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Riparian Zones and Water Quality in the Cache River Watershed. Karl Williard Professor Department of Forestry Southern Illinois University Carbondale NSF Noyce Master Teacher Fellowship Program January 31, 2012. Water Quality.
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Riparian Zones and Water Quality in the Cache River Watershed Karl Williard Professor Department of Forestry Southern Illinois University Carbondale NSF Noyce Master Teacher Fellowship Program January 31, 2012
Water Quality Dr. Karl W.J. WilliardProfessor of Forest Hydrology and Watershed Management • Courses Taught: • FOR 430: Watershed Management • FOR 429: Watershed Management Field Lab • FOR 402: Forest Hydrology • FOR 502: Adv. Watershed Hydrology & Mgmt. • FOR 100: Introduction to Forestry • Research Interests: Nitrogen, phosphorus, and sediment attenuation in riparian buffer zones; water and soil quality in agricultural watersheds; impacts of forest road construction and harvesting on erosion and sedimentation; water quality impacts of invasive, exotic plants.
Riparian Buffer Zone Definition • Transitional land area between terrestrial and aquatic habitats (ecotone) • Agricultural Watersheds • Riparian buffer (trees) • Filter strips (grasses) • Forested Watersheds • Streamside management zone • Typical Width • 30 – 100 feet, depending on slope of land and size of stream
Why are Riparian Buffers Important? • Trap sediment and nutrients in surface runoff • Process nutrients in groundwater • “The last line of defense” – like having a great free safety on your football team • Stabilize stream banks • Shade streams • Provide carbon, large wood to streams • Provide wildlife habitat
Illinois Land Cover 74 % of the state is in agriculture Second only to Iowa
Riparian Buffers in Agricultural Watersheds • Agricultural areas present unique challenges in terms of riparian zone management. • The main challenge is to convince farmers it is a wise choice to take riparian land out of production and put in perennial herbaceous and woody vegetation. • Vehicles to help aid in farmers in their economic decision. • 50-100% cost-share programs – riparian buffers, filter strips, streambank fencing • Conservation Reserve Program (CRP)
Benefits of Riparian Buffer Zones for Farmers • Diversify income – hunting leases, timber, maple syrup • Maintain more topsoil on their property • Promotes good land stewardship/environmental benefits
Relation to Regional Issues – Gulf Hypoxia Summer phytoplankton conditions along the Gulf Coast – 2002-2004 (NOAA)
Features of Riparian Areas in Southern Illinois • Bottomland hardwoods • Presence of unique native species; giant cane (Arundinariagigantea)
Quantifying nutrient and sediment attenuation capacities by riparian zone vegetation • Peterjohn and Correll (1984) found that riparian forests on Maryland’s Rhode River watershed retained 80% of the phosphorus and 89% of the nitrogen from an adjacent agriculture field. • Lowrence et al (1984) calculated that 68% of incoming N and 30% of incoming P were retained by a riparian forest on the coastal plain of Georgia. • Schoonover and Williard (2003) found that 82 to 97% of incoming ground water nitrate was retained in the first 20 feet of giant cane and forest buffers in southern Illinois. • Cooper et al. (1987) estimated that 84 to 94 % of the sediment from cultivated fields were retained by a riparian zone on the coastal plain of North Carolina. • Peterjohn and Correll (1984) calculated that a 50 m riparian zone removed 11 kg of organic N, 1 kg of ammonium-N, 3 kg of nitrate-N, and 45 kg of particulate P per hectare in one year from overland flow. An additional 45 kg/ha/yr of nitrate-N was removed from subsurface flow in the Rhode River watershed. • Peterjohn and Correll (1984), Jacobs and Gilliam (1985), and Schoonover et al. (2005 ) showed that most nitrate and sediment removal occurred within the first 3-20 m of the forest-field boundary.
Importance of Type of Surface Runoff Entering Buffer Sheet Flow Concentrated Flow
What proportion of an agricultural field is drained by concentrated flow? • Ryan Pankau – M.S. Thesis at SIUC 2010 • Intensive surveying of 10 agricultural fields to create detailed digital elevation models and drainage areas of concentrated flow channels
Concentrated Flow Paths: Drainage Area Calculation • 82 – 100% of the fields were drained by concentrated flow
Concentrated Flow Path Development Model – 2 pathways (Pankau et al. 2011) -CFPs enlarge -Majority of field drained by concentrated flow Sheet Flow -Ideal field conditions Deposition of sediment in vegetated riparian buffer CFP formation through buffer Berm Formation Concentrated Flow -From field
USDA NRCS Conservation Innovation Grant Project • Research and demonstration project to address concentrated flow • 2 headwater agricultural watersheds in southern Illinois • Row-crop agriculture (corn and soybean rotation)
Variable Width Riparian Buffers 40’ Switchgrass Big Bluestem 40’ 120’ Switchgrass Big Bluestem Switchgrass 60’ 20’ Switchgrass and Winter Wheat 20’
Buffer Blocks • Stiff stemmed grasses to slow and spread concentrated flow • Cave-in-Rock Switchgrass, Big Bluestem • Establish hedges • Largest concentrated flow paths may require rock installation to help stabilize area for grass establishment • Dormant season planting – Mar. 2012 Switchgrass Big Bluestem
Riparian Zone Journal Articles • Dosskey, M.G. 2001. Toward quantifying water pollution abatement in response to installing buffers on crop land. Environmental Management. 28(5):577-598. • Hill, A.R. 1996. Nitrate removal in stream riparian zones. J. Environ. Qual. 25:743-755. • Jordan, T.E., Correll, D.L., and D.E. Weller. 1993. Nutrient interception by a riparian forest receiving inputs from adjacent cropland. Journal of Environmental Quality. 22:467-476. • Lee, K.H., Isenhart, T.M., and R.C. Schultz. 2003. Sediment and nutrient removal in an established multi-species riparian buffer. Journal of Soil and Water Conservation. 58:1-8. • Lowrance, R., Todd, R., Fail Jr., J., Hendrickson Jr., Ole, Leonard, R., and L. Asmussen. 1984. Riparian forests as nutrient filters in agricultural watersheds. BioScience. 34(6):374-377. • Pankau, R.C., J.E. Schoonover, K.W.J. Williard, and P.J. Edwards. Concentrated flow paths in riparian buffer zones of southern Illinois. Agroforestry Systems. In Press. 2011. • Peterjohn, W.T. and D. Correll. 1984. Nutrient dynamics in an agricultural watershed: observations on the role of a riparian forest. Ecology. 65:1466-1475. • Schmitt T.J., Dosskey, M.G., and Hoagland, K.D. 1999. Filter strip performance and processes for different vegetation, widths, and contaminants. J. Environ. Qual. 28, 1479-1489. • Schoonover, J.E., K.W.J. Williard, C.R. Blattel, and C.M. Yocum. 2010. The utility of giant cane as a riparian buffer species in southern Illinois agricultural landscapes. Agroforestry Systems 80:97-107. • Schultz RC, Isenhart TM, Simpkins WW, Colletti JP. 2004. Riparian forest buffers in agro ecosystems- lessons learned from the Bear Creek Watershed, central Iowa, USA. Agroforestry Systems 61: 35-50.
Contact Information Karl Williard (618) 453-7478 (o) williard@siu.edu 192A Agr. Bld., SIUC