City of Seattle State of the Waters 2007 Volume II: Small Lakes
State of the Waters 2007 Volume II Table of Contents
Part 1 Introduction ...... 1 Understanding the State of Seattle Waters...... 1 Contents of the State of the Waters Report...... 2 Overview of Seattle-Area Water Bodies...... 3 Watercourses and Streams ...... 3 Lakes...... 3 Estuaries...... 4 Marine Ecosystems...... 4
Part 2 A Brief Primer on Lake Ecosystems...... 7 Lake Ecosystem Processes ...... 7 Trophic Status and Eutrophication...... 8 7KHUPDO6WUDWL¿FDWLRQ ...... 9 Lake Zonation...... 10 Disruptions to Lake Ecosystems...... 12 Altered Hydrology...... 13 Water Quality...... 13 Sediment Quality ...... 14 Sediment Dynamics...... 14 Shoreline Connectivity ...... 14 Nonnative Species ...... 15
Part 3 Assessing the State of the Waters ...... 17 Water and Sediment Quality Assessment Methods ...... 17 Water Quality Indicators...... 17 Data Compilation...... 18 Data Quality Assurance Review ...... 19 Data Analysis...... 20 Habitat Assessment Methods...... 24
Part 4 Conditions in Seattle’s Small Lakes...... 25 Bitter Lake ...... 25 Water and Sediment Quality Conditions ...... 27 Habitat Conditions...... 33 Green Lake ...... 34 Water Quality Conditions ...... 36 Sediment Quality Conditions...... 40 Habitat Conditions...... 43
Table of Contents i City of Seattle State of the Waters 2007 Volume II: Small Lakes Haller Lake ...... 48 Water Quality Conditions ...... 50 Habitat Conditions...... 51
Part 5 Small Lakes Comparison and Conclusions ...... 53 Water and Sediment Quality Conditions ...... 54 Habitat Conditions...... 55
Part 6 References and Glossary ...... 57 References and Information Sources...... 57 Glossary of Terms...... 61
ii Table of Contents City of Seattle State of the Waters 2007 Volume II: Small Lakes
Tables
7DEOH 8VHVDQGEHQH¿WVRI6HDWWOHODNHVDQGZDWHUTXDOLW\LQGLFDWRUVRIODNHFRQGLWLRQV...... 18 7DEOH :DWHUTXDOLW\GDWDVRXUFHVIRU6HDWWOH¶VVPDOOODNHV...... 19 7DEOH %HQH¿FLDOXVHGHVLJQDWLRQVDSSOLFDEOHWR6HDWWOH¶VVPDOOODNHVXQGHUVWDWH ZDWHUTXDOLW\VWDQGDUGV ...... 21 7DEOH 7URSKLFVWDWHLQGH[YDOXHVXVHGWRDVVHVVODNHZDWHUTXDOLW\FRQGLWLRQV...... 22 Table 5. Bitter Lake metals concentrations sampled during a storm event compared to human health risk criteria...... 29 Table 6. Bitter Lake organic compounds detected in stormwater samples...... 29 Table 7. Bitter Lake sediment metals concentrations compared to freshwater sediment guidelines...... 30 Table 8. Bitter Lake sediment organic compounds concentrations compared to freshwater sediment guidelines...... 31 7DEOH *UHHQ/DNHZDWHUTXDOLW\GDWDIRU0D\±6HSWHPEHU...... 38 7DEOH*UHHQ/DNHVXPPHUIHFDOFROLIRUPEDFWHULDOHYHOV ± ...... 39 Table 11. Green Lake sediment metals concentrations compared to freshwater sediment guidelines...... 41 Table 12. Green Lake sampling stations with exceedances of freshwater sediment guidelines...... 42 Table 13. Green Lake sediment organic compounds concentrations compared to freshwater sediment guidelines...... 44-45 Table 14. Haller Lake drainage sample results from Meridian storm drain compared to other Seattle stormwater data...... 51 7DEOH&RPSDULVRQVRIZDWHUTXDOLW\DQGVHGLPHQWTXDOLW\FRQGLWLRQVLQ6HDWWOH¶V small lakes...... 53 7DEOH/LVWLQJVRI6HDWWOH¶VVPDOOODNHVDVWKUHDWHQHGRULPSDLUHGZDWHUERGLHV under Clean Water Act Section 303(d)...... 54
Figures Figure 1. Seattle small lakes...... 5 Figure 2. Conceptual model of oligotrophic and eutrophic lake ecosystems...... 8 Figure 3. Conceptual model of the seasonal thermocline in lakes...... 9 Figure 4. Bitter Lake...... 26 )LJXUH %LWWHU/DNHZDWHUTXDOLW\PRQLWRULQJGDWDVXPPDU\IRU ± ...... 27 Figure 6. Green Lake...... 35 )LJXUH *UHHQ/DNHVXPPHUIHFDOFROLIRUPEDFWHULDOHYHOV ± ...... 39 Figure 8. Haller Lake...... 49 )LJXUH +DOOHU/DNHZDWHUTXDOLW\PRQLWRULQJGDWDVXPPDU\IRU ± ...... 50
Table of Contents iii City of Seattle State of the Waters 2007 Volume II: Small Lakes
State of the Waters 2007 Part 1 Introduction
Understanding the State of Seattle Waters
7KH6WDWHRIWKH:DWHUVUHSRUWSUHSDUHGE\ 6HDWWOH3XEOLF8WLOLWLHV 638 GHVFULEHVWKH FXUUHQWK\GURORJLFFKHPLFDOSK\VLFDODQG ELRORJLFDOFRQGLWLRQVLQZDWHUFRXUVHVODNHV and shorelines located within the city limits RI 6HDWWOH 7KHVH FRQGLWLRQV GH¿QH WKH overall watershed health and the ability of city watersheds to perform critical functions DQGSURYLGHVHUYLFHVVXFKDV¿OWHULQJZDWHU PRGHUDWLQJÀRRGVDQGFDSWXULQJVHGLPHQW %DVHGRQDQXPEHURIUHVHDUFKPRQLWRULQJ DQGDVVHVVPHQWUHSRUWVWKLVLQIRUPDWLRQKDV been collectively compiled and organized IRUWKH¿UVWWLPHWREHUHDGLO\DFFHVVLEOHWR City of Seattle staff and interested citizens. Downtown Seattle from Elliott Bay (photo by Bennett)
,QWHUFRQQHFWHGQHVV EHWZHHQ WHUUHVWULDO DQG DTXDWLF HQYLURQPHQWV LV DPRQJ WKH PRVW LPSRUWDQW FRQFHSWVIRUPDQDJLQJZDWHUFRXUVHVODNHVHVWXDULHVDQGPDULQHHQYLURQPHQWV(YROYLQJZDWHUVKHG FKDUDFWHULVWLFVFDQOHDGWRLPSDFWVLQQHDUE\DQGQRWVRQHDUE\DUHDVVRPHWLPHVZLWKXQLQWHQGHGRU XQH[SHFWHGFRQVHTXHQFHV7KHXQSUHGLFWDELOLW\RILPSDFWVRQWKHVHFRQQHFWLRQVRIWHQFUHDWHVGLI¿FXOW FKDOOHQJHV LQ PDQDJLQJ ODQG GUDLQDJH GHYHORSPHQW DQG RWKHU ZDWHUVKHG XVHV ZLWKRXW OHDGLQJ WR DGYHUVHHIIHFWVRQWKHHFRV\VWHPDVDZKROH+HQFHWKHUHLVDQHHGWRLQWHJUDWHPDQDJHPHQWDQG stewardship across a watershed at many levels of action—from pesticide use in residential landscaping WRVWRUPZDWHUPDQDJHPHQWLQODUJHVKRSSLQJPDOOV)RUZDWHUUHVRXUFHVWKLVPHDQVORRNLQJDWRXU DFWLRQVRQODQGDQGXQGHUVWDQGLQJKRZWKRVHDFWLRQVDIIHFWFRQGLWLRQVLQRXUZDWHUFRXUVHVODNHVDQG 3XJHW6RXQG:LWKLQ6HDWWOHLQWHJUDWHGZDWHUVKHGPDQDJHPHQWLVDGHOLFDWHEDODQFHEHWZHHQGHVLUHG KXPDQODQGXVHVDQGHTXDOO\GHVLUHGHFRORJLFDOKHDOWK
7KH&LW\RI6HDWWOHLVFRPPLWWHGWRUHVWRULQJSURWHFWLQJDQGHQKDQFLQJLWVZDWHUERGLHVDQGLQVSLULQJ FLWL]HQVDQGEXVLQHVVHVWRGROLNHZLVH,Q0D\RU*UHJ1LFNHOVLVVXHGDQH[HFXWLYHRUGHUWRFUHDWH DFLW\ZLGHSURJUDPWKDWZRXOGEDODQFHXUEDQJURZWKDQGGHYHORSPHQWZLWKWKHEHQH¿WVRIUHVWRULQJ critical water resources. The Restore Our Waters initiative is a long-term effort to protect and restore DTXDWLFKDELWDWLPSURYHZDWHUTXDOLW\DQGPDQDJHVWRUPZDWHUGUDLQDJH6HDWWOH¶VLQYHVWPHQWVXQGHU this program are to be guided by clear goals that are based in science and tracked through time to show SURJUHVV7KLVUHSRUW6WDWHRIWKH:DWHUVLVDFULWLFDO¿UVWVWHSLQVHWWLQJWKHVHJRDOVE\GRFXPHQWLQJ WKHEDVHOLQHFRQGLWLRQVRI6HDWWOH¶VVXUIDFHZDWHUERGLHV
Part 1 Introduction 1 City of Seattle State of the Waters 2007 Volume II: Small Lakes
,QDGGLWLRQWRGRFXPHQWLQJ6HDWWOH¶VFXUUHQW RUEDVHOLQHFRQGLWLRQVWKLVUHSRUWVHUYHVDV an important foundation step for other city efforts and activities that will affect the health of Seattle water bodies in the coming years. The assessment provided in this document was used to develop a companion UHSRUW 6FLHQFH )UDPHZRUN IRU (FRORJLFDO +HDOWK 638DQG6WLOOZDWHU6FLHQFHV which outlines what healthy urban water ERGLHV FRXOG ORRN OLNH LGHQWL¿HV SRWHQWLDO SDWKZD\V IRU LPSURYHPHQW DQG GH¿QHV D VWUXFWXUH IRU PHDVXULQJ HFRORJLFDO KHDOWK EDVHG RQ WKH EHVW VFLHQWL¿F LQIRUPDWLRQ Downtown Seattle across Lake Union (photo by Bennett) about urban watercourses.
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Contents of the State of the Waters Report
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$%ULHI3ULPHURQ/DNH(FRV\VWHPVGHVFULEHVKRZK\GURORJ\ZDWHUTXDOLW\DQGSK\VLFDOFRQGLWLRQV work together to shape lake habitat and the plant and animal communities that use them.
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2 Part 1 Introduction City of Seattle State of the Waters 2007 Volume II: Small Lakes
Overview of Seattle-Area Water Bodies
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Watercourses and Streams
6XUIDFHZDWHULQ6HDWWOHLVWUDQVSRUWHGWRUHFHLYLQJZDWHUERGLHVE\DFRPSOH[V\VWHPRISLSHVGLWFKHV FXOYHUWVDQGRSHQVWUHDPDUHDV)RUFODULW\WKH&LW\RI6HDWWOHKDVDGRSWHGWKHZRUG³ZDWHUFRXUVH´WR UHIHUWRWKLVQHWZRUN³:DWHUFRXUVH´PHDQVWKHURXWHFRQVWUXFWHGRUIRUPHGE\KXPDQVRUE\QDWXUDO SURFHVVHVJHQHUDOO\FRQVLVWLQJRIDFKDQQHOZLWKEHGEDQNVRUVLGHVLQZKLFKVXUIDFHZDWHUVÀRZ :DWHUFRXUVHVLQFOXGHVPDOOODNHVERJVVWUHDPVFUHHNVDQGLQWHUPLWWHQWDUWL¿FLDOFRPSRQHQWV LQFOXGLQJ ditches and culverts) but do not include receiving waters (Seattle Municipal Code 22.801.240).
9ROXPH,RIWKH6WDWHRIWKH:DWHUVUHSRUWIRFXVHVRQWKRVHSDUWVRIZDWHUFRXUVHVWKDWDUHQRWLQFXOYHUWV LQSDUWLFXODURQZDWHUFRXUVHVHJPHQWVZKHUHWKHUHLVDQRSHQVWUHDPFKDQQHOZLWKQDWXUDOKDELWDW7KH &LW\RI6HDWWOHFRQWDLQV¿YHPDMRUZDWHUFRXUVHV )DXQWOHUR\&UHHN/RQJIHOORZ&UHHN3LSHU¶V&UHHN 7D\ORU&UHHNDQG7KRUQWRQ&UHHN
7KHVH¿YHZDWHUFRXUVHVKDYH\HDUURXQGÀRZDQGVXSSRUWVDOPRQDQGWURXW7KHUHDUHDOVRQXPHURXV VPDOOHUZDWHUFRXUVHVWKDWGRQRWVXSSRUWVDOPRQDQGPD\KDYHRQO\LQWHUPLWWHQWÀRZLQFOXGLQJ0DSHV &UHHN3XJHW&UHHN Lakes Lakes are formed in topographic depressions that retain fresh ZDWHU/DNHVUHFHLYHLQÀRZIURPWKHLUVXUURXQGLQJZDWHUVKHGV WKURXJKULYHUVZDWHUFRXUVHVRYHUODQGDQGVXEVXUIDFHÀRZ and—in developed areas—from drainage pipes. Water W\SLFDOO\H[LWVDODNHWKURXJKDZDWHUFRXUVHRUULYHUDOWKRXJK WKH RXWÀRZV RI PRVW ODNHV LQ 6HDWWOH KDYH EHHQ FKDQQHOHG into constructed drainage systems. Lakes can range in size IURPDIHZDFUHVWRPDQ\VTXDUHPLOHV3ODQWVDQGDQLPDOV that depend on lake environments inhabit shallow-water and deep-water areas and interact in a complex food web. Green Lake (photo by Bennett) Part 1 Introduction 3 City of Seattle State of the Waters 2007 Volume II: Small Lakes 6HDWWOHFRQWDLQVWKUHHVPDOOODNHV +DOOHU/DNH%LWWHU/DNHDQG*UHHQ/DNHVKRZQLQ)LJXUH7KHVH lakes are the focus of this volume (Volume II) of the State of the Waters report. The city also contains WZRODUJHUODNHV/DNH8QLRQDQGSDUWVRI/DNH:DVKLQJWRQ/DNH:DVKLQJWRQLVWKHVHFRQGODUJHVW QDWXUDOODNHLQ:DVKLQJWRQVWDWH7KHVHODUJHUODNHVZLOOEHGHVFULEHGLQDVXEVHTXHQWYROXPH Estuaries (VWXDULHVDUHDUHDVZKHUHIUHVKZDWHUDQGPDULQHZDWHUPL[RQWKHLQWHUIDFHEHWZHHQDQRFHDQDQGD ZDWHUFRXUVHRUULYHU7KHVHHFRV\VWHPVDUHVKDSHGE\VDOWZDWHUWLGDOÀXFWXDWLRQVDQGIUHVKZDWHUÀRZV Plants and animals that inhabit these environments must respond to rapidly changing salinity levels and ÀRZFRQGLWLRQV(VWXDULHVDUHQXUVHU\DUHDVIRUPDQ\¿VKDQGELUGVSHFLHV The Duwamish River estuary primarily serves as the meeting point for Puget Sound and the Green/ 'XZDPLVKULYHUV\VWHPOLHVZLWKLQWKH&LW\RI6HDWWOH7KHFLW\DOVRFRQWDLQVWKHHVWXDU\RIWKH/DNH :DVKLQJWRQZDWHUVKHGDWWKH+LUDP0&KLWWHQGHQ/RFNV WKH%DOODUG/RFNV ZKLFKZDVFUHDWHGE\ UHGLUHFWLQJWKHODNHRXWOHWLQWKHHDUO\ V7KH/DNH:DVKLQJWRQHVWXDU\FUHDWHGE\PDQPDGH FKDQJHVSURYLGHVOLPLWHGHVWXDULQHKDELWDW Marine Ecosystems 0DULQHZDWHUVDUHDUHDVRIVDOLQHZDWHUW\SLFDOO\FRQQHFWHGWRRUSDUWRIWKHRFHDQ0DULQHV\VWHPV DUHVKDSHGE\WLGHVFXUUHQWVVHDÀRRUVKDSHDQGVXQOLJKW3ODQWVDQGDQLPDOVWKDWLQKDELWPDULQH HQYLURQPHQWVDUHDGDSWHGWRKLJKVDOLQLW\FRQGLWLRQVDQGWKHLUXVHRIKDELWDWVFDQYDU\DFURVVZDWHU GHSWKV0DQ\VSHFLHVDUHDGDSWHGWRSHULRGVRILQXQGDWLRQDQGH[SRVXUHZLWKÀXFWXDWLQJWLGHV 6HDWWOHVLWVDORQJPLOHVRI3XJHW6RXQGPDULQHVKRUHOLQH:KLOH3XJHW6RXQGLVDVDOWZDWHUERG\ it is actually considered an estuary because of the numerous tributary rivers that dilute salinities in the VRXQGWRORZHUOHYHOVWKDQW\SLFDOO\IRXQGLQWKH3DFL¿F2FHDQ 4 Part 1 Introduction City of Seattle State of the Waters 2007 Volume II: Small Lakes Seattle Small Lakes The City of Seattle Bitter Lake Puget Sound Piper's Creek Haller Lake Thornton Creek Lake Washington Green Lake Legend Watercourse Open Channel (Stream) Lake Culvert City Boundary Union Major Arterial Major Watershed Boundary Figure 1 Figure 1. Seattle small lakes. Part 1 Introduction 5 City of Seattle State of the Waters 2007 Volume II: Small Lakes State of the Waters 2007 Part 2 A Brief Primer on Lake Ecosystems Lake Ecosystem Processes Bitter Lake (photo by Bennett) $TXDWLFKDELWDWVDUHSURGXFHGE\WKHLQWHUDFWLRQRISK\VLFDOFKHPLFDODQGELRORJLFDOSURFHVVHVWKDW RFFXUERWKLQDQDTXDWLFV\VWHPDQGLQDGMDFHQWDUHDVZLWKLQDZDWHUVKHG 1DLPDQHWDO 7KHVH HFRV\VWHPSURFHVVHVIRUPDTXDWLFKDELWDWVWKDWSURYLGHFHUWDLQHVVHQWLDOIXQFWLRQVIRURUJDQLVPVVXFK DVUHIXJHKDELWDWIRU¿VKRUIRUDJLQJKDELWDWIRUELUGV7KHXVHRIKDELWDWE\SODQWVDQGDQLPDOVLV DUHVSRQVHWRG\QDPLFHFRV\VWHPSURFHVVHVDQGGLVUXSWLRQVWRWKHVHSURFHVVHVZKHWKHUQDWXUDORU KXPDQLQGXFHGFDQDOWHUWKHGLVWULEXWLRQDQGEHKDYLRURIELRWD .DUU 7KH ZDWHUVKHG RU GUDLQDJH EDVLQ RI D ODNH LV D FULWLFDO component in lake processes. Lake ecosystems are shaped by the hydrology and topography of the watershed and the lake EDVLQDVZHOODVE\ZDYHHQHUJ\FXUUHQWVDQGOLJKW :HW]HO 1983; Horne and Goldman 1994). The drainage basin regulates WKHGHOLYHU\RIZDWHURUJDQLFPDWWHUVXEVWUDWHQXWULHQWVDQG FRQWDPLQDQWVWRWKHODNH8SODQGDUHDVVWRUHDQG¿OWHUUDLQIDOO FRQWUROOLQJÀRZVWKDWGLVFKDUJHWRWKHODNHDQGPRGHUDWLQJWKH introduction of nutrients and contaminants (Ziemer and Lisle Haller Lake (photo by Bennett) 1998). /DNHVFRQWDLQOHVVWKDQSHUFHQWRIDOOWKHZDWHURQHDUWK\HWWKH\KROGRYHU SHUFHQWRIWKH OLTXLGIUHVKZDWHUWKDWLVDYDLODEOHRQWKHVXUIDFH%HFDXVHODNHVDUHWKHJHRJUDSKLFHQGSRLQWVIRUWKH SK\VLFDODQGFKHPLFDOLQSXWVLQPDQ\ZDWHUVKHGVDODNHDQGLWVZDWHUVKHGDUHRIWHQFRQVLGHUHGDVLQJOH ecosystem (Likens 1985). Part 2 A Brief Primer on Lake Ecosystems 7 City of Seattle State of the Waters 2007 Volume II: Small Lakes Trophic Status and Eutrophication A lake is generally placed into one of three categories based on LWV SURGXFWLYLW\ RU QXWULHQW ULFKQHVV 7KHVH FDWHJRULHV ZKLOH Lake trophic status is a VRPHZKDW LPSUHFLVH IDOO RQWR D FRQWLQXXP DQG FDQ JLYH DQ measure of the nutrient status, LQGLFDWLRQRIDODNH¶VUHODWLYHWURSKLFVWDWXV2QRQHHQGRIWKH or eutrophication, of a lake. Degrees of eutrophication, FRQWLQXXP DUH ROLJRWURSKLF ODNHV W\SLFDOO\ ODUJH RIWHQ GHHS in increasing levels of KDYLQJ FROG FOHDU ZDWHU DQG D URFN\ RU VDQG\ VKRUHOLQH DQG nutrient enrichment, typically substrate. Oligotrophic lakes contain very low concentrations range from oligotrophic, to of the essential nutrients for plant growth. Few nutrients enter mesotrophic, to eutrophic, to hypereutrophic. WKH ODNH IURP WKH ZDWHUVKHG DQG WKRVH WKDW GR DUH GLOXWHG E\ WKH ODUJH YROXPH RI ZDWHU 7KH SURGXFWLRQ RI SK\WRSODQNWRQ DTXDWLFZHHGVDQGRWKHUSODQWVLVYHU\ORZLQWKHVHODNHVDQGWKHSRSXODWLRQVRI]RRSODQNWRQDQG¿VK DUHVPDOO7KHUHLVYHU\OLWWOHRUJDQLFPDWWHUVHWWOLQJWRWKHODNHERWWRPDQGWKLVNHHSVEDFWHULDDWORZ OHYHOV:LWKVRIHZSODQWVDQGEDFWHULDR[\JHQFRQVXPSWLRQLVPLQLPDODQGROLJRWURSKLFODNHVRIWHQ are rich in dissolved oxygen from top to bottom. 2QWKHRWKHUHQGRIWKHFRQWLQXXPDUHHXWURSKLFODNHVZKLFKDUHKLJKO\SURGXFWLYHDQGULFKLQQXWULHQWV VKDOORZZLWKVRIWVXEVWUDWHVDQGRIWHQFRQWDLQFORXG\JUHHQLVKZDWHU3ODQWJURZWKFDQEHYHU\KLJK HVSHFLDOO\QHDUWKHZDWHUVXUIDFHZLWKDUHVXOWDQWLQFUHDVHLQWKHGHQVLWLHVRI]RRSODQNWRQDQG¿VK0XFK RIWKHRUJDQLFPDWWHUDFFXPXODWHVRQWKHODNHERWWRPSURYLGLQJIRRGIRUKLJKQXPEHUVRIEDFWHULD$V DUHVXOWWKHZDWHULQHXWURSKLFODNHVLVRIWHQGHSOHWHGRIR[\JHQQHDUWKHERWWRP )LJXUH low nutrient input high nutrient input low productionepilimnion high production thermocline hypolimnion high oxygen demand low oxygen demand per unit volume per unit volume OLIGOTROPHIC EUTROPHIC Figure 2. Conceptual model of oligotrophic and eutrophic lake ecosystems. 8 Part 2 A Brief Primer on Lake Ecosystems City of Seattle State of the Waters 2007 Volume II: Small Lakes Lakes that have intermediate productivity lie between oligotrophic and eutrophic on the continuum and are categorized as mesotrophic. Many factors can shape WKHVH LQWHUPHGLDWH FRQGLWLRQV LQFOXGLQJ WKH YROXPH GHSWKDQGDJHRIWKHODNHDVZHOODVFOLPDWHFKDQJH $V D JHQHUDO UXOH ODNHV QDWXUDOO\ EHFRPH PRUH HXWURSKLF RYHU ORQJ SHULRGV RI WLPH DV VHGLPHQWV slowly accumulate to make the lake shallower and the nutrients become more concentrated. Under QDWXUDOFRQGLWLRQVDPHVRWURSKLFODNHZLOOQRWEHFRPH ROLJRWURSKLFZLWKRXWPDMRUFKDQJHVLQFOLPDWHSDWWHUQV or watershed geomorphology. The rate of eutrophication can be greatly affected by human disruption of ecological processes within a lake basin. Lakes collect fertilizers used throughout their ZDWHUVKHGV DQG SHRSOH KLVWRULFDOO\ KDYH XVHG ODNHV as convenient depositories for wastes and sewage. 7KH UHVXOWLQJ KXPDQLQGXFHG LQFUHDVH LQ QXWULHQWV particularly nitrogen and phosphorus (sometimes called cultural eutrophication) can lead to hypereutrophic conditions. Lakes that undergo very rapid enrichment can experience extreme shifts in dissolved oxygen FRQFHQWUDWLRQVGXHWRSODQWGHFRPSRVLWLRQOHDGLQJWR ¿VKNLOOVDQGVKLIWVLQWKHVSHFLHVFRPSRVLWLRQRIWKH ELRWD/LPLWLQJWKHDPRXQWRIQXWULHQWVSKRVSKRUXVLQ Bitter Lake is considered a mesotrophic SDUWLFXODUFDQUHWXUQDODNHWRPHVRWURSKLFFRQGLWLRQV lake (photo by Bennett) 7KHUPDO6WUDWL¿FDWLRQ The temperature throughout the water column in a lake is affected water temperature by seasonal changes in solar radiation and wind activity. During WKH ODWH VSULQJ ZDWHU QHDU WKH VXUIDFH JUDGXDOO\ KHDWV XS DQG winter summer dissolved oxygen levels rise due to wind mixing and increased plant production. This warming and blending results in a layer thermocline of well-oxygenated water at the surface that is less dense than WKHFRROXQPL[HGOD\HUEHORZLW7KHGHSWKRIWKLVVXUIDFHOD\HU WKHHSLOLPQLRQGHSHQGVRQWKHLQWHQVLW\RIVXQOLJKWFODULW\RIWKH ZDWHUDQGVWUHQJWKRIWKHZLQG depth 7KHGHHSHUOD\HURUK\SROLPQLRQVWD\VFRRODQGGHQVHDQGLVSRRUO\ oxygenated due to the lack of photosynthesis and the decomposition Figure 3. Conceptual model RIRUJDQLFPDWWHUE\EDFWHULD$VWKHVXPPHUSURJUHVVHVWKHVHWZR of the seasonal OD\HUVEHFRPHLQFUHDVLQJVWUDWL¿HGDVWKHWHPSHUDWXUHGLIIHUHQWLDO thermocline in ZLGHQV%HWZHHQWKHVHOD\HUVDWKHUPRFOLQHGHYHORSVDUHJLRQ lakes. GH¿QHGE\DUDSLGGHFUHDVHLQWHPSHUDWXUH )LJXUH Part 2 A Brief Primer on Lake Ecosystems 9 City of Seattle State of the Waters 2007 Volume II: Small Lakes $VVXUIDFHWHPSHUDWXUHVFRROLQWKHIDOOWKHZDWHULQWKHHSLOLPQLRQEHFRPHVGHQVHUDQGVLQNV$LGHGE\ IDOOZLQGVWKHHQWLUHZDWHUFROXPQLQDODNHFDQPL[$VWKHWKHUPRFOLQHGLVLQWHJUDWHVWKHWHPSHUDWXUH GHQVLW\DQGGLVVROYHGR[\JHQLQWKHODNHDOOEHFRPHPRUHXQLIRUP7KHFRORUDQGVPHOORIDODNHFDQ change as nutrients and decaying organic matter are cycled up to the surface. This phenomenon is known DVIDOOWXUQRYHU/DNHVWKDWLFHRYHULQWKHZLQWHUH[SHULHQFHLQYHUVHVWUDWL¿FDWLRQZKHUHWKHFROGHVW ZDWHUQHDUWKHLFHLVDFWXDOO\VOLJKWO\OHVVGHQVHWKDQWKHUHVWRIWKHODNHZDWHUDQGWKHLFHSUHYHQWVZLQG PL[LQJ$VWKHLFHEUHDNVDSDUWZLWKZDUPLQJZHDWKHUVSULQJWXUQRYHUFDQRFFXU/DNHVLQWKH3XJHW Sound region generally do not ice over and tend to be continually mixed during the winter. Lake Zonation 7KHSK\VLFDOSURFHVVHVRXWOLQHGDERYHSOD\RXWLQWKHSHODJLFEHQWKLFOLWWRUDODQGULSDULDQ]RQHVRID ODNHZLWKSURFHVVHVDQGHFRORJLFDOLQWHUDFWLRQVLQRQH]RQHDIIHFWLQJWKRVHLQRWKHU]RQHV 6FKLQGOHU and Scheuerell 2002). These four ecological zones are described separately below. Pelagic Zone 7KHSHODJLF]RQHRIDODNHLVRSHQZDWHUZLWKRXWFRQWDFWZLWKWKHODNHERWWRPRUVKRUH +RUQHDQG Goldman 1994). Pelagic zone habitats change with water depth and do not vary substantially within DJLYHQZDWHUGHSWK 6FKLQGOHUDQG6FKHXHUHOO /LJKWOHYHOVZDWHUWHPSHUDWXUHVDQGFKHPLFDO FRQFHQWUDWLRQV HJGLVVROYHGR[\JHQQXWULHQWVVXFKDVQLWURJHQDQGSKRVSKRUXV FKDQJHIURPWKH VXUIDFHZDWHUVWRWKHGHSWKVRIWKHODNHLQSDUWLFXODUGXULQJWLPHVRIVWUDWL¿FDWLRQZKHQZDUPVXUIDFH waters become separated from cooler water at deeper depths. The penetration of light and occurrence of photosynthesis (primary production) follow and exacerbate the differences above and below the VWUDWL¿FDWLRQSRLQWLQWKHODNH LHWKHWKHUPRFOLQH 7KHVHIDFWRUVRIOLJKWQXWULHQWFRQFHQWUDWLRQV ZDWHUWHPSHUDWXUHVDQGVWUDWL¿FDWLRQVKDSHRSHQZDWHUKDELWDWDQGWKHUHIRUHDIIHFWWKHGLVWULEXWLRQRI organisms in the lake water column (Horne and Goldman 1994). 