PREP Reports & Publications
The Complex Systems Research Center at the University of New Hampshire enhanced the GRANIT Data Mapper (http://mapper.granit.unh.edu) by incorporating data describing shoreline buffers in New Hampshire. The project supports an ongoing, comprehensive New Hampshire Estuaries Project (NHEP) outreach initiative that seeks to educate municipal decision-makers about the importance of stream buffers in preserving water quality in coastal New Hampshire. It complements these existing outreach efforts by allowing coastal managers, local land use boards, and the general public to readily visualize the spatial extent of current and/or proposed shoreline regulations in their community. The primary data source for the analysis was the high-resolution New Hampshire National Hydrography Dataset (NHHD). Using standard GIS tools, six concentric buffers incrementing in 50’ widths from 50’ to 300’ were generated around stream and shoreline features recorded in the NHHD. To provide the greatest flexibility to users, two data sets were generated at each buffer increment – one representing shorelines and streams classified as either perennial or intermittent, and the second comprising shorelines and only streams classified as perennial. The resulting buffers were merged with the GRANIT surface water data, and acreage by town and subwatershed was calculated for each buffer category. The shoreline buffer data sets were added to the water resources theme of the Data Mapper, thereby providing the public with the ability to view buffers of varying widths in the context of other data layers (including aerial imagery) available through the viewing tool. The associated acreage data tables were added to the water resources theme tool tab. Findings indicated that aggregated at the HUC-12 level, almost 24,000 acres within the Coastal Basin were covered by 50’ buffers when perennial and intermittent streams as well as shorelines were buffered, with over 133,000 acres covered by 300’ buffers. When only perennial streams and shorelines were considered eligible for buffering, the totals declined to just under 17,000 acres (50’ buffers) and over 96,000 acres (300’ buffers).
Piscataqua Region Estuaries Partnership
New Hampshire Estuaries Project
Rubin, Fay A. and Justice, David G., "Shoreland Buffer Module for GRANIT Data Mapper" (2006). PREP Reports & Publications. 167.