Specific capacity tests are useful for estimating transmissivity in aquifers that have few good‐quality pump tests. In karst aquifers, this has been done by (1) correcting specific capacity for turbulent well loss and using analytical relationships between transmissivity and specific capacity, and (2) correcting specific capacity for well loss and deriving an empirical relationship between transmissivity and specific capacity. This study focuses on the uncertainties of estimating well loss and presents an empirical relationship between transmissivity and uncorrected specific capacity for a karst aquifer.
Well loss is difficult to estimate without good‐quality step‐drawdown tests. Pipe‐flow theory tends to underestimate well loss, and an empirical relationship between specific capacity and well‐loss constant has a large prediction interval that leads to well loss exceeding measured drawdown. To overcome uncertainties of estimating well loss, transmissivity and uncorrected specific capacity were related for aquifer tests from the Edwards aquifer in Texas. The resulting best‐fit line is T = 0.76(Sc)1.08 for T and Sc in m2 d–1 with a coefficient of determination, R2, of 0.89 and a 95‐percent prediction interval spanning approximately 1.4 log cycles. Though the prediction interval is large, approximate but useful estimates of transmissivity can be determined because the relationship extends over five orders of magnitude from 1 to 100,000 m2 d‐1. The relationship is applicable in at least one other karst aquifer and therefore may be useful for others.
Long‐range water planning is complicated by factors that are rapidly changing in the 21st century, including climate, population, and water use. Here, we analyze climate factors and drought projections for Texas as an example of a diverse society straddling an aridity gradient to examine how the projections can best serve water stakeholder needs. We find that climate models are robust in projecting drying of summer‐season soil moisture and decreasing reservoir supplies for both the eastern and western portions of Texas during the 21st century. Further, projections indicate drier conditions during the latter half of the 21st century than even the most arid centuries of the last 1,000 years that included megadroughts. To illustrate how accounting for drought nonstationarity may increase water resiliency, we consider generalized case studies involving four key stakeholder groups: agricultural producers, large surface water suppliers, small groundwater management districts, and regional water planning districts. We also examine an example of customized climate information being used as input to long‐range water planning. We find that while stakeholders value the quantitative capability of climate model outputs, more specific climate‐related information better supports resilience planning across multiple stakeholder groups. New suites of tools could provide necessary capacity for both short‐ and long‐term, stakeholder‐specific adaptive planning.
We synthesize the interconnected impacts of Texas’ water and energy resources and infrastructure including the cascading effects due to Winter Storm Uri. The government’s preparedness, communication, policies, and response as well as storm impacts on vulnerable communities are evaluated using available information and data. Where knowledge gaps exist, we propose potential research to elucidate health, environmental, policy, and economic impacts of the extreme weather event. We expect that recommendations made here — while specific to the situation and outcomes of Winter Storm Uri — will increase Texas’ resilience to other extreme weather events not discussed in this paper. We found that out of 14 million residents who were on boil water notices, those who were served by very small water systems went, on average, a minimum of three days longer without potable water. Available county-level data do not indicate vulnerable communities went longer periods of time without power or water during the event. More resolved data are required to understand who was most heavily impacted at the community or neighborhood level. Gaps in government communication, response, and policy are discussed, including issues with identifying — and securing power to — critical infrastructure and the fact that the state’s Emergency Alert System was not used consistently to update Texans during the crisis. Finally, research recommendations are made to bolster weaknesses discovered during and after the storm including (1) reliable communication strategies, (2) reducing disproportionate impacts to vulnerable communities, (3) human health impacts, (4) increasing water infrastructure resilience, and (5) how climate change could impact infrastructure resilience into the future.
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