Page Banner

United States Department of Agriculture

Agricultural Research Service


Location: Soil Drainage Research

2012 Annual Report

1a. Objectives (from AD-416):
1. Measure and quantify water quality, water quantity, and soil quality effects of innovative conservation and source water protection practices as well as different land use management at the field, farm, and watershed scale for the Upper Big Walnut Creek and other appropriate watersheds. 2. Develop and validate watershed scale water quality models and quantify the uncertainties of model predictions at field, farm, and watershed scales for the Upper Big Walnut Creek and other appropriate watersheds. 3. Develop models and decision support tools to determine the efficacy of management and land use options under conditions of changing climate.

1b. Approach (from AD-416):
Quantify the influence of conservation practices and land use on the water chemistry and hydrology of agricultural drainage ditches and streams in the Upper Big Walnut Creek watershed using a before-after-control-impact (BACI) paired watershed design. Two pairs of watersheds, one pair characterized as drainage ditches and one pair characterized as streams, have been identified and instrumented with flumes and automated samplers. Discharge and water samples will be collected automatically via Isco equipment. To quantify how much the loading to headwater streams is reduced by watershed scale adoption of nutrient and pesticide management practices, water samples will be collected using both time and flow proportional sampling. The samples will be analyzed for nutrients using colorimetric flow injection analysis and for pesticides using gas chromatography and ELISA. Apply a calibrated watershed scale model to aid selection, placement and extent of BMPs. Determine the impact of conservation practices on aquatic communities in lotic ecosystems by measuring and quantifying in-stream habitat (water depth, velocity, wet width, and substrate types), in situ water chemistry measurements (dissolved oxygen, pH, conductivity, water temperature), and aquatic communities in each site three times a year in the spring, summer, and fall for the duration of the study. Conduct field experiments to determine the influence of herbaceous riparian buffers on the physical habitat and aquatic communities in agricultural drainage ditches. Geomorphology and riparian habitat will be sampled once a year, while in-stream habitat, water chemistry, and aquatic communities will be sampled at least three times a year for two years. Laboratory, field, and modeling approaches will be used to assess and characterize the environmental aspects of urban and golf course turf, including the development and evaluation of management strategies and/or technologies. Before – after watershed scale studies will be used to quantify the fate and transport as well as aid in the determination of the processes and management controlling the fate and transport of nutrients, pesticides, and sediment from turf environments and urban landscapes. Laboratory studies, replicated plots, and paired field sites will be used to evaluate innovative technologies, strategies and/or management practices.

3. Progress Report:
The Soil Drainage Research Unit (SDRU) continues to advance understanding of the watershed scale environmental and ecologic impacts of conservation practices as well as assessing and characterizing the environmental aspects of managed turf. Within the Upper Big Walnut Creek (UBWC) watershed, data is collected at nearly 50 nested and paired sites representing surface and subsurface discharge, channelized and unchannelized watersheds, agricultural and urban land uses, and forested and herbaceous riparian buffer areas. These sites are representative of agricultural and urban areas in the Eastern Corn Belt and span an array of spatial scales. We are quantifying the impacts of conservation practices offered through the National Resource Conservation System (NRCS) Environmental Quality Incentive Program (EQIP) as well as those not yet cost shared through the program (i.e. end-of-tile filters) on discharge, nutrients and pesticides. We are investigating the differences in channelized and unchannelized ecological indices and habitats. Additional research has been initiated to investigate the environmental role of managed urban turfgrass. Lifetime Summary of Project: The SDRU established a watershed scale outdoor research facility, representative of different scales and land use practices and validated the paired watershed approach within the UBWC. We developed sampling protocols for assessing ecological effects of conservation practices throughout the ARS Conservation effect Assessment Project (CEAP) watersheds. We made significant progress and contributions toward quantifying hydrology, water quality, and ecological impacts of surface and subsurface drainage and best management practices from agricultural and urban landscapes. Within the agricultural landscape we evaluated hydrologic impacts of stream channelization, quantified the benefits of pesticide management and stream side buffers. We identified the need to pair grass filter strips with other conservation practices to improve water quality in agricultural headwater streams. We investigated water-chemistry fish relationships and provided the insight that the relationship should have on developing and selecting conservation practices, examined the influence of riparian habitat type on aquatic community colonization, and documented the public health risks posed by channelized streams. We contributed to the development of computer simulation tools and databases. A database of all known conservation activities and installed practices was jointly established with the local soil and water conservation district permitting an inventory of conservation practices to be related to collected water quality and ecological data. In the urban landscape we determined the role that managed turf has in transporting agricultural chemicals in surface and subsurface discharge as well as investigated best management practices for managed turf. Additionally we evaluated an end of tile filtration system that utilizes industrial by-products.

4. Accomplishments
1. Special Environmental Quality Incentive Program (EQIP) reduced atrazine in reservoir. We demonstrated the effectiveness of a National Resources Conservation Service (NRCS) special EQIP addressing atrazine in a drinking water supply reservoir. Atrazine is a popular and economical corn herbicide that has a history of exceeding drinking water standards in many supply reservoirs of the upper Midwest. The NRCS EQIP program was utilized to incentivize operators to adopt one of four practices aimed at reducing atrazine in the drinking water supply reservoir. ARS research demonstrated that the combined effect of adopting these practices was a significant reduction of atrazine in the reservoir. The findings also confirmed the economic viability of the program. For every dollar spent in EQIP practice incentives a $2.04 savings was realized for the City of Columbus downstream water treatment facility.

2. Conservation plans need stream physical habitat focus. We identified conservation plans for watersheds containing channelized agricultural headwater streams need to address both physical and chemical habitat degradation. Ecological evaluations of grass filter strips (CP21) and atrazine reduction practices (NRCS practice #595) within channelized agricultural headwater streams (i.e., agricultural drainage ditches) in the Upper Big Walnut Creek watershed documented that implementation of these conservation practices does not influence physical habitat, water chemistry, or the fishes within these degraded streams. These results are concordant with concurrent assessments of fish-habitat relationships that indicate physical habitat has a greater effect on fishes than water chemistry within these small streams (watershed sizes < 8.1 km2). Overall, our results suggest that conservation plans for channelized agricultural headwater streams in the Midwestern United States need to implement conservation practices capable of addressing both physical habitat degradation and poor water quality. This information can be used by state, federal, and private agencies responsible for managing agricultural watersheds and restoring streams.

3. Out of bank flow model calibrated. Working with Ohio State University researchers, we identified the frequency and extent of floodplain interaction on a tributary of Upper Walnut Creek (UBWC). Floodplain interaction has been shown to be important for both nutrient retention and cycling as well as ecological diversity. A tributary of UBWC was surveyed and monitored for one year to determine the frequency and extent of floodplain interaction. The findings were used to populate a computer model to project the number of out of bank flows, and support the movement for development of two-stage ditch design. This knowledge is especially useful to NRCS and to other environmental organizations in developing innovative technologies and practices for improving stream water quality.

Review Publications
Sujithkumar, S., King, K.W., Witter, J.D., Sohngen, B.L., Fausey, N.R. 2011. Importance of crop yield in calibrating watershed water quality simulation tools. Journal of the American Water Resources Association. 47(6):1285-1297.

Last Modified: 2/23/2016
Footer Content Back to Top of Page