Western Hays County Groundwater: “Desired Future Conditions” (DFC)

Submitted to the Wimberley View, January 25, 2016

Desired Future Conditions as defined by the Texas Water Development Board (TWDB), Title 31, Part 10, §356.10 (6) of the Texas Administrative Code: “the desired, quantified condition of groundwater resources within a management area at one or more specified future times as defined by participating groundwater conservation districts within a groundwater management area as part of the joint planning process.”

The Hays Trinity Groundwater Conservation District (HTGCD) is an active, voting member of Groundwater Management Area 9 (GMA9); GMA9 includes 10 groundwater districts in 10 Central Texas counties. In 2010, after extensive review, the GMA9 adopted a DFC of “30 feet average drawdown for the Trinity Aquifer”. Every five years, in accordance with TWDB regulations, Groundwater Management Areas must review, and possibly revise, the projected 50 year DFC. For the 2015 project, GMA9 contracted Blanton & Associates to develop the extensive report required with each DFC submission. In September 2015, a preliminary vote was taken by GMA9 representatives concerning the DFC “30 foot regional drawdown” for the Trinity Aquifer. The resulting vote was nine districts in favor and one abstention (HTGCD). Blanton & Associates held several reviews of their project analyses including a full day presentation in Dripping Springs in September, 2015. Although the Trinity Aquifer is the sole producing unit in western Hays County, the full report for the TWDB incorporates all of the primary and secondary aquifers within GMA9. Each member groundwater district, after internal review and public hearing, has the responsibility to vote on the recommended DFC.

The HTGCD Board of Directors met on Wednesday, December 9, 2015 at Dripping Springs City Hall. The main Hearing agenda item for discussion and possible action was a vote concerning confirmation of the GMA9 recommended DFC. The DFC had been included in the district’s meeting agenda for the past two consecutive monthly Board meetings. Prior to these meetings, HTGCD held an educational workshop at the Wimberley Community Center on September 23, 2015 to review and discuss the DFC with area residents. Speakers at the workshop included representatives from the Barton Springs Edwards Aquifer Conservation District (BSEACD), the Blanco Pedernales Groundwater Conservation District (BPGCD), the HTGCD and local residents. Upon conclusion of the HTGCD Public Hearing on December 9, 2015, the HTGCD Board voted to authorize the District representative to the GMA9 (HTGCD General Manager) to vote for approval of a DCF range between 0 and 30 feet drawdown for the Trinity Aquifer.

What does the DFC mean to residents of western Hays County and how does it affect the water level in local wells? The DFC is part of a state-wide water planning process than begins with the groundwater districts and ends with the State Water Plan. Water usage is forecast over a 50 year period and serves locally as a groundwater management tool. The designated “30 foot drawdown of the Trinity Aquifer” is a regional average “drawdown” spread over the entire groundwater management area during a 50 year period. The forecast is model driven and dependent upon aquifer recharge (precipitation) and discharge (pumpage and natural discharge). Lastly and most importantly it should be noted that water tables that were lowered during Central Texas dry spells during the past ten years recovered with heavy rainfall in 2015.

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