Presa Abelardo L. Rodríguez

The Abelardo L. Rodríguez dam closes off the valley on the eastern edge of Hermosillo, at the point where the Sonora and San Miguel rivers join. Governor Abelardo L. Rodríguez proposed it in 1944 to deal with the capital's chronic water shortage, and he opened it on April 5, 1948, with President Miguel Alemán at his side. Engineers first planned it upstream at El Molinito but moved it to the confluence to catch the San Miguel's flow as well. The wall stands 36 m high, and the reservoir was built for about 254 million cubic meters; silt has since cut that to around 230 million.

Its job was to irrigate ejido farmland south of the Vado del Río. The plan was 15,000 hectares, but in the first year only some 8,000 were watered, because the reservoir only filled halfway. Big-water years have been rare and are still talked about. In 1983 the dam spilled for the first time, releasing around 2 million cubic meters a day, and Hurricane Octavio pushed it over the spillway again that October; it kept spilling in December 1984, and the last overflow came in 1994. The 1983 flood cut traffic across the city and isolated Highway 15, which is why the Vado del Río was later paved as a channel for floodwater.

Drought is the other half of the story. From 1995 inflows kept shrinking, and by 2010 the dam was practically dry, which pushed the state to build the Acueducto Independencia: since 2013 it has piped water to Hermosillo from El Novillo dam, 135 km away. Storage hit zero in 2021, then in 2022 the reservoir came close to full again. Depending on the year, you may find a sheet of water backed by low hills or a vast flat of dry earth and scrub.

Locals walk out along the dam and spillway, which a railway line also crosses. Take care there: in July 2025 a teenager fell about 30 m from the spillway bridge while getting out of the way of a train.