El Granero

El Granero is what everyone calls the Luis L. León Dam, the reservoir that holds back the Río Conchos in Aldama municipality, northeast of Chihuahua City. It is the second-to-last dam on the Conchos before the river cuts through the Peguis canyon and meets the Rio Grande at Ojinaga. The embankment rises 62 meters and went into service in 1968.

It was built to tame the floods that rolled down to the Rio Grande and swamped the lower Conchos, and to water the farmland between the reservoir and the confluence. Of its total capacity of 850 million cubic meters on the 1997 record, 500 are set aside for flood control, 260 for irrigation and 90 for silt. Downstream, along 130 km of river to the El Peguis dam, the Marqués, Pastor, Coyame and Paradero creeks flow in. The dam is named for Luis L. León (1890-1981), an engineer from Ciudad Juárez who served as agriculture secretary under President Plutarco Elías Calles and briefly as governor of Chihuahua in 1929.

Its level swings with drought and with water deliveries owed to the United States under the 1944 treaty. In January 2020 rumors spread that it had been drained; the water agency inspected it and put it at 73.3 percent. In 2022 local ranchers struggled to find enough water for their cattle.

For visitors, El Granero is above all a fishing lake: largemouth bass, the species tournaments target, plus catfish, carp and rainbow trout. The hills around it show tilted beds of Late Jurassic shale from the La Casita Formation, where ammonites turn up around Aldama. There is no village or service on the shore; it is open desert, so bring food and water.