3ODQNWRQLF RUJDQLVPV ZKLFK DUH QRQPRELOH RU weak-swimming microscopic animals or plants WKDW ÀRDW DQG GULIW ZLWK ODNH FXUUHQWV GRPLQDWH the pelagic zone. Examples of plankton include EDFWHULD YLUXVHV SURWR]RD SK\WRSODQNWRQ LH VPDOOSODQWV ]RRSODQNWRQ LHVPDOODQLPDOV DQG early life stages of insects. An important process that occurs in the pelagic zone of lakes is nutrient SURFHVVLQJDVSODQNWRQLVWKHGULYLQJIRUFHLQWKH food web. Lake turnover is also important for WKLVSURGXFWLRQDVEHQWKLFODNHVHGLPHQWVSURYLGH nutrients for planktonic production (Schindler and Scheuerell 2002). Fish also inhabit this zone of the lake. The vertical differences in the water column RIWKHODNHDUHLPSRUWDQWIRUSURYLGLQJ¿VKUHIXJH Bitter Lake (photo by Bennett) and foraging habitats. 10 Part 2 A Brief Primer on Lake Ecosystems City of Seattle State of the Waters 2007 Volume II: Small Lakes Benthic Zone 7KHEHQWKLF]RQHLVWKHDUHDDVVRFLDWHGZLWKWKHODNHERWWRPLQERWKGHHSDQGVKDOORZZDWHUDUHDV Benthic habitats are associated with bottom substrates and can vary substantially across horizontal GLVWDQFHVDQGZDWHUGHSWK'LIIHUHQFHVLQKDELWDWDUHLQÀXHQFHGE\SK\VLFDOVWUXFWXUHVXFKDVVHGLPHQW W\SHVURFNVDTXDWLFSODQWVDQGZRRG\GHEULVDQGE\FKHPLFDOFRPSRQHQWVLQWKHVHGLPHQW 6FKLQGOHU and Scheuerell 2002). %HQWKLFKDELWDWVFRQWDLQDGLYHUVHDUUD\RIRUJDQLVPVWKDWYDU\GHSHQGLQJRQVWUXFWXUHDQGZDWHUGHSWKV ZKLFKLQWXUQLQÀXHQFHOLJKWOHYHOVDYDLODEOHIRUSKRWRV\QWKHVLVDQGRWKHUSULPDU\SURGXFWLRQ7KHVH RUJDQLVPVLQFOXGH¿VKDWWDFKHGDOJDHVKDOORZÀRDWLQJDOJDH LHPHWDSK\WRQ DTXDWLFSODQWV LH PDFURSKW\HVERWKDWWDFKHGWRVXEVWUDWHDQGÀRDWLQJ EDFWHULDSURWR]RDDTXDWLFLQVHFWVDQGRWKHU DTXDWLFLQYHUWHEUDWHV HJFUD\¿VK :LWKWKLVGLYHUVHDUUD\RIRUJDQLVPVEHQWKLFIRRGZHEVDUHUDWKHU FRPSOH[ WKH\FDQEHIXHOHGE\WKHVHWWOLQJRISHODJLFSODQNWRQE\EHQWKLFDOJDHSURGXFWLRQRUE\ WHUUHVWULDOEDVHGLQSXWV IURPWKHVXUURXQGLQJODQGHJULSDULDQDUHDV Nutrient processing and production in the benthic zone are important for the lake ecosystem. The EHQWKLF]RQHLVDOVRLPSRUWDQWLQSURYLGLQJUHIXJHDQGUHDULQJRSSRUWXQLWLHV$PSKLELDQVUHSWLOHV ELUGVDQGPDPPDOVFDQDOVREHSUHVHQWLQWKHEHQWKLF]RQHDOWKRXJKWKH\DUHPRUHW\SLFDOO\IRXQGLQ shallow littoral and riparian areas. Littoral Zone Littoral zones are the shallow DUHDVRIWKHODNHDGMDFHQWWRDQG associated with the lake shoreline. The littoral zone extends out to a depth where light levels are low enough to dramatically reduce photosynthesis (Wetzel 1983; Schindler and Scheuerell 2002). This zone is coupled closely with both the benthic and riparian ]RQHV ZKLFK SURYLGH DQG KHOS to regulate much of the physical VWUXFWXUH LH VXEVWUDWHV DQG woody debris) and chemical structure in the littoral zone. Bitter Lake shoreline and littoral zone (photo by Bennett) Riparian Zone 7KH ULSDULDQ ]RQH LV WKH DUHD DORQJ WKH ODNH VKRUHOLQH DQG VRPH SRUWLRQ RI WKH DGMDFHQW XSODQGV &ROOHFWLYHO\WKHOLWWRUDODQGULSDULDQDUHDVDUHWUDQVLWLRQ]RQHVEHWZHHQWKHWHUUHVWULDOZDWHUVKHGDQG WKHDTXDWLFHFRV\VWHPVRIWKHODNH 6FKLQGOHUDQG6FKHXHUHOO Part 2 A Brief Primer on Lake Ecosystems 11 City of Seattle State of the Waters 2007 Volume II: Small Lakes The littoral zone is occupied by the same VXLWH RI RUJDQLVPV DV WKH EHQWKLF ]RQH DOJDHDTXDWLFSODQWVDTXDWLFLQYHUWHEUDWHV DQG¿VKDPRQJRWKHUV7KHULSDULDQ]RQH contains more of the land-based animals and plants. Plants at the edge of the lake must be adapted to periods of inundation DQGH[SRVXUHDVODNHOHYHOVÀXFWXDWHDQG to wet soils such as in wetland conditions. Littoral zone food webs are based upon both in-water production from algae DQG SODQWV DQG WHUUHVWULDOEDVHG RUJDQLF inputs from upland plants (Schindler and Scheuerell 2002). The condition of the riparian and littoral zones is important for The riparian area around Haller Lake includes varying nutrient processing and production and for amounts of lawns, mature trees, and shrubs (photo by SURYLGLQJIRUDJLQJUHIXJHVSDZQLQJDQG Bennett) migration options. Disruptions to Lake Ecosystems 6HDWWOH¶V VPDOO ODNHV DUH VXEMHFW WR SUHVVXUHV related to development in the watershed and recreational and residential uses of the VKRUHOLQH$VZLWKZDWHUFRXUVHVGHYHORSPHQW LQWKHZDWHUVKHGFDQDOWHUWKHDPRXQWWLPLQJ and content of stormwater runoff to lakes. Shoreline and shallow-water habitat can be DIIHFWHG E\ DGMDFHQW ODQG XVHV DQG RQZDWHU XVHV:DWHUGHSHQGHQWXVHVVXFKDVUHFUHDWLRQ DQG ¿VKLQJ W\SLFDOO\ UHTXLUH GRFNV DQG SLHUV for boat access and moorage. Residential land owners often remove shoreline vegetation and install bulkheads and other forms of bank armoring to take advantage of water views and secure the property. Development along Bitter Lake (photo by Bennett) /DQGXVHSUDFWLFHVLQODNHZDWHUVKHGVDIIHFWULSDULDQDQGOLWWRUDOKDELWDWVWUXFWXUHOLJKWFRQGLWLRQV VHGLPHQWG\QDPLFVDQGZDWHUDQGVHGLPHQWTXDOLW\7KHW\SLFDOGLVUXSWLRQVWRODNHHFRV\VWHPVDUH GLVFXVVHGEHORZ¿UVWIRFXVLQJRQWKRVHWKDWDUHPRVWFRPPRQLQ6HDWWOHODNHV 12 Part 2 A Brief Primer on Lake Ecosystems City of Seattle State of the Waters 2007 Volume II: Small Lakes Altered Hydrology 7KHGHOLYHU\RIZDWHULQWRDODNHFRXSOHGZLWKWKHODNH¶VVL]HDQGRXWOHWGHWHUPLQHKRZORQJZDWHU VWD\VLQWKHODNHRUWKHUHVLGHQFHWLPHZKLFKLVVWURQJO\UHODWHGWRKRZQXWULHQWVDQGODNHSROOXWDQWV are processed and stored (Horne and Goldman 1994). The amount of water reaching a lake is affected by watershed runoff and discharge from watercourses and rivers that enter the lake. The amount and timing of water coming into the lake can be affected by detention or diversion of water for human FRQVXPSWLRQÀRRGFRQWUROQDYLJDWLRQLUULJDWLRQDQGLQGXVWULDOSXUSRVHV Water delivery is also affected by urbanization in the lake watershed. Urban development in upland DUHDV ZKLFK HQWDLOV YHJHWDWLRQ FOHDULQJ VRLO FRPSDFWLRQ DQG FRQVWUXFWLRQ RI URDGV DQG EXLOGLQJV increases the impervious surface area within watersheds. This in turn increases the volume and rate RIVWRUPZDWHUUXQRIIFDXVLQJKLJKZDWHUFRXUVHGLVFKDUJHRUKLJKGLUHFWGHOLYHU\RIZDWHUWRWKHODNH shoreline (Dunne and Leopold 1978; Arnold and Gibbons 1996; Poff et al. 1997). ,QDGGLWLRQFKDQJHVWRWKHODNHRXWOHWFDQDIIHFWODNHK\GURORJ\E\HLWKHULQFUHDVLQJRUGHFUHDVLQJ WKHYROXPHDQGUDWHRIZDWHUOHDYLQJWKHODNHV\VWHP7KLVLQWXUQDIIHFWVZDWHUOHYHOÀXFWXDWLRQVLQ WKHODNHZLWKUHVXOWLQJLPSDFWVRQULSDULDQDQGZHWODQGSODQWVWKDWYDU\LQWKHLUFDSDFLW\WRGHDOZLWK LQXQGDWLRQDQGH[SRVXUH)LQDOO\FKDQJHVLQODNHK\GURORJ\FDQDIIHFWVKRUHOLQHKDELWDWSDUWLFXODUO\ in the littoral and riparian zones. Hydrology also affects nutrient cycling and the basic productivity in the lake. Water Quality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¿VKVSHFLHV ELRORJLFDOSURFHVVHV +XPDQLQGXFHGFKDQJHVWRZDWHUTXDOLW\WKURXJKLQGXVWULDOHIÀXHQWVVHZHURYHUÀRZVDQGXUEDQUXQRII FDQDOWHUODNHZDWHUWHPSHUDWXUHVWXUELGLW\DQGR[\JHQFRQWHQWDVZHOODVQXWULHQWDQGFRQWDPLQDQW FRQFHQWUDWLRQV .DUU :HOFKDQG/LQGHOO )RULQVWDQFHWKHZDUPHUWHPSHUDWXUHVW\SLFDOO\ FDXVHG E\ VWRUPZDWHU LQSXWV RU DWPRVSKHULF ZDUPLQJ FDQ SURGXFH VKRUWWHUP LQFUHDVHV LQ ¿VK PHWDEROLVPWKDWPD\LQWXUQLQFUHDVHSUHGDWLRQ3UHGDWRU\¿VKQHHGWR¿QGPRUHSUH\WRPDLQWDLQWKHLU PHWDEROLVPDQGJURZ+RZHYHUWHPSHUDWXUHVDERYHGHJUHHV&HOVLXV & FDQEHFRPHVWUHVVIXOIRU VDOPRQLGVDQGFDQHYHQFDXVHPRUWDOLW\DERYH& :DWHUWHPSHUDWXUHSODQWUHVSLUDWLRQDQGELRORJLFDOGHFRPSRVLWLRQDUHDOVRLQYHUVHO\UHODWHGWRGLVVROYHG R[\JHQOHYHOVZKLFKSOD\DFULWLFDOUROHVXSSRUWLQJDTXDWLFRUJDQLVPVVXFKDVVDOPRQLGV6LPLODUO\ DONDOLQLW\S+ FRQGLWLRQV DQG QXWULHQW FRQFHQWUDWLRQV LQÀXHQFH ELRORJLFDO SURFHVVHV SDUWLFXODUO\ SK\WRSODQNWRQSURGXFWLRQ+LVWRULFDOO\WKHQDWXUDOEDFNJURXQGOHYHOVRIQXWULHQWVOLPLWHGJURZWKRI DOJDHLQODNHVWKURXJKPXFKRIWKH\HDU%\FRQWUDVWDUWL¿FLDOLQSXWVRIH[FHVVQXWULHQWVFDQQRZOHDG to an abundance of undesirable algal blooms in urban lakes. Part 2 A Brief Primer on Lake Ecosystems 13 City of Seattle State of the Waters 2007 Volume II: Small Lakes )LQDOO\DOOFRPSRQHQWVRIZDWHUTXDOLW\FDQEHDIIHFWHGE\WKHFRQWDPLQDQWVLQXUEDQUXQRII HJ IHUWLOL]HUVSHVWLFLGHVDQGYHKLFXODUSROOXWDQWV DQGE\GLVFKDUJHVIURPUHFUHDWLRQDOLQGXVWULDODQG FRPPHUFLDODFWLYLWLHV HJKHDY\PHWDOVGLR[LQVDQG3&%V Sediment Quality A portion of the contaminants that can enter lakes through direct discharges and stormwater runoff are SUHVHQWDVSDUWLFXODWHPDWWHURUSROOXWDQWVERXQGWRSDUWLFXODWHPDWWHU7KHVHSROOXWDQWVW\SLFDOO\VHWWOH WRWKHODNHERWWRPFRQWDPLQDWLQJWKHVHGLPHQWVRIWKHEHQWKLF]RQH,QDGGLWLRQWUHDWHGOXPEHULQ GRFNVDQGSLHUVPD\LQWURGXFHRUJDQLFFRQWDPLQDQWV HJFUHRVRWH LQWRODNHVHGLPHQWV 2QFHSUHVHQWLQODNHVHGLPHQWVFRQWDPLQDQWVPD\EUHDNGRZQVORZO\RULQVRPHFDVHVQRWDWDOO6RPH contaminants enter the food web through the plants and animals that reside in the bottom sediments. 2QFHLQWKHIRRGZHEWKHVHFRQWDPLQDQWVFDQELRDFFXPXODWHDQGEHLQJHVWHGE\DQLPDOVKLJKHUXSLQ WKHIRRGFKDLQLQFOXGLQJKXPDQV6XFKELRDFFXPXODWLRQFDQXOWLPDWHO\FDXVHDUDQJHRISUREOHPV IURPFKURQLFHIIHFWV LHSHUVLVWHQWDQGORQJWHUPHIIHFWV VXFKDVUHGXFHGLPPXQHV\VWHPHI¿FLHQF\ WRDFXWHHIIHFWV LHTXLFNDQGVHYHUHUHVSRQVHV VXFKDVVLFNQHVVDQGGHDWK Sediment Dynamics 0DLQWHQDQFHRIDODNH¶VVKDOORZZDWHUKDELWDWDQGEHDFKHVLVLPSRUWDQWIRUSURYLGLQJDGHTXDWHVXEVWUDWHV IRUEHQWKLFSURGXFWLRQDQGDVUHIXJHIRUMXYHQLOH¿VKEHFDXVHFRDUVHUVXEVWUDWHVWHQGWRSURYLGHDPEXVK KDELWDWIRUSUHGDWRU\¿VK7KHUHFUXLWPHQWDQGWUDQVSRUWRIVHGLPHQWVLVHVVHQWLDOWRWKHPDLQWHQDQFHRI ODNHEHDFKHVDQGWKHDGMDFHQWVKDOORZZDWHUKDELWDW*HQHUDOO\VHGLPHQWFRPHVLQWRWKHODNHWKURXJK WZRVRXUFHV2QHVRXUFHLVVXUIDFHLQÀRZIURPWULEXWDU\ULYHUVZDWHUFRXUVHVDQGVWRUPZDWHU7KH RWKHUVRXUFHLVWKHODNHVKRUHOLQHZKHUHZDYHDFWLRQDQGLQXQGDWLRQSXOOVHGLPHQWIURPVKDOORZDUHDV +RZHYHUODNHVKRUHOLQHVHGLPHQWUHFUXLWPHQWLVOLPLWHGZKHUHEXONKHDGVDQGRWKHUEDQNDUPRULQJDUH SUHVHQWDQGE\ODNHZDWHUOHYHOÀXFWXDWLRQV Shoreline Connectivity 7KHFRQQHFWLRQVEHWZHHQVKDOORZDTXDWLFDUHDVDQGWKHDGMDFHQWODQGDORQJWKHVKRUHOLQHDUHLPSRUWDQW for creating and maintaining littoral habitat structure. These shallow-water habitats are important areas IRUUHIXJHDQGUHDULQJRSSRUWXQLWLHVIRUMXYHQLOH¿VK5LSDULDQYHJHWDWLRQLQWURGXFHVZRRGDQGVHGLPHQW LQWRWKHZDWHUSURGXFLQJKDELWDWVWUXFWXUH7KHOLWWRUDOKDELWDWVWUXFWXUHVKDSHVZHWODQGDQGDTXDWLF SODQWGLVWULEXWLRQDQGFRXSOHGZLWKWKHLQSXWRIQXWULHQWVDQGRUJDQLFPDWWHUIURPWKHULSDULDQ]RQH this habitat supports production of benthic communities (Schindler and Scheuerell 2002). Leaf litter DQGZRRG\GHEULVSURYLGHQXWULHQWVWRIXHOWKHDTXDWLFIRRGZHEDQGVXSSRUWLQYHUWHEUDWHSURGXFWLRQ 5LSDULDQYHJHWDWLRQDOVRSURYLGHVKDELWDWIRUWHUUHVWULDOLQVHFWVDQGWKHWHUUHVWULDOOLIHVWDJHVRIDTXDWLF LQVHFWV7KHVHLQVHFWVDUHDQLPSRUWDQWSDUWRIWKHDTXDWLFIRRGZHEIRU¿VKWKDWOLYHRUPDNHIRUD\V into shallow-water areas. 14 Part 2 A Brief Primer on Lake Ecosystems City of Seattle State of the Waters 2007 Volume II: Small Lakes 7KHLPSRUWDQFHRIULSDULDQFRQWULEXWLRQVWRDTXDWLFDUHDVGHSHQGVRQWKHVL]HDQGW\SHRIYHJHWDWLRQWKH GHJUHHRIVKRUHOLQHFRPSOH[LW\DQGWKHSURGXFWLYLW\RIWKHDTXDWLFV\VWHP 6FKLQGOHUDQG6FKHXHUHOO 2002). The function of riparian vegetation along lake shorelines is often undermined by invasive plant VSHFLHVFRQYHUVLRQRIULSDULDQDUHDVWRODQGVFDSHG\DUGVDQGWKHSUHVHQFHRIEXONKHDGVRUGRFNV 7KH TXDQWLW\ DQG TXDOLW\ RI VKDOORZ water habitat are affected by the presence RI VKRUHOLQH GRFNV DQG DUPRULQJ HJ EXONKHDGV DQG ULSUDS &DUUDVTXHUR 2001). Armoring is often present within RU EHORZ WKH LQXQGDWLRQ ]RQH RI D ODNH where it reduces the amount of shallow- water habitat that can be used by benthic FRPPXQLWLHV DQG MXYHQLOH ¿VK .RHKOHU 2002; Tabor and Piaskowski 2002). Docks VKDGH VKDOORZZDWHU KDELWDW DIIHFWLQJ WKH DPRXQWRISULPDU\SURGXFWLRQDQGVKDGLQJ FDQDIIHFW¿VKEHKDYLRU &DUUDVTXHUR Tabor et al. 2004). Nonnative predatory ¿VKKDYHEHHQVKRZQWRDJJUHJDWHDURXQG over-water structures; this behavior may Haller Lake (pictured) and Bitter Lake contain many docks affect predator-prey interactions. and shoreline structures (photo by Bennett) Nonnative Species 6SHFLHVIURPRWKHUDUHDVDUHVRPHWLPHVLQWURGXFHGHLWKHULQWHQWLRQDOO\RUDFFLGHQWDOO\LQWRQHZKDELWDWV 1RQQDWLYHVSHFLHVFDQLQFOXGHSODQWV HJ(XUDVLDQZDWHUPLOIRLOUHHGFDQDU\JUDVV LQYHUWHEUDWHV HJ $VLDQFODP DPSKLELDQV HJEXOOIURJ ¿VKHV HJVPDOODQGODUJHPRXWKEDVV\HOORZSHUFK DQG PDPPDOV HJQXWULD 7KHVHQRQQDWLYHLQYDVLYHVSHFLHVFDQDOWHUKDELWDWFRQGLWLRQVE\FKDQJLQJVXEVWUDWH FRPSRVLWLRQ RU ORFDO ZDWHU TXDOLW\ FRQGLWLRQV )RU H[DPSOH GHQVH JURZWK RI (XUDVLDQ ZDWHUPLOIRLO RURWKHUPDFURSK\WHVFDQOHDGWRGLVVROYHGR[\JHQGHSOHWLRQDQG¿VKPRUWDOLW\ )URGJHHWDO Nonnative species can also alter food web dynamics and compete with or prey upon native species. Part 2 A Brief Primer on Lake Ecosystems 15 City of Seattle State of the Waters 2007 Volume II: Small Lakes State of the Waters 2007 Part 3 Assessing the State of the Waters 3HUWLQHQWZDWHUTXDOLW\VHGLPHQWTXDOLW\DQGKDELWDWGDWDKDYHEHHQFRPSLOHGIURPDYDULHW\RIVRXUFHV and evaluated for this report. This chapter describes the data compilation and evaluation procedures XVHGWRDVVHVVFRQGLWLRQVLQ%LWWHU/DNH*UHHQ/DNHDQG+DOOHU/DNH Water and Sediment Quality Assessment Methods :DWHUDQGVHGLPHQWTXDOLW\GDWDIRUVPDOOODNHVLQ6HDWWOHDUHIDLUO\OLPLWHG+DOOHU/DNHKDVEHHQ URXWLQHO\PRQLWRUHGDVSDUWRIWKH.LQJ&RXQW\YROXQWHHUODNHPRQLWRULQJSURJUDPVLQFH DQG the program has monitored Bitter Lake since 1985. Green Lake was intensively monitored from 1992 WKURXJK IRUWKH3KDVH,,UHVWRUDWLRQSURJUDPDQGZDVVSRUDGLFDOO\PRQLWRUHGE\6HDWWOH3DUNVDQG 5HFUHDWLRQEHWZHHQ DQG6LQFH*UHHQ/DNHZDVWUHDWHGZLWKDOXPLQWKHVSULQJRI the lake has been monitored twice each month during the summer by Seattle Parks and Recreation. In 638FRQWUDFWHGZLWK.LQJ&RXQW\WRLQFOXGH*UHHQ/DNHLQWKHYROXQWHHUPRQLWRULQJSURJUDP :KLOH ZDWHU DQG VHGLPHQW TXDOLW\ DUH H[WUHPHO\ LPSRUWDQW DVSHFWV RI DTXDWLF FRQGLWLRQV IRU SODQWV DQGDQLPDOVDVZHOODVKXPDQVGDWDJDSVOLPLWWKHDELOLW\WRDFFXUDWHO\GHVFULEHH[LVWLQJFRQGLWLRQVLQ 6HDWWOHODNHV7KH.LQJ&RXQW\YROXQWHHUODNHPRQLWRULQJSURJUDPPHDVXUHVWHPSHUDWXUHSKRVSKRUXV FKORURSK\OO D DQG 6HFFKL GHSWK D YLVXDO PHDVXUH RI ZDWHU FODULW\ WR DVVHVV ODNH WURSKLF VWDWXV Information on the levels of metals and toxic organic pollutants present in Seattle lakes is generally QRWDYDLODEOHZLWKWKHH[FHSWLRQRIRQHVWXG\RIZDWHUDQGVHGLPHQWLQ%LWWHU/DNHDQGRQHVWXG\RI sediment in Green Lake. Water Quality Indicators 3HRSOH XVH ORFDO ZDWHU ERGLHV IRU D ZLGH YDULHW\ RI SXUSRVHV VXFK DV VZLPPLQJ ERDWLQJ ¿VKLQJ DQGDHVWKHWLFEHQH¿WVDQGWKRVHZDWHUERGLHVSURYLGHYDOXDEOHKDELWDWDQGIRRGQHHGHGE\¿VKDQG RWKHUDTXDWLFRUJDQLVPV:KLOHKXPDQVW\SLFDOO\VHHDTXDWLFHFRV\VWHPVRQO\IURPWKHRXWVLGHWKHUH DUHPDQ\FRPSRQHQWVWRKHDOWK\DTXDWLFFRPPXQLWLHVKLGGHQXQGHUWKHVXUIDFHRUDWWKHHGJHRIWKH ZDWHU6PDOOODNHVVXSSRUWDYDULHW\RIDTXDWLFDQGWHUUHVWULDORUJDQLVPVLQFOXGLQJVXEPHUJHGDQG HPHUJHQWSODQWVULSDULDQYHJHWDWLRQLQVHFWV¿VKDQGPDPPDOV/HVVHDV\WRVHHEXWHTXDOO\LPSRUWDQW DUH WKH PLFURVFRSLF EDFWHULD IXQJL DQG RUJDQLVPV WKDW SURYLGH IRRG IRU RWKHU DTXDWLF DQLPDOV $ KHDOWK\DTXDWLFHQYLURQPHQWRSHUDWHVLQDG\QDPLFIDVKLRQWRPDLQWDLQDGLYHUVHSK\VLFDOKDELWDWDQG WKHVSHFLHVWKDWUHVLGHWKHUH7RJHWKHUERWKWKHKXPDQDQGZLOGOLIHXVHVRI6HDWWOH¶VDTXDWLFV\VWHPV rely on clean water. Part 3 Assessing the State of the Waters 17 City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH VXPPDUL]HV WKH EHQH¿WV DQG XVHV RI 6HDWWOH¶V VPDOO ODNHV DV ZHOO DVWKHZDWHUTXDOLW\LQGLFDWRUVXVHGLQ this assessment to evaluate their overall FRQGLWLRQ :DWHU TXDOLW\ LQGLFDWRUV are select chemical and physical parameters and indices that can be used to characterize overall conditions; they provide criteria and benchmarks for assessing the success of watershed management efforts. More information DERXWNH\ZDWHUTXDOLW\LQGLFDWRUVFDQ Fishing in Seattle’s Green Lake (photo by Bennett) be found in Volume I of this report. 7DEOH8VHVDQGEHQH¿WVRI6HDWWOHODNHVDQGZDWHUTXDOLW\LQGLFDWRUVRIODNHFRQGLWLRQV Use Benefit Key Water Quality Indicators Contact recreation Providing suitable water quality and sediment quality Fecal coliform bacteria for human use of surface waters for contact recreation, including swimming, wading, snorkeling, and diving. Passive recreation Providing opportunities for people to enjoy walking Fecal coliform bacteria and and hiking, playing, observing wildlife and connecting trophic state index with nature. Human Providing suitable water quality and sediment quality Metals and organic compounds consumption for fish and shellfish harvesting. Aesthetics Preventing visual and odor-related degradation of Total petroleum hydrocarbons surface waters to protect their aesthetic value. and trophic state index Aquatic health Providing water quality and sediment quality Conventional parameters conditions to support valuable aquatic species. (dissolved oxygen, temperature, pH, nutrients), trophic state index, metals, organic compounds Data Compilation ,QIRUPDWLRQIRUWKLVDVVHVVPHQWZDVREWDLQHGIURPWKHIROORZLQJVRXUFHV .LQJ&RXQW\:DWHUTXDOLW\GDWDIRU%LWWHU/DNH+DOOHU/DNHDQG*UHHQ/DNHIURPWKH.LQJ&RXQW\ YROXQWHHUODNHPRQLWRULQJSURJUDP .LQJ&RXQW\DEDE %LWWHU/DNHZDWHUDQGVHGLPHQWTXDOLW\VWXGLHV 6HDWWOH/DNHV$OOLDQFH *UHHQ/DNHVHGLPHQWTXDOLW\GDWD 638XQSXEOLVKHG 7DEOHVXPPDUL]HVWKHZDWHUTXDOLW\GDWDVRXUFHVXVHGLQWKLVVWXG\0RQLWRULQJVWDWLRQORFDWLRQVLQ WKHWKUHHVPDOO6HDWWOHODNHVDUHVKRZQRQ)LJXUHVDQG SUHVHQWHGLQ3DUWXQGHUWKHGLVFXVVLRQ of each individual lake). 18 Part 3 Assessing the State of the Waters City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH:DWHUTXDOLW\GDWDVRXUFHVIRU6HDWWOH¶VVPDOOODNHV (Samples/Year) Station ID Storm Flow Type of Sample Period of Record Frequency Category Temperature Dissolved Oxygen Coliform Bacteria Nutrients Parameters Metals, Total Metals, Dissolved Petroleum Location Reference Non-storm flow Sediment Quality Assurance Other Conventional Hydrocarbons Bitter Lake Mid-lake 1 – ¥ G 1985-pres 10-14 2 ¥¥ Multiple stations 2 – ¥ G ¥ 2000 4-8 2 ¥¥ Haller Lake 1 – ¥ G 1997-pres 10-14 2 ¥¥ Green Lake Mid-lake 3– ¥ G 2005-pres 10-14 2 ¥¥ Multiple stations 4– G¥ 2004 7 2 ¥¥ ¥ G = grab sample C = composite sample References: 1. King County (2001a, 2001b, 2002a, 2002b, 2003, 2005) 2. Seattle Lakes Alliance (2000) 3. King County (unpublished) 4. SPU (unpublished) Data Quality Assurance Review 7RLGHQWLI\WKHGDWDVRXUFHVRIDFFHSWDEOHTXDOLW\IRUWKHSXUSRVHRIDVVHVVLQJZDWHUTXDOLW\FRQGLWLRQV WKHDYDLODEOHGDWDZHUHVXEMHFWWRDGDWDTXDOLW\DVVXUDQFHUHYLHZSULRUWRXVH(OHFWURQLFGDWD¿OHV ZHUHH[DPLQHGWRYHULI\WKDWWKHGDWDKDGEHHQFKHFNHGIRUTXDOLW\DQGDFFXUDF\ LHTXDOLW\DVVXUDQFH DQG TXDOLW\FRQWURO>4$4&@ YHUL¿FDWLRQ :KHUHSRVVLEOH ZULWWHQUHSRUWV ZHUH DOVR H[DPLQHGWR FKDUDFWHUL]HWKHOHYHORIGDWDTXDOLW\DQGDFFXUDF\UHYLHZSHUIRUPHG%DVHGRQWKLVUHYLHZWKHFRPSLOHG GDWDIURPHDFKVRXUFHZHUHSODFHGLQWRRQHRIWKUHHFDWHJRULHV 'DWDRINQRZQDQGDFFHSWDEOHTXDOLW\ FDWHJRU\ 4XDOLW\DVVXUDQFHLQIRUPDWLRQIURP¿HOGVDPSOLQJ DQGODERUDWRU\DQDO\VLVLVLQFOXGHGLQWKHVXPPDU\UHSRUWIRUWKHSDUWLFXODUVRXUFH7KLVTXDOLW\DVVXUDQFH LQIRUPDWLRQKDVEHHQUHYLHZHGDJDLQVWVSHFL¿FSUHGH¿QHGREMHFWLYHVIRUDVVHVVLQJGDWDTXDOLW\%DVHG RQWKLVUHYLHZTXDOLI\LQJUHPDUNVDUHDVVLJQHGWRWKRVHGDWDWKDWGRQRWPHHWTXDOLW\DVVXUDQFHREMHFWLYHV 'DWDKDYLQJPLQRUTXDOLW\DVVXUDQFHLVVXHVDUHLGHQWL¿HGLQVXPPDU\WDEOHVDQGDQDO\VHV'DWDKDYLQJ VHYHUHTXDOLW\DVVXUDQFHLVVXHVDUHH[FOXGHGIURPDOOGDWDVXPPDULHVRUDQDO\VHV 'DWDEHOLHYHGWREHRIDFFHSWDEOHTXDOLW\ FDWHJRU\ 4XDOLI\LQJUHPDUNVDUHDVVLJQHGWRVSHFL¿F GDWDWRLQGLFDWHWKHSUHVHQFHRITXDOLW\DVVXUDQFHLVVXHV+RZHYHUWKHVSHFL¿FTXDOLW\DVVXUDQFH REMHFWLYHV IRU WKH GDWD DUH QRW FOHDUO\ LGHQWL¿HG DQG TXDOLW\ DVVXUDQFH LQIRUPDWLRQ IURP ¿HOG sampling and laboratory analysis is not presented along with the data. 