Case Study, Southern Sierra CZO.

Water availability plays a crucial role in forested ecosystems and is often the limiting factor for summer tree growth in Mediterranean climates, which are characterized by heavy winter precipitation and an extended summer drought.  In addition to precipitation, evapotranspiration is the other dominant component of the water balance, and it is the interaction of water with soil in the unsaturated zone that controls the total amount of water available for uptake by plant roots and into the atmosphere. Advances in measurement technology, and particularly in embedded sensor networks and remotely sensed measurements, coupled with parallel advances in cyberinfrastructure and numerical modeling are bringing about fundamental changes in sampling strategies in forest hydrology and biogeochemistry.   The paper presents background and data collected for the NSF-funded Critical Zone Observatory (CZO) project in the Kings River Experimental Watershed (KREW), which is a US Forest Service research site located in the rain snow transition zone in mixed-conifer forest of the southern Sierra Nevada mountain range. We present water-balance instrument cluster and soil hydrological data as collected from various sampling networks across different spatial scales. In addition to soil moisture, water potential and temperature measurements, we present snow-depth and other instrument cluster data as collected using a flux tower, meteorological stations, snow pillow, stream gauges, shallow groundwater monitoring wells and wireless communication. Sensors were placed to capture variability in the landscape, and provide both statistical and physical distributions of snow and soil water quantities.