overview Lake Union and the Lake Washington Ship Canal Washington to Puget Sound. are located in the city of Seattle and combine to In 1916, the 8.6 mile long Lake Washington Ship serve as the primary outlet of Lake Washington Canal was completed, which included the construc- into Puget Sound. In 1916, drainage from Lake tion of the Montlake Cut, the Fremont Cut, and Washington into the Black River was blocked and the Chittenden Locks. The new Ship Canal the Ship Canal and Hiram M. Chittenden Locks provided navigable passage for commercial vessels, were constructed to allow navigable passage barges, and recreational boaters between Lake between Puget Sound, Lake Union, and Lake Washington and Puget Sound. Washington and provide better flushing in Lake Washington. In a 1943 report published by the Washington State Pollution Commission, 45 industries were listed The Lake Union/Lake Washington Ship Canal adjoining Lake Union (Tomlinson 1977). Along system is comprised of the Montlake Cut, Portage with the marinas, houseboats, and commercial Bay, Lake Union, the Fremont Cut, and the Salmon Bay Waterway. The Montlake Cut is an approximately 100-foot wide channel with con- crete bulkheads extending along the length of the channel. Portage Bay is located west of the Montlake Cut and has a natural surface connection to Lake Union. Lake Union covers an approxi- mately 581-acre area. The average depth within the lake is 32 feet. Lake Union is linked to the Salmon Bay Waterway through the Fremont Cut, a steel, rip-rapped channel.

Historical Modifications

Physical Changes The Lake Union/Lake Washington Ship Canal system experienced extensive modification begin- ning in the late 19th century. Historically, no surface water connection existed between Lake Union and Lake Washington. A natural ridge separated the two lakes. Hydrology in Lake Union likely was supported by underground springs, intermittent streams, and stormwater runoff. A small stream flowed from Lake Union into Salmon Bay, which was a long, shallow, tidally influenced embayment of Puget Sound. In the late 1800s, a chute was constructed between Lake Washington and Lake Union and the existing stream flowing to Salmon Bay was excavated to The Ship Canal between Lake Union & Salmon Bay is totally allow movement of harvested timber from Lake man-made.