'DWDRIXQNQRZQTXDOLW\ FDWHJRU\ 4XDOLI\LQJUHPDUNVDUHQRWDVVLJQHGWRDQ\GDWDWRLQGLFDWH WKH SUHVHQFH RI TXDOLW\ DVVXUDQFH LVVXHV 1R LQIRUPDWLRQ LV SUHVHQWHG RQ WKH VSHFL¿F TXDOLW\ DVVXUDQFH REMHFWLYHV IRU WKH GDWD DQG TXDOLW\ DVVXUDQFH LQIRUPDWLRQ IURP ¿HOG VDPSOLQJ DQG laboratory analysis is not presented along with the data. Part 3 Assessing the State of the Waters 19 City of Seattle State of the Waters 2007 Volume II: Small Lakes 'DWDVRXUFHVDVVLJQHG4$FDWHJRU\DQGFODVVL¿FDWLRQVDUHLQFOXGHGLQWKLVVXPPDU\UHSRUWZKLOH QA category 3 data are excluded. The category assigned to each data source is listed in Table 2. Data Analysis 7KHGDWDFRPSLOHGIRUWKLVUHSRUWZHUHHYDOXDWHGXVLQJWKHIROORZLQJWHFKQLTXHV 3ORWWLQJRIWLPHVHULHVJUDSKVWRFKHFNRYHUDOOWUHQGVLQZDWHUTXDOLW\FRQGLWLRQVIRUNH\ZDWHU TXDOLW\SDUDPHWHUV &RPSDULVRQ RI VDPSOH UHVXOWV WR :DVKLQJWRQ VWDWH ZDWHU TXDOLW\ FULWHULD DQG RWKHU DSSOLFDEOH EHQFKPDUNVLQRUGHUWRHYDOXDWHRYHUDOOWR[LFLW\WRDTXDWLFRUJDQLVPV &DOFXODWLRQRIVXPPDU\VWDWLVWLFV LQFOXGLQJDULWKPHWLFPHDQPHGLDQPLQLPXPPD[LPXPDQG FRQ¿GHQFHOLPLWVVKRZQLQER[SORWV &RPSDULVRQRIWURSKLFVWDWHLQGLFHVWRFKDUDFWHUL]HZDWHUTXDOLW\FRQGLWLRQVLQODNHV A brief description of each analysis is provided separately in the following subsections. Time Series Analysis Time series analyses are simple graphs of chemical concentration versus time. The overall scatter and distribution in the chemical values provide an indication of general trends and variability in the sample population. Washington State Water Quality Standards 7KHVWDWHZDWHUTXDOLW\VWDQGDUGV :DVKLQJWRQ$GPLQLVWUDWLYH&RGH>:$&@$ SURYLGHFULWHULD IRUHYDOXDWLQJZDWHUTXDOLW\FRQGLWLRQVLQ6HDWWOHUHFHLYLQJZDWHUERGLHV7KHVWDQGDUGVKDYHEHHQ HVWDEOLVKHGWRSURWHFWSXEOLFKHDOWKDQGDTXDWLFOLIHLQIUHVKZDWHUDQGPDULQHZDWHUV\VWHPVEDVHGRQ VSHFL¿FRUGHVLJQDWHGXVHVRIWKRVHZDWHUERGLHV(VWDEOLVKHGGHVLJQDWHGXVHVLQFOXGHSXEOLFUHFUHDWLRQ HJ¿VKLQJERDWLQJDQGVZLPPLQJ DQGRWKHUPLVFHOODQHRXVXVHVVXFKDVFRPPHUFHQDYLJDWLRQDQG DHVWKHWLFEHQH¿WVDVZHOODVWKHSURSDJDWLRQDQGSURWHFWLRQRI¿VKVKHOO¿VKDQGZLOGOLIH The freshwater standards apply to Seattle small lakes and large lakes (Lake Washington and Lake 8QLRQ ZKLOHWKHPDULQHVWDQGDUGVDSSO\LQ3XJHW6RXQGDQGWKHHVWXDULQHSRUWLRQRIWKH'XZDPLVK :DWHUZD\6WDQGDUGVKDYHEHHQHVWDEOLVKHGIRUPDQ\FRQYHQWLRQDOZDWHUTXDOLW\LQGLFDWRUV LQFOXGLQJ S+WHPSHUDWXUHGLVVROYHGR[\JHQWXUELGLW\EDFWHULDDQGWRWDOGLVVROYHGJDV DQGWR[LFVXEVWDQFHV LQFOXGLQJPHWDOVRUJDQLFFRPSRXQGVDQGUDGLRDFWLYHPDWHULDOV 20 Part 3 Assessing the State of the Waters City of Seattle State of the Waters 2007 Volume II: Small Lakes 7ZROHYHOVRISURWHFWLRQKDYHEHHQHVWDEOLVKHGIRUWR[LFVXEVWDQFHVWRSUHYHQWLQMXU\RUGHDWKWRDTXDWLF RUJDQLVPV WKHDFXWHDQGWKHFKURQLFWR[LFLW\FULWHULD7KHDFXWHWR[LFLW\FULWHULDDUHEDVHGRQVKRUWWHUP H[SRVXUH'HSHQGLQJRQWKHFKHPLFDOWKHDFXWHWR[LFLW\FULWHULRQPLJKWEHWKHLQVWDQWDQHRXVPD[LPXP FRQFHQWUDWLRQQRWWREHH[FHHGHGDWDQ\WLPHRUDRQHKRXUDYHUDJHFRQFHQWUDWLRQRUDKRXUDYHUDJH FRQFHQWUDWLRQ7KHFKURQLFWR[LFLW\FULWHULDUHÀHFWORQJWHUPH[SRVXUHOLPLWVZKLFKUDQJHIURPRQH KRXUGXUDWLRQXSWRGD\GXUDWLRQ)RUWKLVDQDO\VLVVWRUPZDWHUVDPSOHVDUHFRPSDUHGWRWKHDFXWH WR[LFLW\FULWHULDDQGQRQVWRUPÀRZGDWDDUHFRPSDUHGWRWKHFKURQLFWR[LFLW\FULWHULD 7KH:DVKLQJWRQ'HSDUWPHQWRI(FRORJ\ (FRORJ\ UHYLVHGWKHVWDWHZDWHUTXDOLW\VWDQGDUGVLQ7KH 2006 rules are used in this report where samples have been collected appropriately to allow comparison to the revised 2006 criteria. The 1997 rule is used where the existing data are not directly comparable WRWKHUXOH)RUH[DPSOHWKHWHPSHUDWXUHFULWHULRQLQWKHUXOHLVEDVHGRQWKHGD\DYHUDJH RIWKHGDLO\PD[LPXPWHPSHUDWXUHVZKLOHWKH UXOHLVEDVHGRQDVLQJOHPHDVXUHPHQW0RVW of the available data for water temperature were collected on a monthly basis and therefore cannot EHFRPSDUHGWRWKHFULWHULRQ&RQVHTXHQWO\WKHVHGDWDDUHFRPSDUHGWRWKH WHPSHUDWXUH criterion. 7KHEHQH¿FLDOXVHGHVLJQDWLRQVWKDWDSSO\WR6HDWWOHODNHVXQGHUWKH DQGUXOHVDUHOLVWHGLQ Table 3. 7DEOH%HQH¿FLDOXVHGHVLJQDWLRQVDSSOLFDEOHWR6HDWWOH¶VVPDOOODNHVXQGHUVWDWHZDWHU TXDOLW\VWDQGDUGV 2006 Amended Aquatic Recreational Water Supply Miscellaneous 1997 Life Use Uses Use c a b Class AA Class A Class Lake Char Core Summer Habitat Spawning, Rearing, & Migration & Rearing Migration Only Extraordinary Contact Recreation Recreation Industrial Supply And Stock Watering Wildlife Habitat Commercial/Navigation Aesthetics Boating Primary Contact Domestic Supply Agricultural Water Supply Fish Harvesting Bitter Lake ¥¥¥¥ ¥¥¥¥¥¥¥¥ Green Lake ¥¥¥¥ ¥¥¥¥¥¥¥¥ Haller Lake ¥¥¥¥ ¥¥¥¥¥¥¥¥ a Summer (June 15–September 15) salmonid spawning or emergence, adult holding; use as important summer rearing habitat by one or more salmonids; or foraging by adult and sub-adult native char; spawning outside the summer season, rearing, and migration by salmonids. b Salmon or trout spawning and emergence that only occurs outside of the summer season (September 16–June 14); rearing and migration by salmonids. c Used for rearing and migration only, not used for spawning. Part 3 Assessing the State of the Waters 21 City of Seattle State of the Waters 2007 Volume II: Small Lakes Lake Trophic State Index A common way to characterize the overall health of a lake according to its level of biological activity is the trophic state index (TSI) rating (Carlson 7KHWURSKLFVWDWHLQGH[ which calculates trophic status based on three key indicators (chlorophyllaWRWDOSKRVSKRUXV DQG 6HFFKL GHSWK LV XVHG LQ this assessment to compare ZDWHU TXDOLW\ FRQGLWLRQV LQ small lakes. As shown in 7DEOH WKLV LQGH[ LV EDVHG on a scale of zero to 100 and provides a standard measure for Bitter Lake (photo by Bennett) HYDOXDWLQJODNHTXDOLW\ 7DEOH7URSKLFVWDWHLQGH[YDOXHVXVHGWRDVVHVVODNHZDWHUTXDOLW\FRQGLWLRQV TSI value Lake Class Description <40 Oligotrophic Low biological activity associated with high water clarity, low phosphorus concentrations, and low algal levels 40-50 Mesotrophic Moderate biological activity associated with moderate water clarity, low phosphorus concentrations, and moderate algal levels >50 Eutrophic High biological activity associated with low water clarity, high phosphorus concentrations, and high algal levels TSI = trophic state index (Carlson 1977). Lake Sediment Standards :DVKLQJWRQVWDWHKDVQRWHVWDEOLVKHGVWDQGDUGVIRUIUHVKZDWHUVHGLPHQWTXDOLW\)RUWKHSXUSRVHVRI WKLVUHSRUWODNHVHGLPHQWGDWDDUHHYDOXDWHGEDVHGRQFRPSDULVRQVWRWKHIROORZLQJVHGLPHQWTXDOLW\ guidelines or criteria. 22 Part 3 Assessing the State of the Waters City of Seattle State of the Waters 2007 Volume II: Small Lakes Ontario Ministry of the Environment Guidelines 6HGLPHQW TXDOLW\ JXLGHOLQHV KDYH EHHQ HVWDEOLVKHG E\ WKH 2QWDULR 0LQLVWU\ RI WKH (QYLURQPHQW WR SURWHFWERWWRPGZHOOLQJ LHEHQWKLF RUJDQLVPV 3HUVDXGHWDO 7KHIROORZLQJWKUHHWKUHVKROG OHYHOVDUHGH¿QHG 1RHIIHFW OHYHO²WKH FRQFHQWUDWLRQ DW ZKLFK QR WR[LF HIIHFWV KDYH EHHQ REVHUYHG LQ DTXDWLF organisms /RZHVWHIIHFWOHYHO²WKHFRQFHQWUDWLRQDWZKLFKWKHPDMRULW\RIEHQWKLFRUJDQLVPVDUHXQDIIHFWHG Severe-effect level—the concentration at which pronounced disturbance of the sediment-dwelling community can be expected. National Oceanic and Atmospheric Administration Guidelines 7KHVHIUHVKZDWHUVHGLPHQWTXDOLW\JXLGHOLQHVDUHEDVHGRQDFRPSLODWLRQRIVHGLPHQWFKHPLVWU\DQG biological effects in freshwater sediments and were developed as a preliminary screening tool for HYDOXDWLQJ VHGLPHQW TXDOLW\ 12$$ 7KH JXLGHOLQHV HVWDEOLVK WKH IROORZLQJ WKUHH WKUHVKROG OHYHOV Threshold effects level (TEL)—the concentration at which adverse effects are expected to occur only rarely. The TEL is calculated as the geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set. 3UREDEOHHIIHFWVOHYHO 3(/ ²WKHFRQFHQWUDWLRQDWZKLFKDGYHUVHHIIHFWVDUHIUHTXHQWO\H[SHFWHG The PEL is calculated as the geometric mean of the 50th percentile concentration of the toxic effects data set and the 85th percentile of the no-effect data set. Upper effects threshold (UET)—the concentration at which adverse effects would always occur based on the lowest adverse effect threshold (AET) from a compilation of endpoints analogous to the marine AET endpoints. The UET is based on 1 percent total organic carbon content in the sediment. Consensus-Based Standards Consensus-based standards for freshwater sediment have been developed by MacDonald et al. (2000). 7KHVHJXLGHOLQHVHVWDEOLVKWZRWKUHVKROGOHYHOV Threshold effects concentration (TEC)—the concentration below which adverse effects are not expected to occur Probable effects concentration (PEC)—the concentration above which adverse effects are expected WRRFFXUPRUHRIWHQWKDQQRWEDVHGRQ DFRPSLODWLRQRI DYDLODEOHVHGLPHQWTXDOLW\JXLGHOLQHV reported in the literature. The TEC and PEC are calculated as the geometric mean of all the values assigned to each threshold FODVVL¿FDWLRQ Part 3 Assessing the State of the Waters 23 City of Seattle State of the Waters 2007 Volume II: Small Lakes Washington State Proposed Criteria 7KH 'HSDUWPHQW RI (FRORJ\ KDV HYDOXDWHG IUHVKZDWHU VHGLPHQW TXDOLW\ FULWHULD XVLQJ WKH SUREDEOH DSSDUHQWHIIHFWVWKUHVKROG 3$(7FDOFXODWHGDVWKH WKSHUFHQWLOHRIVWDWLRQVH[KLELWLQJQRELRORJLFDO HIIHFWVEDVHGRQWKH0LFURWR[ELRDVVD\ IRURUJDQLFFRPSRXQGVDQGWKHPDULQHVHGLPHQWPDQDJHPHQW standards for metals (Cubbage et al. 1997). Although much progress has been made in evaluating AET YDOXHVFDOFXODWHGXVLQJWKHXSGDWHGIUHVKZDWHUVHGLPHQWGDWD(FRORJ\KDVQRW\HWGHYHORSHGIUHVKZDWHU VHGLPHQWVWDQGDUGV $YRFHW )RUWKHSXUSRVHVRIWKLVUHSRUWWKH LQWHULPIUHVKZDWHUVHGLPHQW TXDOLW\YDOXHVDUHXVHGWRHYDOXDWHVHGLPHQWGDWDIRU6HDWWOHDUHDUHFHLYLQJZDWHUERGLHV Habitat Assessment Methods 6HDWWOHODNHKDELWDWDQG¿VKXVHLQIRUPDWLRQZDVJDWKHUHGIURPH[LVWLQJUHSRUWVEULHIYLVXDOVXUYH\VRI WKHODNHVKRUHOLQHVDQG:DVKLQJWRQ'HSDUWPHQWRI)LVKDQG:LOGOLIH¿VKVWRFNLQJUHFRUGV2YHUDOO OLWWOHRIWKHQHHGHGKDELWDWLQIRUPDWLRQLVDYDLODEOHIRU6HDWWOH¶VVPDOOODNHV +LVWRULFDOO\ZKHQWKHVHVPDOOODNHVKDGVXUIDFHVWUHDPFRQQHFWLRQVZLWKODUJHUODNHV¿VKVXFKDV VWLFNOHEDFNPLQQRZVFKXEVXFNHUVDQGWURXWZHUHFRPPRQLQKDELWDQWV 24 Part 3 Assessing the State of the Waters City of Seattle State of the Waters 2007 Volume II: Small Lakes State of the Waters 2007 Part 4 Conditions in Seattle’s Small Lakes Near-shore and riparian habitat within the small lakes of Seattle have not been intensively studied. :DWHUDQGVHGLPHQWTXDOLW\VWXGLHVDUHOLPLWHGIRFXVLQJRQWKRVHFRQGLWLRQVUHOHYDQWIRUVZLPPLQJ ERDWLQJDQGZDGLQJ7KHUHIRUHXQOLNHWKHDVVHVVPHQWRIZDWHUFRXUVHFRQGLWLRQVLQ9ROXPH,WKLV report (Volume II) summarizes the existing information but does not provide maps of habitat and water TXDOLW\FRQGLWLRQV Bitter Lake %LWWHU/DNHLVDQDFUHODNHLQQRUWKFHQWUDO6HDWWOHERUGHUHGE\/LQGHQ$YHQXH1RUWK1RUWKWK 6WUHHW1RUWKWK6WUHHWDQG*UHHQZRRG$YHQXH1RUWK )LJXUH 7KHODNHZKLFKZDVFUHDWHGE\ JODFLDWLRQWRGD\KDVDPHDQGHSWKRIIHHWDQGDPD[LPXPGHSWKRIIHHW(DUO\LQ6HDWWOHKLVWRU\ a sawmill was located on the lake (Fiset 2001a). Tannic acid from logs stored in the lake gave its water DELWWHUWDVWHKHQFHWKHQDPH%LWWHU/DNH&XUUHQWODQGXVHLQWKHEDVLQLVDPL[WXUHRIVLQJOHIDPLO\ and multifamily residential development. Multifamily properties are concentrated primarily along the PDLQWUDQVSRUWDWLRQFRUULGRUVDORQJ/LQGHQ$YHQXH1RUWKDQG*UHHQZRRG$YHQXH1RUWK Bitter Lake (photo by Bennett) Part 4 Conditions in Bitter Lake 25 City of Seattle State of the Waters 2007 Volume II: Small Lakes N142ND ST Bitter Lake N N AVE E N NT AV The City O EM T FR NNEY I STON AVE of Seattle PH N 141ST ST 1ST C N141ST ST EVAN N14 N140THST N E V A N ON T AVE Y DA INE T N 138TH ST A N138TH ST L PA N AVE N E D N SW-1 LI Sed-1 N 137THST N136THST SW-8 SW-2 CT N D N 137TH ST NGAR WI Sed-2 N VE KA R A HP SW-7 RT Bitter O N N 135THST N VE OOD A N134THST SW-6 GREENW BITT ER PL N SW-3 Sed-3 N133RDST SW-4 N132ND ST SW-5 Sed-4 PALATINE AVE N Legend N130TH ST Streets N VE Park Boundary A K AR Water Quality HP N N RT O Monitoring Stations E AVE N N N EN INE AVE ON AV AVE StormAT N128TH ST T EY AV ON N N PAL O DAYT N I NST Sediment EM PH R F EVA Water THE CITY OF SEATTLE, 2007. All rights reserved No guarantee of any sort implied, including N127TH ST Figure 4 accuracy, completeness, or fitness for use. N127THST Figure 4. Bitter Lake. 26 Part 4 Conditions in Bitter Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes 6XUIDFHZDWHUUXQRIIIURPWKHDSSUR[LPDWHO\ DFUHEDVLQLVWKHSULPDU\VRXUFHRILQÀRZWR%LWWHU /DNH,QWKHSDVWVHHSDJHORVVHVIURPWKH%LWWHU/DNHGULQNLQJZDWHUUHVHUYRLUDOVRGLVFKDUJHGWR%LWWHU /DNH+RZHYHUWKLVVRXUFHRILQÀRZZDVHOLPLQDWHGLQZKHQWKHUHVHUYRLUZDVOLQHGDQGFRYHUHG &XUUHQWO\GLVFKDUJHIURPWKHUHVHUYRLUWR%LWWHU/DNHRFFXUVRQO\ZKHQWKHUHVHUYRLULVGUDLQHGIRU FOHDQLQJDQGPDLQWHQDQFHSXUSRVHVDSSUR[LPDWHO\RQFHHYHU\WR\HDUV $WLWVVRXWKHDVWHUQHQG%LWWHU/DNHGUDLQVWKURXJKDSLSHGRXWOHWWKDWUXQVWKURXJKDVHULHVRIVPDOO ditches and culverts before entering the Densmore storm drain system on Aurora Avenue North. The 'HQVPRUHV\VWHPLVHTXLSSHGZLWKDORZÀRZE\SDVVZKLFKFRQYH\VUXQRIIGLUHFWO\WR/DNH8QLRQ 8QGHUKLJKÀRZFRQGLWLRQVUXQRIISDVVHVWKURXJK*UHHQ/DNHEHIRUHGLVFKDUJLQJWR/DNH8QLRQ Water and Sediment Quality Conditions Bitter Lake is considered a moderately productive (or mesotrophic) lake with relatively good water TXDOLW\ .LQJ&RXQW\D 9ROXQWHHUVIRUWKH.LQJ&RXQW\VPDOOODNHVSURJUDPKDYHPRQLWRUHG ZDWHUTXDOLW\LQ%LWWHU/DNHVLQFH :DWHUVDPSOHVDUHFROOHFWHGWZLFHHDFKPRQWKIURP0D\ WKURXJK2FWREHU.LQJ&RXQW\PRQLWRULQJUHVXOWVIRU ±DUHGLVSOD\HGLQ)LJXUH Secchi depth Total phosphorus Chlorophyll a Average TSI (a) 6 50 (a) TSI = average of TSI-TP, TSI-Chlor-a, and TSI-Secchi 45 5 40 35 4 30 3 25 20 Secchi depth (m) 2 15 Total P, Chlor-a (ug/L), TSI (none) 10 1 5 0 0 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 Year Reference: King County (1999a, 2001a, 2001b, 2002a, 2002b, 2003, 2005). Note: Secchi depth is a measure of water clarity. The higher the value, the better the water clarity. )LJXUH%LWWHU/DNHZDWHUTXDOLW\PRQLWRULQJGDWDVXPPDU\IRU ± Part 4 Conditions in Bitter Lake 27 City of Seattle State of the Waters 2007 Volume II: Small Lakes Average water clarity (as measured visually by Secchi depth) generally ranges from about 3.2 to 3.4 PHWHUVDOWKRXJKKLJKYDOXHVRIWR PHWHUVZHUHREVHUYHGLQ ± Average total phosphorus concentrations in Bitter Lake have been below the recommended maximum of 20 micrograms per liter (μg/L) established by Ecology (WAC 173-201A) for lower mesotrophic ODNHVLQDOO\HDUVPRQLWRUHGZLWKWKHH[FHSWLRQRI DYHUDJHRIJ/ DQG DYHUDJHRI J/ The average trophic state index for Bitter Lake over the 18-year monitoring period has also remained UHODWLYHO\FRQVWDQW WR DQGZHOOZLWKLQWKH±UDQJHHVWDEOLVKHGIRUPHVRWURSKLFODNHV 2QHZDWHUVDPSOHFROOHFWHGRQ$XJXVW FRQWDLQHGFRORQ\IRUPLQJXQLWVSHUPLOOLOLWHUV FIXP/ RIIHFDOFROLIRUPEDFWHULD .LQJ&RXQW\ D 7KLVFRQFHQWUDWLRQH[FHHGVWKHVWDWH ZDWHUTXDOLW\VWDQGDUGIRUH[WUDRUGLQDU\SULPDU\FRQWDFWUHFUHDWLRQHVWDEOLVKHGDVDJHRPHWULFPHDQRI FIXP/ZLWKQRPRUHWKDQSHUFHQW RUDQ\VLQJOHVDPSOHZKHQOHVVWKDQVDPSOHSRLQWV exist) exceeding 100 cfu/100 mL. No other bacteria data are available. The Seattle Lakes Alliance (2000) collected one water sample from each of eight locations in Bitter /DNHGXULQJDVWRUPHYHQWRQ)HEUXDU\7KHVDPSOHVZHUHFROOHFWHGLPPHGLDWHO\RIIVKRUH RIWKHIRXUPDMRUVWRUPGUDLQRXWIDOOV WZRSXEOLFRXWIDOOVDQGWZRSULYDWHRQHV DVZHOODVIURPIRXU VZLPPLQJDUHDVLQWKHODNH VWDWLRQV6:±6: )LJXUH ,QDGGLWLRQODNHVHGLPHQWVDPSOHVZHUH collected from the top 6 inches of sediment offshore of the four storm drain outfalls. Samples were collected within 5 feet of the end of the outfall pipe. Water and sediment samples were analyzed for WRWDOPHWDOVYRODWLOHDQGVHPLYRODWLOHRUJDQLFFRPSRXQGVSRO\FKORULQDWHGELSKHQ\OV 3&%V DQGWRWDO petroleum hydrocarbons. $UVHQLFFKURPLXPFRSSHUOHDGDQG]LQFZHUHGHWHFWHGLQWKHZDWHUVDPSOHVFROOHFWHGIURP%LWWHU /DNH$QWLPRQ\EHU\OOLXPFDGPLXPPHUFXU\VHOHQLXPDQGVLOYHUZHUHQRWGHWHFWHGLQDQ\RIWKH seven samples analyzed. 6WDWHZDWHUTXDOLW\VWDQGDUGVDUHEDVHGRQGLVVROYHGPHWDOVFRQFHQWUDWLRQVDQGDUHGHSHQGHQWRQWKH hardness level in the water column (with the exception that the arsenic standard is not dependent on ZDWHUKDUGQHVV $OWKRXJKGLVVROYHGPHWDOVDQGKDUGQHVVZHUHQRWDQDO\]HGLWLVSRVVLEOHWRFRPSDUH Bitter Lake sample results to state standards based on a reasonable assumption for hardness and DSSOLFDWLRQRIDFRQYHUVLRQIDFWRUWRDGMXVWWKHVWDQGDUGVWRDWRWDOPHWDOVFRQFHQWUDWLRQUDWKHUWKDQD dissolved metals concentration. 6WDWHVWDQGDUGVZHUHQRWH[FHHGHGIRUWKHGHWHFWHGPHWDOVLQDQ\RIWKHZDWHUVDPSOHVDVVXPLQJDW\SLFDO KDUGQHVVRIPLOOLJUDPVSHUOLWHU PJ/ IRUODNHVLQWKH3XJHW6RXQGORZODQGVDQGFRPSDULVRQWR DFXWHWR[LFLW\FULWHULD LHRQHKRXUDYHUDJHIRUVWRUPFRQGLWLRQV IRUWRWDOPHWDOV XVLQJDFRQYHUVLRQ factor of 1.0). $VVKRZQLQ7DEOHWKHLQODNHPHWDOVFRQFHQWUDWLRQVZHUHUHODWLYHO\ORZFRPSDUHGWROHYHOVW\SLFDOO\ REVHUYHGLQXUEDQVWRUPZDWHUUXQRII7KHKLJKHVWFRQFHQWUDWLRQVRIFKURPLXPFRSSHUOHDGDQG]LQF ZHUHPHDVXUHGLQWKHZDWHUVDPSOHFROOHFWHGRIIVKRUHRIWKHODUJHVWVWRUPGUDLQRXWIDOO 6: ZKLFK discharges into the northwestern corner of Bitter Lake near Greenwood Avenue North and North 137th 6WUHHW0HWDOVFRQFHQWUDWLRQVLQWKHRWKHUVDPSOHVZHUHIDLUO\FRPSDUDEOHUDQJLQJZLWKLQSHUFHQW of the mean concentration. 