Description: This dataset depicts forest patches in Vermont. The dataset is reflective of summer 2016 conditions. The forest patch routine is based off of the 2016 high-resolution land cover tree canopy class. Three sizes of forest patches were delineated: small, medium, and large. In general, small patches consist of individual trees or small clumps containing 2-5 trees. Medium patches are generally comprised of 5-20 trees. Large patches contain 20 trees or greater and have a defined core area. The algorithm used to delineate the patches incorporated size, morphology, and perimeter/edge ratio criteria to define the patches. Size alone was not used as a criterion as narrowly configured groups of trees can connect over relatively large areas when viewed from above. One drawback of the processing approach was that the data had to be tiled to accommodate the billions of pixels in the source tree canopy dataset. As a result, artifacts, principally in the way of abrupt patch class changes exist along tile edges. Users should note that due to the size of the dataset basic display and geoprocessing operations can take a considerable amount of time.
Service Item Id: 7c403fed046c48c4b3f3c381e5c13dee
Copyright Text: Developed by the University of Vermont Spatial Analysis Laboratory with funding from: State of Vermont Clean Water Fund, Vermont Agency of Natural Resources, Vermont Agency of Transportation, Lake Champlain Basin Program, and the Vermont Center for Geographic Information.
Description: For a thorough discussion of the purpose, design and management of the Vermont River Corridors dataset, please see the "Vermont DEC Flood Hazard Area and River Corridor Protection Procedures December 5, 2014" http://www.vtwaterquality.org/rivers/docs/FHARCP_12.5.14.pdf . River corridors encompass an area around and adjacent to the present channel where fluvial erosion, channel evolution and down-valley meander migration are most likely to occur. River corridor widths are calculated to represent the narrowest band of valley bottom and riparian land necessary to accommodate the least erosive channel and floodplain geometry (i.e. equilibrium conditions) that would be created and maintained naturally within a given valley setting. River corridors are developed to facilitate ANR’s responsibilities in providing municipalities, regional planning commissions, and Act 250 District Commissions with technical assistance and information concerning river sensitivity and fluvial erosion hazards. Vermont river corridors include areas where active, potentially hazardous river erosion and deposition process have occurred or are likely to occur. These delineations do NOT indicate that areas outside river corridors, particularly those immediately abutting the river or river corridor are free from fluvial erosion hazards.This dataset is part of the “applicable maps” used in conjunction with other best available stream geomorphic data to implement both the Flood Hazard Area and River Corridor “Rule” and “Protection Procedure.” The data will be updated over time as described in the Procedure. The date of the version posted on the Vermont Natural Resource Atlas indicates the most recent update. Users should cite the Creation Date for the version. Data processing was done using ArcGIS 10.x, Spatial Analyst, and Arc Hydro Tools 2.0. Source and digitized data included VT Meander Centerlines (MCLs), VT Reach Break points, VT Hydrography streams, VT 10-meter DEM, VTHYDRODEM, HUC 8 Basins, VT Roads and Railroads, field-verified Valley Walls and Stream Geomorphic Assessment datasets. This 2019 version is a hybrid of Phase I and II levels of detail. River Corridor polygons are divided by subwatershed breaks and by SGA reach/segment breaks. Attributes include SGAT ID, Stream Name, Drainage Area in square miles, Bankfull width in feet, Channel Multiplier, DMS Channel Multiplier, DMS Channel Width, Erosion Power/Risk and Deposition Power/Risk. Major derived datasets include raster and vector valley walls, catchments per stream reach, variable-width MCL buffers, and the final River Corridor. A Frequently-Asked Questions page is available at: http://floodready.vermont.gov/rcfaq
Service Item Id: 7c403fed046c48c4b3f3c381e5c13dee
Copyright Text: Vermont River Corridor and Floodplain Protection Program
VT Dept of Environmental Conservation, ANR