1. SRRTTF Technical Activities Where We’ve Been, Where We’re Going Dave Dilks Spokane River Regional Toxics Task Force Workshop January 13, 2015 1

2. Outline Task Force objectives Where we’ve been Where we are Where we’re going 2

3. 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 3

4. Study Area “Upper” Spokane River – Lake Coeur d’Alene outlet to headwaters of Lake Spokane 4

5. 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 5

6. 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 6

7. 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 7

8. 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 8

9. 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? 9

10. 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 station Unknown source = Downstream load – Upstream load – Known Load 10

11. 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 11

12. 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 12

13. 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 13

14. 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 14

15. 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 15

16. 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 16

17. 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 17