| 8:00 AM-5:00 PM Poster Session I
Quantitative impacts of rock check dams on soil moisture. Reed, Chad*,1, Nichols, Mary2, McReynolds, Kim, 1 University of Arizona, Tucson, AZ2 USDA-ARS, Tucson, AZ
ABSTRACT- Rangelands throughout southeastern Arizona are being treated with check dams to improve their hydrologic and ecologic function. Check dams slow the velocity of the runoff in channels to reduce incision and retain transported sediment. Sediment deposits are expected to retain soil moisture. A research project was initiated in 2006 to evaluate the impact of check dams on a degraded alluvial fan in the Hay Mountain Watershed in southeastern Arizona. The objective of this research was to quantify the spatial and temporal distribution of soil moisture influenced by check dams in comparison with untreated control sites. Thirty nine sites within three incised ephemeral channels were selected for one of three treatments, which consisted of check dams constructed with loose rock, check dams constructed wire bound rock, and untreated controls. Treatments at each site were randomly selected, and fifteen of these treated sites were randomly selected as soil moisture measurement sites. A Frequency Domain Reflectometry capacitance probe was used to measure spatially distributed soil moisture at six depths through the vertical profile to a maximum depth of 30 inches through the summer monsoon season (July, August, and September). Ancillary data was collected from four tipping bucket raingages and soil temperature probes buried at four depths (3,6,9,12 inches), as well as from ambient temperature and relative humidity sensors. Preliminary results indicate differences in soil moisture distribution associated with the presence of the check dams as well as between sediment deposits and consolidated channel banks.
KEY WORDS: erosion control, check dam, arizona, conservation
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