Texas Water Journal (TWJ - Texas Digital Library, TDL E-Journals)
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Estimating statistical power for detecting long term trends in surface water Escherichia coli concentrations
No full textWater quality monitoring programs commonly use the Mann-Kendall test or linear regression to identify statistically significant monotonic trends in fecal indicator bacteria concentrations (typically Escherichia coli [E. coli]). The statistical power of these tests to detect trends of different magnitudes (effect size) is rarely communicated to stakeholders, and it is unlikely they are considered when designing monitoring schedules. The statistical power for detecting trends in surface water E. coli bacteria concentrations using Mann-Kendall and linear regression at water quality monitoring sites across Texas was estimated using Monte Carlo simulation. The probability that an individual water quality monitoring site in Texas had adequate statistical power was also estimated using logistic regression.Mann-Kendall and linear regression trend tests show similar statistical power. Both tests are unlikely to achieve adequate statistical power when E. coli concentrations decrease by 20% or less over 7 years under most sampling frequencies. To adequately detect concentration decreases of 30% to 40% over 7 years, monthly sampling is required. Because many sites across Texas are sampled quarterly, monotonic trends tests will not be powerful enough to detect trends of moderate magnitudes. To better facilitate stakeholder decision-making, it is important to communicate the relative power of statistical tests and detectible magnitudes of changes. I suggest data analysts conduct power analyses to improve monitoring program designs and improve communication of trend test limitations. Software and training for water quality analysts could facilitate communication of power and effect sizes. Alternative trend assessment methods may be more reliable for describing changes in fecal indicator bacteria concentrations
Groundwater Withdrawals Associated with Oil and Gas Production from Water Supply Aquifers in Texas: Implications for Water Management Practices
No full textThe demand for water is continuing to increase as population and industry grow. The Natural Resources Defense Council indicated that Texas is at “extreme risk” for implementation of sustainable water management practices especially since groundwater is the supplier of much of the state’s freshwater. This study is designed to assess groundwater conservation practices in association with oil and gas production from the surrounding areas of the Carrizo-Wilcox formation in Texas. The results of this study reveal that the Railroad Commission of Texas (RRC), the governing agency for Texas oil and gas development, permits produced water to be discharged into surface waters if the discharged water quality meets Texas Surface Water Quality Standards (TSWQS) set by the Texas Commission on Environmental Quality (TCEQ) for the specific receiving water body. After careful evaluation of data provided by the Railroad Commission of Texas, it is believed that nearly 5,331,975 m3 (4,321 ac⋅ft) of produced water per year, with an average TDS of 960 mg L-1, is being removed from the Carrizo-Wilcox aquifer through discharge permits designated as “agricultural”. The RRC is not legally required to share the discharge information with local Groundwater Conservation Districts. Based on an evaluation of the reported Whole Effluent Toxicity (WET) test data, 69 discharges amount to total suspended solid (TDS) levels of less than 1,000 mg L-1, 35 are between 1,000-1,500 mg L-1, and 20 between 1,500 - 4,000 mg L-1. Although 69% of discharges exceed the secondary drinking water standard for TDS (500 mg L-1), the average of all discharges, 960 mg L-1, is in line with the arbitrary upper limit for freshwater based on the suitability for human consumption. In addition, the water quality of surface discharges complies with requirements for several water reuses associated with agricultural and industrial practices. The lack of communication between groundwater users leads to conflicting groundwater practices that have negative impacts such as contribution to aquifer over-exploitation and alteration of hydraulic gradients, in turn negatively impacting existing groundwater conservation efforts
Storage and Regulation of River Flows by Dams and Reservoirs
No full textWater management in Texas is driven by dramatic spatial and temporal hydrologic variability, continual rapid population growth, declining groundwater supplies, and intensifying demands on surface water resources. Dams and reservoirs are essential for providing reliable water supplies and reducing flood risks. Numerous reservoir projects, most constructed during the 1940s through 1980s era of large scale water project construction nationwide, are operated throughout the state to store and regulate extremely variable river flows for beneficial purposes. This paper explores river system hydrology in Texas, operation of dams and reservoirs statewide to deal with extreme flow fluctuations, and associated complexities, issues, and water management strategies. The central focus of the paper is the role of large reservoirs in managing hydrologic variability and associated future uncertainty in an environment of growing demands on limited resources.
Received 18 October 2019, Accepted 5 January 2021, Published online 22 February 2021
Citation: Wurbs RA. 2021. Storage and regulation of river flows by dams and reservoirs. Texas Water Journal. 12(1):10-29. Available from: https://doi.org/10.21423/twj.v12i1.7106
Comment on “Exploring Groundwater Recoverability in Texas: Maximum Economically Recoverable Storage,” published in the Texas Water Journal (2020) 11(1):152-171, by Justin C. Thompson, Charles W. Kreitler, and Michael H. Young
No full textEditor-in-Chief\u27s Note: The Texas Water Journal accepted a request by Robert E. Mace, Executive Director and Chief Water Policy Officer at The Meadows Center for Water and the Environment, to share his thoughts on the article, Exploring Groundwater Recoverability in Texas: Maximum Economically Recoverable Storage,” published in the Texas Water Journal (2020) 11(1):152-171, by Justin C. Thompson, Charles W. Kreitler, and Michael H. Young. The opinion expressed in this commentary is the opinion of the individual author and not the opinion of the Texas Water Journal or the Texas Water Resources Institute
Economic Analyses of the Seadrift Wind-Aided Wastewater Treatment Plant Operations
No full textSeadrift is located on the Texas Gulf Coast with a population of 1,364 people as of the 2010 U.S. Census. In 2012, the city started operation of a 25,500 yearly using wind energy to displace some of the plant’s electrical demand. The plant’s average load is 0.05 million gallons per day, requiring 236,000 kWh (8.05*108 BTU) yearly. The paper details how Seadrift used manufacturer curves to predict turbine energy production, and how preliminary geotechnical, economic, and environmental analyses help design renewable energy projects. From 2012 to 2015, Seadrift saved 211,493. This study shows how government agencies and rural communities can collaborate to find economically viable solutions to water-energy nexus challenges in Texas and beyond.
