THE MIDDLE RIO GRANDE TODAY 37 Infrastructure and Management of the Middle Rio Grande Leann Towne, U.S. Bureau of Reclamation any entities are involved in water management lands within the Middle Rio Grande valley from M in the Middle Rio Grande valley from Cochiti to Cochiti Dam to the Bosque del Apache National Elephant Butte Reservoir. These entities own and Wildlife Refuge. The four divisions are served by operate various infrastructure in the Middle Rio Middle Rio Grande Project facilities, which consist of Grande valley that are highly interconnected and ulti- the floodway and three diversion dams, more than mately affect water management of the Rio Grande. 780 miles of canals and laterals, and almost 400 miles This paper describes major hydrologic aspects of the of drains. Users are served by direct diversions from Middle Rio Grande valley, including water manage- the Rio Grande and from internal project flows such ment activities of the U.S. Bureau of Reclamation, as drain returns. These irrigation facilities are operated major infrastructure of the Middle Rio Grande Project and maintained by MRGCD. (including the Low Flow Conveyance Channel), and focusing on issues downstream of San Acacia COCHITI DIVISION Diversion Dam. Although other entities such as municipalities have significant water management Project diversions from the Rio Grande begin at responsibilities in the Middle Rio Grande valley, they Cochiti Dam, through two canal headings that serve will not be addressed in this paper. the Cochiti Division. The Cochiti East Side Main and The Middle Rio Grande Conservancy District, a Sile Main canals deliver water to irrigators on both political subdivision of the state of New Mexico, was sides of the Rio Grande. Galisteo Creek and Tonque formed in the 1920s as a conglomeration of a number Arroyo, both east side tributaries, join the Rio Grande of acequias (community irrigation ditches) and the six between Cochiti Dam and Angostura Diversion Dam. pueblos of the Middle Rio Grande valley. In 1950 Diversions within the Cochiti Division primarily serve Congress authorized the Middle Rio Grande Project to the Pueblos of Cochiti, Santo Domingo, San Felipe, stabilize and improve the economy of the Middle Rio and Santa Ana and the communities of Pena Blanca Grande valley by rehabilitation of the Middle Rio and Sile. Grande District facilities and by controlling sedimen- tation and flooding on the Rio Grande. The U.S. ALBUQUERQUE DIVISION Bureau of Reclamation and the Corps of Engineers joint- ly planned the development of the project. In the Angostura Diversion Dam, a concrete diversion dam, Middle Rio Grande valley, the Bureau of Reclamation takes water from the Rio Grande to serve the undertook rehabilitation of project irrigation and Albuquerque Division of MRGCD. The Rio Grande drainage works and channel realignment, and the Corps from Angostura Diversion Dam to Isleta Pueblo is of Engineers was responsible for flood protection. influenced by many factors including contributions from the Jemez River, which flows into the Rio MIDDLE RIO GRANDE VALLEY INFRASTRUCTURE Grande just downstream of Angostura Diversion Dam, municipalities adjacent to the river, and MRGCD The Middle Rio Grande Project irrigation distribution operations. The city of Albuquerque waste water and drainage system begins just below Cochiti Dam return flows and soon-to-be-completed drinking water and extends to Elephant Butte Reservoir, 174 miles diversion from the Rio Grande are within this reach. when the reservoir is at maximum capacity. The proj- The Albuquerque Division of MRGCD serves the ect is capable of supplying irrigation water for as many Pueblos of Sandia, Santa Ana, and Isleta, as well as non- as 90,000 acres within the Middle Rio Grande valley Indian users in Bernalillo, Corrales, and Albuquerque. including water for the Pueblos of Cochiti, Santo Domingo, San Felipe, Santa Ana, Sandia, and Isleta. BELEN DIVISION The Middle Rio Grande Conservancy District (MRGCD) consists of four divisions: Cochiti, The Belen Division of MRGCD diverts water from the Albuquerque, Belen, and Socorro, serving irrigated Rio Grande at Isleta Diversion Dam, a concrete diver- WATER RESOURCES OF THE MIDDLE RIO GRANDE 38 CHAPTER TWO sion dam on Isleta Pueblo. The Rio Puerco and the Rio Salado enter the Rio Grande from the west side 42 and 51 miles respectively below Isleta Diversion Dam. These tributaries are a significant source of heavy sedi- ment-laden flows to the Rio Grande, particularly from summer monsoon events and can be a major source of irrigation water to Socorro Division farmers when upstream supplies are limited. Delivery and drainage for the east side of the river ends in this reach where the Lower San Juan Riverside Drain outfalls to the river about three miles upstream of the confluence with the Rio Salado. The Belen Division serves Isleta Pueblo, several New Mexico Department of Game and Fish