CONSIDERING UNREASONABLE IMPACTS IN THE GROUNDWATER PRODUCTION PERMITTING PROCESS

The 2015 annexation of an area in central Hays County, Texas, into the Barton Springs/Edwards Aquifer Conservation District (District) in response to proposed water production of the Middle Trinity Aquifer introduced a new statutory term for consideration of pumping permit applications — unreasonable impacts. However, no definition or criteria was provided in the statute. Alley et al. (1999) define groundwater sustainability as “development and use of ground water in a manner that can be maintained for an indefinite period of time without causing unacceptable environmental, economic, or social consequences.” The term “unacceptable consequences” is similar to the consideration of “undesired results” due to pumping is the concept of safe yield (Todd, 1959) and recently in California’s Sustainable Groundwater Management Act.

Since HB 3405 was passed by the Texas legislature, the District has defined criteria for unreasonable impacts as, “a significant drawdown of the water table or reduction of artesian pressure as a result of pumping from a well or well field, which contributes to or causes:

1. interference resulting in water wells ceasing to yield water at the ground surface;

2. interference significantly decreasing well yields;

3. interference related to the lowering of water levels below reasonable pump intake level;

4. the degradation of groundwater quality;

5. the Desired Future Condition (DFC) to not be achieved;

6. depletion of groundwater supply over a long-term basis (mining);

7. a significant decrease in springflow or baseflow that may cause an established minimum springflow or environmental flow rate to not be achieved;

8. subsidence.

The District’s Aquifer Science Team evaluates pumping applications to determine whether there is potential for unreasonable impacts based on these criteria. The permit review process involves the evaluation of known hydrogeologic conditions and predictive analyses using analytical models.