3534 Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System limnological changes withintheLakeUnion/Ship shoreline developmenthas resulted insubstantial Construction oftheShipCanal andintensive Limnological Changes (Weitkamp seemingly naturalshorelinecharacteristics Union aretheonlyareasthathaveretainedany shoreline, andsmallareasatthesouthendofLake Portage Bay,portionsoftheGasWorksPark habitat (Weitkamp Portage Bay,however,hasretainedshallowwater large live-aboardandhouseboatcommunity. the LakeWashingtonShipCanalstillsupporta system (Weitkamp provides virtuallynonaturalshorelinewithinthe bulkheads, docks,andover-waterstructures shoreline isheavilyarmoredandthepresenceof more modifiedthanitisinLakeWashington.The Habitat intheShipCanalandLakeUnionismuch multi-family residencesalsobordertheshoreline. Other commercialdevelopmentandsingle ing marinas,commercialshipyards,anddrydocks. dependent commercialandindustrialusesinclud- Union systemstillconsistsprimarilyofwater- Current landusealongtheshoresofLake sewage outfallstothelake(Tomlinson1977). to 200houseboatsliningtheshorelinehaddirect residences andcommercialestablishmentsup ant loadingofthelake.In1943report,most and stormdrainagealsocontributedtothepollut- covered andfishwerekilledinitsvicinity.Sewage ties ofoilsothatthesurfacewaterwas equate filtersandoccasionallyspillinglargequanti- routinely dischargingoilywastesthroughinad- one oftheworstsourceswaterpollution, (coal gasification)Plant.Thegasplantwaslistedas Seattle CityLightPowerPlantandtheGas dealing insand,gravel,concreteorasphalt;the and oilstorageservicefacilities;8companies foundries, 10lumberandplywoodmills;12fuel docks, therewere10machineshopsandmetal Duwamish estuary(Weitkamp provide lessfavorablehabitatthandidthe Lake WashingtonShipCanalsystemandtheLocks highly modifiedenvironmentsoftheLakeUnion/ however, itisexpectedthatmigrationthroughthe Effects onChinookhavenotbeenquantified; River Chinookmigrationpatternsandbehavior. ton hasresultedinsubstantialimpactsonCedar the reroutingofCedarRivertoLakeWashing- The constructionoftheShipCanalcoupledwith et al. 2000). et al. et al. 2000).Thesouthsideof 2000). LakeUnionand etal. 2000). 36 35 resulted inbottom sedimentcontamination. Union/Lake WashingtonShip Canalsystemhave Historical industrialpractices withintheLake Sediment 22 Lake WashingtonShipCanalsystemcanreach20- Surface watertemperaturesintheLakeUnion/ Temperature teristics includetemperature,anddissolvedoxygen. Canal watershed.Changesinlimnologicalcharac- meters depth. prevent fishfromusingthewatercolumnbelow10 mg/l. TheselowDOconcentrationswould can reducedissolvedoxygenlevelstolessthan1 along withasignificantoxygensedimentdemand, and canlastuntilOctober.Thelackofmixing, anaerobic conditionsthattypicallybegininJune However LakeUnionstillexperiencesperiodsof Lake WashingtonTechnicalCommittee2001). turned overtotheCityforuseasapark(Greater lake, andthegasplantceasedoperationwas most ofthedirectdischargerawsewageinto During the1960s,CityofSeattleintercepted 1966 whenasaltwaterbarrierwasconstructed. Chittenden Locksbeganin1916andlasteduntil was initiatedsoonafteroperationofthe 1927, Collias1954).Thisconditionmostlikely concentrations whichpreventedmixing(Smith conditions year-roundduetohighsaltwater depths ofLakeUnionexperiencedanaerobic the early1900s.Historicaldataindicatelower when comparedwithconditionsexperiencedsince the waterqualityinLakeUnionhasimproved, ton ShipCanalsystem.Ingeneral,sincethe1960s Washington intotheLakeUnion/LakeWashing- water qualityisinfluencedbyflowfromLake the saltwaterenvironmentinPugetSound.Surface freshwater environmentofLakeWashingtonand system servesasatransitionalzonebetweenthe The LakeUnion/LakeWashingtonShipCanal Dissolved Oxygen 80 daysperyear(Weitkamp of 31daysperyearinthe1970’stoapproximately high temperaturesareincreasingfromanaverage than itwashistorically,andthedurationof onset ofwarmwaterconditionsappearsearlier temperatures arenotincreasing.However,the Historical dataindicatesthatpeaksurfacewater warm laketemperatures(Weatherbee2000). appears tobetheprimaryfactorincontributing o Celsiusduringthesummer.Airtemperature et al. 2000). Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System

