HHUA I and HHUA II

 

 

The Board of Directors of the Hill Country Underground Water Conservation District on August 8, 2006 designated two areas, HHUA I and HHUA II, within Gillespie County as High Historical Groundwater Use Areas and the associated Buffer zone.  This action followed a public hearing held on July 5, 2006.

 

            The new restrictions in a HHUA affects new permitted wells that would be used for municipal, irrigation or commercial purposes, and not existing permitted wells or existing wells used for domestic or livestock purposes.  New wells used solely for domestic or livestock purposes are not affected in a HHUA.

 

The High Historical Groundwater Use designation places more restrictive pumpage conditions on new permitted wells and requests for increased production on existing permitted wells, which includes grandfathered permitted wells.  It also doubles the well spacing requirements on new permitted wells.  In the Buffer Zone, the more restrictive pumpage conditions do not apply, however the doubled well spacing requirement for new permitted wells is required.  These new requirements are applicable only to permitted wells and do not pertain to domestic or livestock wells.

  

This designation is meant to protect existing historic pumpage and to alleviate the possibility of taking the next more restrictive designation of a Critical Groundwater Depletion Area.  A Critical Groundwater Depletion Area designation is made if aquifer mining occurs within an aquifer.  Aquifer mining occurs when more water is being pumped than what is being recharged.  If that designation is made, then all permitted wells will be required to limit production to a level that will terminate aquifer depletion. 

 

Under the current High Historical Groundwater Use designation all current historic production is protected. 

 

HHUA I is located over the Ellenburger aquifer, southeast of Fredericksburg where large drawdowns have occurred in the past.  There, the City of Fredericksburg began producing water as far back as the 1940s.  Irrigation has also increased in the area over this time.  In the summer of 1989 water levels declined to critical levels.  However under current demand, the aquifer is in good shape and not under threat of mining.  This is due in large part to the City developing their new well field to the east of this area near Goehmann Lane thereby reducing pumpage from the old well field.  However, as the City and County continue to grow, a higher demand by the existing permitted pumpage will once again be placed on this portion of the aquifer, and an aquifer mining situation will occur if additional new permitted production is not properly managed now.

 

HHUA II is north of Fredericksburg where the City has municipal historic pumpage dating back to the 1960s.  This area covers a portion of the new Boot Ranch Development.  There, recent test drilling and subsequent pump test data, has delineated a narrow restricted portion of the Hickory aquifer, where high well yields are available.  However due to the limited extend of this portion of the aquifer, heavy pumpage results in significant aquifer drawdowns.  Consequently, additional new production in this area along with the current historic pumpage will stress the aquifer to the point that mining will occur and the aquifer will not be sustainable in the area.