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 Purposes1. 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Regardless of proposed use, maps must be improved Outdated Source data limited by scale and image quality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 doesn’t bring data up-to-date Too generalized Will include many areas where wetlands don’t

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