Although quantitative data is limited, varying Chinook move through the Lake Union/Lake concentrations of organic compounds from Washington Ship Canal system. Habitat require- historic sawmill practices have been identified in ments for rearing and outmigrating Chinook are various areas within the Lake Union/Lake Wash- not expected to vary significantly between Lake ington Ship Canal system (Parametrix, 1992; Washington and the Lake Union/Lake Washing- Cubbage, 1992; Metro, 1993; Herrera and Brown ton Ship Canal system (Weitkamp et al. 2000). As & Caldwell, 1994; Hansen et al. 1994). Another a result, the littoral, shallow area along the shore- identified contaminated area exists along the line is expected to be the preferred habitat for shoreline at the north end of Lake Union at Gas juvenile Chinook. Given the limited quantities of Works Park (Weitkamp et al. 2000). these habitats, the Ship Canal may serve primarily as a migratory corridor rather then a rearing and Exotic Plants and Animals foraging area for juvenile Chinook. In addition to changes in the littoral zone and limnology, exotic plants and animals (i.e., non- Habitat Requirements native) have affected the Lake Union/Lake Wash- ington Ship Canal ecosystem. Twenty-three non- Juvenile Habitat Requirements native fish species have been identified in adjacent Lake Washington (Warner and Fresh 1998). Some Juvenile Chinook use the Lake Union/Lake of these species are known to prey on juvenile Washington Ship Canal system for outmigration salmon (e.g., smallmouth bass) while others are and rearing. In order for Chinook to successfully potential competitors with juvenile salmonids for carry out these activities the habitat must supply food (Fayram 1996; Kahler et al. 2000). sufficient food and refuge from predation. Physi- cal barriers (habitat access) should not block access Eurasian milfoil (Myriophyllum spicatum), an exotic to the migration corridor and water quality should aquatic plant, was introduced into Lake Washing- be of sufficiently high quality that juvenile fish are ton in the 1970’s. Milfoil exists within portions of not directly or indirectly harmed in passing Lake Union and the Ship Canal; however, milfoil through the system. We looked at each of these appears to affect less shoreline in the Ship Canal habitat needs to assess what is known about their and Lake Union than in Lake Washington. This is condition in the Lake Union/Lake Washington most likely a result of deeper areas in the Ship Ship Canal system and their effect on juvenile Canal and Lake Union. Chinook. Due to the intensive industrial and commercial land use within the area, overall Chinook Utilization of the Lake Union/ habitat conditions are more modified in the Lake Lake Washington Ship Canal System Union/Lake Washington Ship Canal system than in Lake Washington. The Lake Union/Lake Washington Ship Canal system is used by Chinook during two stages in Predator Avoidance their lifecycle. Predation was identified as a known factor of o Adult upstream migration, and decline in the WRIA 8 Draft Reconnaissance Assessment (Greater Lake Washington Technical o Juvenile outmigration and rearing Committee 2001). Predation on outmigrating Adults. Adult Chinook salmon use the Lake juvenile Chinook is likely high in constricted Union/Lake Washington Ship Canal system as a passage areas throughout the Lake Union/Lake migration corridor to upstream spawning grounds. Washington Ship Canal system (Ruggerone, 1992). The precise migration routes through Lake Union High predation areas include the narrow regions of and the Ship Canal are unknown; however, their the Ship Canal and the Locks. Predation rates on residency is expected to be brief (a few days). juvenile Chinook are highest in June, which Water temperatures may influence initial entrance corresponds to the peak outmigration period in into the Lake Union/Lake Washington Ship Canal Lake Union (Tabor, 2000; DeVries, 2000; Fayram, system from the Locks as evidenced by the delay 1996). observed in adult passage through the Locks during Results from a 1999 predator study in the Ship high water temperatures in 1998 (Fresh et al. 1999). Canal area show that predation by