28 Part 4 Conditions in Bitter Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes Table 5. Bitter Lake metals concentrations sampled during a storm event compared to human health risk criteria. U.S. EPA Human Health Risk Criteria c Total Metals Number of Bitter Lake Urban Water and Tissue (μg/L) Detections Samples a Runoff b,d Tissue Only Arsenic 7/7 1.04–1.1 NA 0.018 0.018 Chromium 7/7 0.185–0.38 <1.94–20 NA NA Copper 7/7 2.12–2.69 <1–8.1 1,300 NA Lead 6/7 <1–4.78 <1–17.5 NA NA Zinc 7/7 13.9–16.1 19–40 9,100 69,000 μg/L = micrograms per liter. a Sample SW-4 was not analyzed for metals. b Ranges in average concentrations from stormwater sampling conducted in Madison, Milwaukee, and Superior, WI and Marquette, MI (Pitt et. al. 2004). c U.S. EPA (2002). d Copper, lead, and zinc ranges are for four stormwater samples collected from two drains discharging to Bitter Lake and Haller Lake (Seattle University 2001, 2002). Arsenic concentrations in Bitter Lake water samples exceeded the U.S. EPA risk criteria for human KHDOWKEDVHGRQ¿VKDQGZDWHUFRQVXPSWLRQ5LVNLVFDOFXODWHGEDVHGRQFRQVXPSWLRQRIJUDPVSHU GD\RI¿VKDQGOLWHUVSHUGD\RIZDWHU+RZHYHU%LWWHU/DNHLVQRWXVHGIRUGULQNLQJZDWHUDQGWKH H[WHQWWRZKLFKUHVLGHQWVFRQVXPH¿VKFDXJKWLQ%LWWHU/DNHLVXQNQRZQ Metal pollutants accumulate on impervious surfaces in urban watersheds and are washed off during VWRUPV,QDGGLWLRQVRPHPHWDOVDUHERXQGWRVHGLPHQWV VRDVVWRUPÀRZVHQWUDLQVRLODQGVHGLPHQW metals are more easily transported to lakes. Sources of metal pollutants include wear and tear of YHKLFOHSDUWV HJEUDNHSDGVWLUHVUXVWDQGHQJLQHSDUWV DWPRVSKHULFGHSRVLWLRQFRPPRQEXLOGLQJ PDWHULDOV HJJDOYDQL]HGÀDVKLQJPHWDOGRZQVSRXWV DQGURRIPDLQWHQDQFHDFWLYLWLHV HJPRVV control). 1DSKWKDOHQHELV HWK\OKH[\O SKWKDODWHDQGKHSWDFKORUDUHWKHRQO\RUJDQLFFRPSRXQGVGHWHFWHGLQ %LWWHU/DNHZDWHUVDPSOHV&RQFHQWUDWLRQVZHUHORZJHQHUDOO\QHDURUDWWKHUHSRUWLQJOLPLW1DSKWKDOHQH DQGELV HWK\OKH[\O SKWKDODWHUHVXOWVDUHTXDOL¿HGDVHVWLPDWHGYDOXHVEHFDXVHWKHVHFKHPLFDOVZHUH DOVRIRXQGLQWKHPHWKRGRUHTXLSPHQWEODQNVDPSOHV6DPSOHUHVXOWVDUHVXPPDUL]HGLQ7DEOH 7DEOH%LWWHU/DNHRUJDQLFFRPSRXQGVGHWHFWHGLQVWRUPZDWHUVDPSOHV Compound (μg/L) Number of Detections Bitter Lake Samples Naphthalene a 6/8 <0.1–0.138 Bis(2-ethylhexyl)phthalate b 2/8 <50–13.3 Heptachlor 1/8 <0.03–0.0187 a Detected in method blank b Detected in the equipment blank at 18.4 micrograms per liter (μg/L). Part 4 Conditions in Bitter Lake 29 City of Seattle State of the Waters 2007 Volume II: Small Lakes 0HWDOV DQG RUJDQLF FRPSRXQGV GHWHFWHG LQ VHGLPHQW VDPSOHV FROOHFWHG RIIVKRUH RI WKH IRXU PDMRU outfalls to Bitter Lake in 2000 are summarized in Tables 7 and 8 (Seattle Lakes Alliance 2000). Because WKHVWDWHKDVQRWHVWDEOLVKHGVWDQGDUGVIRUIUHVKZDWHUVHGLPHQWTXDOLW\IUHVKZDWHUVHGLPHQWJXLGHOLQHV RUFULWHULDIURPRWKHUMXULVGLFWLRQVDORQJZLWKWKH'HSDUWPHQWRI(FRORJ\¶V SURSRVHGIUHVKZDWHU VHGLPHQWTXDOLW\YDOXHVDUHXVHGLQWKLVUHSRUWWRHYDOXDWHWKH%LWWHU/DNHVHGLPHQWGDWD 7DEOH%LWWHU/DNHVHGLPHQWPHWDOVFRQFHQWUDWLRQVFRPSDUHGWRIUHVKZDWHUVHGLPHQW guidelines. Consensus- Ecology Based Sediment Bitter Lake Guidelines a Quality Values b Ontario c NOAA d Compound Number Units = of Test mg/kg Detections Range TEC PEC FSQV LOEL SEL TEL PEL UET org Arsenic 4/4 1.95–.79 9.79 33 57 6 33 5.9 17 17 I Cadmium 4/4 2.05–5.98 0.99 4.98 5.1 0.6 10 0.596 3.53 3 I Chromium 4/4 20.1–43.8 43.4 111 260 26 110 37.3 90 95 H Copper 4/4 14.1–81.4 31.6 149 390 16 110 35.7 197 86 I Lead 4/4 7.74–255 35.8 128 450 31 250 35 91.3 127 H 0.036– Mercury 4/4 0.193 0.18 1.06 0.41 0.2 2 0.174 0.486 0.56 M 0.206– Selenium 2/4 0.438 NA NA NA NA NA NA NA NA M <0.5– Silver 2/4 0.0536 NA NA 6.1 NA NA NA NA 4.5 I Zinc 4/4 63.4–401 121 459 410 120 820 123.1 315 520 I a MacDonald et. al. (2000) b Cubbage et al. (1997) c Persaud et. al. (1993) d NOAA (1999). mg/kg = milligrams per kilogram FSQV: freshwater sediment quality value TEC: threshold effect concentration PEC: probable effect concentration LOEL: lowest observed effect level SEL: severe effect level TEL: threshold effect level or concentration below which adverse effects are expected to occur only rarely. Geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set. PEL: probable effects level, the level above which adverse effects are frequently expected. Geometric mean of the 50th percentile of impacted, toxic samples and the 85th percentile of the non-impacted samples. UET: Upper effects concentration derived as the lowest adverse effects threshold (AET) from a compilation of endpoints analogous to the marine AET endpoints. M = Microtox bioassay I = Infaunal community impacts H = Hyalella azteca bioassay 30 Part 4 Conditions in Bitter Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH%LWWHU/DNHVHGLPHQWRUJDQLFFRPSRXQGVFRQFHQWUDWLRQVFRPSDUHGWRIUHVKZDWHUVHGLPHQWJXLGHOLQHV Consensus-Based Ecology Sediment Bitter Lake Guidelines a Quality Values b Ontario c NOAA d Number of Range e Range TEC PEC FSQV LOEL SEL TEL PEL UET Test Compound Detections (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) org LPAH Anthracene 1 672 NA 57.2 845 2,100 220 370 NA NA 260 M Phenanthrene 1 1,790 NA 204 1,170 5,700 560 950 41.9 515 800 I HPAH Benzo(a)anthracene 1 1,340 NA 108 1,050 5,000 320 1,480 NA NA NA Benzo(a)pyrene 1 1,570 NA 150 1,450 7,000 370 1,440 31.9 782 700 I Benzo(b)fluoranthene 1 2,130 NA NA NA NA NA NA NA NA NA Benzo(k)fluoranthene 1 672 NA NA NA NA 240 1,340 NA NA 13,400 B Benzo(b+k)fluoranthene 1 2,802 NA NA NA 11,000 NA NA NA NA 13,400 Benzo(g,h,i)perylene 1 1,570 NA NA NA 1,200 170 320 NA NA 300 M Fluoranthene 1 3,030 NA 423 2,230 11,000 750 1,020 111 2,355 1,500 M Pyrene 1 3,250 NA 195 1,520 9,600 490 850 53 875 1,000 I Phthalates Bis(2-ethylhexyl)phthalate 1 16,700 NA NA NA 640 NA NA NA NA 750 M Petroleum hydrocarbons Diesel 4/4 10.9–4,750 NA NA NA NA NA NA NA NA NA Motor oil 3/4 144–9,840 NA NA NA NA NA NA NA NA NA Reference: Seattle Lakes Alliance (2000). NA = Not available a MacDonald et. al. (2000) mg/kg = milligrams per kilogram b Cubbage et al. (1997) μg/kg = micrograms per kilogram c Persaud et. al. (1993) OC = organic carbon d NOAA (1999). FSQV = freshwater sediment quality value e Detection limits varied from 20 μg/kg to as high as 16,800 μg/kg, depending on sample matrix. LPAH = low molecular weight polynuclear aeromatic hydrocarbon TEC: threshold effect concentration HPAH = high molecular weight polynuclear aeromatic hydrocarbon PEC: probable effect concentration LOEL: lowest observed effect level SEL: severe effect level TEL: threshold effect level or concentration below which adverse effects are expected to occur only rarely. Geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set. PEL: probable effects level, the level above which adverse effects are frequently expected. Geometric mean of the 50th percentile of impacted, toxic samples and the 85th percentile of the non-impacted samples. UET: Upper effects concentration derived as the lowest adverse effects threshold (AET) on 1% TOC basis from a compilation of endpoints analogous to the marine AET endpoints. M = Microtox bioassay I = Infaunal community impacts B = Bivalve Part 4 Conditions in Bitter Lake 31 City of Seattle State of the Waters 2007 Volume II: Small Lakes :LWK WKH H[FHSWLRQ RI FDGPLXP PHWDOV FRQFHQWUDWLRQV LQ %LWWHU /DNH VHGLPHQW VDPSOHV ZHUH ZHOO EHORZ(FRORJ\¶VSURSRVHGIUHVKZDWHUVHGLPHQWYDOXHV&DGPLXP PLOOLJUDPVSHUNLORJUDP>PJ NJ@ H[FHHGHGWKHIUHVKZDWHUVHGLPHQWTXDOLW\YDOXHRI PJNJDWRQHRIWKHIRXUVWDWLRQV 6(' located offshore of the Greenwood Avenue North storm drain outfall). All of the metals except silver H[FHHGHGWKHIUHVKZDWHUVHGLPHQWJXLGHOLQHVHVWDEOLVKHGE\RWKHUMXULVGLFWLRQV$UVHQLFFDGPLXP FKURPLXPFRSSHUDQGPHUFXU\H[FHHGHGRQHRUPRUHRIWKHORZHUHIIHFWVOHYHOV LHWKH7(&7(/ RU/2(/ WKHFRQFHQWUDWLRQVEHORZZKLFKELRORJLFDOHIIHFWVDUHXQOLNHO\WRRFFXU&DGPLXPOHDG DQG]LQFH[FHHGHGDQXSSHUHIIHFWVOHYHO LHWKH3(&3(/RU6(/ WKHFRQFHQWUDWLRQDERYHZKLFK ELRORJLFDO HIIHFWV DUH SUREDEOH :LWK WKH H[FHSWLRQ RI FRSSHU DOO H[FHHGDQFHV RFFXUUHG DW VWDWLRQ SED-1. Copper concentrations also exceeded the lower-effects level at stations SED-2 and SED-3. &RSSHUDQG]LQFDUHFRPPRQSROOXWDQWVLQXUEDQUXQRII%RWKDUHXVHGLQDXWRPRELOHV HJEUDNHSDGV WLUHVDQGHQJLQHSDUWV =LQFLVDOVRIRXQGLQJDOYDQL]HGSURGXFWVRIWHQXVHGDVEXLOGLQJPDWHULDOV HJ ÀDVKLQJGRZQVSRXWVDQGIHQFLQJ SLSHV HJFRUUXJDWHGPHWDOSLSHXVHGLQPDQ\VWRUPGUDLQV DQG some products used to control moss growth on roofs and other surfaces. 9RODWLOHRUJDQLFFRPSRXQGV3&%VDQGSHVWLFLGHVZHUHXQGHWHFWHGDWDOORIWKHVHGLPHQWVDPSOLQJ VWDWLRQVLQ%LWWHU/DNHDWGHWHFWLRQOLPLWVUDQJLQJIURPWRPLFURJUDPVSHUNLORJUDP JNJ Polycyclic aromatic hydrocarbons (PAHs) and bis(2-ethylhexyl)phthalate were detected only at station 6('+RZHYHUEHFDXVHWKHVDPSOHVZHUHGLOXWHGSULRUWRDQDO\VLVDQDO\WLFDOGHWHFWLRQOLPLWVIRU WKHVHVHPLYRODWLOHRUJDQLFFRPSRXQGVZHUHTXLWHKLJKUDQJLQJIURPWRJNJ $WVWDWLRQ6('EHQ]R JKL SHU\OHQHZDVGHWHFWHGDWJNJDQGELV HWK\OKH[\O SKWKDODWH ZDVGHWHFWHGDWJNJH[FHHGLQJ(FRORJ\¶VSURSRVHGIUHVKZDWHUVHGLPHQWTXDOLW\YDOXHVRI DQGJNJUHVSHFWLYHO\$OWKRXJKLWLVGLI¿FXOWWRHYDOXDWHWKHVHGLPHQWGDWDGXHWRWKHKLJK DQDO\WLFDOGHWHFWLRQOLPLWVLWDSSHDUVWKDWGLVFKDUJHVIURPWKH*UHHQZRRG$YHQXH1RUWKVWRUPGUDLQ KDYHGHJUDGHGVHGLPHQWTXDOLW\GLUHFWO\RIIVKRUHRIWKHRXWIDOO)XUWKHUHYDOXDWLRQLVQHHGHGDIWHU Ecology develops freshwater sediment standards for Washington state. Bis(2-ethylhexyl)phthalate has been detected in Seattle watercourses as well. Phthalates belong to a class of chemicals known as plasticizers that are used in the production of many polyvinyl chloride (PVC) construction and consumer products. Plasticizers have been used for a long time but have recently become an environmental concern because they have been found at elevated concentrations in sediment in urban receiving water bodies. Phthalates are used to make a wide variety of plastic SURGXFWVVXFKDVÀH[LEOHWXELQJYLQ\OÀRRULQJZLUHLQVXODWLRQZHDWKHUVWULSSLQJXSKROVWHU\FORWKLQJ SODVWLFFRQWDLQHUVDQGSODVWLFZUDSV 'LHVHORLOZDVGHWHFWHGLQDOOIRXUVHGLPHQWVDPSOHVWHVWHG IURP WRPJNJ DQGPRWRURLO ZDVGHWHFWHG IURP WR PJNJ LQWKUHHRIWKHIRXUVDPSOHVFROOHFWHGRIIVKRUHRIWKHVWRUP drain outfalls. The samples collected offshore of the outfall at Greenwood Avenue North and North WK 6WUHHW LH VWDWLRQ 6(' H[FHHGHG WKH 0RGHO7R[LFV &RQWURO$FW 07&$ 0HWKRG$ VRLO FOHDQXS OHYHO IRU WRWDO SHWUROHXP K\GURFDUERQV LH PJNJ 7RWDO SHWUROHXP K\GURFDUERQV detected in sediment samples collected at the other three stations (from <25 to 245 mg/kg) were well below the state soil cleanup levels. Although MTCA soil cleanup levels are not directly applicable to ODNHVHGLPHQWVDPSOHVWKRVHYDOXHVSURYLGHDQLQGLFDWLRQRIODNHVHGLPHQWTXDOLW\ 32 Part 4 Conditions in Bitter Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes Residents living along the Bitter Lake shoreline have complained to Seattle Public Utilities about the accumulation of sediment in the northwestern corner of the lake in the vicinity of the Greenwood $YHQXH1RUWKVWRUPGUDLQRXWIDOO,Q638FUHZVUHPRYHGDERXWFXELF\DUGVRIVHGLPHQWIURP around the outfall. Total petroleum hydrocarbon concentrations were measured in two samples of the GUHGJHGVHGLPHQW GLHVHORLOZDVGHWHFWHGDWPJNJDQGPRWRURLOZDVPHDVXUHGDWWR mg/kg). These concentrations were lower than the concentrations measured near the outfall at station 6('E\WKH6HDWWOH/DNHV$OOLDQFHVWXG\ LHGLHVHORLODWPJNJDQGPRWRURLODW PJNJ DOWKRXJKRQHGUHGJHVDPSOHH[FHHGHGWKH07&$0HWKRG$VRLOFOHDQXSOHYHORIPJNJ $SRWHQWLDOVRXUFHRIWKHVHSROOXWDQWVLVVWRUPZDWHUUXQRII,QXUEDQDUHDVVWRUPZDWHUUXQRIIFDQKDYH HOHYDWHGOHYHOVRISROOXWDQWVW\SLFDOO\DVVRFLDWHGZLWKPRWRUYHKLFOHVLQFOXGLQJRLODQGJUHDVHWRWDO SHWUROHXPK\GURFDUERQVDQGPHWDOV Habitat Conditions The habitat of Bitter Lake has not EHHQ ZHOO VWXGLHG DOWKRXJK WKH ZDWHU TXDOLW\ VWXGLHV LQGLFDWH WKDW WKH ODNH LV moderately productive and therefore able WR VXSSRUW D YDULHW\ RI ¿VK DQG ZLOGOLIH species. The Washington Department of Fish and Wildlife has stocked the lake ZLWKUDLQERZWURXWDQGZDUPZDWHU¿VK VSHFLHVVXFKDVODUJHPRXWKEDVV\HOORZ SHUFK EODFN FUDSSLH SXPSNLQVHHG DQG EURZQEXOOKHDG :'):DE The lake is also used by ducks and geese. The habitat along the lake shoreline consists primarily of landscaped yards JUDVV DQG VKUXEV DQG D SDUN ZLWK D number of residential docks. The lake DOVRFRQWDLQVVRPHDTXDWLFSODQWVSHFLHV Geese along Bitter Lake shoreline (photo by Bennett) Part 4 Conditions in Bitter Lake 33 City of Seattle State of the Waters 2007 Volume II: Small Lakes Green Lake *UHHQ /DNH ORFDWHG QRUWK RI /DNH 8QLRQ between Aurora Avenue North and East *UHHQ /DNH :D\ FRYHUV DSSUR[LPDWHO\ 259 acres (Figure 6). The lake is relatively VKDOORZZLWKDPHDQGHSWKRIDERXWIHHW and a maximum depth of approximately IHHW6LPLODUWRRWKHUODNHVLQWKHDUHD Green Lake was formed by the Vashon JODFLDO LFH VKHHW DERXW \HDUV DJR (DUO\LQ6HDWWOHKLVWRU\WKHODNHZDVIHGE\ springs and streams in surrounding forests WRWKHQRUWKDQGZDWHUH[LWLQJWKHODNHYLD Green Lake circa 1936 (photo courtesy Seattle Ravenna Creek ultimately reached Union Municipal Archives) Bay in Lake Washington. 7RGD\ WKH PDMRU VRXUFHV RI ZDWHU LQ *UHHQ /DNH DUH UDLQIDOO GLUHFW VWRUPZDWHU UXQRII IURP ODQGV LPPHGLDWHO\DGMDFHQWWRWKHODNH LQFOXGLQJ3KLQQH\5LGJHDQG:RRGODQG3DUN DQGRYHUÀRZVIURP the Densmore Avenue storm drain system. Green Lake now discharges to Lake Union through a single RXWOHWORFDWHGQHDU0HULGLDQ$YHQXH1RUWK,QWKHSDVW*UHHQ/DNHDOVRGLVFKDUJHGWRWKHFRPELQHG VHZHUV\VWHPYLDDQXPEHURIRXWOHWVDURXQGWKHODNH+RZHYHUWKHVHRXWOHWVZHUHUHFHQWO\EORFNHG and now are used by Seattle Parks and Recreation only during rainstorms of long duration when the 0HULGLDQ$YHQXH1RUWKRXWOHWLVQRWDGHTXDWHWRPDLQWDLQZDWHUOHYHOVLQ*UHHQ/DNH *UHHQ/DNHZDVRQFHODUJHUWKDQLWLVWRGD\EXWLQ WKHODNHOHYHOZDVORZHUHGE\IHHWDQG SRUWLRQVRIWKHODNHZHUH¿OOHG 6KHUZRRGXQGDWHG )LVHW 6LQFHWKDWWLPHWKHODNHKDVEHHQ VXEMHFWWRDGGLWLRQDO¿OOLQJDQGGUHGJLQJDVZHOODVVKRUHOLQHPRGL¿FDWLRQVLQFOXGLQJDSDYHGSXEOLF IRRWSDWKDURXQGWKHODNHSHULPHWHU7RGD\WKHODNHLVFRQWDLQHGLQDDFUHSXEOLFSDUNVXUURXQGHG primarily by residential and commercial (retail) land uses. 6LQFHDERXW ODUJHVFDOHLQYDVLRQVRIH[RWLFSODQWVDQGDQLPDOVVXFKDVZDWHUPLOIRLODQGFDUSKDYH EHHQREVHUYHGDQGLQVRPHFDVHVDXWKRUL]HGLQ*UHHQ/DNH,Q 6HDWWOH3DUNVDQG5HFUHDWLRQ SXUFKDVHGDQDTXDWLFSODQWKDUYHVWHUWRPDQDJHZDWHUPLOIRLOLQWKHODNH7KHGHSDUWPHQWDOVRLQLWLDWHG a waterfowl reduction program as a way to reduce fecal coliform bacteria levels from geese. ,QWKHHDUO\ V6HDWWOH3XEOLF8WLOLWLHVEHJDQGLYHUWLQJZDWHUWR*UHHQ/DNHIURPWKHFLW\GULQNLQJ water system in an effort to improve algae problems that have existed in the lake since at least 1916 (Herrera 2003a). In this way the lake was diluted at an average annual discharge rate ranging from 1.9 WRPLOOLRQJDOORQVSHUGD\ +HUUHUDE +RZHYHUGXHWRLQFUHDVHGGULQNLQJZDWHUGHPDQGWKH DYDLODELOLW\RIZDWHUWRGLOXWH*UHHQ/DNHKDVGHFUHDVHG%HWZHHQ DQG WKHDYHUDJHGDLO\ diversion from April through September was generally less than 1 million gallons per day. In recent \HDUVGLOXWLRQZDWHUGLVFKDUJHVWR*UHHQ/DNHW\SLFDOO\RFFXURQO\RQFHRUWZLFHHDFK\HDUZKHQ the Roosevelt and Maple Leaf reservoirs are emptied for cleaning. Over a 48-day period during the VXPPHURIDSSUR[LPDWHO\PLOOLRQJDOORQVZDVGLVFKDUJHGWR*UHHQ/DNHLQDQDWWHPSWWR control a large blue-green algae bloom. 34 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes G R I5 E N 80TH ST E N N NLA B E I5 N NE80TH S K T SB N ED AV Green Lake EN VE N N 79T R HST V VE N VE A DA EN N 79THST A TA V N MORE D N OR IA F EA NS OU D The City MO G N E AVE NE DE N 78TH ST O STR T LIN FR N T MERI S S20 NE AL 2ND E VE of Seattle W V 78TH S A S100 N A N 77 N TH S T T N77 TH S T EAST NE 77TH ST SIDE 1S AVE DR N GR E SE100 LISS EEN SUNNY R LAK N76TH S T N N LAK CO EN IN CT N7 N EDRNOR E 5T AV TGRE HST N 75THST S NONA E I SE250 AGLEY AVE STO W W B S250 N 75TH ST NE NE A 75THST W N 74THST VE N OO NWAYN D KEE L AWN AVE N73RD ST N E N AVE NE 72ND ST H EN T V NSED 4 A TON Y N 71ST ST DA EN N70TH ST AV Green Lake B IS C AN FR N 68TH S T PHINNEY AVE N 4 T N67THST HA VE N N E E WOODLAWN AVE N E N 66TH ST AV E N66THST SSED E LAT D EN N E I VE N V L ONA A A YS EN S TA N V S N A 1 PIN P U V NCI A D EN S N N 65TH S H N T 2 C E E FRA V A N65TH ST NE65THST ON T N Y N64TH ST LN A VE P D ND N64THS T NE6 A 4THST N63 DL RD ST VE N A N CORLISS A Green Lake A 6 WOO 3 R D N63RDST N NE STON ST 63RDST N 62ND ST Y AN VE N N WA A E EV AK ENE VE N V AVE EN A N62NDST V N EN L NE62ND ST YTON A N6 E A 1STST IAN D N D GRE ONA A N A T ID T LI S R A E EA L M N61STST NE61STS WHITM T N 60TH ST EN AV LEY PL N ENE AWN N N 60TH P ST I NE 60TH ST DL AV CK N59 T TH ST OO M LOO W 1S PHINNEY AVE N ARK N 59TH ST P NE 59TH ST ND A L K WEST GR E N58T N H ST NE 58TH ST OOD WO W E OD ENLA N KE W PL N A N 57TH Y AVE ST N CA NE 57TH ST N TH FI R E KE O L DPL Y ST HW KI N O NE 56TH ST RKWOO AS NE PL N TH ST KENS N 55THS 56 T N DP N 55TH ST N CLOGSTON WAY NE 55TH ST L IN N G T O N N 54THST NP E V L NE54TH ST A N YN T A H S R 54T O N N R N53RDST EWA N 53RD ST K NE 53RD ST AU AVE EN LA WN E LA N5 R 2ND ST D G NE 52ND ST ST ND 52 WOO N Legend N51ST ST NE 51ST ST N N 50TH ST VE Streets A NE50TH ST IAN D I Sediment TransectsN 49THST MER NE N EN E VE N N V AV A N Park Boundary DA EN N T A NAVE N N 48TH ST EN AV E M 1S EAVE E AVE FOR D N IT V G N N Water Quality ON LI TO WH RE AV EA NE ST S EN N 47THST K Monitoring StationsN AYTO ALLIN MO PL NE UR D VA W EN EAV B NS E V Sediment VE N N46T H ST A DE N VAL AVE N E EA N KERAY T N4 ID 6TH ST AV 2ND P MID S Water HINNEY W AVE N N 46TH ST M Y K KE N ID THAC N AVE N A V N AL L NE U N REMON PAR EP S F R THE CITY OF SEATTLE, 2007. All rights reserved ER N 45THST AY L WAY T AVE IN STE AND NE N45TH A ST NE45TH No guarantee of any sort implied, including E ST TO S BAGLEY AVE N accuracy, completeness, or fitness for use.N ALLEN P L OODL Figure 6 LATONA W N ALLENPL Figure 6. Green Lake. Part 4 Conditions in Green Lake 35 City of Seattle State of the Waters 2007 Volume II: Small Lakes Water Quality Conditions *UHHQ /DNH LV D VKDOORZ KLJKO\ SURGXFWLYH LH HXWURSKLF ODNH ZLWK high concentrations of nutrients such as nitrogen and phosphorus that promote plant and algae growth. Green Lake ZDWHU TXDOLW\ GDWD KDYH EHHQ FROOHFWHG E\ D VHULHV RI DJHQFLHV LQFOXGLQJ 6HDWWOH 3DUNV DQG 5HFUHDWLRQ 6HDWWOH 3XEOLF8WLOLWLHV6HDWWOH8QLYHUVLW\.LQJ &RXQW\DQGWKH:DVKLQJWRQ'HSDUWPHQW RI )LVK DQG :LOGOLIH :DWHU TXDOLW\ investigations have focused on the ODNH¶VSURGXFWLRQRIEOXHJUHHQEDFWHULD (also commonly called blue-green algae or cyanobacteria) and the human health risks caused by the toxic compound City of Seattle water quality volunteer monitoring on Green PLFURF\VWLQ ZKLFK LV SURGXFHG E\ WKH Lake (photo by Bennett) algae (Herrera 2003a). *UHHQ/DNHKDVDORQJKLVWRU\RIDOJDHSUREOHPV3K\VLFDODQGFKHPLFDOSURFHVVHVZLWKLQWKHODNH DVZHOODVGUDLQDJHWRWKHODNHIURPWKHVXUURXQGLQJZDWHUVKHGVXSSO\WKHQXWULHQWVWKDWVXSSRUWWKH blue-green algae blooms. Phosphorus is the main nutrient causing the problem (Herrera 2003a). The Department of Ecology included Green Lake on the 2004 list of threatened and impaired water ERGLHVXQGHU&OHDQ:DWHU$FW6HFWLRQ G OLVWLQJWKHODNHDVDFDWHJRU\ZDWHUERG\ (FRORJ\ $FFRUGLQJO\DWRWDOPD[LPXPGDLO\ORDG 70'/ OLPLWLVUHTXLUHGIRU*UHHQ/DNHEDVHGRQ GHPRQVWUDWHGH[FHHGDQFHVRIWKHVWDWHZDWHUTXDOLW\VWDQGDUGIRUWRWDOSKRVSKRUXV Previous studies have found that most of the phosphorus in Green Lake during the summer months can be attributed to the internal cycling of phosphorus stored in sediment on the lake bottom. The PRYHPHQWRIEOXHJUHHQDOJDHIURPWKHVHGLPHQWWRWKHZDWHUFROXPQKDVDOVREHHQLGHQWL¿HGDVD VLJQL¿FDQWVRXUFHRILQWHUQDOSKRVSKRUXVORDGLQJ 7RFRQWUROEOXHJUHHQDOJDHEORRPVLQ*UHHQ/DNH6HDWWOH3DUNVDQG5HFUHDWLRQZLWKIXQGLQJDVVLVWDQFH IURP(FRORJ\DQGWKH86(3$KDVDGRSWHGDSURJUDPWRLPSURYHWKHODNHZDWHUTXDOLW\DLPHGDW reducing phosphorus concentrations and increasing water clarity during the summer months (Herrera 2003b). Controlling the blooms reduces production of microcystin and eliminates the need for periodic FORVXUHRIWKHODNHWRUHFUHDWLRQDOXVHUV7KHFRUQHUVWRQHRIWKHSURMHFWLVWKHDSSOLFDWLRQRIDOXPLQXP VXOIDWH LH DOXP WR LQDFWLYDWH SKRVSKRUXV LQ WKH VHGLPHQW WKHUHE\ UHGXFLQJ LQWHUQDO SKRVSKRUXV loading and availability to blue-green bacteria. 