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Riparian Streams - Berks County
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This is a county wide analysis of Berks County waterways to determine riparian buffer values given a 50 ft., 50% canopy coverage requirement. The analysis was done by first overlaying the stream shapefile on the orthophotos. Next a 50 ft. buffer shapefile was derived from the streamlines and added. Using the newly created buffer shapefile as a guide, visual analysis was done for entire shapefile. The canopy coverage percentage was interpreted by Heritage Conservancy and buffer shapefile was used to define the 50 ft. distance requirement. At a scale of 1:2,000, the streamlines were attributed with one of three riparian values (full, half, none). - Full Value: both banks of the stream contain 50% or greater canopy coverage for 50 ft from the stream. - Half Value: only one bank of the stream contains 50% or greater canopy coverage. - None Value: neither stream bank contains 50% or greater canopy coverage. The threshold for determining whether or not a shoreline segment or a stream centerline segment should be used for the analysis was if the waterway was wider than 100 ft for a linear distance of approximately 400 ft. If a waterway was wider than 100 ft. for a linear distance of approximately 400 ft., shorelines would be used rather than stream centerlines. Having the threshold include a 400 ft linear distance requirement made many ponds be represented by a centerline rather than a shoreline. In cases were the original data contained two shorelines to represent a stream that was not greater than 100 ft wide, a new centerline was created by Heritage Conservancy by using the orthophotos and the shorelines as guides. Ponds that were delineated to represent headwaters were not included in this analysis. Analysis and editing would begin at the tributary originating from the pond, but the pond itself would not be given a riparian value. Edits to the shape of the streamline were done when they were visually obvious. The point of this analysis was not to delineate new stream lines, but rather to give existing streamlines riparian buffer attributes. The large majority of the segments are identical to the original Berks County Planning Commission streamlines. Stream and shorelines were cut into segments based on the riparian attribute value. Ten sites were chosen for on-site verification and they were visited in July 2007.