Irrigation System Modernization: Case Study of the Middle Rio Grande Valley

The Middle Rio Grande Conservancy District (MRGCD) was officially founded in the 1920s, but it may well be the oldest operating irrigation system in North America. Currently the MRGCD serves about 22,300 ha of irrigated land and provides additional benefits to the Middle Rio Grande MRG Valley by providing proper soil drainage and protection against flooding. In recent years, the demand for water in the MRG Valley has increased drastically due to explosive population growth, expanding industry, and water allocated for environmental and ecological concerns, which include two federally listed endangered species-the silvery minnow (Hybognathus amarus) and the southwestern willow fly catcher (Empidonax traillii extimus). In response to the call for more efficient water use, the MRGCD embarked on a program of irrigation system modernization with supervisory control and data acquisition (SCADA) incorporation. Over the past few years, the MRGCD has developed a SCADA system focused on improving water use efficiency throughout the MRG Valley. This paper examines the five components of the system and how each component was developed and incorporated in the overall SCADA system. The SCADA system and related improvements in operational practices have reduced MRGCD river diversions from 7.4x10(8) m(3)/year a decade ago to an average of 4.3172x10(8) m(3)/year over the last 3 years.