ALBUQUERQUE N.M. - Steady rainfall in New Mexico and west Texas this summer has left many Bureau of Reclamation reservoirs with more water in storage than previously forecast. This is good news as the end of irrigation season approaches.
Elephant Butte Reservoir is now projected to end the season holding approximately 97,000 acre-feet or about 4% of its total capacity. Although this is low, it is significantly better than the projections of less than 1% made before the rain materialized. Caballo Reservoir is projected to end the season storing approximately 15,000 acre-feet.
“Our projections are based on the expected snowpack runoff and the expected demand from downstream users. In a year like this, we didn’t have much of a spring runoff," said Albuquerque Area Office Manager Jennifer Faler. “However, it started raining in late June and the storms continued steadily through July and into August. The monsoon rains are notoriously difficult to predict, so we used conservative but realistic monsoon estimates in our models early this year. They’ve proved to be a big help with water levels this summer."
The rain is a welcome relief to water bodies and users in New Mexico and west Texas. However, it’s important that the public understands that drought conditions, which have been impacting the states for more than two decades, can’t be reversed by a few months of rain. It would take several consecutive years of above average snowfall and summer rains to build-up storage supplies in our reservoirs.
Higher inflow than predicted has helped Elephant Butte storage, but lower demand from downstream farmers due to rainstorms in southern New Mexico and west Texas was an even greater help. Rio Grande Project beneficiaries are scheduled to take their last deliveries from Caballo around August 28. Elephant Butte releases ended on August 16.
Upstream on the Middle Rio Grande Project, farmers expected to end the season in mid-July based on projections. However, a steady amount of rain through the summer and strategic use of its contracted San Juan-Chama Project water allowed the Middle Rio Grande Conservancy District to extend its irrigation season to end a month early on October 1. The rain also kept much of the Rio Grande flowing all the way to Elephant Butte through most of that period, supporting habitat for the endangered Rio Grande Silvery Minnow.
“We typically start seeing drying in some reaches of the Rio Grande south of Albuquerque by June or July," Faler said. “There has been drying this year, but rain helped the river to reconnect and remain continuous into August. There is currently some drying in the Isleta reach, and there remains a chance for drying in other reaches if the rain does not continue."
On the Pecos River, while heavy rain caused flooding in late June, it also allowed Brantley Reservoir’s irrigation storage to fill. The rain added to the upstream reservoirs, with Santa Rosa going from about 3,500 acre-feet to about 14,200 acre-feet, a fourfold increase. The rain also improved the limited volume of water available in Lake Sumner to meet the requirements of the biological opinion for the threatened Pecos Bluntnose Shiner. The Carlsbad Irrigation District had initially informed farmers they would receive less than half a foot of water per acre of land this season. However, the rainfall received this summer increased that allocation to more than a foot of water per acre. A full allocation of water would be 3.7 feet of water per acre.
Source: Bureau of Reclamation
