1. Water-level monitoring and a groundwater model in the Big Wood River Valley Presented by Mike McVay November 5, 2012

2. IDWR Data Logger Network 13 wells have been instrumented; 5 candidates for future deployment. Data loggers are collecting water level readings two times per day. Downloaded every six months.

3. Water level trends 1980’s - current

4. Upper Wood River WMD Well Network 36 wells have been identified as monitoring locations. Semi-annual measurements are proposed for the monitoring frequency.

5. USGS Synoptic Network Over 90 wells were measured in 2006 and re-measured in October 2012.

6. Ground Water Model of the Big Wood Valley Collaboration with the USGS. 2006 synoptic water levels show ground water flow is from north to south.

7. Why a Model of the Big Wood? Fully allocated resource – Designated GWMA in 1991 Water rights distribution problem – Most proposed transfers involve up-basin movement of PODs Conjunctive administration/management on its way – Delivery calls imminent (Big Wood Canal Company) – 2009 petition for CGWA – Measurement district created in 2011

8. Why a Model of the Big Wood (cont’d) IDWR needs unbiased, public domain groundwater flow model to evaluate transfers and mitigation requirements Timing good because USGS study nearing completion – Synoptic water level measurement and trend analysis in 2006 – Water Budget report in 2009 – Hydrogeologic Framework report in 2012

9. The Model A three-year timeframe IDWR collaborating with USGS to develop groundwater flow model with oversight from Technical Advisory Committee Water Board financing with USGS match Used for administration of water – Evaluation of Transfers – Determine Curtailment – Evaluate Mitigation – Won’t be used to determine injury

10. Technical Advisory Committee Provides transparency and is a vehicle for stakeholder input Likely participants: – Previous USGS Cooperators Cities of Bellevue, Hailey, Ketchum, Sun Valley Nature Conservancy Blaine Soil Conservation District Citizens for Smart Growth Sun Valley Water and Sewer – Big Wood Canal Company – Water District 37? – Technical representatives for others

11. Summary of Work Plan Additional data collection – Water level synoptic in October 2012 – Streamflow gain/loss surveys in August and October 2012 and March 2013 – Additional wells Form Technical Advisory Committee Construct and calibrate groundwater flow model – Update water budget – Model discretization – Initial parameterization – Calibration Convert Steady State model to transient model

12. Activities to Date Sponsored 4 new USGS gages in 2010 (North Fork, East Fork, Trail Creek, Warm Springs) Expanded monitoring well network from 6 wells to 18 USGS seepage analysis to quantify reach gains/losses Synoptic water level measurement in 2012 Developed modeling work plan w/ budget and schedule

13. Products Numerical groundwater flow model Final Report describing model and development Reports describing results of scenarios – Drought – Change in land use – Climate change USGS Fact Sheet Response function maps

14. Questions?