bass and Juveniles. Little data is available on how juvenile pikeminnows on Chinook are also very high 3736 Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System reduce foodavailability tojuvenileChinook. Competition fromintroduced speciescouldalso of littoralhabitatsbyoverwater structures. tion fromalossofriparian vegetationorshading result ofsubstratechanges, lossofinsectproduc- chironomids (midgelarvae). Thiscouldoccurasa production ofkeyinvertebratespeciessuchas water structuresinshorelineareascouldaffect Daphnia to thatinLakeWashington(chironomidsand Ship Canal.Itislikelythatthepreybasesimilar Chinook arefeedingoninLakeUnionandthe There islittledirectinformationonwhatspecies Food Availability the natureandextentofthispotentialproblem. dotal observations,nostudieshavebeendoneon bird predation.However,exceptforsomeanec- shorelines mayhaveincreasedtheeffectivenessof of riparianvegetationfrommosttheCity’s vegetation alongtheshorelineasrefuge.Theloss avian predatorsbyusingoverhangingriparian (Roger Tabor,personalcommunication)avoiding Juvenile Chinooksalmonhavebeenobserved tion. in juvenilesbecomingmoresusceptibletopreda- shallow, nearshorehabitatshasmostlikelyresulted be usedasarefugefrompredators.Alossof disrupted growthofaquaticvegetation,whichcan overwater structuresalongtheshorelinehave and dredgingalongtheshoreline.Inaddition, been dramaticallyreducedthroughbankhardening Union/Lake WashingtonShipCanalsystemhave avoid predators.ThesehabitatswithintheLake Juvenile Chinookuseshallow,littoralhabitatsto and riverlamprey. prickly sculpin,rainbowtrout,cutthroat outmigrating juvenilesincludeyellowperch, Other speciesoffishthatmayalsopreyon (Tabor 2000). few predatorswereencounteredinSalmonBay point atthenorthendofLakeUnion.Relatively such astheoutletofUWHatcheryand Pikeminnows tendedtoaggregateatkeylocations mm werefoundtoeatsmoltsof~90insize. identified tothespecieslevel.Bassassmall138 the 30salmonidsconsumedbypredatorsand Chinook smoltsrepresentedapproximately50%of 0.1 forlargemouthbass(MaythroughJuly). for pikeminnows,to0.3smallmouthbass, (Tabor 2000).Smoltsperpredatorrangedfrom0.4 ). Bankhardening,bulkheads,andover- 38 37 ment contaminants resultinthembinding toother However, thechemicalproperties ofthesesedi- Ship Canalsystemalsohave notbeenquantified. nants withintheLakeUnion/Lake Washington Impacts onjuvenilefishfrom sedimentcontami- quantified andrequirefurther study. Water qualityimpactsonChinookhavenotbeen conditions experiencedsincetheearly1900s. Union hasimproved,whencomparedwith general, sincethe1960swaterqualityinLake bodies, pursuanttoCleanWaterAct303(d).In Ecology’s listofimpairedandthreatenedwater- ington. LakeUnionhasbeenincludedon this systemislowerincomparisontoLakeWash- Washington ShipCanalsystem.Waterqualityin water qualitydegradationintheLakeUnion/Lake sewer overflow(CSO)locations,contributeto commercial facilities,inadditiontofourcombined Surface waterdischargefromnearbyindustrialand sufficient (Weitkamp the canalandLake,surfaceoxygenremains portion ofthejuvenileChinookmigratethrough of juvenilesalmonids.InJuly,whenthelatter temperatures occurgenerallyafterpeakmigration factor forjuvenilesalmonbecausehighwater ever, temperaturesdonotappeartobealimiting decline tolethallevelsinJuly(Davis1975).How- levels becomestressful(median:4.3mg/l)andcan juvenile outmigrationinJune,bottomoxygen depths (Weitkamp waters andavoidthelowoxygenatlower Puget Soundareexpectedtoinhabitmostlysurface Union/Lake WashingtonShipCanalsystemto mer. JuvenileChinookmigratingthroughtheLake Washington ShipCanalsystemduringthesum- warmer temperaturesintheLakeUnion/Lake salmon aresuspectedtobeaconsequenceof barrier, anddirectmortalityofadultChinook Higher predationrates,creationofathermalwater Water Quality (Weitkamp, et.al. habitat type(lake)inwhichtheydidnotcoevolve in LakeUnion(includinghatcheryChinook)a are exposedtobothnaturalandexoticcompetitors share theresources.However,juvenileChinook can reduceadverseinteractionsandallowspeciesto to thedevelopmentofnichesandbehaviorsthat Coevolution amongspeciesandtheirhabitatleads where fisharemoresusceptibletopredators. habitats, includingareaswherefoodisscarceor may forcejuvenileChinookintolessdesirable

