An Examination of Soil Moisture Conditions in the Babocomari River Basin: The Flood Event of 23 July 2008

The National Oceanic and Atmospheric Administration (NOAA) Hydrometeorology Testbed (HMT) program has deployed a soil moisture observing network in the Babocomari River Basin located in southeastern Arizona. The Babocomari River is a major tributary of the San Pedro River. At 0000 UTC 23 July 2008 the second highest flow during the period of record was measured just upstream of the location where the Babocomari River joins the main channel of the San Pedro River.

Observations of soil moisture and precipitation at five locations in the basin and two river gauging stations are used to document the hydrometeorological conditions that existed before the flood event. The observations suggest that soil moisture conditions as a function of depth, the location of semi-impermeable layers of sedimentary rock known as caliche, and the spatial distribution of convective precipitation in the basin worked to confine the flooding to the lower part of the basin.

Finally the HMT soil moisture observations are compared with soil moisture products from the NOAA National Weather Service (NWS) National Centers for Environmental Prediction (NCEP) Noah Land Surface Model (LSM). The Noah LSM is used in the NWS operational meteorological numerical weather prediction models.