The Medina project was constructed to create irrigated farmlands west of San Antonio. The Medina Dam, also referred to as the Main Dam, is located on the Medina River, approximately 14 miles upstream of Castroville. The structure is a concrete gravity dam with a maximum base width of 130 feet, a height of 164 feet, and an overall length at the crest of 1, 580 feet. The lake surface water is 5, 575 acres with an approximate volume of 254,0000 acre-feet. When it was completed in 1913, Medina Dam was the fourth largest dam in the United States.

The Diversion Dam, located 4 miles downstream from the Main Dam, is also a gravity structure, although constructed to be slightly arched upstream. The Diversion Dam is slightly more than 50 feet high and 440 feet long. As its name implies, the dam diverts water into the main irrigation canal through its outlet works.

When the Edwards Underground District considered purchasing the Medina Lake Project for use as a recharge facility for the Edwards Aquifer, ARCADIS was retained to conduct comprehensive structural investigations of the dams. The results were included in a study on the feasibility of the purchase.

The structural investigation consisted of historical background development, geotechnical investigation, geological assessment, field inspections, stability analysis, remedial improvements study, and determination of probable cost of improvements.