Ongoing and projected changes in climate are expected to alter discharge and water temperature in riverine systems, thus resulting in degraded habitat. Climate adaptation management strategies are proposed to serve as buffers to changes in air temperature and precipitation, with these strategies potentially providing relatively stable protection for flow and thermal regimes. Using a hydrologic and water temperature modeling approach in the Meramec River basin in eastern Missouri, U.S.A., we examined the ability of forested riparian buffers to serve as a useful climate adaptation strategy against ongoing and projected changes in climate. We developed a multi-scale approach using Soil and Water Assessment Tool (SWAT) hydrologic and water temperature models as well as a Stream Network Temperature Model (SNTEMP) with different amounts of simulated riparian vegetation to estimate streamflow and water temperature variation within the Meramec River basin under both contemporary and projected future climate conditions. Our results suggest that riparian buffers offer benefits to mitigating increases in water temperature due to shading effects; however, patterns in discharge did not vary substantially based on simulations. From an ecological perspective, the addition of riparian buffers is also projected to reduce the impacts of climate change on Smallmouth Bass (Micropterus dolomieu) by decreasing the number of days water temperatures exceed the thermal tolerance of this species.

Nutrient reduction strategies in the Mississippi and Atchafalaya River Basin (MARB) have been implemented to attenuate drinking water concerns and hypoxia in the northern Gulf of Mexico. Of all nutrients, nitrate has been identified as the principal cause of Gulf hypoxia, with loads coming disproportionately from the Upper Mississippi River Basin and the Corn Belt region. Identifying long-term changes of riverine nitrate would provide valuable information to evaluate the performance of reduction strategies. The objective of this study was to estimate the flow-normalized (FN) nitrate-N concentration and yield trends for the 2000-2020 period across the MARB at monitoring sites with adequate data. A harmonization and in-depth screening of paired nitrate-N and streamflow datasets resulted in a robust water quality monitoring network of 217 sites. Trends magnitude and likelihood were computed using the Weighted Regression on Time, Discharge, and Season (WRTDS) coupled to a bootstrap test, and trends results were correlated with basin features and initial values of concentrations and yields. The impact of streamflow long-term variations on trends was separated from all other factors through stationary and non-stationary flow normalizations. Results indicated that 59.4 % of the 217 sites had likely decreasing concentration trends, while 27.7 % likely increased, and the remaining 12.9 % had no likely change detected. Reductions in riverine FN nitrate-N were predominant at watersheds dominated by cultivated cropland areas having relatively high FN concentrations and yields in 2000 followed by likely downward trends. For the vast majority of sites, the non-streamflow component was more dominant, but the streamflow component was nonetheless influential.

Several reservoirs across the United States are filling with sediment, which jeopardizes their functionality and increases maintenance costs. USACE developed the Reservoir Sedimentation Inf... Practical ApplicationsMany communities depend on reservoirs for a variety of socioeconomic benefits, such as providing reliable water sources and flood mitigation. Rivers entering reservoirs are a ...