36 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes *UHHQ/DNHZDVWUHDWHGZLWKDOXPLQ2FWREHU )ROORZLQJWKHWUHDWPHQWSKRVSKRUXVFRQFHQWUDWLRQV GURSSHG DQG ZDWHU FODULW\ LPSURYHG HIIHFWLYHO\ UHGXFLQJ WKH QXPEHUV RI DOJDH OLYLQJ LQ WKH ODNH +RZHYHUWKHWUHDWPHQWHIIHFWVGRQRWODVWLQGH¿QLWHO\ WUHDWPHQWZDVH[SHFWHGWRUHPDLQHIIHFWLYHIRU DERXWWR\HDUV,QWKHVXPPHUVRI DQGEORRPVRIEOXHJUHHQDOJDHDJDLQEHFDPH SUREOHPDWLF'XULQJWKHVHEORRPVSRWHQWLDOO\WR[LFOHYHOVRIPLFURF\VWLQZHUHSURGXFHGDQGWKHODNH was closed to all contact recreation (Herrera 2003a). In March 2004 the city treated the lake with alum DJDLQDSSO\LQJQHDUO\WKUHHWLPHVWKHDPRXQWDSSOLHGLQ 2WKHUHOHPHQWVRIWKH*UHHQ/DNHZDWHUTXDOLW\LPSURYHPHQWSURJUDPLQFOXGHWKHIROORZLQJ +DUYHVWLQJRIDTXDWLFSODQWVIURP WRWRUHGXFHSKRVSKRUXVORDGLQJDVVRFLDWHGZLWK biomass die-off in the lake and improve recreational use (Herrera 2003b) Installation of experimental facilities in 1992 to treat stormwater runoff from parking lots along West Green Lake Way &RQVWUXFWLRQRIDORZÀRZGLYHUVLRQVWUXFWXUHRQWKH'HQVPRUHVWRUPGUDLQV\VWHPLQ WR GLYHUWVRPHRIWKHUXQRIIIURPDDFUHVXEEDVLQQRUWKRI*UHHQ/DNHDZD\IURPWKHODNH7KH VWUXFWXUHGLYHUWVWKHORZHUÀRZV IURPVPDOOVWRUPVDQGSRUWLRQVRIODUJHUVWRUPHYHQWV WR/DNH 8QLRQZKLOHRQO\WKHSHDNÀRZVIURPKLJKLQWHQVLW\VWRUPVDUHURXWHGWKURXJK*UHHQ/DNH7KH GLYHUVLRQVWUXFWXUHLVLQWHQGHGWRGLYHUWWKHPRVWSROOXWHGUXQRIIIURPVPDOOHUVWRUPVDVZHOODV HDUO\SRUWLRQV HJ¿UVWÀXVK RIODUJHUVWRUPVDZD\IURPWKHODNH Discharge of excess drinking water from the city water system to dilute phosphorus concentrations LQWKHODNH,QWKHSDVW638SURYLGHGGLOXWLRQZDWHUIRU*UHHQ/DNHDWQRFRVW+RZHYHUGXHWR LQFUHDVHGGULQNLQJZDWHUGHPDQGVWKHORQJWHUPDYDLODELOLW\RIGLOXWLRQZDWHULVXQFHUWDLQDQG Seattle Parks and Recreation may be charged for this water. Relocation of Canada geese from Green Lake to wildlife areas in eastern Washington and northern ,GDKRDORQJZLWKDQHJJVWHULOL]DWLRQSURJUDPWRFRQWUROWKHUHVLGHQWJRRVHSRSXODWLRQ(XWKDQDVLD has also been used to control Canada geese at Green Lake in recent years. Implementation of a public information program for Green Lake residents and park users. :DWHUTXDOLW\GDWDFROOHFWHGIURP0D\WKURXJK6HSWHPEHUGXULQJWKHVHFRQGVXPPHUIROORZLQJ WKHDOXPWUHDWPHQWDUHVXPPDUL]HGLQ7DEOH 6DPSOHVZHUHFROOHFWHGIURPWKUHHVWDWLRQV including one depth composite sample collected from two stations (stations Green Lake A and B) by 6HDWWOH3DUNVDQG5HFUHDWLRQDQGRQHVXUIDFHJUDEVDPSOHFROOHFWHGIURPVWDWLRQ*UHHQ/DNH%E\WKH .LQJ&RXQW\YROXQWHHUPRQLWRULQJSURJUDP7KHVDPSOLQJUHVXOWVVKRZLPSURYHGZDWHUTXDOLW\ZLWK ZDWHUFODULW\FKORURSK\OODQGSKRVSKRUXVOHYHOVFRPSDUDEOHWROHYHOVPHDVXUHGLQ%LWWHU/DNHDQG +DOOHU/DNHZKLFK²XQOLNH*UHHQ/DNH²DUHFODVVL¿HGDVPHVRWURSKLF Part 4 Conditions in Green Lake 37 City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH *UHHQ/DNHZDWHUTXDOLW\GDWDIRU0D\±6HSWHPEHU Parameter n Minimum Maximum Average Temperature (degrees C) a 38 16.3 23.1 19.9 Dissolved oxygen(mg/L) a 38 7.5 10.3 9.2 Secchi depth (meters) b,c 30 1.3 5.6 3.3 Chlorophyll-a (μg/L) c 28 1.5 6.2 2.7 Total phosphorus (μg/L) c 30 8 20 12.9 Average TSI c 35.2 50.1 41.2 a Samples collected at 1-meter depth intervals (to 7-meter depth) from Green Lake B (May – August 2005). b Secchi depth is a measure of water clarity. The higher the value, the better the water clarity. c Samples collected from stations A, B, and Index stations (May – September 2005). mg/L = milligrams per liter μg/L = micrograms per liter TSI = trophic state index 7KHUHVXOWVPHWWKHZDWHUTXDOLW\JRDOVHVWDEOLVKHGE\WKHLPSURYHPHQWSURJUDPZKLFKLQFOXGHG DVXPPHUPHDQ6HFFKLGHSWKRIJUHDWHUWKDQPHWHUVIRUFODULW\DQGDVXPPHUPHDQWRWDOSKRVSKRUXV concentration of less than 25 μg/L. All of the 2005 samples met the recommended level for total phosphorus established by Ecology (WAC 173-201A) for lower mesotrophic lakes (20 μg/L). ,QDGGLWLRQWRWKHZDWHUTXDOLW\LPSURYHPHQWSURJUDP638KDVFRPSOHWHGDVWRUPZDWHUPDQDJHPHQW SODQIRUWKH'HQVPRUHGUDLQDJHEDVLQWKHODUJHVWVLQJOHEDVLQLQWKHODUJHU*UHHQ/DNHZDWHUVKHG$ ZDWHUTXDOLW\LQYHVWLJDWLRQLVDOVREHLQJFRQGXFWHGDVSDUWRIDEDVLQSODQQLQJHIIRUWWRLGHQWLI\ZDWHU TXDOLW\QHHGVLQWKH'HQVPRUHEDVLQDQGHYDOXDWHRSWLRQVIRUPLWLJDWLQJSRWHQWLDOLPSDFWVRISURSRVHG drainage improvements. This study includes modeling of phosphorus loading in Green Lake under H[LVWLQJDQGSURSRVHGFRQGLWLRQVWRGHWHUPLQHSRVVLEOHLPSDFWVRQZDWHUTXDOLW\LQWKHODNH,Q± WKHFLW\¶VVXUIDFHZDWHUTXDOLW\WHDPLQVSHFWHGLQGLYLGXDOEXVLQHVVVLWHVLQWKH'HQVPRUHEDVLQWR HQVXUHWKDWORFDOEXVLQHVVHVZHUHFRPSO\LQJZLWKWKHFLW\VWRUPZDWHUJUDGLQJDQGGUDLQDJHFRGHDQG to advise business owners of appropriate stormwater pollution prevention practices. *UHHQ/DNHDOVRH[SHULHQFHVDQXPEHURIRWKHUZDWHUTXDOLW\SUREOHPV7KH'HSDUWPHQWRI(FRORJ\ included Green Lake on the 2004 list of threatened and impaired water bodies under Clean Water $FW6HFWLRQ G OLVWLQJWKHODNHDVDFDWHJRU\ZDWHUERG\ ZLWK70'/OLPLWVUHTXLUHGEDVHGRQ GHPRQVWUDWHGH[FHHGDQFHVRIVWDWHZDWHUTXDOLW\VWDQGDUGV IRUIHFDOFROLIRUPEDFWHULDDVZHOODVIRU ¶''(FKORUGDQHDQGWRWDO3&%VZKLFKZHUHIRXQGLQWLVVXHVDPSOHVRIFRPPRQFDUSFROOHFWHG LQ (FRORJ\ $QRWKHUSUREOHPIRUUHFUHDWLRQDOXVHLVWKHRFFXUUHQFHRIVZLPPHU¶VLWFK 6ZLPPHU¶VLWFKFDXVHGE\DQDOOHUJLFUHDFWLRQWRDTXDWLFSDUDVLWHVFDQEHDSUREOHPIRUSHRSOHZKR VZLPLQWKHODNH 6HDWWOH3DUNVDQG5HFUHDWLRQXQGDWHG 38 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes .LQJ&RXQW\PRQLWRUVIHFDOFROLIRUPEDFWHULDOHYHOVDWVZLPPLQJEHDFKHVWKURXJKRXWWKHFRXQW\HDFK ZHHNGXULQJWKHVXPPHUPRQWKV5HVXOWVIRUWKH ±PRQLWRULQJSHULRGLQ*UHHQ/DNHDUH summarized in Table 10 and displayed in Figure 7. Fecal coliform bacteria levels were generally ORZHULQDQGWKDQLQSUHYLRXV\HDUVSRVVLEO\GXHWRWKHDOXPWUHDWPHQWLQ0DUFK7KH reduced lake productivity may have reduced the amount of coliform bacteria that commonly grow in GHFD\LQJRUJDQLFPDWWHUDQGWHVWSRVLWLYHIRUIHFDOFROLIRUPEDFWHULD HJ.OHEVLHOOD DQGLWPD\KDYH UHGXFHGWKHDEXQGDQFHRIZDWHUIRZOWKDWIHHGRQDOJDHDQGDTXDWLFSODQWV:DWHUTXDOLW\LQ*UHHQ/DNH FRQVLVWHQWO\PHWWKHJHRPHWULFPHDQSRUWLRQRIWKHVWDWHZDWHUTXDOLW\VWDQGDUGIRUODNHV DJHRPHWULF PHDQRIFIXP/ LQDOO\HDUVEXWPHWWKHFIXP/UHTXLUHPHQW QRPRUHWKDQSHUFHQW RIDOOVDPSOHVXVHGWRFDOFXODWHWKHJHRPHWULFPHDQH[FHHGLQJFIXP/ LQRQO\¿YHRIWKHWHQ monitoring years. 7DEOH*UHHQ/DNHVXPPHUIHFDOFROLIRUPEDFWHULDOHYHOV ± All Samples Summer Geometric Mean Minimum (cfu/100 mL) 1 6.6 Maximum (cfu/100 mL) 2,500 47 Median (cfu/100 mL) 23 28 Mean (cfu/100 mL) 87 29 Number of samples 174 9 cfu/100 mL = colony-forming units per 100 milliliters. 10,000 25th percentile min median max 75th percentile 1,000 100 Fecal coliform bacteria (cfu/100 mL) 10 1 1996 1998 1999 2000 2001 2002 2003 2004 2005 Year Source: King County )LJXUH*UHHQ/DNHVXPPHUIHFDOFROLIRUPEDFWHULDOHYHOV ± Part 4 Conditions in Green Lake 39 City of Seattle State of the Waters 2007 Volume II: Small Lakes 1RZDWHUTXDOLW\VWDQGDUGVIRUVZLPPLQJEHDFKHVKDYHEHHQHVWDEOLVKHGDVDEDVLVIRUGHWHUPLQLQJZKHQ to close beaches to protect public health. The Washington Department of Health has recommended using one of the following two fecal coliform bacteria standards to evaluate public health conditions at VZLPPLQJEHDFKHV Geometric mean of 200 cfu/100 mL with not more than 10 percent of the samples exceeding 400 cfu/100 mL (U.S. EPA 1976) *HRPHWULFPHDQRIFIXP/ZLWKQRVLQJOHVDPSOHH[FHHGLQJFIXP/ WHQVWDWH VWDQGDUG*UHDW/DNHV±8SSHU0LVVLVVLSSL5LYHU%RDUGRI6WDWH6DQLWDU\(QJLQHHUV 2YHUWKH\HDUSHULRGRIUHFRUGIRU*UHHQ/DNHIHFDOFROLIRUPEDFWHULDOHYHOVWKHVHDVRQDOJHRPHWULF PHDQKDVUDQJHGIURPWRFIXP/2QO\WZRVDPSOHV SHUFHQW KDYHH[FHHGHGFIX P/DQGIRXUVDPSOHV SHUFHQW KDYHH[FHHGHGFIXP/$WRWDORIVDPSOHV SHUFHQW KDYHH[FHHGHGFIXP/$VVWDWHGHDUOLHUWKHVRXUFHRILQFUHDVHGIHFDOFROLIRUPEDFWHULDLV likely the presence of waterfowl. *UHHQ/DNHGDWDIRU ± LQGLFDWHWKDWZDWHUWHPSHUDWXUHVLQWKHODNHUDQJHGEHWZHHQDQG& and dissolved oxygen levels ranged from 4 mg/L at the lake bottom to 12 mg/L at the lake surface. ,QDQR[LFFRQGLWLRQV LHPJ/R[\JHQ ZHUHREVHUYHGDWWKHODNHERWWRP([WUHPHO\ORZ R[\JHQOHYHOVQHDUWKHERWWRPUHVXOWIURPVXPPHUVWUDWL¿FDWLRQZKHUHDWKHUPRFOLQHGHYHORSVEHWZHHQ WKHZDUPZHOOR[\JHQDWHGZDWHUQHDUWKHVXUIDFHDQGWKHFRROGHHSHUZDWHU$VEDFWHULDGHJUDGH WKHRUJDQLFPDWWHUWKDWKDVVHWWOHGWRWKHERWWRPQHDUO\DOOWKHR[\JHQFDQEHFRQVXPHG&RROHUDLU WHPSHUDWXUHVDQGLQFUHDVHGZLQGDFWLYLW\LQWKHIDOOFDXVHWKHODNHZDWHUWRPL[GLVLQWHJUDWLQJWKH thermocline and creating more uniform levels of oxygen and temperature throughout the lake. $VVKRZQLQ7DEOH GDWDIURPWKHVHFRQGVXPPHUVHDVRQIROORZLQJDOXPWUHDWPHQWH[KLELWVLPLODU SDWWHUQVZLWKWHPSHUDWXUHUDQJLQJIURPWR&DQGGLVVROYHGR[\JHQUDQJLQJIURPWR PJ/+RZHYHUDQR[LFFRQGLWLRQVGLGQRWRFFXUGXULQJWKHPRQLWRULQJSHULRG$VQRWHG SUHYLRXVO\FKDQJHVLQWHPSHUDWXUHDQGGLVVROYHGR[\JHQFRQGLWLRQVGLUHFWO\DIIHFWKDELWDWFRQGLWLRQV and the health and vitality of lake biology. Sediment Quality Conditions ,Q 638 FROOHFWHG VHGLPHQW VDPSOHV IURP VHYHQ ORFDWLRQV RIIVKRUH RI WKH 'HQVPRUH$YHQXH 1RUWKVWRUPGUDLQRXWIDOOLQ*UHHQ/DNHWRHYDOXDWHSRVVLEOHLPSDFWVRQVHGLPHQWTXDOLW\UHVXOWLQJ IURPVWRUPZDWHUGLVFKDUJHV VHH)LJXUH 6DPSOHVZHUHDQDO\]HGIRUPHWDOVVHPLYRODWLOHRUJDQLF FRPSRXQGVWRWDOSHWUROHXPK\GURFDUERQVDQG3&%V 0HWDOVZHUHIUHTXHQWO\GHWHFWHGDWPRVWRIWKH*UHHQ/DNHVHGLPHQWVDPSOLQJVWDWLRQV0HWDOVGHWHFWHG LQ*UHHQ/DNHVHGLPHQWVDPSOHVDUHVXPPDUL]HGLQ7DEOH&DGPLXPFKURPLXPOHDGDQG]LQF concentrations were higher at stations located 100 and 250 feet from the Densmore outfall (stations 666(DQG6( WKDQFRQFHQWUDWLRQVDWWKHPLGODNHVWDWLRQV 16('DQG66(' DQG WKHVWDWLRQORFDWHGIHHWIURPWKHRXWIDOO 6 +RZHYHUWKHKLJKHVWFRSSHUFRQFHQWUDWLRQ PJ kg) was measured at mid-lake station NSED. 40 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH*UHHQ/DNHVHGLPHQWPHWDOVFRQFHQWUDWLRQVFRPSDUHGWRIUHVKZDWHUVHGLPHQW guidelines. Consensus- Ecology Green Lake Based Sediment Sediment Data Guidelines a Quality Values b Ontario c NOAA d Compound Number of Test (mg/kg) Detections Range TEC PEC FSQV LOEL SEL TEL PEL UET Org Arsenic 5/7 8–30 9.79 33 57 6 33 5.9 17 17 I Cadmium 4/7 <2–3 0.99 4.98 5.1 0.6 10 0.596 3.53 3 I Chromium 7/7 19.4–64 43.4 111 260 26 110 37.3 90 95 H Copper 7/7 31.8–163 31.6 149 390 16 110 35.7 197 86 I Lead 7/7 68–713 35.8 128 450 31 250 35 91.3 127 H Mercury 4/7 <0.06–0.4 0.18 1.06 0.41 0.2 2 0.174 0.486 0.56 M Zinc 7/7 85.1–516 121 459 410 120 820 123.1 315 520 M mg/kg = milligrams of compound per kilogram of sediment. a MacDonald et al. (2000). b Cubbage et al. (1997). c Persaud et. al., (1993). d NOAA (1999). FSQV: freshwater sediment quality value. TEC: threshold effect concentration. PEC: probable effect concentration. LOEL: lowest observed effect level. SEL: severe effect level. TEL: threshold effect level or concentration below which adverse effects are expected to occur only rarely. Geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set. PEL: probable effects level, the level above which adverse effects are frequently expected. Geometric mean of the 50th percentile of impacted, toxic samples and the 85th percentile of the non-impacted samples. UET: Upper effects concentration derived as the lowest adverse effects threshold (AET) from a compilation of endpoints analogous to the marine AET endpoints. M = Microtox bioassay I = Infaunal community impacts H = Hyalella azteca bioassay :LWKWKHH[FHSWLRQRIOHDGDQG]LQFPHWDOVFRQFHQWUDWLRQVZHUHEHORZWKH (FRORJ\SURSRVHG IUHVKZDWHUVHGLPHQWTXDOLW\YDOXHV+RZHYHUDWRQHRUPRUHVWDWLRQVLQ*UHHQ/DNHDOOPHWDOVH[FHHGHG WKHORZHUHIIHFWVOHYHOVWKHFRQFHQWUDWLRQVEHORZZKLFKELRORJLFDOHIIHFWVDUHXQOLNHO\WRRFFXU LH 7(&7(/RU/2(/ HVWDEOLVKHGE\RWKHUMXULVGLFWLRQV2QO\FRSSHUOHDGDQG]LQFH[FHHGHGXSSHU HIIHFWVOHYHOV HJ3(&3(/RU6(/ WKHFRQFHQWUDWLRQVDERYHZKLFKELRORJLFDOHIIHFWVDUHSUREDEOH 6WDWLRQVH[FHHGLQJ(FRORJ\IUHVKZDWHUTXDOLW\YDOXHVDQGWKHXSSHUHIIHFWVOHYHOVDUHOLVWHGLQ7DEOH (see Figure 6). Part 4 Conditions in Green Lake 41 City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH*UHHQ/DNHVDPSOLQJVWDWLRQVZLWKH[FHHGDQFHVRIIUHVKZDWHUVHGLPHQWJXLGHOLQHV Ecology Freshwater Sediment Upper Effects Station Quality Values Level NSED b BEHP Copper, lead, BEHP, chrysene, benzo(a)anthracene SSED b None Copper, lead S20 a None None S100 Lead, zinc, BEHP Copper, lead, zinc, DDD, BEHP, anthracene, benzo(g,h,i)perylene, benzo(a)anthracene, benzo(a)pyrene, dibenz(a,h,)anthracene, indeno(1,2,3- benzo(g,h,i)perylene, benzo(g,h,i)perylene, chrysene, c,d)pyrene chlordane, dibenz(a,h,)anthracene, indeno(1,2,3- c,d)pyrene S250 Lead, mercury Copper, lead, zinc, DDD, chlordane, SE100 BEHP, carbazole, Lead, zinc, DDD, BEHP, dieldrin, benzo(g,h,i)perylene, benzo(g,h,i)perylene, chrysene, benzo(a)anthracene, benzo(a)pyrene, dibenz(a,h)anthracene, indeno(1,2,3- dibenz(a,h)anthracene, chlordane, lindane, indeno(1,2,3- c,d)pyrene c,d)pyrene SE250 Lead, BEHP, Aroclor 1260 Copper, lead, zinc, DDD, DDE, BEHP, chlordane, Aroclor 1260 BEHP = bis(2-ethylhexyl)phthalate. a Station S20, located near the Densmore outfall, contained mostly coarse-grained material (70 percent coarse sand and gravel). b Stations NSED and SSED, located near the center of Green Lake, contained a large amount of fine-grained material (50–56 percent fine silt and clay) and a low amount of total solids (7.7–8.5 percent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oncentrations of pesticides and high and low molecular weight polycyclic aromatic hydrocarbons +3$+DQG/3$+ DOVRH[FHHGHGWKHXSSHUHIIHFWVOHYHOVHVWDEOLVKHGE\RWKHUMXULVGLFWLRQVDWPXOWLSOH VWDWLRQV LQ *UHHQ /DNH LQGLFDWLQJ D VWURQJ SRWHQWLDO IRU ELRORJLFDO HIIHFWV 3&%V $URFORU exceeded the NOAA upper effects threshold at station SE250. Further evaluation should be conducted when Ecology develops its freshwater sediment management standards. 42 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes Habitat Conditions *UHHQ /DNH KLVWRULFDOO\ ZDV D VKDOORZ KLJKO\ SURGXFWLYH ODNH ,I OHIW LQ D QDWXUDO VWDWH WKH ODNH ZRXOGKDYHYHU\VORZO\¿OOHGLQWKURXJKWLPHDQGEHFRPHDZHWODQG+RZHYHUWKHODNHWRGD\VHUYHV primarily recreational uses. *HQHUDOO\ WKH DTXDWLF HQYLURQPHQW RI *UHHQ /DNH LV KLJKO\ SURGXFWLYH DV UHODWHGWRLWVHXWURSKLFVWDWH+RZHYHUWKH native lake ecosystem has been drastically changed by the introduction of a number of nonnative plant and animal species. The URRWHGDTXDWLFSODQW(XUDVLDQZDWHUPLOIRLO (known as milfoil) has been the largest problem. Milfoil growth expanded during the 1980s to cover over 90 percent of the ODNH VXUIDFH DUHD VHYHUHO\ DOWHULQJ WKH Underwater photo of milfoil in Green Lake, Seattle (photo lake ecosystem and restricting use and by Zisette) HQMR\PHQWRIWKHODNH +HUUHUDD 0LOIRLORIWHQIRUPVDÀRDWLQJFDQRS\WKDWVKDGHVQDWLYHDTXDWLFSODQWVDQGUHGXFHVWKHLUJURZWK7KHVH PLOIRLOPDWVDOVRFDXVHSUREOHPVIRUVZLPPHUVDQGERDWHUVZKRFDQEHFRPHHQWDQJOHGLQWKHSODQW Milfoil contributes to phosphorus loading in the lake sediments through its release of phosphorus GXULQJGHFRPSRVLWLRQGHFUHDVLQJWKHHIIHFWLYHQHVVRIDOXPWUHDWPHQWV0LOIRLODOVRUHGXFHVGLVVROYHG R[\JHQOHYHOVWKURXJKR[\JHQFRQVXPSWLRQGXULQJUHVSLUDWLRQDWQLJKWDVZHOODVGHFRPSRVLWLRQRI dead plants. $VXUYH\RIDTXDWLFSODQWVE\+HUUHUD E LGHQWL¿HGRQO\SHUFHQW DFUHV RI*UHHQ/DNH FRYHUHGLQPLOIRLOFRPSDUHGWRSHUFHQW DFUHV FRYHUHGLQ 7KHREVHUYHG SHUFHQW decline in milfoil coverage is directly proportional to declines in milfoil biomass and internal phosphorus ORDGLQJ$TXDWLFSODQWVSULPDULO\PLOIRLOFRQWULEXWHGSHUFHQWRIWKHWRWDOSKRVSKRUXVORDGLQJWR WKHODNHEHWZHHQ DQG DQGDUHHVWLPDWHGWRKDYHFRQWULEXWHGOHVVWKDQSHUFHQWRIWKHWRWDO phosphorus loading in 2005. 