Loutzenhizer Arroyo Water Quality Monitoring activities in the Lower Gunnison Basin

Previous studies have also found that in areas containing soils and outcrops with high salt content, such as in the Mancos Shale on the east side of the Uncompahgre Valley, considerable salt loading occurs from canal and lateral leakage. Because Mancos Shale is a major source for selenium, it follows that canal lining and lateral piping significantly decreases selenium loading. This was proven in 1998 when the Montrose Arroyo Piping Project data demonstrated that significant selenium reduction benefits occur when salinity-control type projects (e.g. lining or piping) are implemented. The Montrose Arroyo post project monitoring showed reduced seepage, groundwater levels, and selenium and salt loads.

The U.S. Geological Survey (USGS), in cooperation with Delta County and the Shavano Soil Conservation District, developed a characterization study to provide more detailed selenium information for the lower Gunnison River Basin.

The selenium characterization study objectives are: 

1.  To characterize selenium concentrations and loads in tributary streams of the North Fork of the Gunnison and tributaries of the Gunnison River downstream from the Smith Fork to Whitewater. 
2.  To characterize selenium concentrations and loads in Cedar Creek and Loutzenhizer Arroyo. This report summarizes selenium data for streams in the North Fork Basin and for tributary streams of the lower Gunnison River