Location: Soil Drainage Research2009 Annual Report
1a. Objectives (from AD-416)
The overall multi-location CEAP-WAS project objective is to evaluate and develop cost-effective conservation practices, strategies, and technologies for water management and water quality protection that minimize offsite delivery of sediment, nutrients, and agrichemicals from agricultural, urban, and turf watersheds located in the humid region of the United States. The research at this location is focused on the use of conservation practices and industrial by-products as a means of improving soil and drainage water quality from rural and urban components of the landscape, including turf systems, to minimize its impact on surface public drinking water supplies. This region has unique soil and climate characteristics that make it a highly productive and economically important region. CEAP-WAS objectives in the Upper Big Walnut Creek Watershed include: 1. Measure and quantify the effects of innovative conservation practices, source water protection practices, and land use management on water quality, water quantity, and lotic ecosystems at the field, farm, and watershed scales. 2. Assess and characterize the environmental aspects of urban and golf course turf, including the development and evaluation of management strategies or technologies that utilize industrial by-products to mitigate the potential offsite transport of sediment, nutrients, and pesticides. 3. Develop and apply policy-planning tools to aid selection and placement of conservation practices to optimize profit, water quality, and conservation practice efficiency.
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 quantifing 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. The cost benefit analysis will combine the benefits from a recreational use analysis and additional non-use value estimates of the benefits of water quality improvements with the costs of different types of practices that provide those benefits.
3. Progress Report
The Soil Drainage Research Unit (SDRU) continues to make advances in quantifying the watershed scale environmental and economic impacts of conservation practices as well as assessing and characterizing the environmental aspects of managed turf. The Upper Big Walnut Creek (UBWC) watershed in Ohio is one of 14 benchmark watersheds identified in the Conservation Effects Assessment Project (CEAP) to provide detailed assessments of watershed scale implementation of conservation practices. Within the UBWC watershed, data was collected at 46 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 will aid in answering a variety of environmental and economic questions related to the watershed scale impacts of conservation practices. To date, three years of baseline data and one and one half years of treatment data (precision nutrient management or pesticide management) has been collected from the paired watersheds. Quantification of the impacts of those practices is ongoing. Progress continues on assessing the impacts of herbaceous riparian buffers on fish communities. A hydrologic assessment of different headwater streams within the UBWC watershed was completed. The results highlight the seasonal differences in magnitudes, frequency, and rates of change in headwater hydrology. SDRU scientists collaborated with scientists from Ohio State University and Indiana University-Purdue University Fort Wayne to develop a calibrated model for UBWC and investigate the impacts of agricultural drainage ditches on aquatic ecology. The SDRU continues to make progress toward assessing and understanding the environmental role of turf in the watershed landscape. The Unit is a critical component of the agencies turf/drainage/by-products initiative. Turf sites in Texas, Minnesota, and Ohio have been instrumented and baseline surface and subsurface hydrology and water quality conditions quantified. Progress continues to be made on the development and assessment of inline filters designed to clean drainage waters. Cooperative efforts with industry and other ARS locations are underway to identify, deliver, and implement by-product filters at turf sites.
1. Creation of historical conservation practices database. Implementation of conservation practices is often considered and accepted as the best method for sustaining agricultural production and minimizing nonpoint source pollution. To quantify the effects of conservation practice implementation, information on the temporal and spatial resolution of the practices is required. In collaboration with the Delaware County Ohio Soil and Water Conservation District, a database containing cost-shared practices was created identifying the conservation practice, attributes of the practice (i.e. acreage, length, proximity to water body) and date of installment. The database records date back to 1952. The information contained within the database when used with existing water chemistry and ecology measurements will permit an environmental assessment of the historic practices.
2. Hydrologic impacts of headwater stream channelization. Headwater streams comprise greater than 2/3 of all streams in any given watershed and are critical to biogeochemical processing. Biogeochemical processing is governed by the hydrology of the streams. Many headwater streams in the Midwestern United States have been channelized for agricultural drainage. Understanding the hydrologic impacts of stream alteration is necessary for identifying or designing best management practices aimed at restoring natural flow regimes and/or achieving optimal environmental services. Hydrology data was collected from channelized and unchannelized streams within the UBWC watershed. Differences were noted for several flow response variables that characterized the magnitude, frequency, and rate of change in the measured streams. The differences generally followed a seasonal pattern. Knowing that stream types do possess different seasonal hydrology will aid conservationists, watershed planners, and environmental engineers in developing and selecting conservation practices that account for the differences in hydrology and biogeochemical processing.
3. Developed a calibrated SWAT model for portions of UBWC. In collaboration with Ohio State University, the Soil and Water Assessment Tool (SWAT) was populated with the required physical and management parameters and calibrated for hydrology, crop yield, and nitrogen loss on selected subwatersheds of the UBWC. Additionally, uncertainty was quantified for the most sensitive of the hydrology, crop prediction, and nitrogen loss parameters. Application of the calibrated model will aid selection, placement, and extent of best management practices (BMPs). The impact of a suite of individual and combined practices will be investigated. Collected data is being used to verify the model predictions. Varying degrees of practice adoption and number of practices can also be assessed. The calibrated model is currently being used to perform a cost-benefit analysis for multiple nitrogen management scenarios.
4. Effects of conservation practices on fishes in agricultural drainage ditches. Agricultural drainage ditches are created or modified headwater streams that are managed to remove excess water from agricultural fields. Conflicts between water quality laws and drainage laws have been identified and stakeholders in the midwestern United States are seeking new ways of managing these modified streams. A literature review was conducted to identify the current state of information on ecology of fishes, the influence of conservation practices, and the influence of agricultural contaminants on fishes within agricultural drainage ditches. This literature review identified that most research involving fishes in drainage ditches has documented the negative effects of channelization of existing streams and only limited information is available on the effects of conservation practices intended to provide ecological benefits. Conservation practices that enable the movement of fishes within drainage ditches and those that created needed pool habitat and physical structure are likely to have positive benefits on fish communities. This literature review provides four key concepts that will assist state agencies, federal agencies, and NGOs with developing novel management strategies capable of incorporating environmental considerations into the management of agricultural drainage ditches.
5. Water-chemistry fish relationships provide insights towards designing conservation plans for agricultural watersheds. The ecological effect of conservation practices designed to reduce sediment, nutrient, and pesticide loadings from agricultural activities to streams is unclear due to the lack of evaluations and the limited information on the relationships between water chemistry and fishes. The relationships between water chemistry and fishes within agricultural drainage ditches were documented. The research results suggest that conservation practices intended to reduce nutrient, sediment, and pesticide loadings may only have limited ecological benefits. Thus, those conservation plans that use a combination of conservation practices capable of addressing physical habitat and water chemistry degradation are most likely to provide the greatest benefits for fish communities within these impacted headwater streams. These results provide NRCS, Soil and Water Districts, and other stakeholders guidance for designing conservation plans for agricultural drainage ditches.
King, K.W., Smiley, P.C., Baker, B., Fausey, N.R. 2008. Validation of Paired Watersheds for Assessing Conservation Practices in Upper Big Walnut Creek Watershed, Ohio. Journal of Soil and Water Conservation. 63(6):380-395.