Simulation of streamflow and estimation of ground-water recharge in the Upper Cibolo Creek Watershed, south-central Texas, 1992-2004

Scientific Investigations Report 2007-5202
Prepared in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; San Antonio River Authority; San Antonio Water System; and Guadalupe-Blanco River Authority



A watershed model (Hydrological Simulation Program?FORTRAN) was developed, calibrated, and tested by the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, San Antonio River Authority, San Antonio Water System, and Guadalupe-Blanco River Authority, to simulate streamflow and estimate ground-water recharge in the upper Cibolo Creek watershed in south-central Texas. Rainfall, evapotranspiration, and streamflow data were collected during 1992?2004 for model calibrations and simulations. Estimates of average ground-water recharge during 1992?2004 from simulation were 79,800 acre-feet (5.47 inches) per year or about 15 percent of rainfall. Most of the recharge (about 74 percent) occurred as infiltration of streamflow in Cibolo Creek. The remaining recharge occurred as diffuse infiltration of rainfall through the soil and rock layers and karst features. Most recharge (about 77 percent) occurred in the Trinity aquifer outcrop. The remaining 23 percent occurred in the downstream part of the watershed that includes the Edwards aquifer recharge zone (outcrop). Streamflow and recharge in the study area are greatly influenced by large storms. Storms during June 1997, October 1998, and July 2002 accounted for about 11 percent of study-area rainfall, 61 percent of streamflow, and 16 percent of the total ground-water recharge during 1992?2004. Annual streamflow and recharge also were highly variable. During 1999, a dry year with about 16 inches of rain and no measurable runoff at the watershed outlet, recharge in the watershed amounted to only 0.99 inch compared with 13.43 inches during 1992, a relatively wet year with about 54 inches of rainfall. Simulation of flood-control/recharge-enhancement structures showed that certain structures might reduce flood peaks and increase recharge. Simulation of individual structures on tributaries showed relatively little effect. Larger structures on the main stem of Cibolo Creek were more effective than structures on tributaries, both in terms of flood-peak reduction and recharge enhancement. One simulated scenario that incorporated two main-stem structures resulted in a 37-percent reduction of peak flow at the watershed outlet and increases in stream-channel recharge of 6.6 percent in the Trinity aquifer outcrop and 12.6 percent in the Edwards aquifer (recharge zone) outcrop.

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Simulation of streamflow and estimation of ground-water recharge in the Upper Cibolo Creek Watershed, south-central Texas, 1992-2004
Series title Scientific Investigations Report
Series number 2007-5202
DOI 10.3133/sir20075202
Edition Version 1.0
Year Published 2007
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Texas Water Science Center
Description vi, 35 p.
Time Range Start 1992-01-01
Time Range End 2004-12-31
Country United States
State Texas
Online Only (Y/N) N
Additional Online Files (Y/N) N
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