The NOAA/OAR/ESRL/PSD Physical Science Division in collaboration with the National Weather Service (NWS) Colorado River Basin Forecast Center (CBRFC) has instrumented the Babocamari tributary of the San Pedro River in Southeastern Arizona with soil moisture, soil temperature and precipitation observing capability. The stations are deployed in a way that can help hydrologists look at Basin and Hydrologic Rainfall Analysis Project (HRAP) scale variability in soil moisture, and precipitation along the Babocamari River. The observations are also being used to evaluate and hopefully improve the performance of the Sacramento Soil Moisture Accounting Heat Transfer model (SAC-SMA-HT) developed by the NWS Office of Hydrological Development (OHD).

Five soil moisture observing station were installed and became operational on 1 June, 2008, in time for the start of the 2008 North American Monsoon Season. The stations are capable of measuring soil moisture, soil temperature at 5, 10, 20, 50, and 100 cm in addition to rainfall. In our presentation we plan on showing soil moisture and precipitation observations made prior and after a heavy precipitation that occurred late in the afternoon of 22 July. During the event river heights at the USGS river gauge located near Whetstone, AZ showed that the river height increased from less than a 30 cm to over 2 m in less than 15 minutes. In addition we will compare the CBRFC derived soil moisture and QPE from the SAC-SMA-HT and Multisensor Precipitation Estimates (MPE) with the PSD in-situ measurements.