San Juan Chama Project
The San Juan-Chama Diversion Project is very important to the BDD Project for the following reasons:
2. This 5,605 acre-feet of water per year will provide approximately two-thirds of the BDD Project’s allowable annual maximum diversions. It is a little more than half of the total annual potable water use by the City and County public water systems and Las Campanas over the last several years.
3. The San Juan-Chama Project water is from a renewable surface water resource.
4. Water from the San Juan-Chama Project is unusually reliable.
5. The State Engineer has issued a permit to the City of Santa Fe and Santa Fe County for diversion of 5,605 acre-feet of water per year at the BDD Project.
6. As much as 25% additional San Juan-Chama water can be diverted at the BDD Project under the State Engineer permit in any year, subject to availability of the water and the prior approval of the State Engineer.
The San Juan-Chama Diversion Project, which was constructed and is owned by the Bureau of Reclamation, diverts water from three headwater streams of the San Juan River in southern Colorado and delivers the imported water into the Chama River in New Mexico.
Photo of the Rio Chama in 2005 courtesy of the Albuquerque Bernalillo County Water Utility Authority.
Designed to Benefit Our Region
This water flows through a tunnel under the continental divide into Heron Reservoir. It is part of New Mexico’s 11 percent share of water from the Upper Colorado River Basin.
Planning and investigations that led to the San Juan-Chama Project started in the 1930s. Planners recognized a need for additional water along the Rio Grande in New Mexico and the possibility of using some of our state’s allocation of water from the Upper Colorado River Basin Compact to meet some of those needs.
According to the Bureau of Reclamation, the primary “purposes of the Project are to furnish a water supply, via trans-basin diversions, to the middle Rio Grande valley for agricultural, municipal, domestic, and industrial uses. The Project is also authorized for incidental recreation and fish and wildlife benefits.”
The Bureau of Reclamation signed contracts with various New Mexico municipalities and irrigation districts for the “firm yield” of water provided by the project. According to the Bureau of Reclamation, “the estimated amount of SJC water that can be provided from Heron Reservoir with reasonable certainty each year (known as firm yield) is 96,200 acre-feet.”
Some of these contracts are as follows:
City of Albuquerque – 48,200 acre-feet per year
Middle Rio Grande Conservancy District – 20,900 acre-feet per year
Jicarilla Apache Nation – 6,500 acre-feet per year
City/County of Santa Fe – 5,605 acre-feet per year.
Other contractors for San Juan-Chama Project water include San Juan Pueblo, Los Alamos County, the municipalities of Belen, Bernalillo, Española, Los Lunas, Taos, and Taos Ski Valley, and the Pojoaque Valley Irrigation District.
The City of Santa Fe, Santa Fe County, and the Public Service Company of New Mexico signed a single 40-year contract with the Bureau of Reclamation in 1976 for the 5,605 acre-feet of water per year. At that time, the Public Service Company of New Mexico owned and operated the Santa Fe public water system. This original contract was replaced by two permanent contracts that were signed in 2006. The City contract is for 5,230 acre feet per year. The County contract is for 375 acre-feet per year.
About the Heron Reservoir
The San Juan-Chama Project began importing water into Heron Reservoir in 1971. Heron Dam, which is part of the San Juan-Chama Project, is built across the mouth of Willow Creek at its confluence with the Rio Chama. Heron Reservoir stores only San Juan-Chama water and holds 400,000 acre-feet, which is approximately equal to four years of full supply for all of the contractors. Diversions from the San Juan River headwater flow into Heron Reservoir and are limited to 1,350,000 acre-feet in any ten-year period. Diversions are allowed any time during the year when the flow in any of the three headwater streams exceeds the minimum flow that must continue downstream. Most of the diversions occur during the spring snowmelt period.
Heron Reservoir is operated to supply the San Juan-Chama Project’s calculated “firm yield” by releasing previously stored water in drier years and storing water in wetter years. Annual diversions of water into Heron Reservoir depend on the snowpack along the Continental Divide in Colorado south of Wolf Creek Pass. No shortages have yet occurred. Future shortages, if any, will be shared by all contractors. If, for example, a 20% shortage were to occur some year in the future, Albuquerque would forgo 9,640 acre-feet, which is 20% of its annual contract amount. The City of Santa Fe and Santa Fe County would forgo 1,121 acre-feet, which is 20% of their combined contracts.
Contractors place orders for their annual contract allocation to be released from Heron Reservoir to the Chama River. Those orders must specify the destination and the intended beneficial use for the water that are in accordance with the authorizing legislation and the particular contract involved. Any part of an annual contract allocation of water that is not timely ordered and released reverts to undesignated water stored in Heron Reservoir for delivery in subsequent years. Water does not become a contractor’s property until it is released from Heron Reservoir.
The New Mexico State Engineer administers San Juan-Chama Project water as separate and distinct from native Rio Grande water. Full supplies of San Juan-Chama water could be available in years when shortages of Rio Grande water might lead to curtailed diversions under native Rio Grande water rights.
San Juan-Chama Project water diverted for the Santa Fe region by the Buckman Direct Diversion Project is an additional source of water and protection from drought. Although climate change is expected to reduce streamflow and mountain snowpacks in the southwest, the Santa Fe region’s water supply from the San Juan-Chama Project via the Buckman Direct Diversion Project should be more reliable than the supply in most New Mexico rivers. This is due to the high elevation of the diversions from the San Juan River headwater streams, Heron Reservoir storage that is used to “firm” the annual San Juan-Chama Project deliveries to contractors, and the shortage sharing provisions of the federal authorizing legislation.
The City and County pay a combined total of approximately $60,000 a year to the Bureau of Reclamation for their share of Reclamation’s annual operations and maintenance expenses for the San Juan-Chama Project. They also pay approximately $165,000 per year as repayment for their share of the project capacity. The latter payments will be completed in 2015.