7KHZKLWHZDWHUOLO\DQLQWURGXFHGQRQQDWLYHÀRDWLQJOHDYHGSODQWLVWKHRQO\RWKHUDEXQGDQWDTXDWLF SODQWLQ*UHHQ/DNHFRYHULQJSHUFHQW DFUHV RIWKHODNHLQ0RVWRIWKHVKRUHOLQHLV GRPLQDWHGE\HLWKHUQRQQDWLYHVSHFLHV SULPDULO\\HOORZÀDJLULVUHHGFDQDU\JUDVVDQG+LPDOD\DQ EODFNEHUU\ RUDJJUHVVLYHQDWLYHVSHFLHV FDWWDLOV RULVXQYHJHWDWHGGXHWRWKHSUHVHQFHRIUHWDLQLQJ walls or disturbances by humans and dogs (Herrera 2005b). Part 4 Conditions in Green Lake 43 City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH*UHHQ/DNHVHGLPHQWRUJDQLFFRPSRXQGVFRQFHQWUDWLRQVFRPSDUHGWRIUHVKZDWHUVHGLPHQWJXLGHOLQHV Consensus-Based Ecology Sediment Green Lake Guidelines a Quality Values b Ontario c NOAA d Number of Range e Range TEC PEC FSQV LOEL SEL TEL PEL UET Compound Detections (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) Test Org LPAH Acenaphthene 1/7 <70–140 <0.9–1.0 NA NA 3,500 NA NA NA NA 290 M Anthracene 2/7 <69–440 <0.9–6.9 57.2 845 2,100 220 370 NA NA 260 M Fluorene 1/7 <69–170 <0.9–1.3 77.4 536 3,600 190 160 NA NA 300 M Phenanthrene 6/7 <96–2,500 <0.9–35 204 1,170 5,700 560 950 41.9 515 800 I HPAH Benzo(a)anthracene 6/7 <96–2,000 <0.9–30 108 1,050 5,000 320 1,480 NA NA NA Benzo(a)pyrene 5/7 <96–2,400 <0.9–30 150 1,450 7,000 370 1,440 31.9 782 700 I Benzo(b)fluoranthene 6/7 <96–3,100 <0.9–30 NA NA NA NA NA NA NA NA Benzo(k)fluoranthene 4/7 <96–3,100 <0.9–30 NA NA NA 240 1,340 NA NA 13,400 B Benzo(b+k)fluoranthene <96–4,200 <0.9–60 NA NA 11,000 NA NA NA NA Benzo(g,h,i)perylene 5/7 <96–1,700 <0.9–23 NA NA 1,200 170 320 NA NA 300 M Chrysene 6/7 <96–2,900 <0.9–38 166 1,290 7,400 340 460 57.1 862 800 I Dibenz(a,h)anthracene 3/7 <69–520 <0.9–7 33 NA 230 60 130 NA NA 100 M Indeno(1,2,3-c,d)pyrene 5/7 <96–1,800 <0.9–25 NA NA 730 200 320 NA NA 330 M Fluoranthene 6/7 <96–5,200 <0.9–68 423 2,230 11,000 750 1,020 111 2,355 1,500 M Pyrene 6/7 <96–4,900 <0.9–67 195 1,520 9,600 490 850 53 875 1,000 I Phthalates Bis(2-ethylhexyl)phthalate 6/7 <96–8,600 <0.9–101 NA NA 640 NA NA NA NA 750 M Butylbenzylphthalate 5/7 <20–1,800 <0.9–17 NA NA NA NA NA NA NA NA Dimethylphthalate 1/7 <20–120 <0.9–0.9 NA NA NA NA NA NA NA NA Di-n-octylphthalate 5/7 <69–3,200 <1–40 NA NA NA NA NA NA NA NA Pesticides 4,4’-DDD 6/7 <2–98 <0.02–1.4 4.88 28 NA 8 6 3.54 8.51 60 I 4,4’DDE 3/7 <1.4–37 <0.02–0.54 3.16 31.3 NA 5 19 1.42 6.75 50 I 4,4’-DDT 1/7 <0.99–21.9 <0.02–0.24 4.16 62.9 NA 7 12 NA NA <50 I Aldrin 1/7 <0.98–8.21 <0.01–0.06 NA NA NA 2 8 NA NA 40 I Part 4 Conditions in Green Lake 44 City of Seattle State of the Waters 2007 Volume II: Small Lakes 7DEOH FRQWLQXHG *UHHQ/DNHVHGLPHQWRUJDQLFFRPSRXQGVFRQFHQWUDWLRQVFRPSDUHGWRIUHVKZDWHUVHGLPHQWJXLGHOLQHV Consensus-Based Ecology Sediment Green Lake Guidelines a Quality Values b Ontario c NOAA d Number of Range e Range TEC PEC FSQV LOEL SEL TEL PEL UET Compound Detections (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) (μg/kg) (mg/kg OC) (μg/kg) (μg/kg) (μg/kg) Test Org Dieldrin 2/7 <1.8–19.7 <0.025–0.151.9 61.8 NA 2 91 2.85 6.67 300 I Gamma chlordane 6/7 <0.99–65 <0.01–0.61 3.24 17.6 NA 7 6 4.5 8.9 30 I Lindane 1/7 <0.98–9.64 <0.01–0.06 2.37 4.99 NA 3 1 0.94 1.38 9 I Heptachlor 1/7 <0.98–8.64 <0.005–0.062.47 16 NA NA NA NA NA 10 I PCBs NA NA NA Aroclor 1260 1/7 <20–58 <0.2–0.84 59.8f 676f 21f 5g 24g 34.1f 277f 26f M TPH Diesel 7/7 11–850 -- NA NA NA NA NA NA NA NA Motor oil 7/7 55–4,000 -- NA NA NA NA NA NA NA NA Others Carbazole 2/7 <70–280 <0.9–4.1 NA NA NA NA NA NA NA NA Dibenzofuran 1/7 <69–80 <0.9–0.59 NA NA NA NA NA NA NA NA NA = not available a MacDonald et. al. (2000). b Cubbage et al. (1997). c Persaud et. al. (1993). d NOAA (1999). e Detection limits varied from 20 μg/kg to as high as 16,800 μg/kg, depending on the sample matrix. f total PCBs. g tentative guidelines. FSQV: freshwater sediment quality value. TEC: threshold effect concentration. PEC: probable effect concentration. LOEL: lowest observed effect level. SEL: severe effect level. TEL: threshold effect level or concentration below which adverse effects are expected to occur only rarely. Geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set. PEL: probable effects level, the level above which adverse effects are frequently expected. Geometric mean of the 50th percentile of impacted, toxic samples and the 85th percentile of the non-impacted samples. UET: Upper effects concentration derived as the lowest adverse effects threshold (AET) on 1% TOC basis from a compilation of endpoints analogous to the marine AET endpoints. M = Microtox bioassay I = Infaunal community impacts B = Bivalve mg/kg = milligrams per kilogram μg/kg = micrograms per kilogram Part 4 Conditions in Green Lake 45 City of Seattle State of the Waters 2007 Volume II: Small Lakes $TXDWLFSODQWKDUYHVWLQJHTXLSPHQWZDVSXUFKDVHGLQ DQGRSHUDWHGWKURXJK DVSDUWRIWKH SURJUDPWRLPSURYHZDWHUDQGVHGLPHQWTXDOLW\LQ*UHHQ/DNH7KHKDUYHVWHUZDVXVHGSULPDULO\WR clear milfoil from the rowing (crew) lanes in the lake and was not expected to reduce the coverage of PLOIRLO+RZHYHUKDUYHVWLQJRIPLOIRLOIURPWKHODNHGHFOLQHGLQ +HUUHUDE DQGKDUYHVWLQJ was completely suspended in 2000 because of a dramatic decline in milfoil coverage and density reported by Seattle Parks and Recreation (Herrera 2005b). The decline of milfoil coverage in 2000 was attributed to the concurrent decline in water clarity—and resulting light limitation—caused by severe EORRPVRIEOXHJUHHQDOJDH F\DQREDFWHULD ZKLFKSURGXFHGSRWHQWLDOO\WR[LFOHYHOVRIPLFURF\VWLQDQG SURPSWHGFORVXUHRIWKHODNHWRDOOFRQWDFWUHFUHDWLRQLQ DQGDJDLQLQDQG An effort to control milfoil was made in 2001 with the introduction of 777 Asian grass carp (made sterile WRFRQWUROWKHLUSRSXODWLRQ ZKLFKJUD]HRQDTXDWLFYHJHWDWLRQ)LVKVXUYH\VRI*UHHQ/DNHLQ DQGLOOXVWUDWHWKDW$VLDQJUDVVFDUSDUHKHDOWK\LQWKHODNHHFRV\VWHPKDYLQJPRUHWKDQGRXEOHG in median length from 32 centimeters in 2002 to 66 centimeters in 2005 (Herrera 2005b). These results DQGWKHORZDEXQGDQFHRIPLOIRLODQGRWKHUVXEPHUJHGDTXDWLFSODQWVPHDVXUHGLQVXJJHVWWKDW WKHJUDVVFDUSSRSXODWLRQLVFRQWUROOLQJWKHJURZWKRIPLOIRLOLQ*UHHQ/DNH+RZHYHULWLVDQWLFLSDWHG that milfoil coverage will increase in response to the dramatic increase in water clarity resulting from the 2004 alum treatment. Qualitative observations of milfoil coverage in the lake indicate that coverage substantially increased from 2004 to 2005 (Herrera 2005a). 7KH$VLDQJUDVVFDUSLVEXWRQHRIDQHFOHFWLFPL[RI¿VKVSHFLHVLQ*UHHQ/DNH7KHODNHFRQWDLQV QDWLYHUDLQERZWURXW VWRFNHGLQWRWKHODNH DQGVFXOSLQDORQJZLWKQRQQDWLYHODUJHPRXWKEDVVFRPPRQ FDUS WLJHU PXVN\ VWRFNHG LQWR WKH ODNH \HOORZ SHUFK EURZQ EXOOKHDG URFN EDVV EODFN FUDSSLH SXPSNLQVHHGDQGFKDQQHOFDW¿VK :'):DE )LVKVXUYH\VFRQGXFWHGLQWKHODNHVLQFH 1993 indicate that common carp and largemouth bass are the dominant species. Given the conditions LQWKHODNHLWLVXQOLNHO\WKDWDVHOIVXVWDLQLQJSRSXODWLRQRIWURXWRURWKHUQDWLYH¿VKHV HJWKUHHVSLQH stickleback or northern pike minnow) can be established. 7KHSUHVHQFHRIFRPPRQFDUSLVRQHRIWKHLPSHGLPHQWVWRLPSURYHGZDWHUTXDOLW\LQ*UHHQ/DNH WKHLU population likely reduces the effectiveness of alum treatments. Common carp are bottom feeders that root and dig in the sediments for worms and insects. Their feeding and spawning activities suspend bottom VHGLPHQWVDQGXSURRWDTXDWLFSODQWV LHPDFURSK\WHV :KHQERWWRPVHGLPHQWVDUHLQVXVSHQVLRQ QXWULHQWVVXFKDVSKRVSKRUXVDUHUHOHDVHGWRWKHZDWHUFROXPQIXHOLQJEDFWHULDOEORRPV7KHLQFUHDVLQJ sediment suspended in the water column also reduces light penetration and restricts native plant growth. Common carp may also contribute to the spread of milfoil to other areas of the lake by uprooting or EUHDNLQJSODQWVLQWRIUDJPHQWV0LOIRLOFDQUHURRWDQGJURZIURPWKHVHVPDOOIUDJPHQWV,QDGGLWLRQ FRPPRQFDUSUHGXFHDTXDWLFLQVHFWSRSXODWLRQVE\SUHGDWLRQDQGE\HOLPLQDWLQJQDWLYHDTXDWLFSODQWV WKDWSURYLGHFRYHU2WKHU¿VKDQGVRPHZLOGOLIHVSHFLHVFDQEHDGYHUVHO\DIIHFWHGE\WKHORVVRILQVHFW IRRGVRXUFHVDQGDTXDWLFSODQWVWKDWSURYLGHFRYHUIRUODUYDODQGMXYHQLOH¿VK Common carp are long-lived and grow to large sizes. They have no natural predators and are JHQHUDOO\XQGHVLUDEOHWR¿VKHUPHQ ZLWKWKHH[FHSWLRQRIVRPH¿VKHUPHQZKRREWDLQSHUPLWVIURP the Washington Department of Fish and Wildlife to net common carp from Green Lake and other lakes LQZHVWHUQ:DVKLQJWRQGXULQJWKHVSULQJ &RQVHTXHQWO\FRPPRQFDUSKDYHEHHQWKULYLQJLQ*UHHQ /DNH(OHFWUR¿VKLQJFDWFKUDWHVIRUFRPPRQFDUSLQFUHDVHGIRXUIROGIURP WR DQG*UHHQ Lake common carp were among the largest compared to those caught in 25 other western Washington lakes (WDFW 2000). 46 Part 4 Conditions in Green Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes ,QDQHIIRUWWRFRQWUROFRPPRQFDUSSRSXODWLRQVWKH'HSDUWPHQWRI)LVKDQG:LOGOLIHVWRFNHG*UHHQ /DNHLQ1RYHPEHUZLWKVWHULOHWLJHUPXVN\DVSHFLHVWKDWLVDFURVVEHWZHHQPXVNHOOXQJHDQG QRUWKHUQSLNH +HUUHUDE 7KHVH¿VKZHUHH[SHFWHGWRIHHGRQMXYHQLOHFRPPRQFDUSDQGFRQWURO WKHLUSRSXODWLRQ7KHGHSDUWPHQWKDVFRQGXFWHG¿VKVXUYH\VVLQFHWKHVWRFNLQJDQGWKHFRPELQHG UHVXOWVVKRZWKDWWKDWFRPPRQFDUSLVVWLOOWKHGRPLQDQWVSHFLHVFRPSULVLQJDSSUR[LPDWHO\SHUFHQW RIWKHWRWDO¿VKELRPDVVDQGSHUFHQWRIWKHWRWDO¿VKQXPEHUV7KHVHFRQGPRVWDEXQGDQWVSHFLHV E\ELRPDVVLVWLJHUPXVN\ SHUFHQW DQGE\QXPEHULVODUJHPRXWKEDVV SHUFHQW +HUUHUDE The potential impact of tiger musky on the common carp population has not been evaluated. )URP0D\WR-XQHWKH'HSDUWPHQWRI)LVKDQG:LOGOLIHFRQGXFWHGDFDUSUHPRYDOSURJUDP in Green Lake for Seattle Parks and Recreation. The capture methods used to remove carp included the XVHRIHOHFWUR¿VKLQJJLOOQHWWLQJDQG¿VKWUDSV%DVHGRQWKHPDUNDQGUHFDSWXUHGDWDFROOHFWHGGXULQJ WKHLQLWLDOSKDVHRIWKHSURJUDPWKHFDUSGHQVLW\ZDVHVWLPDWHGDWNLORJUDPVSHUKHFWDUH NJ KD EHIRUHFDUSUHPRYDODFWLYLWLHVEHJDQ8SRQFRPSOHWLRQRIWKHSURJUDPLQ-XQHFDUSGHQVLW\ ZDVHVWLPDWHGWRKDYHGURSSHGWRNJKD +HUUHUDD UHSUHVHQWLQJDUHGXFWLRQRIWKHFRPPRQ carp population in Green Lake of approximately 38 percent. Because the size of the carp population LVGHSHQGHQWRQWKHODNHSURGXFWLYLW\DQGIRRGVXSSO\LWLVOLNHO\WKDWWKHFDUSSRSXODWLRQZLOOUHPDLQ reduced as long as the 2004 alum treatment is effective. Carp bioturbation modeling results suggest that the sediment suspended by common carp contributes approximately 5 percent of the phosphorus load to Green Lake (Herrera 2005a). Because most of WKHVXVSHQGHGSKRVSKRUXVLVERXQGWRDOXPLQXPDQGQRWDYDLODEOHIRUXSWDNHE\EDFWHULDDQGDOJDH FDUSUHPRYDOLVQRWOLNHO\WRSURYLGHDPHDVXUDEOHLPSURYHPHQWWR*UHHQ/DNHZDWHUTXDOLW\ +HUUHUD 2005a). 7KHVKRUHOLQHKDELWDWDURXQG*UHHQ/DNHFRQVLVWVSULPDULO\RIODUJHDUHDVRIRSHQJUDVVDQGODQGVFDSLQJ with pockets of vegetation both along the shoreline and in setback areas. The pedestrian/bicycle path WKDWFLUFOHVWKHODNHLVLPPHGLDWHO\DGMDFHQWWRPRVWRIWKHVKRUHOLQHZKLFKLVUHLQIRUFHGLQVRPHSODFHV ZLWKEDQNDUPRULQJ7KHODNHDOVRKDVVHYHUDOGRFNVXVHGIRU¿VKLQJDQGQRQPRWRUL]HGERDWXVH &XUUHQWO\6HDWWOH3DUNVDQG5HFUHDWLRQWULHVWRPDLQWDLQDEDODQFHEHWZHHQKXPDQXVHRIWKHODNHDQG SURWHFWLRQRIKDELWDWIRUELUGV7\SHVRIELUGVWKDWKDYHEHHQVHHQDW*UHHQ/DNHLQFOXGHGXFNVJUHEHV JXOOVYDULRXVVSHFLHVRIVRQJELUGVDQGVRPHELUGVRISUH\0RVWELUGVDUHQRWSHUPDQHQWUHVLGHQWV DWWKHODNHDQGWKHLUDSSHDUDQFHPD\EHVHDVRQDORUUDUHGHSHQGLQJRQWKHVSHFLHV%LUGVLJKWLQJVRI SDUWLFXODULQWHUHVWLQFOXGHJUHHQKHURQKRRGHGPHUJDQVHUEDOGHDJOHSHUHJULQHIDOFRQDQGJUHDWEOXH KHURQ 6HDWWOH3DUNVDQG5HFUHDWLRQXQGDWHG Canada geese are common at Green Lake and are considered a nuisance by some because of the droppings they leave around the lake. The droppings are unpleasant to recreational users and can increase phosphorus and fecal coliform bacteria levels in the lake. Habitat conditions at the lake VXSSRUWWKHJRRVHSRSXODWLRQE\SURYLGLQJSOHQW\RIJUDVVDQGDTXDWLFYHJHWDWLRQWRIHHGRQDQGHDV\ DFFHVVIURPWKHODNHWRWKHVXUURXQGLQJRSHQJUDVV\DUHDV*HHVHDQGRWKHUZDWHUIRZODOVRFDQFDUU\ WKHSDUDVLWHWKDWFDXVHVVZLPPHU¶VLWFKDOWKRXJKZDWHUIRZOSOD\RQO\RQHUROHLQWKHGHYHORSPHQWRI VZLPPHU¶VLWFK²WUDQVPLVVLRQ²DQGDUHQRWWKHVROHFDXVH Part 4 Conditions in Green Lake 47 City of Seattle State of the Waters 2007 Volume II: Small Lakes Haller Lake Haller Lake (photo by Bennett) +DOOHU/DNHLVORFDWHGLQQRUWKFHQWUDO6HDWWOHEHWZHHQ'HQVPRUH$YHQXH1RUWK&RUOLVV$YHQXH1RUWK 1RUWKQG6WUHHWDQG1RUWKWK6WUHHW )LJXUH )RUPHGE\WKH9DVKRQJODFLDWLRQWKHODNH FRYHUVDSSUR[LPDWHO\DFUHVZLWKDPD[LPXPGHSWKRIIHHW+DOOHU/DNHRULJLQDOO\ZDVFDOOHG :HOVK/DNHEXWZDVUHQDPHGIRU7KHRGRUH1+DOOHUZKRSODWWHGWKHQHLJKERUKRRGLQ )LVHW E 7KHDUHDGUDLQLQJWR+DOOHU/DNHLVSULPDULO\UHVLGHQWLDOZLWKOLPLWHGSXEOLFDFFHVVSRLQWVDW the ends of Meridian Avenue North and North 125th Street. +DOOHU/DNHZKLFKUHFHLYHVVWRUPZDWHUUXQRIIIURPDGUDLQDJHDUHDRIDERXWDFUHVGLVFKDUJHV WKURXJKDQRXWOHWFRQWUROVWUXFWXUHRQWKHZHVWHUQVLGHRIWKHODNHHYHQWXDOO\GUDLQLQJWR/DNH8QLRQ YLDWKH'HQVPRUHVWRUPGUDLQV\VWHP3DVWDWWHQWLRQWR+DOOHU/DNHKDVIRFXVHGRQZDWHUTXDOLW\IRU KXPDQXVHVVXFKDVVZLPPLQJERDWLQJDQGZDGLQJ/LWWOHHIIRUWKDVIRFXVHGRQKDELWDWLVVXHVIRU¿VK and wildlife. 48 Part 4 Conditions in Haller Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes Haller Lake The City VE N ISS A EN of Seattle V CORL EA ID YS N N U S N 130TH ST NE 1 30TH ST N E AN AV I RID ME N128TH ST E N AVE ST 1 CO R LI S S AVE N Haller N 125THST NE 125THST DEN S N M 12 O 2N RE DPL A V E N N 122ND ST N E AV AVE N E N K A N 121STST IDI BUR ER Legend M Streets DENSMORE AVE N N120TH ST NE 120TH ST Park Boundary N Water Quality E AV E Monitoring Stations N E BURK Water SAV S I ORL THE CITY OF SEATTLE, 2007. All rights reserved C No guarantee of any sort implied, including accuracy, completeness, or fitness for use. Figure 8 )LJXUH+DOOHU/DNH Part 4 Conditions in Haller Lake 49 City of Seattle State of the Waters 2007 Volume II: Small Lakes Water Quality Conditions 2YHUDOO ZDWHU TXDOLW\ LQ +DOOHU /DNH LV UHODWLYHO\ JRRG DQG WKH ODNH LV FODVVL¿HG DV PRGHUDWHO\ SURGXFWLYH RU PHVRWURSKLF 9ROXQWHHUVIRU WKH .LQJ &RXQW\ VPDOO ODNHV SURJUDP KDYH PRQLWRUHG ZDWHUTXDOLW\LQ+DOOHU/DNHVLQFH :DWHUVDPSOHVDUHFROOHFWHGWZLFHDPRQWKIURP0D\WKURXJK 2FWREHU$YHUDJHUHVXOWVIRU ±DUHGLVSOD\HGLQ)LJXUH Secchi depth Total phosphorus Chlorophyll a Average TSI (a) 50 (a) TSI = average of TSI-TP, TSI-Chlor-a, and TSI-Secchi 4 45 40 35 3 30 25 2 20 Secchi depth (m) 15 Total P, Chlor-a (ug/L) TSI (no units) 1 10 5 0 0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Year Reference: King County (1999a, 2001a, 2001b, 2002a, 2002b, 2003, 2005). Note: Secchi depth is a measure of water clarity. The higher the value, the better the water clarity. )LJXUH +DOOHU/DNHZDWHUTXDOLW\PRQLWRULQJGDWDVXPPDU\IRU ± Average water clarity (measured by Secchi depth) generally ranges from about 2.6 to 3.2 meters. With WKHH[FHSWLRQRIDQQXDODYHUDJHFRQFHQWUDWLRQVRIWRWDOSKRVSKRUXVLQ+DOOHU/DNHKDYHEHHQ below the recommended level established by the Department of Ecology for lower mesotrophic lakes (20 μg/L; WAC 173-201A). The 2001 average total phosphorus concentration (22.3 μg/L) was affected E\ WZR XQXVXDOO\ KLJK PHDVXUHPHQWV DQG J/ WKDW RFFXUUHG RQ -XQH DQG 6HSWHPEHU respectively. All but one other phosphorus measurement in 2001 were below 20 μg/L. The average WURSKLFVWDWHLQGH[RYHUWKH\HDUPRQLWRULQJSHULRGKDVDOVRUHPDLQHGUHODWLYHO\FRQVWDQW ± DQGZHOOZLWKLQWKHUDQJHHVWDEOLVKHGIRUPHVRWURSKLFODNHV ± 2QO\RQHVDPSOHZDVFROOHFWHGIRUIHFDOFROLIRUPEDFWHULDLQ+DOOHU/DNHRQ$XJXVW 7KLV VDPSOHFRQWDLQHG FIXP/IHFDOFROLIRUPEDFWHULD .LQJ&RXQW\ D PHHWLQJWKHVWDWHZDWHU TXDOLW\VWDQGDUGIRUH[WUDRUGLQDU\SULPDU\FRQWDFWUHFUHDWLRQHVWDEOLVKHGDVDJHRPHWULFPHDQRI FIXP/ZLWKQRPRUHWKDQSHUFHQW RUDQ\VLQJOHVDPSOHZKHQOHVVWKDQVDPSOHSRLQWVH[LVW exceeding 100 cfu/100 mL. 50 Part 4 Conditions in Haller Lake City of Seattle State of the Waters 2007 Volume II: Small Lakes ,Q 6HDWWOH 8QLYHUVLW\ VWXGHQWV PDQXDOO\ FROOHFWHG D FRPSRVLWH VWRUPZDWHU VDPSOH IURP WKH 0HULGLDQ$YHQXH1RUWK VWRUP GUDLQ WKH ODUJHVW VWRUP GUDLQ GLVFKDUJLQJ WR +DOOHU /DNH DV SDUW RI an SPU-sponsored drainage improvement evaluation. The results for this sample are similar to results reported for runoff from other urban areas that have been monitored in the Puget Sound region 7DEOH 7KH0HULGLDQ$YHQXH1RUWKVDPSOHH[FHHGHGWKHVWDWHZDWHUTXDOLW\FULWHULDIRUIHFDOFROLIRUP EDFWHULDDQG86(3$UHFRPPHQGHGZDWHUTXDOLW\FULWHULDIRUQXWULHQWV QLWURJHQDQGSKRVSKRUXV LQ rivers and streams. Dissolved copper and lead were not detected in the sample (at 0.001 μg/L detection OLPLWV GLVVROYHG]LQFZDVGHWHFWHGDWJ/ZHOOEHORZWKHVWDWHZDWHUTXDOLW\FULWHULRQ 7DEOH+DOOHU/DNHGUDLQDJHVDPSOHUHVXOWVIURP0HULGLDQVWRUPGUDLQFRPSDUHGWRRWKHU 6HDWWOHVWRUPZDWHUGDWD Units Meridian Drain a Other Seattle Area Runoff b Fecal coliform bacteria cfu/100 mL 300E 180–8,400 c Total suspended solids mg/L 39 10–154 Total phosphorus Pg/L 128 57–387 Total copper Pg/L 3.4 3.6–24.8 Total lead Pg/L <1 <1–36.6 Total zinc Pg/L 46 31–168 Dissolved copper Pg/L <1 1.4–11.7 Dissolved lead Pg/L <1 <1–3.1 Dissolved zinc Pg/L 20 10–89 E = estimated value. a Manually composited sample collected on March 1, 2001. b Twenty (20) stormwater samples collected from 25-acre residential area along Lake City Way in north Seattle (Taylor and Seattle Public Utilities 2005). c Twenty-two (22) stormwater samples collected from residential area in north Seattle, 2003–2005 (Engstrom 2004; Seattle Public Utilities unpublished). mg/L = milligrams per liter μg/L = micrograms per liter cfu/100 mL = colony forming units per 100 milliliters Habitat Conditions The wildlife habitat of Haller Lake has not been well studied. Fish species inhabiting the lake include UDLQERZ WURXW ODUJHPRXWK EDVV \HOORZ SHUFK EURZQ EXOOKHDG DQG EODFN FUDSSLH :'): D 2005b). The Washington Department of Fish and Wildlife stocks rainbow trout into the lake each year. The lake is also used by ducks and geese. The habitat along the lake shoreline consists primarily of ODQGVFDSHG\DUGVZLWKDVPDOOQXPEHURIUHVLGHQWLDOGRFNVRQWKHODNH6RPHVKRUHOLQHVHFWLRQVKDYH UHODWLYHO\LQWDFWVWDQGVRIPDWXUHWUHHV7KHODNHDOVRFRQWDLQVDQXPEHURIÀRDWLQJVXEPHUJHGDQG HPHUJHQWDTXDWLFSODQWVSHFLHVVRPHRIZKLFKDUHFODVVL¿HGDVQR[LRXVZHHGV .LQJ&RXQW\ E Part 4 Conditions in Haller Lake 51 City of Seattle State of the Waters 2007 Volume II: Small Lakes State of the Waters 2007 Part 5 Small Lakes Comparison & Conclusions &RPSDULVRQVRIZDWHUTXDOLW\DQGVHGLPHQWTXDOLW\FRQGLWLRQVLQ%LWWHU/DNH*UHHQ/DNHDQG+DOOHU Lake are summarized in Table 15. Table 15. &RPSDULVRQVRIZDWHUTXDOLW\DQGVHGLPHQWTXDOLW\FRQGLWLRQVLQ6HDWWOH¶VVPDOOODNHV Bitter Lake Green Lake c Haller Lake Aquatic Life Indicators Temperature and dissolved oxygen – – pH – – Turbidity and total suspended solids Nutrients b Toxic Pollutants Ammonia – – – Metals – – – Organic compounds – – – Public Health Indicators Fecal coliform bacteria – Metals a – – Organic compounds a – – Indicators in Sediment Metals – Organic compounds – a Based on U.S. EPA toxics rule (EPA 2002a). b Water quality criteria for nutrients have been established to prevent eutrophication and water quality problems associated with nutrient enrichment. c Nutrient and fecal coliform bacteria levels in Green Lake declined significantly after the 2004 alum treatment. Poor water quality, frequent exceedances of state water quality standards. Potential water quality problem (e.g., 303d category 2 listing, occasional exceedance of water quality standard). Adequate water quality based on existing data. – Insufficient data available to evaluate. Part 5 Small Lakes Comparison and Conclusions 53 City of Seattle State of the Waters 2007 Volume II: Small Lakes Water and Sediment Quality Conditions :DWHUDQGVHGLPHQWTXDOLW\FRQGLWLRQVLQ6HDWWOH¶VVPDOOODNHVKDYHEHHQHYDOXDWHGE\FRPSDULQJH[LVWLQJ FKHPLVWU\GDWDWRDYDLODEOHVWDQGDUGVDQGEHQFKPDUNVSDUWLFXODUO\WKH:DVKLQJWRQVWDWHZDWHUTXDOLW\ VWDQGDUGVDQGDYDLODEOHVHGLPHQWTXDOLW\FULWHULDZKLFKUHSUHVHQWOHYHOVWKDWDUHSURWHFWLYHRIDTXDWLF RUJDQLVPVRUKXPDQKHDOWK,QDGGLWLRQWKH'HSDUWPHQWRI(FRORJ\KDVUHFHQWO\FRPSOHWHGDZDWHU TXDOLW\DVVHVVPHQWLGHQWLI\LQJLPSDLUHGZDWHUERGLHVLQ:DVKLQJWRQDVUHTXLUHGXQGHU6HFWLRQ G RIWKH&OHDQ:DWHU$FW (FRORJ\ 7KH G OLVWLQJVIRU6HDWWOH¶VVPDOOODNHVDUHVXPPDUL]HG in Table 16. 7DEOH/LVWLQJVRI6HDWWOH¶VVPDOOODNHVDVWKUHDWHQHGRULPSDLUHGZDWHUERGLHVXQGHU &OHDQ:DWHU$FW6HFWLRQ G Category 5 a Category 2 b Bitter Lake None Fecal coliform bacteria Green Lake Fecal coliform bacteria, total phosphorus, total Total phosphorus PCBsc, 4,4’-DDEc, chlordane c Haller Lake None None Source: Ecology (2004). a Total maximum daily load (TMDL) limit required due to demonstrated exceedances of state water quality standards. b Water of concern. c Based on fish tissue concentrations. :DWHUTXDOLW\LQ+DOOHU/DNHDQG%LWWHU/DNHLVUHODWLYHO\JRRGDQGERWKODNHVDUHFODVVL¿HGDVPRGHUDWHO\ SURGXFWLYHRUPHVRWURSKLF+RZHYHU*UHHQ/DNHKDVDORQJKLVWRU\RIZDWHUTXDOLW\SUREOHPVUHODWHG WR H[FHVVLYH JURZWK RI DOJDH DQG EDFWHULD FDXVHG E\ DQ RYHUDEXQGDQFH RI QXWULHQWV SDUWLFXODUO\ phosphorus. The Department of Ecology included Green Lake on the 303(d) list of threatened and LPSDLUHGZDWHUERGLHVDVDFDWHJRU\ZDWHUERG\ LHLPSDLUHG GXHWRHOHYDWHGFRQFHQWUDWLRQVRIWRWDO phosphorus (Ecology 2004). 