refuges, the Sevilleta National Wildlife Refuge, and irrigators in several communities including Bosque Farms, Los Lunas, Los Chaves, and Belen. SOCORRO DIVISION About 55 miles downstream of Isleta Diversion Dam, the final Rio Grande diversion for MRGCD is the San Acacia Diversion Dam, a concrete diversion dam that serves the Socorro Division. The Socorro Division also relies on flows from several sources within the project systems, including the Unit 7 Drain, supplied by sur- face water and ground water return flows from the Belen Division, and direct diversions from the Low Flow Conveyance Channel. The Socorro Division serves users in the Socorro area, and the U.S. Fish and Wildlife Service Bosque del Apache National Wildlife Refuge. SAN ACACIA DIVERSION DAM TO ELEPHANT BUTTE RESERVOIR As of October 2006 it was approximately 78 river miles from the San Acacia Diversion Dam to the Elephant Butte Reservoir pool. This distance varies depending on the elevation of Elephant Butte Reservoir. When Elephant Butte Reservoir is at maxi- mum capacity, it is about 54 river miles from San Acacia Diversion Dam to the reservoir pool. There are no major tributaries to the Rio Grande below San Acacia Diversion Dam. However, several arroyos and two flood control channels enter the Rio Grande from both sides of the river. The east side of the river is constrained not by a levee or drain, but rather by the east mesa valley wall. The mainstream Rio Grande channel in this section of the river is roughly 200 to Middle Rio Grande Project features. DECISION-MAKERS FIELD GUIDE 2007 THE MIDDLE RIO GRANDE TODAY 39 600 feet wide and is meandering near San Acacia, LOW FLOW CONVEYANCE CHANNEL becoming more braided downstream. This stretch of river contains two parallel channels: The Middle Rio Grande Project’s LFCC parallels the the mainstem Rio Grande and the Low Flow Rio Grande on the west side and originally extended Conveyance Channel. The Low Flow Conveyance from San Acacia Diversion Dam to the narrows of Channel is located on the western side of the Rio Elephant Butte Reservoir. The LFCC is owned, operat- Grande, runs parallel to it at a lower elevation, acting ed, and maintained by the Bureau of Reclamation. as a drain, and is protected from the river by a contin- Construction began in 1951 and was completed in uous spoil dike. As previously mentioned, there are 1959. The LFCC was constructed to aid delivery of diversions from the Low Flow Conveyance Channel Rio Grande compact waters and sediment to Elephant for the MRGCD and the Bosque del Apache National Butte Reservoir. It also served to improve drainage and Wildlife Refuge. There is a flow constriction approxi- provide additional water for irrigation. It is a riprap- mately 45 miles downstream of San Acacia Diversion lined channel that parallels a 54-mile reach of the Rio Dam near the San Marcial Railroad Bridge. This con- Grande from San Acacia to San Marcial. The LFCC striction is due to the river bed rising (aggradation) at collects river seepage and irrigation surface and sub- the bridge. The Corps of Engineers is currently evalu- surface return flows, thus reducing evaporation. The ating options for replacing the spoil dike protecting usefulness of the LFCC is dependent upon the water the Low Flow Conveyance Channel (LFCC) and relo- level of Elephant Butte Reservoir. Depending upon the cation of the San Marcial Railroad Bridge. condition of the outfall, a maximum of 2,000 cfs can Sediment deposition has a significant impact on this be diverted into the LFCC at San Acacia. stretch of the river. High sediment loads in the Rio Diversions from the river into the LFCC began in Grande have led to significant aggradation of the river 1953, and diversions at San Acacia began in 1960. from the Bosque del Apache National Wildlife Refuge With above average water years the reservoir was rela- to Elephant Butte Reservoir. Due to this aggradation, tively full through the 1980s. During this time the the river bed is generally above the level of the sur- lowest reaches of the LFCC, which were inundated by rounding valley floor downstream of the refuge. This the reservoir, became filled with sediment. This made aggradation and other factors such as vegetation the outfall of the LFCC difficult to maintain, and growth have made maintaining a connected river to therefore diversions ceased in 1985. Since that time the Elephant Butte Reservoir pool an issue since the the LFCC has carried only drainage and irrigation early 1950s. River channelization projects have histor- return flows, with minor exceptions. ically been needed to ensure delivery of water to Currently the spoil dike that protects the LFCC (and Elephant Butte Reservoir. These projects are coopera- surrounding lands such as the Bosque del Apache tively funded and constructed between the Bureau of National Wildlife Refuge) from Rio Grande flooding is Reclamation and the state of New Mexico.