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SRRTTF Technical ActivitiesWhere We’ve Been, Where We’re Going

Dave Dilks Spokane River Regional Toxics Task Force Workshop

January 13, 2015

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Outline

• Task Force objectives• Where we’ve been• Where we are• Where we’re going

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Objectives: What are We Doing, & Why?

• Primary Task Force objective– Identify and implement appropriate actions

needed to make measurable progress towards meeting applicable water quality standards

• Associated objective– Characterize the sources of toxics in the Spokane

River

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Study Area• “Upper” Spokane River– Lake Coeur d’Alene outlet to headwaters of Lake Spokane

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Phasing of Technical Activities

• Phase 1– Gather existing data, identify data gaps– December, 2013 workshop– Prepare a monitoring plan

• Phase 2– Collect new data

• Phase 3– Analyze data and characterize sources

• Phase 4– Assess potential Best Management Practices and develop a

Comprehensive Plan

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Where We’ve Been: Phase 1 Findings

• A large amount of data had already been collected in the Spokane River watershed– Dept. of Ecology (2011) PCB Source Assessment

• Primary data gaps defined in 2013– Sources contributing to stormwater loads– Significance of loading from groundwater sources– Significance of loading from atmospheric sources– Sources upstream of the Idaho/Washington border

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Where We’ve Been: Phase 1 Findings

• Conclusions from December 2013 workshop– Not feasible to address all gaps at once – First year of monitoring should focus on

characterizing dry weather sources

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Phasing of Technical Activities

• Phase 1– Gather existing data, identify data gaps– December, 2013 workshop– Prepare a monitoring plan

• Phase 2– Collect new data

• Phase 3– Analyze data and characterize sources

• Phase 4– Assess potential Best Management Practices and

develop Comprehensive Plan

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Phase 1 Monitoring Plan Components

• Synoptic Study– Support mass balance assessment

• Seasonally Integrated Sampling– Provide information on the seasonal variability of

loading from Lake Coeur d’Alene• Confidence Testing– Can we expect to get meaningful results from

standard grab sampling?

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Intent of Synoptic Survey • Support dry weather mass balance assessment– Measure river concentration at flow gaging locations– Measure all known dry weather sources

• Identify unknown sources between each stationUnknown source = Downstream load – Upstream load – Known Load

NPDES Permited Location Gauging Station Location Hangman Creek

Inland Empire PaperLiberty Lake Coeur d'Alene

City of Spokane Spokane County Kaiser Post FallsHayden

SpokaneTrent Avenue Bridge Barker Rd. Post Falls Coeur d'Alene Lake Outlet

Spokane Gage Trent Avenue Bridge Barker Rd. Post Falls Coeur d'Alene Lake Outletto to to to to

Nine Mile Dam Spokane Gage Trent Avenue Bridge Barker Rd. Post Falls

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Seasonally Integrated Sampling

• Provide information on the seasonal variability of loading from Lake Coeur d’Alene– Spring high flow– Summer low flow– Winter moderate flow

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Confidence Testing• Determine if meaningful results can be

expected from standard grab sampling– Conducted in

conjunction with seasonally integrated

sampling– Two locations

sampled May 13-19, 2014

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Confidence Testing Results

• Concentrations were low (8-80 pg/L) and at similar levels as blanks (8-54 pg/L)

• Synoptic survey not expected to satisfy objective of supporting a rigorous mass balance assessment

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Confidence Testing Results

• River concentrations expected to be higher during summer survey– Much lower river flows means much less dilution of

PCB sources• In-river “signal” expected to rise above

measurement “noise”– Especially as we move downstream

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Confidence Testing Conclusions

• Synoptic survey still of value– Capable of identifying presence of larger sources

• Data quality objectives modified– Support a semi-quantitative mass balance

assessment, i.e. be able to identify if and where significant unknown sources exist

– Support an adaptive management approach• Provide grab sample results that can be directly

compared to results from other sampling methods

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Where We Are

• Synoptic survey and mass balance assessment completed

• Results consistent with expectations– Concentrations low upstream– Increase as you go downstream

• Area of likely groundwater PCB source identified

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Where We’re Going

• Define appropriate next steps• Workshop segments– Day 1: Review existing results• Review analytical methods• Discuss sampling results• Mass balance assessment

– Day 2: Identify next steps• Data gaps, necessary monitoring, control actions,

analyses