Center for Embedded Network Sensing

A mountain-to-valley "virtual" hydrologic observatory in Central California provides a focus for data and information in support of hydrologic research, a testbed for prototype measurement systems, and guidance for development of measurement and cyber infrastructure in an actual observatory. Physically, the multiple rivers and watersheds making up the 60,000 km2 greater San Joaquin drainage are physically disconnected by foothills dams that provide flood control, hydropower, seasonal water delivery and recreation. However, the mountain and valley portions are institutionally connected in multiple ways. For example, each year the winter snowpack and watershed conditions determine the magnitude of annual runoff. Errors in snowpack measurements and runoff forecasts have huge economic implications for valley water users. Second, valley flood control, water quality, irrigation demand and hydropower operations have a very strong interest in influencing mountain watershed management. The broader aim of the Sierra Nevada-San Joaquin Hydrologic Observatory is to build research infrastructure and promote research for improving the knowledge base for sound hydrologic management in the Sierra Nevada, San Joaquin Valley and across the West. In the Sierra Nevada the current focus is on developing instrument clusters for estimating distributed watershed water balances, blending satellite data with that from strategically placed, ground-based instrument clusters. Five instrument clusters at or just above the rain-snow transition are in place and under development. In the San Joaquin Valley, the focus is on sensor systems for observing fertilizer application rates in agriculture, groundwater-surface water exchanges in rivers, and flow and mixing in the confluence zones between the main stem San Joaquin and tributary Merced Rivers. A common digital library and analysis framework further links the mountain and valley portions of the virtual observatory.