ES Requests DFCs to protect Colorado River and Tributaries

Environmental Stewardship requests Desired Future Conditions be adopted to protect the Colorado River and its tributaries from impacts of groundwater pumping

Environmental Impact of Groundwater Pumping on the Colorado River and its Tributaries


Environmental Stewardship’s Executive Director, Steve Box, presented a power point review of its request that Groundwater Management Area 12 establish standards to protect the Colorado River from the impacts of over-pumping of groundwater at GMA-12’s December 10 virtual meeting (see video below).   The presentation was a part of item 9 on the attached agenda.  The standards requested, know as Desired Future Conditions (DFCs), are based on original research that show that the best science available predicts unreasonable impacts on the Colorado River and its tributaries.   Environmental Stewardship is requesting that specific standards be established that directly address the impact of groundwater pumping on surface waters within the management area.


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Environmental Stewardship provided written comments to GMA-12 October 28, 2020. In the cover letter, Environmental Stewardship recognized the opportunity it has had to work with GMA-12 to move towards desired future conditions that fully consider environmental impacts, including interactions between surface water and groundwater, as the GMA is charged to consider under Texas Water Code § 36.108(d)(4).

For the reasons expressed in these comments, Environmental Stewardship asks that GMA-12:

  • Monitor impacts of groundwater pumping on the mainstem of the Colorado River and its tributaries;
  • Perform certain hydrograph separation studies to evaluate groundwater flow contributions to the Colorado River and its tributaries under drought conditions;
  • Seek to establish criteria to qualitatively and quantitatively evaluate the impacts of reduced contributions of groundwater to baseflows into rivers and streams;
  • Seek to establish factors to be considered in evaluating whether impacts on surface water resulting from reduced contributions of groundwater have become unreasonable, requiring remedial action;
  • Adopt DFCs which include the current DFC parameters, while adding DFC parameters specifically focused on surface water dynamics. Environmental Stewardship proposes the following parameters for this purpose:
    •  Maintain subsistence flow in the Colorado River at the Bastrop Gage 100% of the time; and,
    •  Maintain base-dry and base-average flow in the Colorado River at the Bastrop Gage to protect Blue Sucker spawning during the spring (March – June).
  • Develop a DFC for the Colorado Alluvium Aquifer to protect tributaries which includes a surface water component.

Environmental Stewardship provided replies to the questions raised by District representatives addressing the following topics:

  • The approach of other Groundwater Management Areas,
  • The “beginning” of the conversation of surface water DFCs in GMA-12 has passed, and action is now warranted in the form of the adoption of surface-water DFCS; the conversation has been ongoing for more than a decade,
  • The role of Senate Bill 3 flows and jurisdiction to protect surface waters, and
  • Balancing of surface water flows and property rights.

“For these reasons”, the comments conclude, Environmental Stewardship maintains its request that the GMA fully incorporate the protection of surface water resources in the development of a DFC, followed by continuous evaluation and refinement of that DFC in future rounds.


Environmental Stewardship comments on DFCs to GMA-12     October 28, 2020

Environmental Stewardship GMA-12 Meeting Presentation    December 10, 2020

Environmental Stewardship GMA-12 PPT    December 10, 2020

Environmental Stewardship Supplemental Comments/Replies to Questions    December 29, 2020