Potential Economic Impacts of Instream Flows for Central Texas Freshwater Mussels

Presented on Wednesday, May 1, 2013
Brad D. Wolaver, PhD1, Cassandra E. Cook, BS1, David L. Sunding, PhD2, Stephen F. Hamilton, PhD3, Bridget R. Scanlon, PhD1, Michael H. Young, PhD1 and Xianli Xu, PhD1, (1)Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, (2)Department of Agricultural and Resource Economics, University of California at Berkeley, Berkeley, CA, (3)Orfalea College of Business, California Polytechnic State University, San Luis Obispo, CA

Texas water resources already taxed by drought are becoming more important as population grows. Environmental flows (EF) for aquatic habitat preservation could further reduce supplies if five Central Texas freshwater unionid mussel species are listed as endangered. This study estimates potential economic impacts of water shortages induced by EF for mussels in Brazos, Colorado, and Guadalupe-San Antonio River basins (36% Texas area,~95,000 square miles). Water supply reductions for EFs were simulated with Water Availability Model, aggregated by county, and categorized by: (1) steam electric, (2) commercial and industrial, (3) municipal, and (4) agriculture. Counties were identified with surface water supply deficits, and power plant cooling reservoir operating level frequency changes were calculated. Economic impacts were estimated with and without water transfers (“integrated market” and “segmented market”). EF- impacted counties already had supply issues. Reductions ranged from 3–33% to 13–67% of baseline stream flow under low and high EF scenarios (95% and 75% exceedances probabilities, respectively). Brazos River basin has no shortages. Colorado River basin shortages include Tom Green (55,000 acre-feet/year, af/yr) and Wharton Counties (82,000 af/yr) in worst-case. Groundwater imports reduce Bexar (74,000 af/yr) and Medina County (4,000 af/yr) Guadalupe-San Antonio River basin shortages to 8,000 af/yr. Bexar County power plant reservoir supply reductions cause economic impacts up to $107M if no water transfers occur. Non-power economic impacts can be almost entirely mitigated by water transfers, which reduce worst-case total losses from $80M to $11M. Establishing water markets (and also including conjunctive use of surface water and groundwater, aquifer storage and recovery, interbasin transfers, and conservation) should mitigate most economic impacts if mussels are listed. In light of Texas’ water supply challenges, approaches need to be developed for environmental flows and to have a broad range of strategies to decrease any economic impacts related to flow reductions.


Brad D. Wolaver, PhD
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
Brad Wolaver is a Research Associate at the Bureau of Economic Geology, Jackson School of Geosciences, at the University of Texas at Austin. His research focuses on sustainable groundwater management for people and the environment, particularly in semiarid and arid regions, and is grouped into three research themes: (1) Water, Energy, and Minerals: Effective groundwater management for energy and mining, with focuses on groundwater monitoring for CO2 geologic sequestration and groundwater evaluation for unconventional energy projects; (2) Sustainable Aquifer Management: Groundwater flow, transport, and recharge processes; and (3) Ecohydrology: Springs, groundwater-dependent ecosystems, instream flows, and surface water–groundwater interactions.

Cassandra E. Cook, BS
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
Cassie is a Research Assistant at the BEG and has a bachelor's degree in Ecology and Evolutionary Biology from the University of Michigan. She is interested in wildlife conservation ecology, particularly species-habitat interactions, and would like to pursue a graduate degree on this topic.
David L. Sunding, PhD
Department of Agricultural and Resource Economics, University of California at Berkeley, Berkeley, CA
David Sunding is the Thomas J. Graff Professor in the College of Natural Resources at UC Berkeley, where he is also the Co-Director of the Berkeley Water Center. His research concerns environmental and resource economics, regulation, technological change, applied econometrics, risk and public finance. Prof. Sunding teaches courses in natural resource economics, water resources, and law and economics.
Stephen F. Hamilton, PhD
Orfalea College of Business, California Polytechnic State University, San Luis Obispo, CA
Dr. Hamilton is recognized internationally for his research and consulting related to environmental and land use regulation, energy and water markets, groundwater managements, and antitrust. His academic and professional honors include providing a plenary address at an international conference sponsored by the European Science Foundation, selection as a research fellow in the Rural Development Research Consortium at the University of California, Berkeley, serving on the sustainable management panel that governs the Tallgrass Prairie National Preserve, and receiving the Early Career Award for Outstanding Faculty Research.
Bridget R. Scanlon, PhD
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
Evaluation of the impact of climate variability and land use change on groundwater recharge, application of numerical models for simulating variably saturated flow and transport, controls on nitrate contamination in aquifers.
Michael H. Young, PhD
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
Associate Director: Environmental Division. Michael has published extensively in the broad fields of water resources and soil science and is Co-Editor for Vadose Zone Journal. He has served the past five years as Technical reviewer for the National Science Foundation.
Xianli Xu, PhD
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
Dr. Xu is interested in climate change and biogeochemical (C, N) cycles, vadose zone hydrology and ecohydrology, ecosystems function and service (restoration & assessment), soil threats assessment (sealing, compaction, erosion & carbon loss), and GIS and remote sensing.
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