Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2010
Publication Date: 4/4/2010
Citation: Piechnik, D., Goslee, S.C., Veith, T.L. 2010. Assessing performance of conservation-based best management practices: coarse vs. fine-scale analysis. In: Laband, D.N., editor. Emerging Issues along Urban-Rural Interfaces III:Linking Science and society, April 4-7, 2010, Atlanta, Georgia. p. 183.
Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Animal agriculture in Spring Creek watershed of Central Pennsylvania contributes sediment to the stream and ultimately to the Chesapeake Bay. Best Management Practices (BMPs) such as streambank buffers are intended to intercept sediment moving from heavy-use areas toward the stream. Water quality and sediment loads were studied within two treatment sub-watersheds with conservation BMPs applied to 91% and 61% of farms along the stream (BMP1 and BMP2), and one unmodified reference sub-watershed (REF). Land-use mapping within a 100m stream buffer from aerial photography for the three sub-watersheds covered an area of 1,980 ha (40% agricultural use). Percentage of agricultural land-use for each sub-watershed was 46% (BMP1), 37% (BMP2), and 17% (REF). Total hectares for each sub-watershed was 625 ha (BMP1), 699 ha (BMP2), and 653 ha (REF). Percentage of woodland area per sub-shed was greatest within the REF sub-shed at 45% (377 ha), while the +BMP sub-watersheds had less forested area (BMP1: 19%, 159 ha; BMP2: 36%, 306 ha). Residential, commercial, and transit land-use were similar for all sub-watersheds. Flow paths calculated from coarse- (USGS 30-m DEM) and medium- (10m DEM) and fine-grain (1m DEM) topographic data were overlain on landuse and BMP- placement maps. Flow pathways derived from 1m DEM data show considerably more potential source-to-stream links than do those from the USGS data. Not all buffers are placed to block movement along these flow pathways; fine-scale drainage networks are not typically considered when placing BMPs. Where fine-scale DEMs are available, efficacy of new BMP locations might increase by considering and including such drainage pathways. LiDAR DEMs are available for Pennsylvania through the PAMAP program to be used in plans to reduce agricultural sediment and nutrient loadings into local watersheds and ultimately the Chesapeake Bay.