Riparian Management for Water Quality, the Bear Creek Example: Getting the Message Out

While a considerable body of evidence confirms that exiting vegetated streamside zones can be effective sinks for nonpoint source pollution (Castelle et al. 1994, Osborne and Kovacic 1993, Lowrance 1992, Cooper et al. 1987, Jacobs and Gilliam 1985, Lowrance et al. 1985, 1984, Peterjohn and Correll 1984), little information is available for restored or constructed streamside buffer systems. To demonstrate the benefits of properly functioning riparian zones in the heavily row-cropped midwestern U.S., the Agroecology Issue Team of the Leopold Center for Sustainable Agriculture and the Iowa State Agroforestry Research Team (IStART) are conducting research on the design and establishment of integrated riparian management systems. The purpose of these systems is to restore the essential ecological functions that these riparian areas once provided. Specific objectives of such buffers are to intercept eroding soil and agricultural chemicals from adjacent crop fields, slow flood waters, stabilize streambanks, provide wildlife habitat, and improve the biological integrity of aquatic ecosystems

Improving Soil and Water Quality with Riparian Buffers

The agricultural landscape has four major sources of non-point source (NPS) pollutants. These are: 1) surface and subsurface runoff which carry sediment and agricultural chemicals to streams; 2) eroding streambanks which can contribute more than fifty percent of the sediment load to the stream; 3) field tile drains which contribute the highest concentrations of soluble agricultural chemicals to streams; and 4) livestock grazing of streamside or riparian areas which contribute to bank instability and add animal waste and pathogens to the water. Maintaining or establishing a forested or prairie buffer along streams and rivers provides more than just a beautiful landscape. While a considerable body of evidence confirms that existing vegetated streamside zones can be effective sinks for NPS pollution (Castelle et a!. 1994, Osborne and Kovacic 1993, Lowrance 1992, Cooper eta!. 1987, Jacobs and Gilliam 1985, Lowrance eta!. 1985, 1984, Peterjohn and Correll 1984), little information is available for restored or constructed streamside buffer systems. Designing and establishing the right combination of native trees, shrubs and grasses as buffer strips and integrating them with constructed wetlands, soil bioengineering and rotational grazing can improve water quality

Identifying Riparian Zones Best Suited to Installation of Saturated Buffers: A Preliminary Multi-Watershed Assessment

Saturated riparian buffers are a new type of conservation practice that divert subsurface tile drainage water from direct discharge to surface water into distribution pipes that discharge the tile water into riparian soils. This enables natural processes of biological uptake and denitrification to decrease nutrient loads that are being lost from croplands via tile drains, reducing water quality impacts from agriculture at relatively little cost. This chapter suggests and evaluates draft criteria that identify riparian zones within a watershed that are suited to installation of saturated buffers. Soils criteria, evaluated using soil survey information, include subsurface accumulations of soil organic matter (SOM) (\u3e 1% SOM at 0.75–1.2 m depth), relatively fine-textured subsoils (\u3c 50% sand at 0.75–1.2 m depth), and a shallow water table (\u3c 1 m depth) April through June. These criteria highlight riparian locations where soil conditions should enhance nutrient removal. Criteria are also proposed to avoid locations where streambank failure and/or inundation of crops adjacent to the buffer may occur, which are evaluated using high-resolution digital elevation models, now widely available through LiDAR (light detection and ranging) surveys. The criteria were evaluated in three Midwestern HUC-12 watersheds dominated by fine-grained glacial deposits. Results showed topographic criteria were more restrictive than soils criteria, especially in the flattest landscapes, but 30 to 60% of streambank lengths in the test watersheds were deemed suitable to installation of saturated buffers. This evaluation contributed to inclusion of a saturated buffer siting tool in the Agricultural Conservation Planning Framework (ACPF). Local information is needed to design this practice to fit site conditions