| Agricultural and grazing practices have detrimental and long-lasting effects on water quality. Large investments in conservation actions aim to mitigate these impacts and restore ecosystem services. Since 1982, an estimated $62.9M have been spent on conservation and restoration programs within Marsh Creek in southeast Idaho. Between 1969 and 2017 suspended sediment (SS) flux in Marsh Creek was reduced 75%. A time-series comparison between conservation investments and SS flux shows a strong negative correlation between dollars spent and flow-normalized flux with lags of 6 and 7 years. Despite considerable investment in conservation actions, from 2004 to 2012 Marsh Creek still exceeded high- and low-flow SS limits more than 50% of the time. Future conservation investments will yield the greatest benefit through continued reduction of near-channel sediment sources, water quality monitoring, reconnecting the channel with the floodplain, and community education.
Keywords:
Best management practices (BMPs), conservation, conservation reserve program (CRP), environmental quality incentives program (EQIP), section 319 grants, river restoration, conservation history, stream water quality, agricultural water quality, water quality trend analysis, aerial image analysis, suspended sediment, bank erosion, semi-arid, southeast Idaho, Idaho State University, Bannock County, Marsh Creek, Portneuf River |