1a. Objectives (from AD-416)
The Natural Resources Conservation Service (NRCS) and the Agricultural Research Service (ARS) have agreed to work together, as part of the national Conservation Effects Assessment Project (CEAP) initiative to quantify the environmental benefits of conservation practices at the watershed scale. The project plan detailed in this document represents one of 12 ARS CEAP watersheds established under the national CEAP initiative to address conservation and environmental research issues. Objectives of the project are to: 1) develop and implement a data system to organize, document, manipulate, and compile water, soil, management, and socio-economic data for assessment of conservation practices at field, farm, and watershed scales for the Mark Twain Lake watershed; 2) measure and quantify water quality, water quantity, and soil quality effects of conservation practices at the field, farm, and sub-watershed scale for the Mark Twain Lake; and 3) validate models, quantify uncertainties in model output, and conduct analyses with hydrologic models at field, farm, and watershed scales, and develop methodologies and decision support tools for application on watersheds within the Mark Twain Lake watershed.
1b. Approach (from AD-416)
This research will focus on developing tools and techniques to quantify the impact of implementing conservation practices within a watershed in the most economically efficient manner to achieve sustainable and targeted reductions of nutrients, sediment, herbicide, and pathogen loadings to the Salt River/Mark Twain Lake basin. The research encompasses the following approaches: 1) participation in the development of the STEWARDS database; 2) conduct water quality monitoring to characterize the hydrologic balance and nutrient/chemical loading to Mark Twain Lake; 3) conduct studies at field and plot scales to determine the effectiveness of various conservation practices and cropping systems to reduce nutrient, sediment, and herbicide transport; 4) develop a real-time PCR (RT-RCR) method for quantitation of pathogenic water-borne bacterial species; 5) use the SWAT model to evaluate conservation practices and conservation systems abilities to reduce nutrient, sediment, pesticide, and pathogen loadings in agricultural watersheds; and 6) apply the SWAT model to improve surface water quality assessment and planning.
3. Progress Report
In 2009, cooperation between ARS and Environmental Resources Coalition (subsidiary of Missouri Corn Growers Association) staff facilitated efficient springtime re-installation of the Salt River monitoring network, which was in place by early April 2009. In collaboration with ERC, two field studies initiated in 2008, both dealing with remediating water from Parallel Terrace Outlets (PTO), have continued. One study utilizes grass buffers and the other wetlands. The wetland study was inundated by flooding in 2008 and re-established in 2009. Last year, the CSWQRU Water Quality Lab received 1,115 CEAP and 149 PTO samples for nutrient, herbicide, and sediment analyses. Other CEAP activities in 2009 involved continuation of a streambank erosion project at 33 sites located in Crooked and Otter Creek watersheds in the Salt River Basin. Treatments include stream order (1st through 3rd) and adjacent land use (cropped, riparian forest, forest, and pasture). Another related activity involves the application and validation of a risk assessment tool for vulnerability to pesticide transport on two contrasting watersheds (Youngs Creek, a claypan watershed; and Bonne Femme Creek, a karst watershed). Substantial improvements to the model have been achieved in 2009 in properly assessing risk for soils with restrictive clay layers. The risk assessment tool will determine the vulnerability of different herbicides to losses by leaching, solution runoff, and particle-adsorbed runoff. In addition, the Missouri CEAP completed the upload of watershed data to STEWARDS in 2009. The PAS work has been continued under this project, with five years of field data collected. On-going PAS management this year included planting and harvest of a cover crop, waterway stabilization, plant residue maintenance with no-till, targeting of crops to match the soil resource, and variable-rate nutrient applications. Soil sampling to assess quality changes since the inception of the PAS project was conducted. Analysis of recreation lake water for specific human gut bacteria (Bacterioides sp.) revealed that detection was correlated with dates when intensity of human activity was high compared with dates of lower recreational use. The molecular methods developed for detection will be used for advanced quantitation with the RT-PCR approach. Results are important because we have a more accurate tool for specifically detecting human sources of waterborne pathogen contamination in water bodies. On-going modeling activities in the Mark Twain watershed included development and calibration of field and watershed models. Modeling revealed the sensitivity of water quality to the timing of field operations and to management in field areas with shallow top soil. Grower meetings continued, with the goal of implementing an incentive-based approach to BMP adoption in Goodwater Creek. The incentive-based approach will require the acquisition of grant funds to be used for fully testing the risk assessment tool at the field level and for payments to farmers willing to implement BMPs to address water quality issues.
1. Overview of the Missouri Conservation Effects Assessment Project. 1) The Mark Twain Lake/Salt River Basin was selected as one of 12 USDA-Agricultural Research Service benchmark watersheds for the Conservation Effects Assessment Project (CEAP) because of documented soil and water quality problems and broad stakeholder interest. 2) The basin is characterized by the predominance of claypan soils that result in especially high vulnerability to soil erosion and surface transport of herbicides. 3) Results from cropping system best management practice (BMP) studies showed that no-till cropping systems did not reduce surface runoff compared to tilled systems and led to increased transport of soil-applied herbicides. 4) Grass filter strip studies showed that warm and cool season grasses can reduce herbicide transport in surface runoff. 5) A major challenge in the claypan region is the need to develop cropping systems that incorporate soil-applied herbicides yet minimize soil erosion. 6) Current and future research efforts will continue to focus on BMP studies, development of needed tools to improve watershed management, and refinements in the calibration and validation of the Soil and Water Assessment Tool (SWAT) model. Refereed Publication serving as basis for accomplishment: ARIS # 213177.
2. Habitat vegetation of seasonal wetlands changes under flooding with wastewater effluent. Soils from seasonal wetlands established within a wildlife management area using municipal wastewater effluent (WWE) were assessed for seedbank composition to determine effects on subsequent plant community structure. Vegetative taxa richness, plant density, and biomass were significantly reduced in WWE-irrigated soils compared with Missouri river water; salinity and sodicity also increased with WWE and was linked to inhibition of germination or seedling growth of many plant species. Results are important because potential detrimental effects on wildlife habitat due to use of WWE for seasonal wetland management are documented as well as demonstrating a need for strategies to overcome such effects of an otherwise attractive application of a waste treatment by-product for environmental conservation. Refereed Publication serving as basis for accomplishment: ARIS # 258544
3. Modeling Flow and Pollutant Transport in a Karst Watershed with SWAT. The Soil and Water Assessment Tool was assessed for its ability to simulate stream flow and water quality in a karst watershed. Changes were introduced to simulate the rapid transport of water and pollutants through sinkholes and losing streams. These changes improved the partition between surface and groundwater flow, which is particularly critical in karst geologic contexts. Results demonstrate that SWAT can be used to compare risks of contamination from different management strategies in karst areas, thus extending applicability of an important ARS decision support tool to include these environmentally vulnerable regions of the country. Refereed publication serving as basis for accomplishment: ARIS # 231559
5. Significant Activities that Support Special Target Populations
On the waterborne pathogen research study, ARS mentored a minority graduate student who was a University of Missouri McNair Scholar, which recognizes outstanding African-American students.
Sadler, E.J., Steiner, J.L., Chen, J., Wilson, G.J., Ross, J.D., Oster, T., James, D.E., Vandenberg, B.C., Hatfield, J.L. 2008. Sustaining the Earth's Watersheds-Agricultural Research Data System: Data development, user interaction, and operations management. Journal of Soil and Water Conservation. 63(6):577-589.