Henri Castro, who colonized this area in the 1840s, envisioned irrigated farms along the Medina River. The project was delayed, however, until after the turn of the century, when Dr. Fred Stark Pearson, an internationally known engineer, persuaded British investors to finance construction of a dam at this site. Completed in 1912, Medina Dam was hailed as the largest in Texas and the fourth largest in the United States. Limestone boulders from a nearby quarry added bulk to the massive concrete structure. Four miles downstream, a small diversion dam conducted water into a system of irrigation canals. Gravitational force delivered the water to fields. The outbreak of World War I (1914) disrupted ties with British investors. Seeking new capital, Dr. Pearson and his wife left for England in 1915 on the "Lusitania" and were killed when a German submarine torpedoed the ship. The irrigation network created by Medina Dam brought new prosperity to this region. Vegetables raised in irrigated fields became a valuable crop. Water and electricity were made available to rural residents. In 1925 voters established the Bexar-Medina-Atascosa Counties Water Improvement District No. 1 to manage the project. (1978)