3KRVSKRUXVFDQEHFRQWULEXWHGWRODNHVIURPPDQ\VRXUFHVLQFOXGLQJVWRUPZDWHUUXQRIIDQGZDWHUIRZO +RZHYHUGXULQJWKHVXPPHUPRQWKVZKHQDOJDODQGEDFWHULDOEORRPVDUHFRPPRQWKHSULPDU\VRXUFH RISKRVSKRUXVLQ*UHHQ/DNHKDVEHHQDWWULEXWHGWRLQWHUQDOSURFHVVHVVXFKDVUHOHDVHRISKRVSKRUXV stored in the sediment on the lake bottom (Herrera 2003a). (OHYDWHGQXPEHUVRIIHFDOFROLIRUPEDFWHULDKDYHEHHQUHSRUWHGLQ*UHHQ/DNH ±FRORQ\IRUPLQJ XQLWVSHUPLOOLOLWHUV>FIXP/@ DQGLQ%LWWHU/DNH FIXP/LQRQHVDPSOHFROOHFWHGRQ $XJXVW &RQVHTXHQWO\*UHHQ/DNHLVOLVWHGRQWKH(FRORJ\ G OLVW (FRORJ\ DV DQLPSDLUHGZDWHUERG\ FDWHJRU\ VHH7DEOH IRUIHFDOFROLIRUPEDFWHULDDQG%LWWHU/DNHLVOLVWHG as a water body of concern (category 2; see Table 16). Haller Lake is not currently listed for any water TXDOLW\SDUDPHWHU IHFDOFROLIRUPEDFWHULDFRQFHQWUDWLRQVPHDVXUHGLQWKHRQHVDPSOHWHVWHGWRGDWH FIXP/ ZHUHZLWKLQWKHVWDWHZDWHUTXDOLW\VWDQGDUG 54 Part 5 Small Lakes Comparison and Conclusions City of Seattle State of the Waters 2007 Volume II: Small Lakes :DWHUTXDOLW\GDWDIRUPHWDOVDQGRUJDQLFFRQWDPLQDQWVDUHJHQHUDOO\ODFNLQJIRUWKHWKUHHVPDOOODNHV Limited sediment data available for Bitter Lake and Green Lake indicate that some metals exceeded SUREDEOH HIIHFWV OHYHOV 3(/ HVWDEOLVKHG E\ RWKHU MXULVGLFWLRQV SDUWLFXODUO\ LQ VDPSOHV FROOHFWHG RIIVKRUHRIVWRUPGUDLQRXWIDOOV+RZHYHUWKH'HSDUWPHQWRI(FRORJ\¶VLQWHULPIUHVKZDWHUVHGLPHQW TXDOLW\YDOXHVZHUHH[FHHGHGRQO\E\%LWWHU/DNHFDGPLXPFRQFHQWUDWLRQV ± PLOOLJUDPVSHU NLORJUDP>PJNJ@ DQGE\*UHHQ/DNHOHDGFRQFHQWUDWLRQV ±PJNJ DQG]LQFFRQFHQWUDWLRQV ±PJNJ Organic compounds are not commonly detected in sediment samples collected from Bitter Lake and Green Lake. One sampling station in Bitter Lake reported polycyclic aromatic hydrocarbons (PAHs) DW±PLFURJUDPVSHUNLORJUDP JNJ DQGELV HWK\OKH[\O SKWKDODWHDSODVWLFL]HUDW JNJ7RWDOSHWUROHXPK\GURFDUERQVZHUHGHWHFWHGDWPXOWLSOHORFDWLRQVLQ%LWWHU/DNH ± JNJGLHVHODQG± JNJRLO $OORWKHURUJDQLFFRPSRXQGV 3&%VYRODWLOHRUJDQLFFRPSRXQGV DQGSHVWLFLGHV ZHUHXQGHWHFWHGLQ%LWWHU/DNHVHGLPHQWVDOWKRXJKDQDO\WLFDOGHWHFWLRQOLPLWVZHUH KLJK XSWRJNJ IRUVRPHFRQVWLWXHQWV None of the sediment samples collected from Green Lake exceeded the interim Ecology freshwater VHGLPHQWTXDOLW\YDOXHVIRURUJDQLFFRPSRXQGV+RZHYHUKLJKDQGORZPROHFXODUZHLJKW3$+ +3$+ and LPAH) compounds exceeded the upper effects levels (UEL)—concentrations at which biological HIIHFWVDUHSUREDEOH²HVWDEOLVKHGE\RWKHUMXULVGLFWLRQV7RWDOSHWUROHXPK\GURFDUERQV ±PJNJ GLHVHODQG±PJNJRLO ZHUHDOVRGHWHFWHGDWDOOVHGLPHQWVWDWLRQVVDPSOHGLQ*UHHQ/DNH Habitat Conditions The physical conditions for wildlife KDELWDWLQ6HDWWOH¶VVPDOOODNHVKDYH QRW EHHQ ZHOO VWXGLHG ,Q JHQHUDO %LWWHU/DNH*UHHQ/DNHDQG+DOOHU Lake all appear to lack habitat FRPSOH[LW\ VKRUHOLQH YHJHWDWLRQ and connectivity between lake and shoreline. All three small lakes VXSSRUWVRPH¿VKDOWKRXJKPRVWRI WKHVH¿VKDUHLQWURGXFHGRUVWRFNHG into the lakes. Sunset behind Green Lake (photo by Bennett) Part 5 Small Lakes Comparison and Conclusions 55 City of Seattle State of the Waters 2007 Volume II: Small Lakes State of the Waters 2007 Part 6 References & Glossary References and Information Sources $UQROG &/ DQG &- *LEERQV ,PSHUYLRXV 6XUIDFH &RYHUDJH 7KH (PHUJHQFH RI D .H\ (QYLURQPHQWDO,QGLFDWRU$PHULFDQ3ODQQHUV$VVRFLDWLRQ-RXUQDO ± $YRFHW'HYHORSPHQWRI)UHVKZDWHU6HGLPHQW4XDOLW\9DOXHVIRU8VHLQ:DVKLQJWRQ6WDWH3KDVH ,,5HSRUW 'HYHORSPHQWDQG5HFRPPHQGDWLRQRI649VIRU)UHVKZDWHU6HGLPHQWVLQ:DVKLQJWRQ6WDWH 3UHSDUHGIRUWKH6HGLPHQW0DQDJHPHQW8QLW7R[LFV&OHDQXS3URJUDP:DVKLQJWRQ6WDWH'HSDUWPHQW RI(FRORJ\E\$YRFHW&RQVXOWLQJ.HQPRUH:DVKLQJWRQ &DUOVRQ5( $7URSKLF6WDWH,QGH[IRU/DNHV/LPQRO2FHDQJU ± &DUUDVTXHUR-2YHU:DWHU6WUXFWXUHV )UHVKZDWHU,VVXHV3UHSDUHGIRU:DVKLQJWRQ'HSDUWPHQW RI)LVKDQG:LOGOLIH:DVKLQJWRQ'HSDUWPHQWRI(FRORJ\DQG:DVKLQJWRQ'HSDUWPHQWRI7UDQVSRUWDWLRQ 2O\PSLD:DVKLQJWRQ &XEEDJH-'%DWWVDQG6%UHLGHQEDFK &UHDWLRQDQG$QDO\VLVRI)UHVKZDWHU6HGLPHQW9DOXHV LQ:DVKLQJWRQ6WDWH (QYLURQPHQWDO ,QYHVWLJDWLRQV DQG /DERUDWRU\ 6HUYLFHV 3URJUDP:DVKLQJWRQ 6WDWH'HSDUWPHQWRI(FRORJ\2O\PSLD:DVKLQJWRQ 'XQQH7DQG/%/HRSROG :DWHULQ(QYLURQPHQWDO3ODQQLQJ)UHHPDQ3UHVV1HZ Ecology. 2004. Washington State Department of Ecology Final Integrated Report 2002/2004 (303(d) /LVWDQG E 5HSRUW VXEPLWWHGWR86(3$IRUDSSURYDO-XQH (QJVWURP$0&KDUDFWHUL]LQJ:DWHU4XDOLW\RI8UEDQ6WRUPZDWHU5XQRII ,QWHUDFWLRQVRI +HDY\0HWDOVDQG6ROLGVLQ6HDWWOH5HVLGHQWLDO&DWFKPHQWV0DVWHU¶VWKHVLV8QLYHUVLW\RI:DVKLQJWRQ 'HSDUWPHQWRI&LYLODQG(QYLURQPHQWDO(QJLQHHULQJ6HDWWOH:DVKLQJWRQ )LVHW/6HDWWOH1HLJKERUKRRGV *UHHQ/DNH±7KXPEQDLO+LVWRU\+LVWRU\/LQNRUJ¿OH $YDLODEOHRQOLQHDW ZZZKLVWRU\OLQNRUJ )LVHW/D6HDWWOH1HLJKERUKRRGV %URDGYLHZDQG%LWWHU/DNH±7KXPEQDLO+LVWRU\+LVWRU\/LQN RUJ¿OH$YDLODEOHRQOLQHDW ZZZKLVWRU\OLQNRUJ )LVHW/E6HDWWOH1HLJKERUKRRGV +DOOHU/DNH±7KXPEQDLO+LVWRU\+LVWRU\/LQNRUJ¿OH $YDLODEOHRQOLQHDW ZZZKLVWRU\OLQNRUJ )URGJH -' '$ 0DULQR *% 3DXOH\ DQG */ 7KRPDV 0RUWDOLW\ RI ODUJHPRXWK EDVV (Micropterus salmoides) and steelhead trout (Oncorhynchus mykiss) in densely vegetated littoral areas WHVWHGXVLQJLQVLWXELRDVVD\/DNHDQG5HVHUY0DQDJH Part 6 References and Information Sources 57 City of Seattle State of the Waters 2007 Volume II: Small Lakes *UHDW /DNHV±8SSHU 0LVVLVVLSSL 5LYHU %RDUG RI 6WDWH 6DQLWDU\ (QJLQHHUV 5HFRPPHQGHG 6WDQGDUGVIRU%DWKLQJ%HDFKHV+HDOWK(GXFDWLRQ6HUYLFH$OEDQ\1HZ Herrera. 2003a. Green Lake Alum Treatment Study. Prepared for Seattle Parks and Recreation by +HUUHUD(QYLURQPHQWDO&RQVXOWDQWV,QF6HDWWOH:DVKLQJWRQ Herrera. 2003b. Green Lake Integrated Phosphorus Management Plan. Prepared for Seattle Parks and 5HFUHDWLRQE\+HUUHUD(QYLURQPHQWDO&RQVXOWDQWV,QF6HDWWOH:DVKLQJWRQ +HUUHUDD +HUUHUDE*UHHQ/DNH$TXDWLF3ODQW6XUYH\3UHSDUHGIRU6HDWWOH3DUNVDQG5HFUHDWLRQE\ +HUUHUD(QYLURQPHQWDO&RQVXOWDQWV,QF6HDWWOH:DVKLQJWRQ +RUQH$OH[DQGHU-DQG&KDUOHV5*ROGPDQ /LPQRORJ\6HFRQGHGLWLRQ0F*UDZ+LOO,QF 1HZ .DUU-5 &OHDQ:DWHU,V1RW(QRXJK,OODKHH ± .DUU -5 +HDOWK ,QWHJULW\ DQG %LRORJLFDO$VVHVVPHQW 7KH ,PSRUWDQFH RI:KROH7KLQJV 3DJHV ±LQ'3LPHQWHO/:HVWUDDQG5)1RVVHGLWRUV(FRORJLFDO,QWHJULW\ ,QWHJUDWLQJ (QYLURQPHQW&RQVHUYDWLRQDQG+HDOWK,VODQG3UHVV:DVKLQJWRQ'& .LQJ&RXQW\ D.LQJ&RXQW\/DNH9ROXQWHHU0RQLWRULQJ5HSRUW 'HSDUWPHQWRI1DWXUDO 5HVRXUFHV DQG 3DUNV :DWHU DQG /DQG 5HVRXUFHV 'LYLVLRQ /DNH 6WHZDUGVKLS 3URJUDP 6HDWWOH Washington. .LQJ&RXQW\ E1R[LRXV:HHG6XUYH\IRU)LYH.LQJ&RXQW\/DNHV)LQDOUHSRUWIRUWKH.LQJ &RXQW\1R[LRXV:HHG%RDUG3UHSDUHGE\6KDURQ:DOWRQ'HSDUWPHQWRI1DWXUDO5HVRXUFHV6HDWWOH Washington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art 6 References and Information Sources City of Seattle State of the Waters 2007 Volume II: Small Lakes .LQJ&RXQW\%HDFKPRQLWRULQJUHVXOWVIRU*UHHQ/DNH ± 2EWDLQHG0DUFK IURP.LQJ&RXQW\'HSDUWPHQWRI1DWXUDO5HVRXUFHVDQG3DUNVZHEVLWH KWWS GQUPHWURNFJRYZOU waterres/swimbeach/bacteriaarchive.aspx. .LQJ&RXQW\XQSXEOLVKHG9ROXQWHHUPRQLWRULQJUHVXOWVIRU*UHHQ/DNH :DWHUDQG/DQG 5HVRXUFHV'LYLVLRQ6HDWWOH:DVKLQJWRQ .RHKOHU0('LHWDQG3UH\5HVRXUFHVRI-XYHQLOH&KLQRRN6DOPRQ 2QFRUK\QFKXVWVKDZ\WVFKD 5HDULQJLQWKH/LWWRUDO=RQHRIDQ8UEDQ/DNH067KHVLV8QLYHUVLW\RI:DVKLQJWRQ6HDWWOH /LNHQV*( HG $Q(FRV\VWHP$SSURDFKWR$TXDWLF(FRORJ\ 0LUURU/DNHDQGLWV(QYLURQPHQW 1HZ 0DF'RQDOG''&*,QJHUVROODQG7$%HUJHU'HYHORSPHQWDQG(YDOXDWLRQRI&RQVHQVXV Based Sediment Quality Guidelines for Freshwater Ecosystems. Arch. Environ. Contam. Toxicol. ± 1DLPDQ 5- -- 0DJQXVRQ '$ 0F.QLJKW -$ 6WDQIRUG DQG -5 .DUU )UHVKZDWHU (FRV\VWHPVDQG7KHLU0DQDJHPHQW $1DWLRQDO,QLWLDWLYH6FLHQFH ± 12$$ 6FUHHQLQJTXLFNUHIHUHQFHWDEOHV1DWLRQDO2FHDQLFDQG$WPRVSKHULF$GPLQLVWUDWLRQ 6HDWWOH:DVKLQJWRQ2EWDLQHG0D\IURPDJHQF\ZHEVLWH KWWS UHVSRQVHUHVWRUDWLRQQRDD JRYFSUVHGLPHQWVTXLUWVTXLUWKWPO 3HUVDXG'5-DDJXPDJLDQG$+D\WRQ *XLGHOLQHVIRUWKH3URWHFWLRQDQG0DQDJHPHQWRI $TXDWLF6HGLPHQW4XDOLW\LQ2QWDULR:DWHU5HVRXUFHV%UDQFK2QWDULR0LQLVWU\RIWKH(QYLURQPHQW 2QWDULR&DQDGD 3LWW55%DQQHUPDQ6&ODUNDQG':LOOLDPVRQ6RXUFHVRI3ROOXWDQWVLQ8UEDQ$UHDV 3DUW ²5HFHQW6KHHWÀRZ0RQLWRULQJ3S±LQ (IIHFWLYH0RGHOLQJRI8UEDQ6WRUPZDWHU 6\VWHPV0RQRJUDSK:-DPHV.1,UYLQH($0F%HDQDQG5(3LWW HGLWRUV &+,*XHOSK Ontario. 3RII 1/ -'$OODQ 0% %DLQ -5 .DUU ./ 3UHVWHJDDUG %' 5LFKWHU 5( 6SDUNV DQG -& 6WURPEHUJ 7KH 1DWXUDO )ORZ 5HJLPH $ 3DUDGLJP IRU 5LYHU &RQVHUYDWLRQ DQG 5HVWRUDWLRQ %LR6FLHQFH ± 6FKLQGOHU'(DQG0'6FKHXHUHOO+DELWDW&RXSOLQJLQ/DNH(FRV\VWHPV2LNRV ± 189. 6HDWWOH/DNHV$OOLDQFH%LWWHU/DNH0RQLWRULQJ3URJUDP5HSRUW-XQH3UHSDUHGE\WKH 6HDWWOH/DNHV$OOLDQFH±%LWWHU/DNH6HDWWOH:DVKLQJWRQ Seattle Parks and Recreation. Undated. Green Lake Park Vegetation Management Plan. Available online DW KWWS ZZZVHDWWOHJRYSDUNVSDUNVSDFHV*UHHQ/DNH3DUN903KWP Seattle University. 2001. Haller Lake Drainage Improvements. Prepared for Seattle Public Utilities E\6HDWWOH8QLYHUVLW\6FLHQFHDQG(QJLQHHULQJ3URMHFW&HQWHU6FKRRORI6FLHQFHDQG(QJLQHHULQJ 6HDWWOH:DVKLQJWRQ Part 6 References and Information Sources 59 City of Seattle State of the Waters 2007 Volume II: Small Lakes Seattle University. 2002. Bitter Lake Drainage Improvements. Prepared for Seattle Public Utilities E\6HDWWOH8QLYHUVLW\6FLHQFHDQG(QJLQHHULQJ3URMHFW&HQWHU6FKRRORI6FLHQFHDQG(QJLQHHULQJ 6HDWWOH:DVKLQJWRQ 6KHUZRRG'8QGDWHG6HDWWOH3DUNVDQG5HFUHDWLRQ6KHUZRRG+LVWRU\)LOHV$YDLODEOHRQOLQHDW www.ci.seattle.wa.us/parks/history/sherwood.htm SPU. Unpublished. Sediment sampling results for Green Lake offshore of the Densmore Avenue 1RUWKVWRUPGUDLQ6HDWWOH3XEOLF8WLOLWLHV6HDWWOH:DVKLQJWRQ 638 XQSXEOLVKHG :DWHUTXDOLW\UHVXOWVIRUVWRUPZDWHUVDPSOHVFROOHFWHGIURP%URDGYLHZ JUHHQJULGSURMHFW ± 6HDWWOH3XEOLF8WLOLWLHV6HDWWOH:DVKLQJWRQ 638DQG6WLOOZDWHU6FLHQFHV$6FLHQFH)UDPHZRUNIRU(FRORJLFDO+HDOWKLQ6HDWWOH¶V6WUHDPV 6HDWWOH3XEOLF8WLOLWLHV&LW\RI6HDWWOH:DVKLQJWRQ 7DERU 5$ DQG 50 3LDVNRZVNL 1HDUVKRUH +DELWDW 8VH E\ -XYHQLOH &KLQRRN 6DOPRQ LQ Lentic Systems of the Lake Washington Basin. U.S. Fish and Wildlife Service report prepared for Seattle Public Utilities. 7DERU5&0F&R\6&DPDFKR0&HOHGRQLD69HFKWDQG07LPNR+DELWDW8VHDQG 0RYHPHQWVRI-XYHQLOH&KLQRRN6DOPRQLQ6RXWK/DNH:DVKLQJWRQ,QYHVWLJDWLRQV3UHVHQWDWLRQ DWWKH*UHDWHU/DNH:DVKLQJWRQ&KLQRRN:RUNVKRS)HEUXDU\6KRUHOLQH:DVKLQJWRQ 7D\ORU$VVRFLDWHVDQG6HDWWOH3XEOLF8WLOLWLHV6WRUPZDWHU7UHDWPHQW7HFKQRORJLHVDQ(YDOXDWLRQ RI3ROOXWDQW5HPRYDO3HUIRUPDQFH3UHSDUHGE\7D\ORU$VVRFLDWHV,QFDQG6HDWWOH3XEOLF8WLOLWLHVLQ DVVRFLDWLRQZLWK&+0+LOO6HDWWOH:DVKLQJWRQ 86(3$ 4XDOLW\&ULWHULDIRU:DWHU86(QYLURQPHQWDO3URWHFWLRQ$JHQF\2I¿FHRI:DWHU DQG+D]DUGRXV0DWHULDOV:DVKLQJWRQ'& 86 (3$ 1DWLRQDO 5HFRPPHQGHG:DWHU4XDOLW\ &ULWHULD (3$5 86 (QYLURQPHQWDO3URWHFWLRQ$JHQF\2I¿FHRI:DWHU2I¿FHRI6FLHQFHDQG7HFKQRORJ\:DVKLQJWRQ'& :'): *UHHQ/DNH6XUYH\V $VSHFWVRIWKH%LRORJ\RI&RPPRQ&DUSZLWK1RWHVRQWKH :DUPZDWHU)LVK&RPPXQLW\7HFKQLFDOUHSRUW)373UHSDUHGE\.:0XHOOHU:DVKLQJWRQ Department of Fish and Wildlife. :'):D5HJLRQ&DWFKDEOH7URXW$OORWPHQW3ODQ6XPPDU\$YDLODEOHIURP:DVKLQJWRQ 'HSDUWPHQWRI)LVKDQG:LOGOLIHZHEVLWHDW KWWS ZZZZGIZZDJRY¿VKSODQWVUHJLRQVUHJLQGH[KWP :'):E:DUPZDWHU)LVKHVRI:DVKLQJWRQ5HSRUW)0 :DVKLQJWRQ'HSDUWPHQWRI)LVK DQG:LOGOLIH2O\PSLD:DVKLQJWRQ :HOFK(%DQG7/LQGHOO(FRORJLFDO(IIHFWVRI:DVWHZDWHU $SSOLHG/LPQRORJ\DQG3ROOXWDQW (IIHFWV6HFRQGHGLWLRQ( )16SRQ1HZ)HWWHU/DQH/RQGRQ :HW]HO 5* /LPQRORJ\ 6HFRQG HGLWLRQ 6DXQGHUV &ROOHJH 3XEOLVKLQJ 3KLODGHOSKLD Pennsylvania. 753 pp. =LHPHU55DQG7(/LVOH +\GURORJ\3DJHV±LQ 5LYHU(FRORJ\DQG0DQDJHPHQW /HVVRQV IURPWKH3DFL¿F&RDVWDO(FRUHJLRQ5-1DLPDQDQG5(%LOE\HGLWRUV6SULQJHU9HUODJ1HZ 60 Part 6 References and Information Sources City of Seattle State of the Waters 2007 Volume II: Small Lakes Glossary of Terms G OLVW$VWDWHLQYHQWRU\RILPSDLUHGZDWHUERGLHVFUHDWHGDFFRUGLQJWRWKHIHGHUDO&OHDQ:DWHU$FW Section 303(d). acute conditions&KDQJHVLQDQRUJDQLVP¶VSK\VLFDOFKHPLFDORUELRORJLFDOHQYLURQPHQWLQYROYLQJD VWLPXOXVVHYHUHHQRXJKWRUDSLGO\LQGXFHDUHVSRQVHUHVXOWLQJLQLQMXU\RUGHDWKWRWKHRUJDQLVPDIWHU short-term exposure. acute exposure value The threshold value below which there should be no unacceptable effects on IUHVKZDWHUDTXDWLFRUJDQLVPVDQGWKHLUXVHVLIWKHRQHKRXUDYHUDJHFRQFHQWUDWLRQGRHVQRWH[FHHG that value more than once every 3 years on average. Also known as the criterion maximum concentration (CMC). DTXDWLFÀRUDDQGIDXQDDTXDWLFELRWD$OOIRUPVRISODQWV ÀRUD DQGDQLPDOV IDXQD IRXQGOLYLQJLQ or rooted in water. algae6PDOODTXDWLFSODQWVFRQWDLQLQJFKORURSK\OOWKDWRFFXUDVVLQJOHFHOOVFRORQLHVRU¿ODPHQWVDQG ÀRDWLQWKHZDWHURUDWWDFKWRODUJHUSODQWVURFNVDQGRWKHUVXEVWUDWHV,QGLYLGXDOVDUHXVXDOO\YLVLEOH RQO\ZLWKDPLFURVFRSH([FHVVLYHQXPEHUVFDQPDNHWKHZDWHUDSSHDUFORXG\DQGFRORUHGFUHDWLQJ DQXLVDQFHZKHQFRQGLWLRQVDUHVXLWDEOHIRUSUROL¿FJURZWK algal bloom3UROLIHUDWLRQRIOLYLQJDOJDHRQWKHVXUIDFHRIDODNHVWUHDPRUSRQG RIWHQVWLPXODWHGE\ SKRVSKDWHRYHUHQULFKPHQW$OJDOEORRPVUHGXFHWKHR[\JHQDYDLODEOHWRRWKHUDTXDWLFRUJDQLVPV anoxic Devoid of oxygen. baseline condition7KHVWDWHRIDV\VWHPSURFHVVRUDFWLYLW\EHIRUHWKHRFFXUUHQFHRIDFWLRQVRUHYHQWV that may result in changes; used as the starting point for comparative analysis. basin7KHDUHDRIODQGGUDLQHGE\DULYHUDQGLWVWULEXWDULHVGUDLQLQJZDWHURUJDQLFPDWWHUGLVVROYHG QXWULHQWVDQGVHGLPHQWVLQWRDODNHRUVWUHDP benchmark$VWKHWHUPLVXVHGLQWKLVUHSRUWEHQFKPDUNVUHSUHVHQWLQWHULPZDWHUTXDOLW\FULWHULDWKDWDUH useful for comparison to existing or past conditions found in Seattle surface water bodies. Benchmarks LGHQWL¿HGLQWKLVUHSRUWDUHEDVHGRQ86(3$ZDWHUTXDOLW\FULWHULDEXWGRQRWUHÀHFWDGRSWHGZDWHU TXDOLW\VWDQGDUGV%HFDXVHWKHVHEHQFKPDUNVUHSUHVHQWVXUIDFHZDWHUTXDOLW\FRQGLWLRQVWKDWDUH PLQLPDOO\LQÀXHQFHGE\KXPDQDFWLYLW\H[FHHGLQJDEHQFKPDUNGRHVQRWQHFHVVDULO\LQGLFDWHD YLRODWLRQRIWKHZDWHUTXDOLW\VWDQGDUG EHQH¿FLDOXVHV7KRVHXVHVRIZDWHULGHQWL¿HGLQVWDWHZDWHUTXDOLW\VWDQGDUGVWKDWPXVWEHDFKLHYHG DQG PDLQWDLQHG DV UHTXLUHG XQGHU WKH IHGHUDO &OHDQ:DWHU$FW 7KH WHUPV ³EHQH¿FLDO XVH´ DQG ³GHVLJQDWHGXVH´DUHRIWHQXVHGLQWHUFKDQJHDEO\ benthic invertebrates $TXDWLF ERWWRPGZHOOLQJ RUJDQLVPV LQ VWUHDPV DQG ODNHV LQFOXGLQJ VPDOO LQYHUWHEUDWHLQVHFWVFUXVWDFHDQVPROOXVNVDQGZRUPV benthic zone7KHDUHDDVVRFLDWHGZLWKWKHODNHERWWRPLQERWKGHHSDQGVKDOORZZDWHUDUHDV Part 6 Glossary of Terms 61 City of Seattle State of the Waters 2007 Volume II: Small Lakes bioaccumulation The process by which substances that are very slowly metabolized or excreted increase LQFRQFHQWUDWLRQLQOLYLQJRUJDQLVPVUHVXOWLQJLQWKHDFFXPXODWLRQRIFKHPLFDOFRPSRXQGVLQWKHLU body tissues. bioavailable'HVFULEHVWKHGHJUHHWRZKLFKDVXEVWDQFH HJDWR[LQ LVDEVRUEHGLQWRDOLYLQJV\VWHP or is made available at the site of physiological activity. biomass 7KH ZHLJKW RI ELRORJLFDO PDWWHU HJ ¿VK DOJDH DQG DTXDWLF SODQWV SUHVHQW LQ D ERG\ RI water). biota$OOOLYLQJRUJDQLVPV SODQWVDQGDQLPDOV ZLWKLQDVSHFL¿HGDUHD blue-green algae A group of algae having a blue pigment in addition to the green chlorophyll. A stench is often associated with the decomposition of dense blooms of blue-green algae in fertile lakes. channel$QDWXUDOVWUHDPWKDWFRQYH\VZDWHU DQDWXUDORUDUWL¿FLDOZDWHUFRXUVHZLWKGH¿QLWHEHGDQG EDQNVWRFRQ¿QHDQGFRQGXFWÀRZLQJZDWHU RUDGLWFKH[FDYDWHGIRUWKHÀRZRIZDWHU chlorophyll a $W\SHRIFKORURSK\OOSUHVHQWLQDOOW\SHVRIDOJDHVRPHWLPHVLQGLUHFWSURSRUWLRQWRWKH ELRPDVVRIDOJDHWKDWLVFRPPRQO\XVHGDVDPHDVXUHRIWKHDOJDOFRQWHQWRIZDWHU chronic conditions&KDQJHVLQDQRUJDQLVP¶VSK\VLFDOFKHPLFDORUELRORJLFDOHQYLURQPHQWLQYROYLQJD VWLPXOXVRIH[WHQGHGGXUDWLRQUHVXOWLQJLQLQMXU\RUGHDWKWRWKHRUJDQLVPDVDUHVXOWRIUHSHDWHGRU constant exposure over an extended period of time. chronic exposure value The threshold value below which there should be no unacceptable effects on IUHVKZDWHUDTXDWLFRUJDQLVPVDQGWKHLUXVHVLIWKHGD\DYHUDJHFRQFHQWUDWLRQGRHVQRWH[FHHGWKDW value more than once every 3 years on average. Also known as the criterion continuous concentration (CCC). Clean Water Act (CWA) The basic federal water pollution control law in the United States (Federal :DWHU3ROOXWLRQ&RQWURO$FWFRGL¿HGDW86&± 3URYLVLRQVRIWKHVWDWXWHLQFOXGH WHFKQRORJ\EDVHG HIÀXHQW VWDQGDUGV IRU SRLQW VRXUFHV RI SROOXWLRQ D VWDWHDGPLQLVWHUHG FRQWURO SURJUDPIRUQRQSRLQWSROOXWLRQVRXUFHVDFRQVWUXFWLRQJUDQWSURJUDPWREXLOGRUXSJUDGHPXQLFLSDO VHZDJHWUHDWPHQWSODQWVDUHJXODWRU\V\VWHPIRUVSLOOVRIRLODQGRWKHUKD]DUGRXVZDVWHVDQGD wetlands preservation program. FRPELQHGVHZHU'UDLQDJHV\VWHPSLSHVWKDWFDUU\ERWKVDQLWDU\VHZDJH LHZDVWHZDWHUIURPEXLOGLQJV and stormwater runoff to a wastewater treatment plant. culvert$SLSHRUFRQFUHWHER[VWUXFWXUHWKDWGUDLQVRSHQFKDQQHOVVZDOHVRUGLWFKHVEHQHDWKDURDGZD\ RUHPEDQNPHQWW\SLFDOO\ZLWKQRFDWFKEDVLQVRUPDQKROHVDORQJLWVOHQJWK designated uses 7KRVHXVHVRIZDWHULGHQWL¿HGLQVWDWHZDWHUTXDOLW\VWDQGDUGVWKDWPXVWEHDFKLHYHG DQG PDLQWDLQHG DV UHTXLUHG XQGHU WKH IHGHUDO &OHDQ:DWHU$FW 7KH WHUPV ³EHQH¿FLDO XVH´ DQG ³GHVLJQDWHGXVH´DUHRIWHQXVHGLQWHUFKDQJHDEO\ detection limit The smallest concentration of a constituent that can be measured with a stated level RIFRQ¿GHQFH ,QSUDFWLFHGHWHFWLRQOLPLWVFDQEHGHWHUPLQHGE\GLIIHUHQWPHWKRGVLQGLIIHUHQW laboratories.) 62 Part 6 Glossary of Terms City of Seattle State of the Waters 2007 Volume II: Small Lakes discharge5XQRIIOHDYLQJDQDUHDYLDEXLOWFRQYH\DQFHV\VWHPVRURYHUODQGÀRZW\SLFDOO\GHVFULEHG DVDYROXPHRIÀXLGSDVVLQJDSRLQWSHUXQLWRIWLPHVXFKDVFXELFIHHWSHUVHFRQGFXELFPHWHUVSHU VHFRQGJDOORQVSHUPLQXWHJDOORQVSHUGD\RUPLOOLRQVRIJDOORQVSHUGD\ dissolved oxygen7KHDPRXQWRIR[\JHQGLVVROYHGLQZDWHUDQGDYDLODEOHIRUDTXDWLFOLIHPHDVXUHGLQ PLOOLJUDPVSHUOLWHU&HUWDLQDPRXQWVRIGLVVROYHGR[\JHQDUHHVVHQWLDOWRDTXDWLFDQLPDODQGSODQW OLIHDVZHOODVEDFWHULDOGHFRPSRVLWLRQRIRUJDQLFPDWWHU disturbed habitat A habitat in which naturally occurring ecological processes and species interactions KDYHEHHQVLJQL¿FDQWO\GLVUXSWHGE\WKHGLUHFWRULQGLUHFWUHVXOWVRIKXPDQSUHVHQFHDQGDFWLYLW\ drainage basin7KHWULEXWDU\DUHDWKURXJKZKLFKGUDLQDJHZDWHULVFROOHFWHGUHJXODWHGWUDQVSRUWHGDQG discharged to receiving waters. ecological health,QVXUIDFHZDWHUV\VWHPVHQYLURQPHQWDOFRQGLWLRQVH[KLELWLQJWKHHFRORJLFDOIXQFWLRQV DQGIHDWXUHVQHFHVVDU\WRVXSSRUWGLYHUVHQDWLYHVHOIVXVWDLQLQJDTXDWLFDQGULSDULDQFRPPXQLWLHV HIÀXHQW/LTXLGZDVWHVIURPVHZDJHWUHDWPHQWVHSWLFV\VWHPVRULQGXVWULDOVRXUFHVWKDWDUHUHOHDVHGWR a surface water body. emergent plants$TXDWLFSODQWVWKDWDUHURRWHGLQWKHERWWRPVHGLPHQWEXWSURMHFWDERYHWKHZDWHU VXUIDFH VXFK DV FDWWDLOV DQG EXOUXVKHV 7KHVH ZHWODQG SODQWV RIWHQ KDYH KLJK KDELWDW YDOXH IRU wildlife and waterfowl and can aid in pollutant uptake. environmentally critical areas (ECAs)/DQGVOLGHSURQHDUHDVOLTXHIDFWLRQSURQHDUHDVÀRRGSURQH DUHDVULSDULDQFRUULGRUVZHWODQGVVWHHSVORSHV¿VKDQGZLOGOLIHKDELWDWFRQVHUYDWLRQDUHDVDQG DEDQGRQHGODQG¿OOVDVGH¿QHGDQGUHJXODWHGXQGHUWKH6HDWWOHFULWLFDODUHDUHJXODWLRQV epilimnion7KHXSSHUPRVWZDUPHVWZHOOPL[HGOD\HURIDWKHUPDOO\VWUDWL¿HGODNH GXULQJVXPPHUWLPH extending from the surface to the thermocline. estuary$QDUHDZKHUHIUHVKZDWHUPHHWVVDOWZDWHUDWWKHORZHUHQGRIDULYHURUZKHUHWKHWLGHPHHWV WKHULYHUFXUUHQW HJED\VPRXWKVRIULYHUVDQGZDWHUFRXUVHVVDOWPDUVKHVDQGODJRRQV (VWXDULHV VHUYHDVQXUVHULHVDQGDVVSDZQLQJDQGIHHGLQJJURXQGVIRUPDQ\PDULQHRUJDQLVPVDQGSURYLGH shelter and food for birds and wildlife. eutrophic³:HOOQRXULVKHG´ IURPWKH*UHHN WKHWHUPGHVFULEHVDODNHRIKLJKSKRWRV\QWKHWLFDFWLYLW\ DQG ORZ ZDWHU WUDQVSDUHQF\ FKDUDFWHUL]HG E\ KLJK QXWULHQW FRQFHQWUDWLRQV DQG DVVRFLDWHG KLJK organic productivity. eutrophication 7KH DGGLWLRQ RI QXWULHQWV HVSHFLDOO\ QLWURJHQ DQG SKRVSKRUXV WR D ERG\ RI ZDWHU UHVXOWLQJLQKLJKRUJDQLFSURGXFWLRQUDWHVWKDWPD\RYHUFRPHQDWXUDOVHOISXUL¿FDWLRQSURFHVVHV )UHTXHQWO\UHVXOWLQJIURPSROOXWDQWVRXUFHVRQDGMDFHQWODQGVHXWURSKLFDWLRQSURGXFHVXQGHVLUDEOH HIIHFWVLQFOXGLQJDOJDOEORRPVVHDVRQDOO\ORZR[\JHQOHYHOVDQGUHGXFHGVXUYLYDORSSRUWXQLWLHVIRU ¿VKDQGLQYHUWHEUDWHV fall turnover7KHDXWXPQPL[LQJWRSWRERWWRPRIODNHZDWHUFDXVHGE\FRROLQJDQGZLQGGHULYHG energy. Part 6 Glossary of Terms 63 City of Seattle State of the Waters 2007 Volume II: Small Lakes fecal coliform bacteria0LFURVFRSLFRUJDQLVPVDVVRFLDWHGZLWKDQLPDOIHFHVFRPPRQO\PHDVXUHG LQZDWHUTXDOLW\VDPSOHVDVDQLQGLUHFWLQGLFDWRURIWKHSUHVHQFHRIRWKHUGLVHDVHFDXVLQJEDFWHULD 8VHGDVDSULPDU\SDUDPHWHUDQGVWDQGDUGRIZDWHUTXDOLW\ UHSRUWHGLQQXPEHURIRUJDQLVPVRU colony-forming units per 100 milliliters of water. ¿OOLQJ3ODFHPHQWRIHDUWKHQPDWHULDOWRLQFUHDVHWKHVXUIDFHHOHYDWLRQDWDVLWHXVLQJDUWL¿FLDOPHDQV usually making the ground especially vulnerable to erosion. geographic information system (GIS) $FRPSXWHUGDWDEDVHV\VWHPWKDWFDQLQSXWVWRUHPDQLSXODWH DQDO\]HDQGGLVSOD\JHRJUDSKLFDOO\UHIHUHQFHGGDWDLQPDSIRUPDWV geometric mean A calculated mean or average value that is appropriate for data sets containing a few YDOXHVWKDWDUHYHU\KLJKUHODWLYHWRWKHRWKHUYDOXHVRUVNHZHG7RUHGXFHWKHELDVLQWURGXFHGE\ WKHVHYHU\KLJKQXPEHUVWKHQDWXUDOORJDULWKPVRIWKHGDWDDUHDYHUDJHGDQGWKHDQWLORJRIWKLV average is the geometric mean. The geometric mean is used to compare fecal coliform bacteria OHYHOVWRZDWHUTXDOLW\VWDQGDUGV habitat7KHVSHFL¿FDUHDRUHQYLURQPHQWLQZKLFKDSDUWLFXODUW\SHRISODQWRUDQLPDOOLYHV$QRUJDQLVP GHSHQGVXSRQLWVKDELWDWIRUDOORIWKHEDVLFUHTXLUHPHQWVIRUOLIH hardness A measure of the concentration of dissolved calcium carbonate in water; hard water has high concentrations. heavy metals 0HWDOVRIKLJKVSHFL¿FJUDYLW\SUHVHQWLQPXQLFLSDODQGLQGXVWULDOZDVWHVZKLFKSRVH ORQJWHUPHQYLURQPHQWDOKD]DUGV6XFKPHWDOVLQFOXGHFDGPLXPFKURPLXPFREDOWFRSSHUOHDG PHUFXU\QLFNHODQG]LQF hydrology7KHVFLHQFHRIWKHEHKDYLRURIZDWHULQWKHDWPRVSKHUHRQWKHVXUIDFHRIWKHHDUWKDQGLQWKH VRLODQGXQGHUO\LQJURFNV LWVRFFXUUHQFHGLVWULEXWLRQFLUFXODWLRQSK\VLFDODQGFKHPLFDOSURSHUWLHV and reaction with the environment. hypolimnion7KHGDUNFROGERWWRPOD\HURIZDWHULQDWKHUPDOO\VWUDWL¿HGODNH,WOLHVEHORZWKH WKHUPRFOLQHLVQRQFLUFXODWLQJDQGUHPDLQVSHUSHWXDOO\FROG hypereutrophic conditions ([FHVVLYH QXWULHQW FRQFHQWUDWLRQV LQ D ZDWHU ERG\ UHVXOWLQJ LQ KLJK SURGXFWLYLW\6XFKZDWHUVDUHRIWHQVKDOORZZLWKDOJDOEORRPVDQGSHULRGVRIR[\JHQGH¿FLHQF\ LPSDLUHGZDWHUV:DWHUERGLHVQRWIXOO\VXSSRUWLQJWKHLUEHQH¿FLDOXVHVDVGH¿QHGXQGHUWKHIHGHUDO &OHDQ:DWHU$FW6HFWLRQ G impervious surface A hard surface area that either prevents or retards the entry of water into the soil PDQWOH DVRFFXUVXQGHUQDWXUDOFRQGLWLRQVSULRUWRGHYHORSPHQW IURPZKLFKZDWHUUXQVRIIDWDQ LQFUHDVHGUDWHRIÀRZRULQLQFUHDVHGYROXPHV&RPPRQLPSHUYLRXVVXUIDFHVLQFOXGHURRIWRSV ZDONZD\VSDWLRVGULYHZD\VSDUNLQJORWVVWRUDJHDUHDVFRQFUHWHRUDVSKDOWSDYLQJJUDYHOURDGV SDFNHGHDUWKHQPDWHULDOVDQGRLOHGRUPDFDGDPVXUIDFHV indicator An observed or calculated characteristic that shows the presence of a condition or trend. :DWHUTXDOLW\LQGLFDWRUVDUHVHOHFWHGFKHPLFDODQGSK\VLFDOSDUDPHWHUVDQGLQGLFHVWKDWFDQEHXVHG to characterize overall conditions in the receiving water and also provide benchmarks for assessing the success of watershed management efforts. 