Pulsey, patchy water quality in the delta: Implications for meaningful monitoring

Valuable water quality and biological datasets have been gathered in the Sacramento-San Joaquin Delta for decades, most notably by the Interagency Ecological Program’s Environmental Monitoring Program (EMP). These extensive data have provided a means of analyzing and detecting long-term trends in water quality and ecosystem function (Jassby and others 2002; Kimmerer and Orsi 1996; Orsi and Mecum 1996) and may shape future restoration actions in the region. EMP water quality data—as well as data generated by the San Francisco Estuary Institute’s (SFEI) Regional Monitoring Program (RMP) and research groups like our own—have often focused on single, monthly or seasonal samples taken at several discrete points in space. Although such discrete data often push the practical limits of our equipment and human resources, higher resolution monitoring  approaches can reveal limitations (in some cases severe) of these more coarse sampling schemes.