Reclamation Information Sharing Environment (RISE)

Stable water isotope data (hydrogen-2 and oxygen-18) were used to characterize the isotopic composition of source waters to the southern Sacramento-San Joaquin River Delta (i.e., water from the San Joaquin River, the Sacramento River, the San Francisco Bay, groundwater, or local discharges). Water isotope data measured from the southern Delta were compared with the source water dataset to determine if discharges from groundwater or local water users could be detected. Water samples were collected at roughly 40 locations in the Sacramento-San Joaquin River Delta and Lower San Joaquin River Basin at roughly monthly intervals during calendar year 2023.