Lake Whatcom Tributary Monitoring – Phase II Summary Whatcom County Department of Public Works April 26 | 2013

Lake Whatcom Tributary Monitoring: Phase II Summary April 26, 2013

Project Background Phase I & II Monitoring Summary Discussion Agenda Brown and Caldwell 3

Lake Whatcom DO levels have declined due to elevated P Since 2007, various monitoring efforts have taken place In 2008, Ecology issued report recommending TMDLs for P inputs to the lake from 22 principal tributaries (subwatersheds) Five of these sub-watersheds (Agate Bay, North Shore, Blue Canyon, South Bay and Strawberry) encompass more than one stream system. Ten of these sub-watersheds have had routine monitoring or special studies conducted by various entities over the past decades. Background Brown and Caldwell 4

Collected stormflow and bimonthly (mostly baseflow) samples for the nine main tributaries during Data sondes collected continuous turbidity Evaluated correlations between TP and turbidity, TSS, and SRP Phase I Activities Brown and Caldwell 5

Phase I Monitoring Locations 9 tributary subbasins (shaded areas) Brown and Caldwell 6

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8 Phase I Sampling Events 6/12/077/20/078/9/079/27/0710/16/0712/2/0712/11/071/24/083/13/085/8/085/13/088/21/0810/31/0811/6/08 Rainfall (in.) # of events AndersonXXXXXXXXXXXX X13 AustinXXXXXXXXXXXXXX14 BrannianX X X XXXX X 8 CarpenterX X X XXXX X 8 EuclidX X XXXX X 7 MillXX XXXXXXXXXX12 OlsenXXXXXXXXXXXXXX14 Silver BeachXXXXXXXXXXXXXX14 SmithXXXXXXXXXXXXXX14 Phase I Monitoring Summary

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Significant correlations for TP & TSS & turbidity HSPF modeling suggested model may underestimate TP from Austin, Olsen and Smith Maybe due to lack of storm data for model calibration Recommended sampling new and existing locations, and collecting winter stormflow samples to address key gaps and to help identify why model under-predicted P. Phase I Findings Brown and Caldwell 13

Sample numerous tribs with little or no existing data Ecology had used data from 9 tribs to represent >15 unmonitored tribs Measure wet weather P concentrations in tributaries 9 Phase I tributaries 15 additional tributaries with little or no previous monitoring Up to six events at each location (144 total) Rotating panel of three groups of sampling locations Phase II Plan Brown and Caldwell 14

Brown and Caldwell 15 Phase II Monitoring Locations 15 tributary subbasin (shaded areas) & Panel Rotations (South, Southeast, and Northeast)

Sampled 28 locations during 3 to 5 stormflow events (134 total) Only three storms >1”, however Phase II Status Brown and Caldwell 16

Phase II Subbasin Panel Details Brown and Caldwell 17 North Panel (continuing clockwise around lake perimeter) 1. Silver Beach Creek 2. Academy 3. Eagle Ridge 4. Agate 5 5. Agate 6 6. Carpenter 7. Olsen 8. North Shore 1 (NS1) 9. Smith 10. Blue Canyon 8 (1 mile bike ride down the “Hertz” trail) Southeast Panel (Blue Canyon road end to South Bay, clockwise around lake perimeter): 1. Blue Canyon 3 (historical samples; small, but perennial trib) 2. Blue Canyon 1 3. Anderson 4. Fir 5. Brannian 6. South Bay 1 7. South Bay 6 8. Wildwood 9. South Bay 9A South panel (continuing clockwise around lake perimeter) 1. Austin 2. Sudden Valley 3. Strawberry 1A 4. Strawberry 1 5. Strawberry 2 6. Strawberry 3 7. Coronado 8. Euclid 9. Donovan Subbasin Name Area (sq mi) # of tributaries Academy1.21 Agate3.37 Anderson 41 Austin8.31 Blue Canyon Brannian 3.81 Carpenter1.81 Coronado -- Donovan 0.11 Eagle Ridge0.141 Euclid Fir North Shore1.95 Olsen3.81 Silver Beach0.511 Smith51 South Bay Strawberry 1.26 Sudden Valley0.951 Wildwood --

