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Browsing Centers and Institutes by Author "Butler, William"
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Item How Much Water is in the Pedernales?(2015-09) Wierman, Douglas A.; Butler, William; Miller, Meredith; Zappitello, Saj; Schwartz, Benjamin F.Thanks to the generous support from the Cynthia and George Mitchell Foundation over the past several years, the Meadows Center for Water and the Environment has been working to answer the question – How much water is in the Hill Country? At first blush this seems like a very straightforward question that merits a straightforward answer. However, the reality is that the largely hidden and unknown complexities of Hill Country hydrogeology make it challenging to answer. In 2015, the Meadows Center focused its efforts on understanding the intricacies of the Pedernales watershed and underlying hydrogeology. It is important to first note that over the years, various aspects of the Pedernales River have been studied by several entities dating as far back as the 1950s. One such report, the Hill Country Alliance’s “The State of the Pedernales: Threats, Opportunities and Research Needs” report released in early 2015, provides an overview of the main characteristics of the watershed and summarizes many of these studies, their findings, and further research needs. The gain-loss study conducted by the USGS in 1962 confirmed the 1956 study that the Pedernales River is a gaining stream, in other words, as one moves downstream from the headwaters, the flow rate increases due to springs, seeps, and inflows from the tributaries. Since the 1950’s, land use activities have changed that can affect the flow in the river and the groundwater-surface water interaction. Due to these changes and a large number of wells now pumping from the basin’s aquifers, it is important to know how land use change, groundwater pumpage, and the increase in demands affect the river flow today and long into the future. By further refining a gain-loss study with groundwater information using current hydrology we will be able to better identify threatened or critical river segments to guide management efforts to protect and enhance recharge, maintain river and tributary flows, and sustain the current high river water quality. One of the first steps to determine how much water is in the Pedernales River was the Summer 2015 Hydro-blitz that is summarized in this interim report. Observations were made at 931 river and tributary sites to document the existence of flows in the river and tributaries during a summer dry spell to establish the groundwork for a future gain-loss study. An important outcome of the Hydro-blitz was the confirmation of the previous gain-loss studies’ findings that over 20 major tributaries play a vital role in sustaining and adding to the river flows, resulting in the realization that a future gain-loss study should extend into key tributaries to pinpoint priority water management areas and appropriate strategies. This will benefit the landowners, tourism, growing cities, agricultural practices and preserve the river ecology to ensure the Pedernales River continues to be one of the landmarks of the Texas Hill Country.Item How Much Water is in the Pedernales? (Appendix A)(2015-09) Wierman, Douglas A.; Butler, William; Miller, Meredith; Zappitello, Saj; Schwartz, Benjamin F.This document is a list of proposed Conservation Strategies within Management Measure Categories for the Pedernales watershed. Information was collected from a variety of sources, including peer-reviewed literature, scientific studies, Environmental Protection Agency (EPA), United States Department of Agriculture (USDA), Bureau of Land Management (BLM), United States Forest Service and other resources. Management Measures are defined as a category of practices that can be cooperatively implemented to achieve water quality and quantity goals and standards. Conservation Strategies, also known as Best Management Practices (BMPs), are individual practices within Management Measures that determine the most effective, practical means of preventing or reducing pollution from nonpoint sources. For example, Sedimentation Management Measures reduce the quantity of sediment from surrounding lands to receiving waters. A Riparian Buffer, on the other hand, is a Conservation Strategy that reduces sedimentation loading and falls under the Sedimentation Management Measure category. Conservation Strategies also can be practices to preserve water quantity through the protection of groundwater recharge or the conservation of surface and groundwater supplies. It is important to consider that hydrological connections exist between groundwater and surface water in the watershed and one Conservation Strategy may protect both water quality and quantity. The following Conservation Strategies have been compiled for the purpose of inclusion in management plans to prevent or remediate current and future expected water quality pollution and reductions in water quantity within the watershed. Conservation Strategies can be implemented alone or in combination with others, across the basin or in specific areas of the basin. Descriptions, details, cost, pollutants treated, existing operational support, and complimentary strategies are provided for each item where available. In other sections, narratives and examples are provided for Conservation Strategies that are intended to be used on a larger scale or do not specify associated costs and details.Item How Much Water is in the Pedernales? (Appendix B)(2015-09) Wierman, Douglas A.; Butler, William; Miller, Meredith; Zappitello, Saj; Schwartz, Benjamin F.No abstract prepared.Item How Much Water is in the Pedernales? Occurrence of Flowing Water and Water Quality during Base Flow Conditions in the Pedernales River Basin(2017-04) Wierman, Douglas A.; Walker, Jenna; Butler, William; Zappetello, Sarah; Warren, Emily; Miller, MeredithThe Pedernales River is in relatively good condition with respect to base flow conditions and base flow water quality. The Pedernales River and its tributaries traverse parts of eight counties in the Hill Country of Central Texas and are an important contributor of water to Lake Travis, the source of water for the City of Austin. Multiple aquifers contribute to base flow in the Pedernales River. Springs and streams originating in the Edwards and Glen Rose Aquifers appear to provide the majority of the main channel base flow in the western part of the Pedernales Basin. The Paleozoic and Trinity Aquifers contribute to base flow in the eastern basin area. Changes in land cover from 2001 to 2011 indicate land cover did not significantly change over the ten year period, and the basin is generally scrubland and forest. However the amount of developed land increased in the Fredericksburg and Johnson City areas. Increasing impervious cover in developed areas may have implications for storm water quality. Due to the sandy nature of the Hensel (red sands) versus the carbonate characteristics of the majority of the other geologic units in the basin, areas underlain by Hensel are more buildable and amenable to agricultural and urban development and therefore more susceptible to water quality impacts. Overall, the Pedernales River is a gaining river, meaning flow generally increases moving downstream, though there are losing reaches where surface water recharges the underlying aquifers. Common gaining and losing reaches were observed in the 1962 and 2016 gain/loss studies. Gaining and losing reaches are generally attributable to the underlying geology, though groundwater pumpage may be influencing Pedernales River base flow near the City of Fredericksburg. A significant gaining reach occurs between Johnson City and the confluence with Lake Travis. The occurrence of multiple droughts over the last decade and a half have caused a significant decrease in base flow of the river. In general, water quality in the river under base flow conditions is good. While there have been changes in water quality, at least partly due to human impact, there have not been significant changes since a comparable study in the 1960s was performed. Analysis of several water chemistry parameters indicate water chemistry is primarily influenced by geology and land cover. Now is the time to gain a more solid understanding of natural systems and the interconnectedness between surface and groundwater for water planning, wise water policy and the health of Hill Country springs, streams and rivers in the future.Item Pedernales Watershed Atlas(2017-07) Wierman, Douglas A.; Walker, Jenna; Miller, Meredith; Butler, WilliamNo abstract prepared.