As we updated you last month, on February 20, BSEACD sent Electro Purification a preliminary finding that EP's production permit application to produce 2.5 million gallons a day from the Trinity Aquifer has the potential to cause unreasonable impacts to existing wells. Below are pertinent excerpts from BSEACD's detailed memo, which you can read here.
TESPA is meeting with BSEACD staff on April 9th to discuss the District's finding that the EP application will cause unreasonable impacts to wells. If you have questions or concerns, please email Vanessa at firstname.lastname@example.org
BSEACD's next board meeting is on April 12th at 6:00 PM. Landowners concerned about the impact the EP application will have on their wells and how BSEACD intends to mitigate these impacts should attend and make comments during the public comment period.
The aquifer test determined that after about a week of pumping at the requested volume, water levels could decline below a reasonable pump intake level (Table 1). Water levels in the Woods #1 and Escondida wells drew down to within 23 ft and 18 ft of the pump level, respectively. If we assume drought conditions with water levels being an additional 50 ft of lower, existing local well interference, and the appropriate depth of water needed above a pump intake to yield water, it is likely that these and other wells will cease to yield water. If those factors are considered, the number of impacted wells will likely increase in the vicinity of EP.
It is uncommon, in the experience of the BSEACD, for an aquifer test to produce drawdown that indicates negative impacts to surrounding water-supply wells (without considering modeling results). This is likely due to the magnitude of the requested pumping rate and the compartmentalized nature of the Middle Trinity Aquifer (BSEACD, 2017, 2018).
Projecting the effects of drawdown after pumping for 1 year results in significant drawdown that approaches the top of the Cow Creek in the EP pumping and observation wells. The simulated drawdown from 1 year of pumping is sufficient to understand the potential effects of pumping for a long duration. Modeling 7 years of drawdown effectively shows de-watering of the Cow Creek, which would be an unreasonable impact
The aquifer tests were conducted at a time when water levels were above average in central Hays County. When a factor of 50 ft, to account for severe drought conditions, is subtracted from the aggregate drawdown from the tests, resulting water levels would be such that the Woods #1 and Escondida wells would cease to produce water. Modeling has shown that with longer periods of pumping will cause even greater drawdown. Thus, we conclude that the proposed production of 2.5 MGD of groundwater from the existing EP wells has potential for unreasonable impacts.