Technical Abstract: Although rock check dams have been used for centuries to control erosion and support subsistence agriculture on western US rangelands, there is a lack of data for quantifying their impact on soil moisture distribution. The purpose of this study was to measure and document soil moisture in association with loose rock structures and wire bound rock structures in comparison with untreated control sites. A field experiment was conducted on a degraded alluvial fan in southeastern Arizona where erosion control structures were built on three small ephemeral channels. Soil moisture was measured three times per week at depths ranging from 15 to 46 cm at six points on the upstream side of 13 loose rock structures, 13 wire bound structures, and at 13 control sites throughout the 2006 summer monsoon season. Rainfall and runoff during 2006 were above average, and significant differences in soil moisture measured through the soil profile on channel banks were found in association with both loose rock and wire bound check dams in comparison with controls sites. Although not statistically significant, there was generally an increasing difference in the mean soil moisture at the deepest measurement depths between the lose rock structure sites and the wire/bound structure sites. Erosion control structures are expected to increase local soil moisture in response to water impoundment. These results quantify this response and will be useful in designing rangeland restoration strategies that rely on soil moisture to improve vegetative cover.