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Tradeoffs in Brush Management for Water Yield and Habitat Management in Texas: Twin Buttes Drainage Area and Edwards Aquifer Recharge Zone

Christopher R. Narayanan, Urs P. Kreuter, J. Richard Conner

With the current population boom, the number of Texas residents will almost double by 2030. With the expected increase in demand for water, the scarcity of water is an urgent issue and research is being conducted to find ways to improve water yield. Rangelands provide the major catchments for both surface reservoirs and aquifers. Brush control as a means of increasing water yields was first studied in the 1970s (Bach and Conner 2000) and a number of studies have reviewed the feasibility of removing brush as a means to increase water yields (Wilcox 2002). For example, a study on the North Concho River watershed (Upper Colorado River Authority, 1998) indicated that removing brush could result in a significant increase in water yield and, in response to this report, the Legislature for the State of Texas appropriated funds to study the feasibility of this practice on eight additional watersheds (Bednarz et al., 2000). The Texas Agricultural Experiment Station sponsored additional studies for two of these eight watersheds (Twin Buttes and Edwards Aquifer) to determine the tradeoff between brush management for increased water yield and wildlife habitat improvement. These two watershed areas are the subjects of this report.

Since a significant portion of Texas lands are privately owned, it is important to account for landowners’ willingness to participate in any brush management program, especially when such programs are intended to produce off-site benefits. Landowner participation is generally dependent upon expected economic benefits received (Bach and Conner 2000).

In our study, 300 questionnaires were each sent to randomly selected landowners from both the Edwards Aquifer Recharge Zone and the Twin Buttes (Middle and South Concho River) Drainage Area. Names and addresses of rural landowners with tracts of 50 or more acres were compiled with the help of local county appraisal districts. In the questionnaire, survey participants were asked several questions to measure their willingness to participate in different scenarios, as well as the amount of compensation required. This report examines the results of the survey.

Of the 300 questionnaires sent to the Edwards Aquifer area, 131 were returned and usable, 50 were returned but unusable, and 119 were never returned. In the Twin Buttes area, 141 questionnaires were returned and usable, 38 were returned but were unusable, and 121 were not returned.

This report examines each watershed separately. All survey questions are considered. Results include mean, median, and quartile data, and frequency distributions.

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