1. TTWG Report & Technical Topics SRRTTF Meeting Dave Dilks June 1, 2016

2. Items Magnitude of Source Areas and Pathways memo – Proposed format for displaying WWTP data 2016 Monthly Monitoring – Deferral of June event to fall? Homolog analysis – Implications for Comprehensive Plan Cost/Effectiveness of PCB Control Actions – Overview/implications for workshop

3. Table 4: Magnitude of Source Areas Current draft table summarizes a lot of information Request from last Task Force meeting to separate Synoptic Survey and Routine Monitoring results

4. Proposed Format for Table 4 Synoptic Survey results

5. Proposed Format for Table 4 – Part 2 Routine Monitoring Still awaiting raw data from many of you to allow us to calculate 3x values – Finalization of memo requires this data

6. 2016 Monthly Sampling Update March through May sampling completed – No PCB results received yet – Laboratory error with March samples, archive samples being analyzed – One incorrect sampling location in April Barker Rd. sampled instead of Trent Is June sampling worthwhile? – “make a determination of whether sampling in June of 2016 will be worthwhile in terms of capturing the effects of snowmelt”

7. Remaining Snow Pack 61% of median year snow pack remains Normal precipitation – Much of the snow pack lost due to early snowmelt

8. Flows in Lake Coeur d’Alene Tribs Higher than normal flows in February – April – Below average now Recommend deferring June sampling

9. What Were Conditions During Events?

10. March and May events two days after significant rainfall – High flows (1500 cfs) in Latah Creek during March event What Were Conditions During Events?

11. Homolog Mass Balance Assessment Mass balance assessments conducted for Task Force have been conducted on total PCBs – Concluded presence of significant groundwater load entering between Mirabeau Park and Trent Ave Spokane County has recently conducted similar analyses looking at individual homologs – Findings consistent with those for total PCBs between Mirabeau Park and Trent – Interesting results downstream of Trent

12. Preliminary County Findings Trent to Green Section Large loss in di- through tetra- homologs Large gain in penta- through hepta- homologs

13. Ramifications to Comprehensive Plan No change regarding originally identified load Identifies potential presence of new load – Groundwater loading in other reaches have been identified as uncertain – Homolog analysis raises the threat level, but likely won’t affect selected 2016 Control Actions Next steps – Definitely merits further examination – Prime candidate for Future Studies section of Comp Plan – Include in 2015 report?

14. Cost/Effectiveness of Control Actions First draft coming out today Lots of information Lots of opportunity for input

15. Cost/Effectiveness of Control Actions Naïve initial impression/hypothetical example

16. Cost/Effectiveness of Control Actions Naïve initial impression/hypothetical example

17. Cost/Effectiveness of Control Actions Naïve initial impression/hypothetical example

18. Cost/Effectiveness of Control Actions Complications Incomplete information on costs and effectiveness from existing studies Uncertain magnitudes of transport pathways and delivery mechanisms Memo currently shows magnitudes of sources and pathways for each source area, and which Control Action(s) apply

19. Legacy Fixed Building Sources

20. Legacy Non-Fixed Building Sources

21. Legacy Surface Soils

22. Industrial Equipment

23. Cost/Effectiveness of Control Actions Complications (good) – Many Control Actions already being implemented WWTPs – Upgrades required for DO TMDL – Toxics Management Action Plans Stormwater – City of Spokane’s Integrated Clean Water Plan – Most other stormwater is being diverted to groundwater – this is considered a Control Action in most places MTCA clean-up

24. Selection of Control Actions Potential Selection Criteria – Affects qualitatively significant pathways – Qualitatively cost effective – Has a responsible party capable of implementation – High on the pyramid Don’t make it > Don’t use it > Use less of it > Manage it properly > Dispose of it properly > Treat it

25. Selection of Control Actions Other Potential Selection Criteria – Leverages or supports existing Control Actions – Provides ancillary benefits – Addresses a pathway not currently covered by existing Control Actions

26. Cost/Effectiveness of Control Actions Official Schedule – Final draft due July 14 Proposed Interim Schedule – Initial comments requested by June 15 (or earlier) – Second draft provided by June 22 – Official review draft by July 6