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Much time and money has been spent over the last 40 years in the U.S. by farmers, soil scientists, hydrologists, geomorphologists, engineers, and ecologists attempting to document how agricultural best management practices, natural vegetation in riparian corridors, and stream rehabilitation or bank stabilization reduces sediment yields and improves ecological conditions at watershed outlets. These issues are especially pertinent in the steep erodible landscape of the Driftless Area in southwest Wisconsin, where many miles of world-class spring-fed trout streams remain on state impaired waters lists from excessive sedimentation and degraded habitat even though this area was the birthplace of the conservation movement...
The high load of suspended sediments in Kansas rivers and reservoirs has raised many concerns about the quality of the state's water supply. Erosion originating in pastures, croplands, gullies and channel-banks accounts for the majority of the suspended sediment load. Pasture and cropland adjacent to river and stream banks without riparian buffers increase de-stabilization allowing for bank deterioration and contribute non-point source pollutants such as fertilizers, pesticides and fecal matter. Determining high-risk areas along rivers and tributaries for either riparian remediation or bank stabilization is part of our research. Using GIS technology with present day and historical aerial images, high risk areas...
Since the mid 1990's, Lake Erie has experienced seasonal eutrophication. This investigation was designed to look at potential causes for eutrophication in Lake Erie. It was also designed to see if any correlations exist between agriculturally applied fertilizers (including sewage sludge) and cyanobacterial blooms in the Western Basin of Lake Erie that occurred during the months of July, August, and September for the years 1999-2003. An algorithm was used on available LANDSAT Thematic Mapper (TM) frames to monitor phycocyanin growth caused by cyanobacteria. These images were analyzed in conjunction with Maumee River water quality data, planted winter wheat, local weather data, and records of agriculturally applied...
Sediment and Phosphorous runoff from the Maumee River watershed, with the largest drainage of any of the great lakes watersheds, have been identified as significant contributors to water quality problems in the western basin of Lake Erie. Sediment and nutrient loading have been associated with increased harmful algal blooms and these blooms and sediment impact the most productive fishery in the Great Lakes. We use a calibrated SWAT model and climate model predictions to model the anticipated changes of discharge, sediment and phosphate from the Maumee River, both in terms of total volume and in temporal distribution of discharge. The model was calibrated to flow volume, sediment concentration and P concentrations....
Both climate and land use changes can affect the sustainability of water resources. Field studies and modeling efforts have provided valuable information regarding the impacts of these changes on surface water and groundwater resources. However, the use of physically-based fully-integrated hydrologic models to explore the entire hydrologic system in a holistic manner under climate and land use change has only just emerged. This type of modeling framework can be used to quantitatively evaluate the impact of both climate and land use changes on surface and subsurface hydrology, contaminant and thermal energy transport, and the interactions between the surface and subsurface flow and transport regimes. In this work,...
The Frenchman Creek basin in semi-arid southwestern Nebraska is an area dominated by agriculture where water levels in the aquifer have declined significantly since predevelopment. Analysis of streamflow data at several gages along Frenchman Creek indicates a streamflow reduction since the 1950s. The cause of this reduction is a combination of groundwater abstraction for irrigation, terracing, and other land use changes. However, the relative influence for each factor is not well quantified. The objective of this study is to develop a physically-based analytical model that characterizes the effects of pumping, terracing, and other land use changes on streamflow of Frenchman Creek from predevelopment to today. The...
Sediment cores extracted from three lake basins in Northeast Ohio reveal a marked transition from organic rich late Holocene muds to sediments richer in clastics in two of the basins, while the third and smallest lake basin contained no such transition. Analyses of sediment cores from Long Lake were conducted at the LacCore facilities in Minneapolis, Minnesota and revealed an increase in magnetic susceptibility and gamma density measurements, which are consistent with an influx of eroded soils into the aquatic system. Radiocarbon dating of material gathered from the noted transition dates to the early 19>th) century. The drainage basins range in size from Odell Lake, which is 52 km>2) to Long Lake, at 6 km>2) to...
The Root River Watershed (RRW) in southeastern Minnesota is a focus of the state's Clean Water Initiative because of its high-value ecological, recreational, and agricultural resources. Accordingly, several agencies are currently assessing land use impacts on RRW trout streams. The bedrock in the watershed is predominantly Ordovician sedimentary rocks, including carbonate rocks forming the largest karst terrain in the upper Midwest. The karst terrain poses significant challenges in assessing and managing water resources. In order to provide a baseline for assessing future agricultural BMP implementation, we performed a detailed geomorphic assessment of the morphology and hydraulics of three RRW subwatersheds (Bridge...
Understanding basin-scale hydrological processes is complex. Efforts are on to close the water budget for a given watershed by the hydrological modeling community, but to assess the highly variable surface process including evapotranspiration, soil moisture over decadal time scales and to draw conclusions on their interannual variability is quite challenging. We employ the Soil Water Assessment Tool (SWAT) model in this simulation exercise. In this presentation, we demonstrate the application of the SWAT (Soil Water Assessment Tool) model over a few large basins in Nebraska and verify the results with the Automated Weather Data Network (AWDN) soil moisture observations. Analysis shown in this presentation on the...
