Ground Water Balance at Barton Springs Seyoum Asamenaw Surface Water Hydrology, 03/23/2005

Out line Study Objectives The Study area (Geology, Hydrogeology) Ground Water Recharge Cell Water Budget What is left

Study objectives Estimating the Ground Water Recharge Calibrating the Modflow model and doing water budget study for the model boundary Interpreting the predictive simulations through 2050

The Edwards Aquifer http://www.edwardsaquifer.org/Pages/frames_aquifer.html

Barton Springs : http://www.edwardsaquifer.net/ Part of the Edwards Aquifer Includes Travis and Hay counties 80 % unconfined 20% confined 85 % of recharge comes from Streams 15 % diffused inter stream recharge : http://www.edwardsaquifer.net/

Geology Lower Cretaceous Carbonate Marine Transgressive-Regressive sediments Conglomerate, Shale, Marl, Sand Stone, Austin Chalk and Del Rio Clay http://www.geo.ucalgary.ca/~macrae/timescale/time_scale.gif

Hydrogeology Geology Drainage Area Recharge Zone Artesian Zone

Cell Water Budget

Change in storage

Estimating Recharge

Estimating Recharge Year 2002 Gage at loop 360 (cfs) Lost Creek (cfs) Barton Springs (cfs) Est. R (cfs) Est. R (feet/day/cell) January 55.2 72.3 112 35 0.1223 February 17.3 34.6 109 30 0.1033 March 3.34 19.2 102 19 0.0664 April 1.39 14.9 98 15 0.0515 May 0.017 3.39 90.5 3 0.0117 June 16.9 20.6 79.7 0.0712 July 494 592 96.7 138 0.4769 August 9.3 33.8 101 0.1029 September 0.032 9.94 92 10 0.0344 October 34.1 48.3 85.8 32 0.1101 November 78.2 98.7 98.2 39 0.1361 December 115 130 106 44 0.1532

On going and future works Calibrating the predictive simulation through 2050 Writing the report

Thanks Dr. Maidment Gil Strassberg