etal. 2000). Aggressivecompetitors etal. 2000).Duringthepeak 2000). Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System

Lake Union Diagram

Urban Landscape Habitat Habitat Population Constraints Processes Processes Requirements Functions

Channel / Sediment Hydrological Production Modifications Shoreline (bank erosion) Shallow (Littoral) Habitat Formation / Juvenile Maintenance Predator Bulkheading Shoreline Survival and Armoring Currents Avoidance Littoral Overwater Vegetation Riparian Juvenile Structures Vegetation Food Growth and Woody Debris Condition Organic Matter Accumulation Inputs Zooplankton Nutrient Production Land Cycling Development Benthic Invertebrate Production Exotic Species Predators & Introductions Temperature/ Competitors Dissolved Oxygen Water Quality Non-point Stratification Contaminants Barriers Habitat Access

Figure 5. Hierarchical relationship between urban constraints, landscape processes, and Chinook habitat requirements in the Lake Union / Lake Washington Ship Canal system. bottom elements, which potentially limits their behavioral cues to migrating juvenile Chinook availability for uptake in the water column and salmon. The formation and maintenance of epithelial cells in fish (Weitkamp et al. 2000). The shallow littoral areas is dependent upon complex issue of impacts of contaminated sediments on interactions among a number of physical and migrating Chinook juveniles needs further study. biological processes. These processes can be generally described as hierarchical with respect to Habitat Access habitat formation, with landscape (watershed) processes driving localized habitat forming pro- There are no physical barriers that prevent migra- cesses responsible for creating and maintaining the tion through the Lake Union/Lake Washington shallow littoral habitat required for juvenile Ship Canal system, except for the Chittendon Chinook salmon survival and growth (Figure 5). Locks at the western end. There have been fish passage problems at the Locks throughout their Land use within Lake Union and the Ship Canal is history. Observation and physical alterations to primarily composed of water-dependent commer- improve successful passage at the Locks continue cial and industrial uses, including marinas, com- (see Locks section). Piers, bulkheads, and over- mercial shipyards, and dry-docks. Other commer- water structures are thought to potentially affect cial and residential development also borders the juvenile out-migration; however, little data is shoreline of Lake Union. Overwater coverage, available on this subject. bulkheads, and shoreline armoring associated with these uses is extensive. As a result, there is rela- Landscape and Habitat Forming Processes tively little shallow water habitat (natural or altered) along the Lake Union shorelines and Trophic Interactions (Weitkamp et al. 2000). The presence of hardened Recent studies indicate that Chinook fry prefer shorelines and piers has severely reduced nearshore shallow areas with small substrates (sand and habitats available to juvenile Chinook. Bank gravel) (Roger Tabor, USFWS, personal communi- armoring has resulted in a loss of the shallow water cation). Shallow littoral habitats provide both habitat and aquatic vegetative covering that foraging opportunities and protection from allowed prey species recruitment and protection predators. They may also provide important from predators. In addition, bank hardening has

3839 Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System area offocus. Among thesefactors,the protection andrestorationoftheshallowlittoralhabitat emergesasakey Canal system. significant factorsforjuvenileChinooksurvivalandfitnessintheLakeUnion/LakeWashingtonShip Based ontheanalysisabove,followingtablesummarizesourunderstandingofmostlikely the survivalofjuvenileChinooksalmonthan species maybeasbeneficialormoreto ton ShipCanal,reducingpredationbyexotic ecosystem likeLakeUnionandtheWashing- further study.Itispossiblethatinahighlyaltered Lake WashingtonShipCanalsystemrequires juvenile ChinookrearingwithintheLakeUnion/ The effectofnearshorehabitatmodificationon beaches andshallowwaterhabitats. lake systemfromuplandenvironmentsthatcreates limited thekindofsubstraterecruitmentinto outmigration rearing and Juvenile Population Function Requirements Access Habitat Quality Water Availability Food Avoidance Predator Habitat No barriers Need morestudy concern; othereffects Temperature, some refuge/cover/food Spatial distributionof mud, smallgravel) Fine substrates(sand, slope) Shallow gradient(<1% depth) Shallow Water(<1m characteristic/condition Preliminary Focus Areas Habitat 40 39 Union andtheShipCanalin2001. research onjuvenileChinooksalmoninLake predators. TheCityofSeattlehasfundedfurther may attractandprovideenhancedhabitatforsome there issomeconcernthatwoodaccumulation important refugehabitatstojuvenileChinook, patches andwoodaccumulationsmayprovide is stillunderdebate.Whileaquaticvegetation prey dynamicsintheshallowlittoralenvironment debris). Theroleofwoodydebrisinthepredator- processes (e.g.recruitmentandroutingofwoody restoration ofsomethenaturalhabitatforming output Stream drift/organic Littoral vegetation Riparian vegetation output Stream sediment sloughing Bank erosionand Habitat forming process Substrate hardening Overwater structures vegetation Loss ofriparian Stream modifications bank armoring Bulkheading and Contraints Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System