64 Part 6 Glossary of Terms City of Seattle State of the Waters 2007 Volume II: Small Lakes invasive species2SSRUWXQLVWLFQRQQDWLYHVSHFLHVRILQIHULRUELRORJLFDOYDOXHWKDWWHQGWRRXWFRPSHWH more desirable forms and become dominant. invertebrates$QLPDOVZLWKRXWLQWHUQDOVNHOHWRQV6RPHUHTXLUHPDJQL¿FDWLRQWREHVHHQZHOOZKLOH RWKHUVVXFKDVZRUPVLQVHFWVDQGFUD\¿VKDUHYLVLEOHWRWKHQDNHGH\H FDOOHGPDFURLQYHUWHEUDWHV %HQWKLFLQYHUWHEUDWHV OLYLQJLQVHGLPHQWV DUHFROOHFWHGDVVDPSOHVWREHLGHQWL¿HGDQGFRXQWHG More varied invertebrate communities generally indicate healthier water bodies. lake An area permanently inundated by water in excess of two meters deep and greater than 20 acres in area as measured at the ordinary high water marks. limiting nutrient The nutrient that is in lowest supply relative to the demand. The limiting nutrient will EHH[KDXVWHG¿UVWE\DOJDHZKLFKUHTXLUHPDQ\QXWULHQWVDQGOLJKWWRJURZ,QSXWVRIWKHOLPLWLQJ QXWULHQWUHVXOWLQLQFUHDVHGDOJDOSURGXFWLRQEXWDVVRRQDVWKHOLPLWLQJQXWULHQWLVH[KDXVWHGJURZWK stops. Phytoplankton growth in lake waters of temperate lowland areas is generally phosphorus- limited. littoral zone7KHVKDOORZVKRUHZDUGUHJLRQRIDODNHKDYLQJOLJKWSHQHWUDWLRQWRWKHERWWRPH[WHQGLQJ out to the greatest depth occupied by rooted plants. ORZHVWHIIHFWOHYHO /(/ 7KHFRQFHQWUDWLRQRIDSROOXWDQWLQVHGLPHQWVDWZKLFKWKHPDMRULW\RIEHQWKLF organisms are unaffected (Persaud et al. 1993). macrophtyes5RRWHGRUÀRDWLQJDTXDWLFYDVFXODUSODQWVFRPPRQO\FDOOHGZDWHUZHHGV DVGLVWLQFWIURP the microscopic plants). mesotrophic A term used to describe a lake of moderate plant productivity and moderate water transparency. A mesotrophic lake is not as rich in nutrients as a eutrophic lake but is richer in nutrients than an oligotrophic lake. metaphyton6KDOORZÀRDWLQJDOJDH mg/L (milligrams per liter) and μg/L (micrograms per liter) Units of measure used in describing the DPRXQWRIDVXEVWDQFHLQDJLYHQYROXPHRIZDWHUDVLQPLOOLJUDPVRIR[\JHQSHUOLWHURIZDWHU microcystin$WR[LFFRPSRXQGSURGXFHGE\EOXHJUHHQDOJDHRUF\DQREDFWHULD monitoring Systematic measurement and data collection by various methods for the purposes of XQGHUVWDQGLQJQDWXUDOV\VWHPVHYDOXDWLQJWKHLPSDFWVRIGLVWXUEDQFHVDQGDOWHUDWLRQVDQGDVVHVVLQJ the performance of mitigation measures. native vegetation Vegetation consisting of plant species (other than noxious weeds) that are indigenous to the region and that reasonably could be expected to occur naturally within the region. natural conditions6XUIDFHZDWHUTXDOLW\WKDWZDVSUHVHQWEHIRUHDQ\KXPDQFDXVHGSROOXWLRQ:KHQ HVWLPDWLQJQDWXUDOFRQGLWLRQVLQWKHKHDGZDWHUVRIDGLVWXUEHGZDWHUVKHGLWPD\EHQHFHVVDU\WRXVH the less disturbed conditions of a neighboring or similar watershed as a reference condition. QLWUDWHQLWULWH 123122)7ZRW\SHVRIQLWURJHQFRPSRXQGVWKDWDUHQXWULHQWVRUIRUPVRIQLWURJHQ that algae may depend upon for growth. Part 6 Glossary of Terms 65 City of Seattle State of the Waters 2007 Volume II: Small Lakes QRHIIHFWOHYHO 1(/ The concentration of a pollutant in sediments at which no toxic effects have been REVHUYHGLQDTXDWLFRUJDQLVPV 3HUVDXGHWDO QRQSRLQWVRXUFHSROOXWLRQ RIZDWHU Pollution that enters a water body from diffuse origins in the ZDWHUVKHGDQGGRHVQRWKDYHGLVFHUQLEOHFRQ¿QHGRUGLVFUHWHSRLQWVRIRULJLQ QR[LRXVZHHG$SODQWWKDWLVXQGHVLUDEOHWURXEOHVRPHDQGGLI¿FXOWWRFRQWURORUHUDGLFDWH nutrient An organic or inorganic chemical essential for growth and reproduction of organisms. In VXUIDFHZDWHUERGLHVQXWULHQWVDIIHFWLQJZDWHUTXDOLW\LQFOXGHWRWDOSKRVSKRUXVVROXEOHUHDFWLYH SKRVSKRUXVQLWUDWHQLWURJHQQLWULWHQLWURJHQDQGDPPRQLDQLWURJHQPHDVXUHGLQPLOOLJUDPVSHU liter of water. oligotrophic³3RRUO\QRXULVKHG´ IURPWKH*UHHN WKHWHUPGHVFULEHVDODNHRIORZFRQFHQWUDWLRQVRI QXWULHQWVDQGDOJDHDQGKLJKZDWHUWUDQVSDUHQF\$QROLJRWURSKLFODNHKDVORZHUQXWULHQWOHYHOVWKDQ a mesotrophic or eutrophic lake. RUGLQDU\KLJKZDWHUPDUN7KHOLQHRQWKHVKRUHHVWDEOLVKHGE\WKHÀXFWXDWLRQVRIZDWHUOHYHODQG LQGLFDWHGE\SK\VLFDOFKDUDFWHULVWLFVVXFKDVDFOHDUO\YLVLEOHQDWXUDOOLQHLPSUHVVHGRQWKHEDQN VKHOYLQJFKDQJHVLQWKHFKDUDFWHURIVRLOGHVWUXFWLRQRIWHUUHVWULDOYHJHWDWLRQRUWKHSUHVHQFHRI litter and debris. outfall*HQHUDOO\WKHSRLQWRIGLVFKDUJHIURPDVWRUPGUDLQ2XWIDOOVPD\GLVFKDUJHWRVXUIDFHZDWHUV or ground water. outlet *HQHUDOO\ WKH SRLQW RI ZDWHU GLVFKDUJH IURP D ZDWHUFRXUVH ULYHU ODNH WLGHZDWHU RU VWRUP drain. 3$+V SRO\F\FOLFDURPDWLFK\GURFDUERQV $FODVVRIRUJDQLFFRPSRXQGVVRPHRIZKLFKDUHSHUVLVWHQW DQGFDQFHUFDXVLQJWKDWDUHXELTXLWRXVLQWKHHQYLURQPHQW3$+VDUHFRPPRQO\IRUPHGE\WKH FRPEXVWLRQRIIRVVLOIXHOVDQGE\IRUHVW¿UHVRIWHQUHDFKLQJWKHHQYLURQPHQWWKURXJKDWPRVSKHULF IDOORXWKLJKZD\UXQRIIDQGRLOGLVFKDUJH parameter2QHRIDVHWRIYDULDEOHPHDVXUDEOHSURSHUWLHVZKRVHYDOXHVGHWHUPLQHWKHFKDUDFWHULVWLFV RIDV\VWHPVXFKDVDZDWHUERG\6HHZDWHUTXDOLW\SDUDPHWHU PCBs (polychlorinated biphenyls) A group of manmade organic chemicals comprising 209 closely UHODWHG FRPSRXQGV FRQJHQHUV PDGH XS RI FDUERQ K\GURJHQ DQG FKORULQH ,I UHOHDVHG WR WKH HQYLURQPHQW3&%VSHUVLVWIRUORQJSHULRGVRIWLPHDQGFDQFRQFHQWUDWHLQIRRGFKDLQV pelagic zone 7KHRSHQDUHDRIDODNHH[WHQGLQJIURPWKHHGJHRIWKHOLWWRUDO]RQHWRWKHFHQWHURIWKH lake. pesticide $ JHQHUDO WHUP GHVFULELQJ DQ\ VXEVWDQFH XVXDOO\ FKHPLFDO XVHG WR GHVWUR\ RU FRQWURO XQGHVLUDEOH RUJDQLVPV SHVWV 3HVWLFLGHV LQFOXGH KHUELFLGHV LQVHFWLFLGHV IXQJLFLGHV DOJDFLGHV and other substances. S+$PHDVXUHRIWKHDONDOLQLW\RUDFLGLW\RIDVXEVWDQFHRQDVFDOHRIWRGHWHUPLQHGE\PHDVXULQJ the concentration of hydrogen ions in the substance. A pH value of 7.0 indicates neutral water. A 6.5 reading is slightly acidic. 66 Part 6 Glossary of Terms City of Seattle State of the Waters 2007 Volume II: Small Lakes phosphorus One of the elements essential as a nutrient for the growth of organisms. In western :DVKLQJWRQODNHVLWLVXVXDOO\WKHDOJDOQXWULHQWLQVKRUWHVWVXSSO\ KHQFHDGGLQJPRUHSKRVSKRUXV FDXVHVPRUHDOJDOJURZWK9DULRXVPHDVXUHVRISKRVSKRUXVLQZDWHUVDPSOHVDUHPDGHLQFOXGLQJ total phosphorus and the dissolved portion of phosphorus. photosynthesis The process by which living plant cells produce simple sugars and starches from carbon GLR[LGHDQGZDWHUZLWKWKHDLGRIFKORURSK\OODQGWKHSUHVHQFHRIOLJKW phytoplankton0LFURVFRSLFDOJDHDQGPLFUREHVWKDWÀRDWIUHHO\LQRSHQZDWHURIODNHVDQGRFHDQV plankton1RQPRELOHRUZHDNVZLPPLQJPLFURVFRSLFDQLPDOVRUSODQWVWKDWÀRDWDQGGULIWZLWKODNH FXUUHQWVVXFKDVEDFWHULDYLUXVHVSURWR]RDSK\WRSODQNWRQ LHPLFURVFRSLFSODQWV ]RRSODQNWRQ LHPLFURVFRSLFDQLPDOV DQGHDUO\OLIHVWDJHVRILQVHFWV pollutant$VXEVWDQFHLQWURGXFHGLQWRWKHHQYLURQPHQWWKDWKDVDGYHUVHHIIHFWVRQRUJDQLVPVLQFOXGLQJ GHDWKFKURQLFSRLVRQLQJLPSDLUHGUHSURGXFWLRQFDQFHURURWKHUHIIHFWV SROOXWLRQ RIZDWHU 7KHKXPDQLQGXFHGDOWHUDWLRQRIWKHFKHPLFDOSK\VLFDOELRORJLFDORUUDGLRORJLFDO integrity of water. probable effects concentration (PEC) The concentration of a pollutant in sediments above which DGYHUVH HIIHFWV DUH H[SHFWHG WR RFFXU PRUH RIWHQ WKDQ QRW EDVHG RQ D FRPSLODWLRQ RI DYDLODEOH VHGLPHQWTXDOLW\JXLGHOLQHVUHSRUWHGLQWKHOLWHUDWXUH 0DF'RQDOGHWDO probable effects level (PEL) The concentration of a pollutant in sediments at which adverse effects are IUHTXHQWO\H[SHFWHG7KH3(/LVFDOFXODWHGDVWKHJHRPHWULFPHDQRIWKHWKSHUFHQWLOHFRQFHQWUDWLRQ of the toxic effects data set and the 85th percentile of the no-effect data set (NOAA 1999). UHFHLYLQJZDWHUV%RGLHVRIZDWHURUVXUIDFHZDWHUV\VWHPVVXFKDVDODNHRUZDWHUFRXUVHWRZKLFK surface runoff is discharged. residence time7KHDPRXQWRIWLPHUHTXLUHGWRFRPSOHWHO\UHSODFHWKHYROXPHRIZDWHULQDODNHZLWKDQ HTXDOYROXPHRIQHZZDWHUFRPPRQO\FDOOHGWKHK\GUDXOLFUHVLGHQFHWLPH riparian Pertaining to the bank of a water body. Riparian habitat is associated with stream and lake PDUJLQVW\SLFDOO\FKDUDFWHUL]HGE\GHQVHYHJHWDWLRQVXSSRUWLQJDYDULHW\RIZDWHUIRZOVRQJELUGV DPSKLELDQVDQGVPDOOPDPPDOV riprap$IDFLQJOD\HURUSURWHFWLYHPRXQGRIURFNVXVHGWROLQHFKDQQHOVWRSUHYHQWEDQNHURVLRQFDXVHG E\K\GUDXOLFIRUFHVRIVXUIDFHÀRZDQGVWRUPZDWHUUXQRII runoff:DWHURULJLQDWLQJIURPUDLQIDOODQGRWKHUSUHFLSLWDWLRQWKDWÀRZVWRGUDLQDJHIDFLOLWLHVULYHUV ZDWHUFRXUVHVVSULQJVSRQGVODNHVZHWODQGVDQGVKDOORZJURXQGZDWHU salmonid$PHPEHURIWKH¿VKIDPLO\6DOPRQLGDHLQFOXGLQJ&KLQRRNFRKRFKXPVRFNH\HDQGSLQN VDOPRQ FXWWKURDWEURRNEURZQUDLQERZDQGVWHHOKHDGWURXW 'ROO\9DUGHQ NRNDQHH DQGFKDU species. Secchi depth$YLVXDOPHDVXUHRIZDWHUWUDQVSDUHQF\ FODULW\ PHDVXUHGE\ORZHULQJDEODFNDQGZKLWH RUDOOZKLWHGLVN 6HFFKLGLVNFHQWLPHWHUVLQGLDPHWHU LQWRWKHZDWHUXQWLOLWLVQRORQJHUYLVLEOH and recording the depth in units of meters or feet. Part 6 Glossary of Terms 67 City of Seattle State of the Waters 2007 Volume II: Small Lakes sediment %RWWRP PDWHULDO LQ D ZDWHU ERG\ WKDW RULJLQDWHV IURP UHPDLQV RI DTXDWLF RUJDQLVPV SUHFLSLWDWLRQRIGLVVROYHGPLQHUDOVDQGHURVLRQRIVXUURXQGLQJODQGV&HUWDLQFRQWDPLQDQWVWHQGWR collect on and adhere to sediment particles. sediment management standards6WDWHUHJXODWRU\VWDQGDUGVSHUWDLQLQJWRWKHTXDOLW\RIVHGLPHQW found in the Washington Administrative Code (WAC) 173-204. severe-effect level The concentration of a pollutant in sediments at which pronounced disturbance of the sediment-dwelling community can be expected (Persaud et al. 1993). VKHHW ÀRZ 5XQRII WKDW ÀRZV RYHU WKH JURXQG VXUIDFH DV D WKLQ HYHQ OD\HU QRW FRQFHQWUDWHG LQ D channel. spring turnover 7KH VWUDWL¿FDWLRQ RI ODNH ZDWHU WKDW EHJLQV LQ VSULQJ DQG DFFHOHUDWHV LQ VXPPHU primarily caused by warming of surface waters. storm event7HFKQLFDOWHUPIRUDVSHFL¿FSUHFLSLWDWLRQRFFXUUHQFH IRUH[DPSOHWKH\HDUKRXU VWRUPHYHQWWKH\HDUKRXUVWRUPHYHQWRUWKH\HDUKRXUVWRUPHYHQW storm drain*HQHUDOO\DFRQYH\DQFHRUV\VWHPRIFRQYH\DQFHVWKDWFDUULHVVWRUPZDWHUVXUIDFHZDWHU and other drainage (but not sanitary wastewater or industrial wastes) toward points of discharge (sometimes called a storm sewer). VWRUPZDWHU*HQHUDOO\SUHFLSLWDWLRQDQGVXUIDFHUXQRIIDQGGUDLQDJH VWRUPZDWHUGUDLQDJHV\VWHP&RQVWUXFWHGDQGQDWXUDOIHDWXUHVWKDWIXQFWLRQWRJHWKHUWRFROOHFWFRQYH\ FKDQQHOKROGLQKLELWUHWDLQGHWDLQLQ¿OWUDWHGLYHUWWUHDWRU¿OWHUVWRUPZDWHU VWRUPZDWHUUXQRII Stormwater that directly leaves an area in surface drainage. VWUDWL¿FDWLRQRIODNHV$OD\HULQJHIIHFWRIWKHZDUPLQJRIODNHVXUIDFHZDWHUVGXULQJVXPPHUFDXVHGE\ GLIIHUHQFHVLQZDWHUGHQVLW\8SSHUZDWHUVDUHSURJUHVVLYHO\ZDUPHGE\WKHVXQDQGGHHSHUZDWHUV UHPDLQFROG%HFDXVHRIWKHGLIIHUHQFHLQGHQVLW\ ZDUPHUZDWHULVOLJKWHULQZHLJKW WKHWZROD\HUV UHPDLQVHSDUDWH XSSHUZDWHUVÀRDWRQGHHSHUZDWHUVDQGZLQGFDXVHGPL[LQJRFFXUVRQO\LQWKH XSSHUOD\HU2[\JHQLQWKHERWWRPZDWHUVPD\EHFRPHGHSOHWHG,QIDOODVWKHXSSHUZDWHUVFRROWKH ZKROHODNHPL[HVDJDLQDQGUHPDLQVPL[HGWKURXJKRXWWKHZLQWHU7KHUPDOVWUDWL¿FDWLRQLVW\SLFDO of most deep lakes during summer. substrate The nonliving material forming the bed of a water body with particles described in terms of VL]HDVERXOGHUVFREEOHVJUDYHOVDQGVLOWRUFOD\ VZLPPHU¶VLWFK$UDVKFDXVHGE\DZDWHUERUQHSDUDVLWLFÀDWZRUPLQWKHLPPDWXUH FHUFDULDO VWDJHRI LWVOLIHF\FOHZKHQLWSHQHWUDWHVEHQHDWKWKHVNLQRIEDWKHUV$OWKRXJKWKHRUJDQLVPGLHVDVVRRQDVLW SHQHWUDWHVWKHVNLQWKHUDVKPD\SHUVLVWIRUZHHNV $VKRZHURUDOFRKROUXEGRZQLVUHFRPPHQGHG to minimize penetration.) thermocline,QDVWUDWL¿HGODNHDKRUL]RQWDOSODQHDWWKHGHSWKRIWKHPRVWUDSLGYHUWLFDOFKDQJHLQ temperature and density. threshold effects concentration (TEC) The concentration of a pollutant in sediments below which adverse effects are not expected to occur (MacDonald et al. 2000). 68 Part 6 Glossary of Terms City of Seattle State of the Waters 2007 Volume II: Small Lakes threshold effects level (TEL) The concentration of a pollutant in sediments at which adverse effects are expected to occur only rarely. The TEL is calculated as the geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effect data set (NOAA 1999). WRWDOPD[LPXPGDLO\ORDG 70'/ 8QGHU6HFWLRQ G RIWKHIHGHUDO&OHDQ:DWHU$FWZDWHUTXDOLW\ standards must be used to identify threatened and impaired water bodies. Category 2 (threatened) ZDWHUERGLHVDUHWKRVHWKDWRFFDVLRQDOO\H[FHHGZDWHUTXDOLW\VWDQGDUGVZKLOHFDWHJRU\ LPSDLUHG ZDWHUERGLHVDUHWKRVHWKDWIUHTXHQWO\H[FHHGVWDQGDUGV,PSDLUHGZDWHUERGLHVDUHUHTXLUHGWREH HYDOXDWHGWRLGHQWLI\WKHSROOXWDQWVDQGVRXUFHVUHVSRQVLEOHIRUWKHZDWHUTXDOLW\SUREOHPV7RWDO PD[LPXPGDLO\ORDG 70'/ OLPLWVDUHWKHQHVWDEOLVKHGDQGDOORFDWHGWRVSHFL¿FSROOXWDQWVRXUFHVLQ RUGHUWRUHGXFHSROOXWDQWGLVFKDUJHVDQGPRYHWRZDUGPHHWLQJZDWHUTXDOLW\VWDQGDUGV$70'/LV the sum of the allowable loads of a single pollutant from all contributing point sources and nonpoint VRXUFHVLQFOXGLQJDPDUJLQRIVDIHW\DQGDFFRXQWLQJIRUVHDVRQDOYDULDWLRQVLQZDWHUTXDOLW\ toxic3RLVRQRXVFDUFLQRJHQLFRURWKHUZLVHGLUHFWO\KDUPIXOWROLIH transparency&ODULW\RIZDWHULQDODNHPHDVXUHGE\ORZHULQJDEODFNDQGZKLWH6HFFKLGLVNLQWRWKH water and recording the depth at which it is no longer visible. Transparency of lakes is determined by the color of the water and the amount of material suspended in it. Generally in colorless waters RIWKH3XJHWORZODQGZDWHUWUDQVSDUHQF\LQVXPPHULVGHWHUPLQHGE\WKHDPRXQWRIDOJDHSUHVHQW LQ WKH ZDWHU 6XVSHQGHG VLOW SDUWLFOHV SDUWLFXODUO\ DV D UHVXOW RI VWRUP HYHQWV PD\ DOVR UHGXFH transparency. trophic status$UDWLQJRIWKHFRQGLWLRQRIDODNHRQWKHVFDOHRIROLJRWURSKLF±PHVRWURSKLF±HXWURSKLF 7UDQVSDUHQF\FKORURSK\OODOHYHOVSKRVSKRUXVFRQFHQWUDWLRQVDPRXQWRIPDFURSK\WHVDQGTXDQWLW\ of dissolved oxygen in the hypolimnion can be used to assess the trophic state. trophic state index$FDOFXODWLRQRIWURSKLFVWDWXVEDVHGRQWKUHHNH\LQGLFDWRUV FKORURSK\OODWRWDO SKRVSKRUXVDQG6HFFKLGHSWK &DUOVRQ turbidity A measure of the reduced transparency of water due to the suspension of minute particles such DVDOJDHVLOWRUFOD\W\SLFDOO\H[SUHVVHGLQQHSKHORPHWULFWXUELGLW\XQLWV 178 upland7KHJHQHUDOWHUPXVHGIRUODQGDUHDVWKDWGRQRWPHHWWKHFULWHULDIRUFODVVL¿FDWLRQDVZHWODQGV upper effects threshold (UET) The concentration of a pollutant in sediments at which adverse effects would always occur based on the lowest adverse effect threshold (AET) from a compilation of endpoints analogous to the marine AET endpoints. The UET is based on 1 percent total organic carbon content in the sediment (NOAA 1999). urban runoff6WRUPZDWHUIURPVWUHHWVDQGDGMDFHQWGHYHORSHGSURSHUWLHV Washington Administrative Code (WAC)7KHFRGL¿HGUHJXODWLRQVRIWKHVWDWHRI:DVKLQJWRQ ZDWHUFROXPQ,QDZDWHUERG\ZDWHUEHWZHHQWKHLQWHUIDFHZLWKWKHDWPRVSKHUHDWWKHVXUIDFHDQGWKH interface with the sediment layer at the bottom. ZDWHUFRXUVH$QHWZRUNRIRSHQVWUHDPFKDQQHOVSLSHVGLWFKHVDQGFXOYHUWVLQZKLFKVXUIDFHZDWHU LVWUDQVSRUWHGWRDUHFHLYLQJZDWHUERG\:DWHUFRXUVHVLQFOXGHVPDOOODNHVERJVVWUHDPVFUHHNV DQGLQWHUPLWWHQWDUWL¿FLDORUFRQVWUXFWHGFRPSRQHQWVEXWGRQRWLQFOXGHUHFHLYLQJZDWHUV 6HDWWOH Municipal Code 22.801.240). Part 6 Glossary of Terms 69 City of Seattle State of the Waters 2007 Volume II: Small Lakes ZDWHU TXDOLW\ *HQHUDOO\ WKH FKHPLFDO SK\VLFDO DQG ELRORJLFDO FKDUDFWHULVWLFV RI ZDWHU XVXDOO\ LQ respect to its suitability for a particular purpose. ZDWHUTXDOLW\FULWHULD(OHPHQWVRIVWDWHZDWHUTXDOLW\VWDQGDUGVH[SUHVVHGDVTXDQWLWDWLYHFRQVWLWXHQW FRQFHQWUDWLRQV OHYHOV PHDVXUHV RU GHVFULSWLYH VWDWHPHQWV UHSUHVHQWLQJ D TXDOLW\ RI ZDWHU WKDW VXSSRUWV D SDUWLFXODU XVH :KHQ FULWHULD DUH PHW ZDWHU TXDOLW\ JHQHUDOO\ SURWHFWV WKH ZDWHU¶V designated use. ZDWHUTXDOLW\SDUDPHWHU One of a set of properties of water that are routinely measured and analyzed WRDVVHVVZDWHUTXDOLW\VXFKDVWHPSHUDWXUHWXUELGLW\FRQGXFWLYLW\S+ DFLGLW\ GLVVROYHGR[\JHQ FRQWHQWSKRVSKRUXVFRQFHQWUDWLRQIHFDOFROLIRUPEDFWHULDFRQFHQWUDWLRQDQGRWKHUV ZDWHUTXDOLW\VWDQGDUGV Provisions of state or federal law consisting of designated uses for a water ERG\DQGZDWHUTXDOLW\FULWHULDEDVHGXSRQVXFKXVHVSXUVXDQWWRWKHIHGHUDO&OHDQ:DWHU$FW :DWHUTXDOLW\VWDQGDUGVDUHHVWDEOLVKHGWRSURWHFWSXEOLFKHDOWKRUZHOIDUHHQKDQFHWKHTXDOLW\RI ZDWHUDQGVHUYHWKHSXUSRVHVRIWKH&OHDQ:DWHU$FW ZDWHUVKHG A geographical region bounded by topographic high points within which water drains into DSDUWLFXODUULYHUZDWHUFRXUVHRUERG\RIZDWHU:DWHUVKHGVFDQEHDVODUJHDVWKRVHLGHQWL¿HGDQG QXPEHUHGE\WKHVWDWHRI:DVKLQJWRQDVZDWHUUHVRXUFHLQYHQWRU\DUHDV :5,$V RUWKH\FDQEH LGHQWL¿HGDVVPDOOHUGUDLQDJHDUHDV ZHWODQG$QDUHDWKDWLVLQXQGDWHGRUVDWXUDWHGE\VXUIDFHZDWHURUJURXQGZDWHUDWDIUHTXHQF\DQG GXUDWLRQVXI¿FLHQWWRVXSSRUWDSUHYDOHQFHRIYHJHWDWLRQW\SLFDOO\DGDSWHGIRUOLIHLQVDWXUDWHGVRLO FRQGLWLRQV:HWODQGVJHQHUDOO\LQFOXGHVZDPSVPDUVKHVERJVDQGVLPLODUDUHDV ZRRG\GHEULV/RJVVWXPSVRUEUDQFKHVWKDWKDYHIDOOHQRUEHHQFXWDQGOHIWLQSODFH 70 Part 6 Glossary of Terms