Each mission had its own system of acequias (irrigation ditches) to supply water from the San Antonio River to the mission and farmland. Using Native American labor, the Spanish constructed seven acequias; each with its own dam and an aqueduct. Five of the acequias brought water to the missions and the other two supplied water to the municipio. This system extended 15 miles and irrigated 3,500 acres of land. A key element of an acequia system is a weir dam to divert water from the river to the irrigation ditches.
Water: An Essential Element for the Missions
Since prehistoric times, the San Antonio River has been a vital resource to the inhabitants of the San Antonio River Watershed contributing to the rich history of the area. Archaeological excavations have produced evidence that the first human habitation along the San Antonio River occurred as far back as 12,000 years ago.
The indigenous people knew that the natural spring-fed San Antonio River and nearby San Pedro Creek, with their abundant fish and vegetation, provided the perfect source of water. Later, the Spanish colonial missionaries recognized the importance of these sources of water.
The locations of the five Spanish missions in San Antonio were chosen because of their proximity to the San Antonio River. Bringing the water to the missions for cooking, personal and agricultural uses required the digging of irrigation channels known as acequias. The Spanish missionaries used technology dating to ancient Mesopotamia for the acequias, gates, and dams. Construction of acequia systems began immediately after the first settlers arrived in 1718. Ultimately, there were miles of acequias for the Missions, the town of Bexar, and the military presidio.
Concepciόn/Pajalache—The original acequia was 3.3 miles long, but it grew to more than 7.5 miles. The largest of the irrigation canals, it was reportedly wide enough for small boats and was in continual use until 1869.
Acequia Madre de Valero—Construction of this canal took 20 years. Sections of the acequia can be seen within Hemisfair Park and the elongated fishpond behind the east wall of the Alamo chapel.
San José Acequia—This acequia provided irrigation for crops and water to a mill constructed on mission property around 1790.
San Juan Acequia—The channel originated at a diversion dam located across the San Antonio River from Mission San José and traveled south 3 miles. It has the oldest Water Right in the state of Texas. Water was restored to the acequia in late 2011. Water flows from the dam along the acequia madre to the acequia medio, which flows through the San Juan labores and returns to the river south of the farm fields.
Espada Dam, Acequia and Aqueduct— The Espada Aqueduct was constructed in 1745 to serve the mission lands of Espada. Espada Dam is the city’s only Spanish Colonial dam that still functions. Built of limestone and lime mortar, the dam has a unique reverse curve design. The aqueduct was built to carry water over Piedras Creek, 1.5 miles from the dam. The aqueduct also still exists and is considered the system’s most remarkable feature. You can access the dam, acequia and aqueduct in San Antonio Missions National Historical Park.