Desired Future Conditions

 

Desired Future Conditions (DFCs) are  defined as “ the desired, quantified condition of groundwater resources (such as water levels, spring flows, or volumes) within a management area at one or more specified future times as defined by participating groundwater conservation districts within a groundwater management area( GMA) as part of the joint planning process.”  A DFC, in essence, is a management goal that addresses how an aquifer should be managed. A DFC answers the question- what do you want your aquifer/s to look like in the future?  For example, a DFC could be based on spring flow or, perhaps, on water levels.The process for determining DFCs, involve running computer models (developed by the Texas Water Development Board) which simulate the effects of pumping an aquifer. After running a model through several iterations of various pumping from high to low,one will be able to see a range of impacts.  During the 83rd legislative session, Senate Bill 660 added additional requirements for GMAs to consider when developing DFCs.

 

Every 5 years a GMA must propose and adopt DFCs. The deadline for proposing a DFC for this round is May 1, 2021, with the deadline for adoption being January 5, 2022 . All groundwater districts in a GMA, including PCCD, will hold local public hearings for any  proposed DFCs. Once DFCs are adopted, the TWDB issues Modeled Available Groundwater (MAG) numbers which are required to be considered by Groundwater Conservation Districts when granting permits. A MAG is the amount of water that may be produced on an average annual basis to achieve a DFC. The aquifers concerning GMA 10 planning are the Trinity, Fresh Edwards, Saline Edwards, Leona, Buda and Austin Chalk. In GMA 13 aquifers include the Wilcox,Carrizo, Edwards, Yegua-Jackson, Queen City, Reklaw, Sparta, and Weches. 

 

PCCDs Desired Future Conditions:

 

GMA Aquifers Adopted DFC Adoption Date
10 Trinity Group Trinity Aquifer, in the hydrologically confined zone downdip of the Trinity outcrop:Outside of Uvalde and Bexar Counties: Average regional well drawdown not exceeding 25 feet during average recharge conditions (including exempt and non-exempt use)  June 26, 2017
10 Saline Edwards Saline Edwards Aquifer in the Northern GMA Subdivision:No more than 75 feet of regional average potentiometric surface drawdown due to pumping when compared to pre-development conditions June 26, 2017
13 Carrizo-Wilcox, Etal The first proposed desired future condition for the Carrizo-Wilcox, Queen City and Sparta aquifers in Groundwater Management Area 13 is that 75 percent of the saturated thickness in the outcrop at the end of 2012 remains in 2070. This desired future condition is considered feasible despite model predictions to the contrary as detailed in GMA 13 Technical Memorandum 16-08”, And

 

In addition, a secondary proposed desired future condition for the Carrizo-Wilcox, Queen City, and Sparta aquifers in Groundwater Management Area 13 is an average drawdown of 48 feet for all of GMA 13. The drawdown is calculated from the end of 2012 conditions to the year 2070. This desired future condition is consistent with Scenario 9 as detailed in GMA 13 Technical Memorandum 16-01 and GMA 13 Technical Memorandum 16-08

 

November 21, 2016