Aquifer Framework Restoration (AFR) in an Alluvial Aquifer, Central Texas.

The Brazos River Alluvium aquifer (BRAA) near Waco, Texas is an aquifer whose framework has been physically impacted by sand and gravel mining. The most productive portions of the BRAA framework are being excavated and kept as pit lakes or filled with different material. GIS identification of mined areas was estimated to cover 4.4% of the BRAA from which evaporative losses was calculated to be 10% of average annual recharge. Permeameter tests suggest that foreign material comprised of large limestone gravel or construction debris has high K and implications to improve production compared to fine grained native (overburden) fill. Construction debris had elevated sulfate and magnesium signatures that were found to decrease from weathering over time. Groundwater models showed foreign and native materials to on average increase and decrease groundwater flow respectively. Characterization of fill material is essential for Aquifer Framework Restoration (AFR).