Fluid Sources and Salinity of Dos Palmas Springs and Natural Preserve, Coachella Valley
Authors:Katrina Kaiser, Jake Loukeh
Mentor:Stephen Osborn, Assistant Professor of Geology, Cal Poly Pomona
Dos Palmas Springs and Natural Preserve function as a water oasis for migratory birds, endangered Desert Pupfish, other wildlife, and recreation in the arid Coachella Valley, California. The springs are managed by the Bureau of Land Management (BLM) and are located approximately four miles northeast of the Salton Sea shoreline and nestled in the foothills of the Orocopia Mountains. The BLM has observed diminished water discharge and increased salinization of the preserve in recent years. This observation has direct bearing on best management practices of not only the springs, but several up-gradient water resources, including the Coachella Branch of the All American Canal (diverted Colorado River water), a near by groundwater recharge basin, and mountain-front groundwater recharge. Therefore, there is great interest by the BLM as well as other stakeholders such as the Coachella Water District and the City of San Diego (a water rights owner) to understanding the source of waters and salinity discharging to the springs. To address this problem, 27 water samples were collected between two sampling events (April and September, 2013). Samples were divided into three categories: springs, spring-ponds (springs discharge into), and up-gradient groundwater wells. Groundwater wells that were sampled for this study lie between the All American Canal (up-gradient) and the spring-ponds (down-gradient). Field and laboratory measurements included pH, alkalinity titration, chloride and bromide relationships (salinity), and oxygen and hydrogen isotope values (source of fluids). Preliminary results indicate that there are two source of water that are apparently mixing in the subsurface and discharging to the springs/ponds. These sources are most likely water from the All American Canal and mountain front groundwater recharge. The source of salinity is most likely due to evaporation and possibly from Colorado River water as well.