Location:2012 Annual Report
1a. Objectives (from AD-416):
1)Quantify the ability of best management practices (BMPs) to mitigate the impact of land-use change and extreme climatic events on hydrology and water quality a)Quantify weather and precipitation inputs to watershed models; b)Quantify impacts of land use on runoff and water quality; 2)Quantify the effects of grazing systems on surface runoff and subsurface flow and soil and water quality. 3)Quantify the rate, fate and transport of sediment, nutrients, and agricultural chemicals after implementing agricultural management systems.
1b. Approach (from AD-416):
Precipitation, weather, water-quality, and runoff data will be monitored from experimental watersheds and plots subjected to different conservation, pasture, and land-management practices. Archived data will be used for estimations of baseline and treatment effects, for precipitation studies, and for concept development.
3. Progress Report:
Urbanization: Data were collected on 2 watersheds which each had imperviousness (2000 ft2 roof), and 2 smaller watersheds with plastic to mimic a roadway. Due to lack of rainfall data and funds to construct new roofs, imperviousness was not increased. In one watershed the roof was placed far from the outlet and the other was placed near the outlet. Management-Intensive and Organic Grazing (MIG): Surface runoff, sediment, and subsurface water samples were collected from the MIG & continuous grazing watersheds. Forage species composition, animal health and amino acids in milk, and impact on surface and subsurface water and soil were measured. With adequate rainfall, MIG favors greater forage production and length of grazing period; in drier years, little difference is observed. No differences were observed in the quality of groundwater. The experiment was transitioned into an organic grazing system which uses poultry litter instead of mineral fertilizer. Precipitation/climate studies: A new storm modeling concept is being tested, wherein both storm depth and storm duration are being modeled simultaneously. To understand how to adjust beginning times of storms (BTS) within a day, an investigation of spatial monthly BTS was made. BTS distribution changed between unimodal and bimodal and BS can be estimated from a nearby rain gauge. Studies of improved simulation of intensities within storms and probabilistic precipitation patterns were started. While times between storms can be estimated using monthly precipitation, storm depth parameter estimation has not yielded a simple relationship. Preliminary analysis of air temperature shows an increasing trend since 1979. Evaluation of climate effects must be completed prior to exploring further parameter relationships for simulating storms. An effect of climate change on times between storms was found the NAEW, but more regional data require more preparation to determine regional effects. Soil carbon: Soil sampling and analysis were performed to compare impacts of various land management practices on soil organic carbon & soil properties. Manure plots: For initial winters of this project, beef slurry manure was applied to 4 plots when the ground was frozen; Two ~2-acre small watersheds received liquid swine manure; 2 watersheds received turkey manure; and 2 watersheds were controls. “Dustpan” samplers were installed at the lower edge of the application areas and below the application area on plots. Runoff samples were collected and analyzed for nutrients, E. coli, and enterococci. Starting the 4th winter, only swine manure was used. Filter socks: Filter socks were treated with a proprietary sorbent, compost, and biochar downstream in channels from watersheds growing corn. Pesticides, sediment, common ions, and nutrients were measured. BMP evaluations: This study required much data checking of runoff and precipitation data prior to investigations which was completed. Studies of the low end of flow duration curves suggest that a Box-Cox transformation may work well but more study is needed to include this finding with quantifying other components of the entire curve.
Owens, L.B., Barker, D.J., Loerch, S.C., Shipitalo, M.J., Bonta, J.V., Sulc, R.M. 2011. Inputs and losses by surface runoff and subsurface leaching for pastures managed by continuous or rotational stocking. Journal of Environmental Quality. 41(1):106-113.