Habitat Improvement Projects in the Lake Union/Lake Washington Ship Canal System Habitat improvement projects should focus on improving those habitat qualities that the science indicates will likely provide the greatest benefit for fish. Habitat restoration projects will be monitored whenever possible. Monitoring will track those critical variables that will help the City to assess effectiveness in meeting project objectives. The City will seek to design and monitor habitat restoration projects that create benefits for multiple species where this is practical and where doing so does not undermine the main objectives of the project. The following table notes projects which have already been completed and projects which might be considered and notes the benefits for fish which each project may create. Our lack of knowledge on how juvenile Chinook salmon exactly behave in the Ship Canal and Lake Union as they migrate through it, has resulted in fewer currently identified projects for this habitat area. Two major research studies of juvenile Chinook in the Ship Canal and Lake Union are planned in 2003. These studies should improve our understanding of juvenile Chinook behavior and life history in this area and our understanding of habitat improvements that may be needed there.

Project Name Project Cost or Estimate Habitat Requirement Status of Project Predator Food Project Description Avoidance Availability

Gas Works Park The shoreline of this Park offers Shoreline opportunities to restore shallow water Restoration habitats which may be used by juvenile outmigrants. No estimate available Potential

South Lake Union This project will result in reduction in Restoration of the Riparian Shoreline overwater coverage and installa-tion of shallow littoral habitat vegetation Improvements light prisms. The pier and docks may provide increased access to the shallow $2,100,000 water below by increasing the light Underway penetrating beneath the over-water structures. Preservation of the existing cove at the south west corner will be beneficial.

4041 Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System .Methodsforalteringthebalancebetween 6. Impactofwaterqualityandsedimenton 5. Whetherfoodavailabilityisafactorof 4. Theroleofwoodydebrisandother 3. Theroleofoverwaterstructures(docksand 2. Overallhabitatusebyjuveniles 1. Key researchandassessmentissuesinclude: Addressing Uncertainties and avian)tofavorChinook. juvenile Chinookandtheirpredators(fish juveniles. tors arehavingasignificantimpact. decline inthelake,andwhethercompeti- juveniles. structural complexityinpredationon predation onjuveniles. piers) astheyinfluencepreyavailabilityand 42 41 Hansen, L.,T.Georgianna,D.Houck,J.Frodge. Greater LakeWashingtonTechnicalCommittee. Fresh, K.,E.Warner,R.Tabor,D.Houck.2000. Fayram, A.H.1996.Impactsoflargemouthbass Dillion, F.1993.LakeUnion:BaselineEnviron- DeVries, P.2000.PITtaggingofJuvenileSalmon Cubbage, J.1992.Surveyofcontaminantsin Collias, E.andG.Seckel.1954.LakeWashington Literature Cited Services. Seattle,WA. review. KingCountyDept.Metropolitan 1994. LakeUniondatacomp-ilationand of salmonids.202pp. habitat factorsthatcontributetothedecline 2001. Draftreconnaissanceassessment– Wastewater TreatmentDivision,Nov.2000. with ultrasonictelemetry.KingCounty- watershed in1998and1999asdetermined Salmon spawningintheLakeWashington Migratory behaviorofadultChinook ton. Seattle,WA. ton. Mastersthesis.UniversityofWashing- tions ofjuvenilesalmonidsinLakeWashing- ( ( 1993. tor CSOControlProject,METRO,Jan. mental Characterization.UniversityRegula- of Engineers,Nov.2000. 2000 PilotStudyResults.U.S.ArmyCorps Smolts intheLakeWashingtonBasin:Year Olympia, Washington.72p. and GroundwaterInvestigationsSection. tory ServicesProgram:Toxics,Compliance, Environmental InvestigationsandLabora- Northwest RegionalOffice.Preparedby Washington DepartmentofEcology, Deborah North,UrbanBayActionTeam, Canal, andPortageBay).Preparedfor waters (SalmonBay,LakeWashingtonShip sediments inLakeUnionandadjoining Project NR083012,Apr.1954 of NavalResearch,ContractN8onr-520/III, Ship CanalData,SpecialReport#2,Office Micropterus dolomieui Micropterus salmoides ) andsmallmouthbass ) predationonpopula- Seattle’s Aquatic Environments: Lake Union/Lake Washington Ship Canal System

