The San Antonio Missions National Historical Park includes four of five Spanish frontier missions in San Antonio, Texas. These missions formed part of a colonization system in the Spanish Southwest in the seventeenth, eighteenth, and nineteenth centuries. The fifth mission, the Alamo, is owned by the State and is operated by the Daughters of the Republic of Texas.
Three of the park missions (Concepción, San José, and Espada) were originally founded in east Texas, along with several others, serving as buffers against French encroachment from Louisiana. Illness, floods, fires, enemies, and limited supplies prompted several relocations of these missions in 1731 to the banks of the San Antonio River.
In geographic order from north (upstream of the San Antonio River) to south (downstream), the missions are located as follows: Misión Nuestra Señora de la Purísima Concepción de Acuña (Mission Concepción), Misión San José y San Miguel de Aguayo (Mission San José), Misión San Juan Capistrano (Mission San Juan), and Misión San Francisco de la Espada (Mission Espada). Unless temporarily closed for restorations, these missions continue to serve as parishes and to offer Mass on Sundays. The Alamo is located upstream of Mission Concepción.
Each mission had its own system of irrigation, known as an acequia, to carry water from the San Antonio River to the fields. The Romans and the Moors brought the concept of acequias to the arid regions of Spain and Portugal. When Franciscan missionaries arrived in the desert Southwest, they realized the system would work well in the hot, dry environment. In order to distribute water to the missions along the San Antonio River, the Franciscans oversaw the construction of a 15-mile (24-km) network that irrigated approximately 3,500 acres (14 km2) of land through seven gravity-flow ditches, dams, and at least one aqueduct.
Both the San Juan and the Espada missions have elements of the irrigation system that can be seen today. The main ditch of the Mission Espada acequia still delivers water to local residents. Extensive work has been done on the San Juan acequia, and in September 2011 part of the irrigation system built during the colonial period was restored. By 2013 the acequia is expected to irrigate a 2.5-acre demonstration Colonial Spanish farm at the mission and subsequently about seventy more acres of nearby farmland.