Brown and Caldwell 18 Land Use Summaries for Phase II Areas

Brown and Caldwell 19 Percentages per WRIA subbasin by land use category Source: WDOE, Volume 2. Water Quality Improvement Report and Implementation Strategy. ( February 2013) Total acres per subbasin by land use category WRIA Basin Name Developed / Impervious DevelopedOpenAgricultureMixed Forest Deciduous Forest Evergreen ForestWater/Wetlands Total Acres of Subbasin Anderson Creek Gage Mirror Lake Austin Creek at Gage Austin Creek Outlet Upper Austin Creek Beaver Cr trib Austin Cr Brannian Creek Gage Brannian Creek Outlet Carpenter Cable and Euclid Oriental (Mill Wheel Creek) North Shore Academy, Agate Bay, Eagle Ridge and Silver Beach Blue Canyon Fir Olsen Hillsdale Smith Creek Gage Smith Creek Outlet South Bay Strawberry Sudden Valley Percentages per subbasin by land use category WRIA Basin Name Developed / Impervious DevelopedOpenAgricultureMixed Forest Deciduous Forest Evergreen ForestWater/Wetlands Total Acres of Subbasin Anderson Creek Gage0% 5%3%29%23%39%0%100% Mirror Lake0% 19%0%25%40%6%10%100% Austin Creek at Gage4%14%1%0%21%8%53%0%100% Austin Creek Outlet8%30%2%0%22%6%25%6%100% Upper Austin Creek0% 19%6%74%0%100% Beaver Cr trib Austin Cr1%4%0% 38%20%37%0%100% Brannian Creek Gage0%1%4%0%27%21%47%0%100% Brannian Creek Outlet6%17%3%0%36%24%16%1%100% Carpenter2%8%5%1%40%19%24%0%100% Cable and Euclid6%23%1%0%34%16%19%0%100% Oriental (Mill Wheel Creek)6%22%1%0%40%13%18%1%100% North Shore3%9% 0%39%22%16%1%100% Academy, Agate Bay, Eagle Ridge and Silver Beach5%19%3% 27%36%6%1%100% Blue Canyon0% 6%0%34%14%44%1%100% Fir0% 1%2%24%23%50%0%100% Olsen0%1% 0%33%15%46%0%100% Hillsdale9%31%4%0%29%15%12%0%100% Smith Creek Gage0% 3%0%36%15%46%0%100% Smith Creek Outlet0%3%10%0%45%30%10%0%100% South Bay2%6%7%0%33%30%21%1%100% Strawberry13%48%2%0%16%12%9%0%100% Sudden Valley6%23%1%0%27%14%27%2%100%

Brown and Caldwell 20 Phase II Sampled Storm Events 8/31/109/26/1011/1/1012/13/101/5/113/1/113/30/114/27/115/11/119/22/1111/2/1111/22/112/21/1210/14/121/8/13# of storms Rainfall (inches) # Samples Collected Panel SoutheastSouthNorthSoutheastSouthNorthSoutheastSouthNorthSoutheastSouthNorthSoutheastSouthNorth- Blue Canyon 3 X X X X X 5 Anderson X X X X X 5 Fir X X X X X 5 Brannian X X X X X 5 South Bay 1 X X X X X 5 South Bay 6 X X X X X 5 Wildwood X X X X 4 Donovan X X X X X 5 Euclid X X X X X 5 Coronado X X X X X 5 Strawberry 3 X X X X X 5 Strawberry 2 X X X X X 5 Strawberry 1 X X X X 4 Strawberry 1A X X X X X 5 Sudden Valley X X X X X 5 Austin X X X X X 5 South Bay 9A X X X X X 5 Silver Beach X X X X X5 Academy X X X X X5 Eagle Ridge X X X X X5 Agate 5 X X X X X5 Agate 6 X X X X4 Carpenter X X X X X5 Olsen X X X X X5 North Shore 1A X X X X4 Smith X X X X X5 Blue Canyon 8 X X X X X5 Blue Canyon 1 X X X 3

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Brown and Caldwell 25 Correlations between Grab Turbidity, TP and TSS from samples collected during Phase I & II PanelTP & Turbidity CorrelationTP & TSS Correlation Academy 89%96% Agate 5 92%73% Agate 6 92%88% Anderson 69%73% Austin 71%92% Blue Canyon 1 90%85% Blue Canyon 3 86%88% Blue Canyon 8 76%1% Brannian 91%93% Carpenter 94% Coronado 61%60% Donovan 44%70% Eagle Ridge 70%91% Euclid 66%88% Fir 97%16% Mill 30%35% North Shore 1A 88%96% Olsen 82%93% Silver Beach 89%92% Smith 83%94% South Bay 1 94%22% South Bay 6 90%89% South Bay 9A 92%27% Strawberry 1 95%72% Strawberry 1A 43%60% Strawberry 2 72%77% Strawberry 3 71%82% Sudden Valley 58%86% Wildwood 32%50%

Regression Analysis for select storm dates - Total P vs. Continuous and Grab Turbidity Brown and Caldwell 26

Regression Analysis for select storm dates - Total P vs. Continuous and Grab Turbidity Brown and Caldwell 27

Several new Phase II sites indicate elevated levels of TP (e.g., Coronado, Academy, Eagle Ridge, Donovan Most TP is in Austin, Olsen, and Smith creeks is in particulate form. TDP and SRP concentrations consistently similar, indicating that dissolved P predominately in SRP form. SRP showed much less response to stormflow hydrographs compared with TP TP and TSS showed strong correlations, suggesting that most of the TP is associated with particulates suspended in the water column Phase II Findings Brown and Caldwell 28

Correlations between TP and continuous turbidity Strong relationships during large storms Weaker during smaller storms and baseflow, when turbidity and TSS were low Silver Beach, Smith, Olsen showed best correlations Anderson & Austin did not show good correlations Perhaps due to Mirror Lake diversion (Anderson) Perhaps due to low concentrations during storm events (Austin) Most sampling events had total precipitation of 0.5 inches or less during sampling. Phase II Findings, continued Brown and Caldwell 29

Drop TDP? Adjust sampling criteria? Adjust locations? HSPF modeling? TMDL implementation support? Discussion Brown and Caldwell 30