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Short instrumental climatic records prevent appropriate statistical and historical characterization of extreme events such as the extent, duration, and severity of multiyear droughts. The best solution is to extend climatic records through well understood proxies of climate. One of the best such proxies is climate-sensitive annual tree rings, which can be dated precisely to the year, are easily sampled, and are widely distributed. We created 3 new baldcypress chronologies in South Central Texas and used them, along with existing Douglas-fir chronologies from West Texas and a composite post oak chronology in Central Texas, to calibrate 1931–2008 and reconstruct June Palmer Drought Severity Index (PDSI) in Texas climate divisions 5 (Trans Pecos), 6 (Edwards Plateau), 7 (S. Central), and 8 (Upper Coast) 1500–2008. We validated the reconstructions against observed data not used in calibration. Most water planners in Texas at present use the drought of the 1950s, 1950–1956, as a worst-case scenario. Our reconstructions show, however, that a number of extended droughts of the past were longer and/or more intense than the 1950s drought. Furthermore, extended droughts have been a consistent feature of southwestern climate since the 800s, including at least 4 megadroughts 15- to 30-years long centered in central or northern Mexico (Stahle et al. 2009; 2011b). This and previous studies indicate that severe decadal-scale droughts have occurred in Texas at least once a century since the 1500s. Current use by water planners of the 1950s drought as a worst-case scenario, therefore, is questionable. When water managers consider past droughts, population growth, and climate change, it becomes highly probable that the future poses unprecedented challenges. Citation: MK Cleaveland, TH Votteler, DK Stahle, RC Casteel, JL Baner. 2011.Extended chronology of drought in South central, Southeastern, and West Texas. Texas Water Journal. 2(1): 54-96. Available from: https://doi.org/10.21423/twj.v2i1.2049.

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The Edwards Aquifer is the primary source of water for a region in South-Central Texas that includes San Antonio and irrigated agriculture to the west. The aquifer also contributes to surface water flow in the Guadalupe River through Comal and San Marcos Springs, which are home to endangered aquatic species. In 1956, during the multiyear Texas drought of record, Comal Springs ceased to flow initiating a multi-decadal transboundary water dispute over the aquifer. This dispute pitted urban, agricultural, and environmental interests and surface water right holders against one another. In 1993, a federal district court ruled that the Endangered Species Act required that adequate flows from the springs be ensured for the endangered species. The Texas Legislature responded to the court by establishing the Edwards Aquifer Authority to regulate groundwater withdrawals. In 2007, with a key deadline looming to create a species protection plan, the Texas Legislature intervened again and mandated that the rival regional water interests engage in a stakeholder process to develop the plan. That process, which was called the Edwards Aquifer Recovery Implementation Program, resulted in a diverse group of parties with opposing interests collaborating to develop, approve, fund, and implement the landmark Edwards Aquifer Habitat Conservation Plan, which is in its 10th year of implementation.

Editor-in-Chief’s Note: September 1 of every odd-numbered year is the date when most new legislation from the most recent session of the Texas Legislature typically goes into effect. With this in mind, the Texas Water Journal invited seven organizations that work closely with the Texas Legislature to provide their take on the changes to Texas water policy and law that were made during the 2021 session. The opinions expressed in these summaries are the opinions of the individual organizations and not the opinions of the Texas Water Journal or the Texas Water Resources Institute.Organizations:Texas Water Conservation AssociationTexas Alliance of Groundwater DistrictsTexas Water FoundationSierra Club, Lone Star ChapterTexas Water Infrastructure NetworkTexas Rural Water AssociationTexas Desalination Association