Submitted to: Agroforestry Systems
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/17/2008
Publication Date: 6/16/2008
Citation: Tomer, M.D., Dosskey, M.G., Burkart, M.R., James, D.E., Helmers, M.J., Eisenhauer, D.E. 2008. Methods to prioritize placement of riparian buffers for improved water quality. Agroforestry Systems. Available: http://www.springerlink.com/content/p316k5622l171003. Interpretive Summary: Conservation practices will not be equally effective in all locations. Therefore mapping techniques that help land managers and conservation planners identify where conservation practices are most likely to be effective should be developed and demonstrated. This work demonstrated two mapping techniques that can assist conservation planning by identifying where riparian buffers are most likely to be effective in trapping runoff and sediment, and/or remove contaminants from ground water. One technique used soil survey information and applied a riparian model to rank and map soil map units for their capacity to trap runoff. The other calculated terrain indices that indicate potential buffer effectiveness through analysis of topographic data. The methods are not duplicious, consider complementary information, and can be applied at similar mapping scales that are used in conservation planning. Results are of interest to conservation planners and practitioners who recognize the need to target conservation practices but do not have planning tools to enable consistent and effective targeting.
Technical Abstract: Riparian forest buffers can improve stream water quality, provided they intercept and remove contaminants from surface runoff and/or shallow groundwater. Soils, topography, hydrology, and surficial geology determine the capability of forest buffers to intercept and treat these flows. This paper describes two landscape analysis techniques for identifying and mapping locations where forest buffers can effectively improve water quality. One technique employs soil survey and climate information to rate soil map units for how effectively a buffer would treat runoff. Results allow soil map units to be compared for relative effectiveness of buffers for improving water quality and, thereby, to prioritize locations for buffer establishment. A second technique uses topographic and stream-flow information to help identify specific locations where buffers are most likely to intercept water moving towards streams. For example, a wetness index, an indicator of potential soil saturation on given terrain, identifies where buffers can readily intercept surface runoff and/or shallow groundwater flows. Maps based on this index can be useful for site-specific buffer placement at farm and small-watershed scales. A case study utilizing this technique shows that riparian forests likely have the greatest potential to improve water quality along first-order streams, rather than larger streams. Some locations are better than others for improving water quality using riparian forest buffers. These landscape analysis techniques use public data and produce results that are broadly applicable to identify priority areas for riparian buffers. The information can guide projects and programs at scales ranging from farm-scale planning to regional policy implementation.