1. EAA Groundwater Modeling Initiatives Presented to: National Academy of Sciences National Research Council Committee Presented by: Geary M. Schindel Chief Technical Officer Aquifer Sciences – Program Manager Edwards Aquifer Authority

2. Groundwater Modeling Initiatives (1999) < 1999 Edwards Aquifer models produced by US Geological Survey (USGS), Edwards Aquifer Research Data Center (EARDC), and Texas Water Development Board (TWBD) (GWSIM IV) Optimization Technical Studies Report (May 1999) –Model development one of 17 research initiatives

3. Groundwater Modeling Initiatives (1999) USGS and TBEG selected as contractor EAA, Department of Defense (DOD), San Antonio Water Systems (SAWS), and USGS were funding partners Formed Groundwater Modeling Advisory Panel (GMAP) to provide oversight to contractors MODFLOW groundwater modeling software selected

4. Groundwater Modeling Initiatives (1999 – 2004) GMAP composed of representatives from EAA, SAWS, TWDB, Southwest Research Institute (SWRI), DOD, two outside karst scientists and four consultants Oversight and guidance to USGS and Texas Bureau Economic Geology (BEG) –How to model convergent/turbulent flow system using a laminar flow model –No good numerical models for karst –Recharge, dry cells, springs, faults, etc.

5. Groundwater Modeling Initiatives (1999 – 2004) Model to be used for: –Demand Management/Critical Period Management Issues –Enhanced recharge evaluations –Evaluation of aquifer cap issues HCP ASR Spring Augmentation Recharge and Recirculation

6. Groundwater Modeling Initiatives (2004) USGS MODFLOW model completed in 2004. –Management modules

7. Groundwater Modeling Initiatives (2011) 2011 Groundwater Model Initiative –Improve confidence in modeling efforts –Provide additional research tool –Improve model resolutions MODFLOW –Verification and post audit process Finite Element initiative

8. Groundwater Modeling Initiatives (2012) Finite Element initiative –March 2012 SWRI Contractor Selected Groundwater Model Review Panel formed –Martin Saar –Neven Kresic –Bill Hutchison –James Beach (appointed by SAWS)

9. Groundwater Modeling Initiatives (2011 – 2014) MODFLOW model updates initiated –Data Set updates (2001 – 2009) –Model Verification process –Post Audit

10. Groundwater Modeling Initiatives (2014) Two current EAA modeling initiatives – MODFLOW Post Audit Updates –Finite Element Model –Both to be completed by December 2014 EAA Modeling efforts are a “continuous improvement process”