Technical Reports Document Library

The concept of recharge and recirculation (R&R) for the Edwards Aquifer embodies the integrated use of groundwater, surface water, and storage units to optimize the availability of water for pumpers during drought periods and to accommodate water needs for endangered species in Comal and San Marcos springs. The purpose of this Phase 1 report is to outline work performed by Todd Engineers to evaluate various documents related to the concept of R&R and to document Todd Engineers review of a MODFLOW groundwater model of the Edwards Aquifer for use in simulating R&R scenarios. The report also discusses two preliminary R&R scenarios simulated with the model. Subsequent phases of the project will use the model to simulate numerous R&R scenarios to evaluate possible benefits for aquifer water levels and springflows.

[From Introduction of Phase 2 report]
In April 2004, Edwards Aquifer Authority (EAA) contracted with Todd Engineers to conduct a multi-phase study on enhanced recharge and recirculation (R&R) strategies. Phase 1 of that work was completed in September 2004. This Phase 1 report includes a review of existing studies, an analysis of Edwards Aquifer hydraulics, installation and operation of the 2004 U.S. Geological Survey (USGS) MODFLOW model of the Edwards Aquifer, and application of the model for test runs at two hypothetical recharge sites. Test runs indicated that long-term benefits measured in years can be achieved for Comal Springs flow by increasing aquifer recharge. Further, the magnitude and duration of increased springflow was found to vary significantly from site to site.