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Rio Chama Studies
Client: New Mexico Interstate Stream Commission and New Mexico Office of the State Engineer
Surface and Ground Water Hydrology

The Rio Chama river is located in northern New Mexico and is a tributary of the Rio Grande river. Water is diverted from the Rio Chama for irrigation through a system of community ditches known as acequias. The acequias have been in use for many centuries, with priority dates dating back to 1714. The acequias have rights to native water of the Rio Chama river, but not to imported water from the San Juan-Chama Project, which delivers water from three tributaries of the San Juan River, via the Rio Chama river, to water users within the Rio Grande basin above Elephant Butte Reservoir.

The water rights diverted by the acequias were adjudicated in Federal District Court in Case No. 69CV07941. In this decree, the acequias in the reach below the Abiquiu Reservoir were assigned priority dates and a duty of water.  Authorized maximum rates of flow for each acequia were developed and have been used for administration since 1972. In 2003, the Rio Chama Acequia Association expressed concern that the flow rates may have been set too low, and the New Mexico Interstate Stream Commission agreed to examine the maximum flow rates used for administration.

SWE was retained to investigate the historical basis for the current authorized rates of diversion and develop alternative maximum diversion rates based on documented criteria and repeatable calculations. In addition to this work, SWE was also retained to document the existing conditions of the measuring stations of main stem diverters, to evaluate the viability of quantifying return flows, to digitally map existing structures, and to provide recommendations for improvements to existing facilities as well as the potential for new measuring stations for diversions or stream flows.


Spronk Water Engineers, Inc.
1000 N Logan Street
Denver, Colorado, 80203-3011
Phone: (303) 861-9700  |  Fax: (303) 861-9799