Update on EAA Groundwater Modeling Initiatives Presented by: Geary M Update on EAA Groundwater Modeling Initiatives Presented by: Geary M. Schindel Jim Winterle Edwards Aquifer Authority

Groundwater Modeling Initiatives (1999 - 2004) GWSIM-IV (<1999) MODFLOW (2004) Both are accepted GAMs for TWDB

Groundwater Modeling Initiatives (1999 – 2004) MODFLOW conceptual model issues – How to model convergent/turbulent flow system using a laminar flow model No good numerical models for karst Recharge, dry cells, springs, faults, etc.

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

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 MODFLOW revisions and FEFLOW development were required by HCP

MODFLOW Model Status Verification Analysis was completed in August 2013 Ran existing model using inputs for 2001-2009 Evaluated errors, uncertainties to support recommended model updates Post-Audit Updates in progress to be completed by December 31, 2014 Revise model boundaries Update aquifer top and bottom elevations Update representation of inter-formational flows Update representation of hydrologic flow barriers Recalibrate transient simulation using inputs and observations for 2001-2011

Finite Element Model Status Hydrogeologic Framework Model completed in 2013 Recharge, pumping, and observation datasets developed for period 2001-2011 Preliminary model presently undergoing transient calibration Calibrated model using FEFLOW code expected by September 2014 Draft Final Report, data sets, and model expected by December 2014