Evaluation of vadose zone fate and transport of pesticides using numerical models can be an effective tool in managing pesticide environmental risks in regions experiencing water quality impairment such as the High Plains aquifer. The Environmental Protection Agency (EPA), under the 1947 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and amendments, maintains responsibility for balancing "adverse environmental effects" against the economic benefits of pesticide use in approving chemical registration and applicator certification. Until recently, evaluations of aquifer vulnerability have historically been more empirical rather than quantitative, limiting assessment of various agricultural scenarios. Using...
Initial results of a Minnesota Pollution Control Agency (MPCA) funded collation of nitrate databases for surface and groundwater of the 10 counties of southeastern Minnesota's (SE MN) karst region are presented. The goal is to identify existing data that can help define time trends and mechanisms of nitrate water pollution. The U.S. Geological Survey's National Water Information System contains data collected from 1889 to present for the entire nation and is available on the Internet. The MPCA created three successive state-wide ambient (background) groundwater monitoring programs, which includes nitrate data, maintained in the EPA's STORET database: from 1978 to 1990, from 1992 to 1996, and from 2003 to present....
In the fall of 1985, Jacob Rubin and his colleagues presented their vision for the future U.S. Geological Survey National Water Quality Assessment Program (NAWQA). Their strategy involved implementing an extensive monitoring program, supplemented by later studies focused on enhancing geographic assessment and process understanding. An outcome of this vision, the Agricultural Chemicals Team (ACT), initiated studies in 2001 to develop an understanding of the sources, transport, and fate of nutrients and pesticides in agricultural settings. A major goal of ACT has been to estimate the watershed-scale nitrate mass budget in multiple agricultural watersheds: Morgan Creek, MD; Leary Weber Ditch, IN; Maple Creek, NE; and...
Beginning in the 1970's there has been an increase in the public awareness of the quality of surface waters due to the increase of chemicals being applied to farmland and an increase in soil erosion. Nutrient losses associated with agricultural activities have an adverse effect on surface and subsurface drainage water by increasing nitrate, phosphate and dissolved organic carbon (DOC). In recent years there has been more research in comparing conventional till (CT) soil management practices to those of no till (NT) soil management practices. The results of the implementation of NT soil management practices are changes in subsurface drainage, river recharge, and nutrient fluxes. The change in nutrient fluxes associated...
Insight into the connection between erosional processes and nutrient exports is important for designing best management practices for sustainable agriculture and minimizing impacts on water quality. We present a mass balance approach to characterize rill and sheetwash erosion during a June 2004 thunderstorm event in Treynor, Iowa, USA. Observed sediment and radionuclide yields and soil profiles were modeled (Simulation of Rill and Sheetwash Erosion Model, SiRSEM) to solve for the areal extent and depth of rill and sheetwash erosion and from this information calculate sediment and nutrient losses. Results indicate that sheetwash eroded 98% of the plot to a depth of 0.078 mm and rills eroded 1% of the plot to a depth...
The Mississinewa River watershed is located on the heavy clay soil of the central till plain and ranks among the highest levels of impact of agricultural runoff potential in the State of Indiana. Our goal in this project is to determine the greatest areas of sediment loading within the Mississinewa for priority setting and potential funds allocation for conservation practices. To facilitate manipulation of the land use, soils, and topographic data of the watershed, we developed and implemented an ArcView (super R) Geographic Information System (GIS) based sediment-yield model. The model has been validated by in-stream sediment sampling from outlets of four representative 14-digit Hydrologic-Unit-Code (HUC) watersheds...
Understanding the cumulative impact of a suite of simultaneously occurring environmental stresses on stream water quality is essential for developing effective management and restoration strategies at the watershed scale. Although it is well known that land use and geology are the most important factors regulating nutrient concentrations in streams ecosystems, most of the variation in stream chemistry cannot be explained by one of these factors alone, suggesting that these systems are influenced by multiple factors acting at multiple spatial and temporal scales. Furthermore, the combined effect of land use and geology on stream water quality produces more than simply additive impacts and such dynamic is still poorly...
Non-point source pollution is currently the primary threat to riverine water quality in both urban and agricultural settings. Nevertheless, our ability to make better predictions on the fate of urbanized/agriculturally impacted aquatic ecosystems is greatly hindered by our lack of understanding of the relationship between land use change, hydrology and water quality. Here we present water chemistry data from the Clear Fork River, which drains a mixed urban-agricultural watershed in north-central Ohio. The watershed has experienced an increase in urbanization associated with a decrease in farmland. Between 1982 and 1997, urban land increased 22%, while 16% of farmland was lost. At the center of the watershed is the...
The Pearson Creek Watershed (61 km2) drains both the City of Springfield and more rural, agricultural areas. Water quality of the creek is affected by unknown toxicants potentially responsible for the decline in aquatic life. The purpose of this study is to complete an assessment of pollutant concentrations found within the watershed and to support efforts to develop a Total Maximum Daily Load (TMDL) for Pearson Creek. From November 2007 to December 2008, 15 sampling sites were monitored 2 to 3 times per month during both baseflow and runoff conditions. Analtyes of interest included total nitrogen, total phosphorus, total lead, total cooper, total zinc, Escherichia coli, total coliform, and total suspended solids....