Grand Ditch Restoration Adaptive Management Monitoring

Description

The Grand Ditch breach in 2003 sent tens of thousands of cubic yards of sediment into Lulu Creek and the Colorado River, and a portion of this sediment was eventually deposited in the Lulu City wetland. Impacts from the breach and the need for restoration are documented in the Final EIS. Restoration is planned to begin during the summer of 2017, with heavy machinery operations lasting two years. This proposal outlines the monitoring needs for during and after the restoration process. The final restoration design (Sueltenfuss and Cooper, 2017) is meant to restore the Colorado Riverâ¿¿s historic meander through Lulu City wetland and the tall willow riparian community supported by this landscape. The deposition of material from the 2003 breach, and earlier debris flows, formed a large alluvial fan at the head of Lulu City Wetland and diverted the river from its historic path through the center of the valley to its current path along the western edge of the valley. The debris directing water toward the west edge of the valley, onto topographically high terrain, results in a sheet flow of surface water southeast across the entire meadow toward the historic Colorado River channel, providing continual saturation of the meadow all summer. This permanently saturated regime has altered the vegetation of the historic floodplain from a highly diverse tall willow community conducive to beaver populations to an herbaceous wet meadow dominated by just a few herbaceous species (Carex utriculata, Calamagrostis canadensis and Carex aquatilis).

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