Impacts of Grade Control Structure Installations on Hydrology and Sediment Transport as an Adaptive Management Strategy
What are the impacts of Grade Control Structures (GCSs) installed in ephemeral drainages on storm flows, local hydrology, soil moisture, and sediment transport and do GCSs reduce sediment deposition in reservoirs, enhance local water resources, reduce stream velocities, support ecosystems and optimize watershed function? Land owners and managers of degraded landscapes install GCSs for land and ecosystem restoration however these installations typically do not include hydrologic monitoring. Water managers increasingly include GCSs as adaptation strategies for watershed resource planning. When storm flows are slowed do GCSs "capture flood flows" (ARS 45-141) and infringe on surface water appropriations? Anecdotal evidence indicates increases in local water resources following installation of GCSs. Hydrologic and sediment transport monitoring is required to accurately assess the impact of GCS installations.
Need and Benefit
Recent trends suggest that some areas of the West are experiencing less frequent yet stronger precipitation events and fewer moderate events. GCSs may be installed to reduce sediment deposition in reservoirs, improve water quality, provide soil moisture for ecosystems, and increase water resources. However; hydrologic data are needed to inform policy. Reclamation has capabilities to conduct research and external partners will provide technical expertise with GCS installations and with sharing applicable research. USDA-ARS research provides a great foundation to build on, however there is "lack of (and need for) data to quantify their (GCS) impacts" (Nichols, et al., 2010). While a limited number of studies quantify the "impacts of check dams on sediment retention, studies specifically quantifying soil moisture impacts have not been conducted." (Nichols, et al., 2010). If this research is not funded, hydrologic and sediment transport data will not be available to assess GCSs as an adaptive water resource management strategy.
Contact the Principal Investigator for information about partners.
Contact the Principal Investigator for information about these documents.