Citation: Mbarga AHA, Rainwater K, Song L, Theodore C, Williams WR. 2021. Economic Analyses of the Seadrift Wind-Aided Wastewater Treatment Plant Operations. Texas Water Journal. 12(1):42-57. Available from: https://doi.org/10.21423/twj.v12i1.7096
Best Management Practices for Firefighting in the Karstic Edwards (Balcones Fault Zone) Aquifer of South-Central Texas
No full textKarst aquifers are highly vulnerable to hazardous contaminants and pollution that can rapidly harm drinking water supplies. This paper presents tools and best management practices designed to enable first responders to protect karst watersheds and important aquifer drinking water supplies from potentially catastrophic hazardous and polluting materials that can enter the aquifer in water or other liquids runoff from firefighting and other response to emergencies, including ordinary accidental fire and fire caused by arson, terrorist attack, flood, high wind, lightening, and explosion in structures and along transportation corridors.
Received 2 February 2020, Accepted 10 October 2020, Published online 1 February 2021.
Citation: Schindel GM, Rosen RA. 2021. Best management practices for firefighting in the karstic Edwards (Balcones Fault Zone) Aquifer of south-central Texas. Texas Water Journal. 12(1):1-9. Available from: https://doi.org/10.21423/twj.v12i1.7110
Pricing Options on Water in Texas
No full textFreshwater scarcity is a growing concern in Texas and the issues that surround it are expected to grow in the coming years. As climate change impacts the variability of precipitation patterns, some of the most useful tools to help allocate this precious, limited resource may be the tools that are most adaptable in the face of growing uncertainty. While market mechanisms are budding in the state, another market-based tool can create opportunities for efficient water allocation among stakeholders: the water option. An option is a financial product that provides a vehicle to interested parties (buyers and sellers) to create a contract that formalizes the terms of the possible future delivery of water. In cash markets for resources, the exchange of cash and the resource happens when the trade is made; in options markets, the flexibility of delivery is amplified considerably, making them useful for mitigating risk. The buyer of the contract is securing the right—not the obligation—to buy a specific amount of a resource, by a specific time, for a defined price and has the ability to decide if and when the contract gets exercised over the term of the contract. This work discusses the utility of these contracts and outlines a method to price them.
 
Water Rights Analysis Package Modeling System
No full textThe water rights analysis package simulates surface water development, allocation, management, and use and performs reliability and frequency analyses of simulation results. The computer modeling system facilitates assessments of hydrologic and institutional water availability and reliability in satisfying requirements for reservoir storage, water supply diversions, environmental instream flows, and hydroelectric energy generation. Reservoir system operations for flood control can be simulated. Capabilities are also provided for tracking salinity concentrations. Basin-wide impacts of water resources development projects and management practices are modeled. The modeling system is generalized for application anywhere, with input datasets being developed for particular river systems of concern. The water availability modeling system maintained by the Texas Commission on Environmental Quality and routinely applied by the professional water management community consists of the water rights analysis package and simulation input datasets for all of the river basins of Texas. Model-users modify the input datasets as appropriate to evaluate alternative water use scenarios, development projects, and management strategies of interest. This paper explores concepts and methodologies incorporated in the water rights analysis package and other comparable modeling systems, implementation of water availability modeling in Texas, and contributions to effective water management
Reply to comment received from Robert E. Mace, published in the Texas Water Journal (2021) 12(1):202-205, regarding “Exploring Groundwater Recoverability in Texas: Maximum Economically Recoverable Storage,” published in the Texas Water Journal (2020) 11(1):152-171, by Justin C. Thompson, Charles W. Kreitler, and Michael H. Young
No full textEditor-in-Chief\u27s Note: The Texas Water Journal accepted a request by authors, Justin C. Thompson, Charles W. Kreitler, and Michael H. Young, to reply to the commentary by Robert E. Mace on their article published in the Texas Water Journal (2021) 12(1):202-205, regarding “Exploring Groundwater Recoverability in Texas: Maximum Economically Recoverable Storage,” published in the Texas Water Journal (2020) 11(1):152-171, by Justin C. Thompson, Charles W. Kreitler, and Michael H. Young. The opinions expressed in this commentary are the opinions of the individual authors and not the opinion of the Texas Water Journal or the Texas Water Resources Institute
Texas Reimagines the Fight Against Floods
No full textThe Texas Water Journal invited former Chairman of the Texas Water Development Board (TWDB) and current Chairman of the Public Utility Commission of Texas, Peter Lake, to share his thoughts on the 2019 state flood assessment and other framework efforts. The opinion expressed in this commentary is the opinion of the individual author and not the opinion of the Texas Water Journal or the Texas Water Resources Institute.
In response to the TWDB’s 2019 state flood assessment and other efforts initiated in the wake of Hurricane Harvey, the 86th Texas Legislature developed a visionary new framework to fight future floods. The TWDB was tasked with overseeing and coordinating this new effort in conjunction with fellow state and federal agencies. In accordance with the guiding legislation, the TWDB is using a familiar framework based on key functional areas: science, planning, and financing. In the case of floods, that framework transforms into mapping, planning, and mitigation—the three pillars of fighting floods in Texas.
Citation: Lake P. 2021. Texas Reimagines the Fight Against Floods. Texas Water Journal. 12(1):58-67. Available from: https://doi.org/10.21423/twj.v12i1.7133