Effects of the water transfer project on land use and land cover change: The case of the State Water Project in California, United States

This study presents an analysis of the land use land cover change (LUCC) of the donor (exporting) and recipient (importing) basins in the major water transfer system in California as exemplified by the case of the State Water Project. The State Water Project is the nation's largest, state-built water transfer system that delivers water over 700 kilometers long from Northern to Southern California. We evaluated the State Water Project effect on LUCC by comparing the land use pattern from 1978 to 2018 in 8-year interval-based along the California Aqueduct. The donor basin is the Clifton court Forebay at the southwestern corner of the Sacramento-San Joaquin River Delta (California Aqueduct) and the major recipient basins are the Santa Barbara County (Coastal Branch), Los Angeles County (West Branch), and the San Bernardino County (East Branch). This research is based on six Landsat imageries using the maximum likelihood classification in ENVI 5.5 software. We additionally analyzed the potential LUCC driving forces using historical water allocation data from Bulletin 132, the regional gross domestic product growth data and demography data. Through before and after comparison, we found that agricultural and developed (municipal and industrial) land use has increased in the recipient basin, which corresponds to the timing of the intermittent conveyance of water from a donor to recipient basin. However, in the donor basin, water delivery system to some extent led to the retirement of irrigated land which led to the loss of agricultural jobs and related businesses that inhibited future economic growth in the donor basin. We discuss several reasons for this result, including the Mediterranean climate and water allocation policies. We conclude that (a) the State Water Project has different LUCC effect in the donor and recipient basins and (b) historical, demographic, and economic factors should be considered when explaining and assessing the LUCC due to the water transfer system.