Presentation on theme: "Use of Maps for Identifying Regulated Wetlands in Vermont Comments by Ralph Tiner U.S. Fish & Wildlife Service."— Presentation transcript:
Use of Maps for Identifying Regulated Wetlands in Vermont Comments by Ralph Tiner U.S. Fish & Wildlife Service
Basic Questions Does the State want to regulate all wetlands or only a subset deemed significant? If latter, what wetlands should really be classified as significant from a function and value perspective? Should size and connectivity be considered? If so, is there any concern about vernal pools and other small wetlands (e.g., bog or fen)?
Comments re: Maps If the State wants to regulate all wetlands, then maps would be strictly for guidance as it is virtually impossible to map all wetlands. If regulating the significant subset, need to know criteria for determining significance…would help in identifying best approach for mapping them.
Options for Using Maps for Regulatory Purposes 1. Show official boundaries 2. Show significant wetlands with boundaries refined on-the-ground 3. Use as guidance only to show locations of areas that may be regulated
Option 1 Maps show official boundaries with minimal changes in the field Best if only looking to regulate wetlands that can be readily mapped through remote sensing How does that relate to significant criteria? Best done with large-scale photography (or digital imagery) but expensive (photography, interpretation, and field verification costs) Still many wetlands will be difficult to delineate with precision
Option 2 Show significant wetlands and refine boundaries on-the-ground May be current practice Informs public on where regulatory wetlands are (generally) Workable, but issues of connectivity and actual boundaries require field resolution Maps need improvement, probably should be liberal as they serve to target areas where project-specific determinations/delineations would be required Need to update maps based on field inspections (GPS)
Option 3 Use maps for guidance only Basic federal regulatory approach All mapped wetlands are potentially significant, need to determine significance on a case-by-case basis Will areas not mapped be regulated if they meet significance criteria? How and who determines this? Alerts the public to potential areas of jurisdiction, but questions remain as to whether wetland is significant or not, and whether areas not mapped are regulated How does one evaluate program effectiveness?
Improved Maps Regardless of proposed use, maps must be improved Outdated Source data limited by scale and image quality and late 1970s knowledge of wetlands Shallow water wetlands were not transferred in preparing the Vermont significant wetlands maps
Goals for Improving Maps Reflect current-day conditions Identify more significant wetlands More accurate boundaries Produce wetland data in digital form for easy updating in future Add Vermont stream locations Make data available online
Option 1 Add hydric soil map units and shallow water wetlands to existing Vermont significant wetland inventory (VSWI) maps Short-term fix doesnt bring data up-to-date Too generalized Will include many areas where wetlands dont exist
Option 2 Use updated NWI data when available to improve VSWI maps Half of state already updated with NWI Will show more wetlands What significant wetlands are missed? No schedule for updating NWI maps for rest of state (State can fund remainder) Can be accomplished in one to two years (if funding is available) Data could be made available online
Option 3 Use updated NWI + undeveloped hydric soil map units to improve VSWI maps Shows wetlands and potential wetlands (lands with potential for regulation) Add Vermont stream data (connectivity) Half of state already updated with NWI Will show more wetlands What significant wetlands are missed? No schedule for updating NWI maps for rest of state (State can fund remainder $440K) Can be accomplished in two years if funding is available Also can update NWI with Vermont 2003 1-m digital imagery or newer photography (added $s)
Option 4 Prepare town-by-town or county-by- county maps Most detailed maps depending on source imagery Town participation (could add to town master plans?) Costly and time consuming State project management and oversight Will take several to many years to complete
Option 5 Update NWI statewide and do detailed mapping in specific areas as needed (combination of Options 3 and 4) Could have statewide 2003-era mapping finished in two years ($700K) Produce detailed data where needed as time and funding permits Can update NWI with newer photography as needed Should do pilot study to compare detailed vs. NWI to understand the difference (product/$).
Option 6 Produce zoning maps showing areas where wetlands may occur and where wetland determinations/delineation will need to be performed Like Option 3 but can be broader Shows public where regulations apply Field evaluations (determinations/delineations) required for any regulated activity in the designated zone
Possible Short-term Solution to Improving VSWI Mapping Within one year: Combine updated NWI maps with undeveloped hydric soil map units and identify significant wetlands For other areas, take original NWI data, add undeveloped hydric soil map units and identify significant wetlands Later Finish updating NWI statewide and bring data up to 2003/4 era and determine if more detailed mapping is required in some areas