A Tool to Assess How the Blanco River Interacts with Its Aquifers: Creating the Numerical Model: Phase II
Date
2019-08
Authors
Mace, Robert E.
Wierman, Douglas A.
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Abstract
There is and continues to be a very high level of economic development and growth along the I-35 corridor between Austin and San Antonio as well as west of I-35 in ecologically sensitive areas of the Hill Country. A significant by-product of this growth is the stress and demand placed on natural resources, foremost of which are water resources in the Blanco River watershed. Increased demand for water leads to more wells and more pumping which in turn affect springs and baseflow to rivers and streams. For example, water levels in the Middle Trinity Aquifer declined between 3 and 54 feet between 1980 and 1997 (Jones and others 2011). A historical observational well near Wimberley shows a decrease in water levels of more than 100 feet since the mid-1980s (TWDB 2018a). Water wells near the river also show substantial water-level declines during drought when pumping is typically higher. For example, a well in Blanco near the river showed more than 80 feet of water-level decline during drought periods (TWDB 2018b). Water-level declines decrease spring and baseflow which in turn affect iconic springs; flows in the river for the environment, recreation, and water supplies; and recharge to the Edwards Aquifer (which affects other iconic springs).
As a result, a new groundwater model—specific to the aquifers in the Blanco River watershed—will be developed to create the tool needed by local landowners, communities, and groundwater conservation agencies to better understand and manage groundwater resources in the Hill Country.
This new, more local model would not replace Texas Water Development Board’s groundwater availability model; instead, it would supplement the Texas Water Development Board’s model with more detailed data that local groundwater conservation agencies can use to not only inform local management decisions but to inform decisions on desired future conditions and to improve subsequent updates of the regional model.
The project will be a collaborative effort involving numerous stakeholders and experts. These will include, but are not limited to, Southwest Research Institute©, The Meadows Center for Water and the Environment, Barton Springs Edwards Aquifer Conservation District, Blanco-Pedernales Groundwater Conservation District, Cow Creek Groundwater Conservation District, Hays Trinity Groundwater Conservation District, and Edwards Aquifer Authority.
Description
Keywords
Blanco River Aquifer, surface water, assessments, sustainability
Citation
Mace, R. E., & Wierman, D. A. (2019). A tool to assess how the Blanco River interacts with its aquifers: Creating the numerical model: Phase II (Report No. 2019-06). Texas State University, San Marcos, Texas.