Herrera Environmental Consultants, and Brown Smith, V. and T. Thompson 1927. Salinity of the and Caldwell Consultants. 1994. Lake Lake Washington Ship Canal, Bulletin No. Union water quality/environmental assess- 41, University of Washington Engineering ment project. Executive and technical Experimental Station, May 1, 1927. summary (Vol. 1), project report (Vol. 2), Tabor, R. and B. Footen 2000. Predation of and stormwater and basin maps (Vol. 3). juvenile salmon by littoral fishes in the Lake Herrera Environmental Consultants, Seattle, Washington - Lake Union Ship Canal, Washington. preliminary result, King County - Wastewa- Houck, D. 2001. Unpublished Data, King County- ter Treatment Division, Nov. 2000. Wastewater Treatment Division, January Tomlinson, R., et.al., A baseline study of the water 2001. quality, sediments, and biota of Lake Union, Kahler, T., M. Grassley, and D. Beauchamp. 2000. METRO, Mar. 1977. A summary of the effects of bulkheads, piers Warner, E.J., and K.L. Fresh.1998. Technical and other artificial structures and shorezone review draft: Lake Washington Chinook development on ESA-listed salmonids in salmon recovery plan. Muckleshoot Indian lakes. Final report prepared for the City of Tribe and Washington Department of Fish Bellevue. and Wildlife. March 25, 1998. 141pp. Metro, 1993. Lake Union data compilation and Washington Department of Ecology. 2000. review. Municipality of Metropolitan Washington Department of Ecology 303d Seattle, Seattle, Washington. Prepared by list at: www.ecy.wa.gov/programs/wq/ Lisa Hansen, Primary Investigator, with 303d/1998_by_wrias.html Tom Georgianna, Doug Houck and Jonathon Frodge. Publication 851. Weitkamp, D., G. Ruggerone, L. Sacha, J. Howell, and B. Bachen. 2000. Factors affecting Parametrix, Inc. 1992. Lake Union capping Chinook populations, background report. feasibility study. Report prepared for City Prepared by Parametrix Inc., Natural of Seattle Planning Department. July 31, Resources Consultants, and Cedar River 1992. Associates for the City of Seattle, June 2000. Serdar, D., J. Cubbage, & D. Rogowski. 2000. 224 p. Concentrations of chemical contaminants Weatherbee, P. and D. Houck. 2000. Reconnais- and bioassay response to sediments in sance analysis of water quantity and quality Salmon Bay, Seattle: Results of Phase III trends in the Lake Washington watershed. Sampling, WDOE, Publication No. 00-03- King County - Wastewater Treatment 053, Dec. 2000. Division, Nov. 2000.

4243