Critical Area Mapping Update on Pilot Project

1
Critical Area MappingUpdate on Pilot Project

• Local Critical Area Planners
• Quarterly Meeting
• October 23, 2008

2
Critical Area MappingExisting Maps Arent Current

• Existing paper maps are 20 years old
• Maps were never ortho-rectified or georeferenced
• Methodologies varied
• Maps of municipalities are inadequate
• Shoreline and wetland changes have occurred
• Sea level rise has affected wetland acreage

3
Critical Area MappingBetter Graphic Information

• Electronic maps need to match the landscape
• Need to be web accessible
• Shoreline and edge of wetlands should be based on
  current data
• 1,000 boundary should be digitally created and
  georeferenced

4
HB 1253 Includes Mapping Provisions

• Requires change from Critical Area as delineated
  on 1972 Wetlands Maps to Critical Area as
  delineated on Statewide Base Map
• Aerial imagery from 2007 2008 is Base Map
• Boundary to be accurate to a scale of 11200 (1
  100)
• Shoreline and edge of wetlands to be identified
  by the State with local input
• Imagery, CIR imagery, 1972 Wetlands Maps, DNR
  Wetlands Maps are being used

5
HB 1253 Includes Mapping Provisions

• Consistent methodology and source data to be used
  in all jurisdictions
• CA Boundary to be digitally generated and
  georeferenced
• Edge match problems among jurisdictions will be
  eliminated
• Pilot project to be used to determine procedures,
  identify source documents, and facilitate the
  development of regulations
• Regulations will address many aspects of the
  mapping effort
• Mapping methodology
• Shoreline/wetland changes
• Designation of new areas added into the
  Critical Area
• Property owner notification

6
Mapping IssueOpen Water Areas Filled

• Determine if fill was legally permitted
• Use aerial imagery to determine boundary of
  upland
• CA boundary adjusted appropriately (waterward)
• Land area to be classified based on time of fill,
  permit requirements, justification, and land use
  as of original mapping date or July 1, 2008

7
Open Water Areas FilledHart-Miller Island

• Islands eroded over time and are being restored
• State lands
• Will be classified as not intensely developed and
  will generate growth allocation

8
Mapping IssueAreas Excavated New Tidal Waters

• Determine if excavation was legally permitted
• Use aerial imagery and other source data to
  determine boundaries of open water and wetlands
• CA boundary adjusted appropriately (inland)
• Mapping software will determine acreage changes
  in RCA, LDA, or IDA

9
Mapping IssueNatural Changes in Wetlands

• Areas of wetlands converted to open water due to
  storm events, erosion, sea level rise, etc.
• Verify configuration and tidal connection
• Critical Area boundary may or may not change

10
Mapping IssueNetwork of Islands Changed

• Identify changes in upland and wetland areas
• Use aerial imagery and other source data to
  determine boundary of upland
• Consider Countys original mapping
• CA boundary may be affected
• Upland areas to be classified the same as they
  were originally

11
Mapping IssueShoreline Has Substantially Eroded

• Use aerial imagery to determine boundary of
  upland
• Knowledge of shoreline condition (low cliff, high
  cliff, undercut, etc.) helpful
• CA boundary will move landward (to maintain 1,000
  feet)
• Old shoreline and boundary will still be shown on
  the draft maps for information, comparison,
  discussion purposes
• New area will be classified based on land use
  as of July 1, 2008

12
Mapping IssueShoreline Has Substantially Eroded
13
Mapping IssueAreas Mapped IDA are Less Than 20
Acres

• Several areas mapped as IDA are less than 20
  acres
• Appear to be an error in original mapping
• Commission will not require a correction of the
  designation
• Correction of errors -local government
  coordination

14
Mapping IssueVerifying Head of Tide Determination

• Common issue throughout maps
• Complex to address historical knowledge is
  necessary
• Some wetland areas have changed
• Using all map resources and heads-up digitizing
  and analysis to make a determination
• Analyze evidence of change related to
  obstructions, storm events, beach erosion, etc.
• Limited ground truthing will be necessary in
  areas where there is significant change

15
Mapping IssueVerifying Head of Tide Determination
16
Mapping IssueChange in Extent of Wetlands

• Most common problem
• Numerous review points identified
• All map resources and vegetation analysis used to
  make determination
• Historical knowledge, project data, old aerial
  imagery, and topographic data may be used
• Ground truthing will be necessary in some areas

17
Mapping IssueChange in Extent of Wetlands
18
Mapping Schedule

• Baltimore County shoreline and wetlands review
  almost complete
• Final review underway
• New Critical Area boundary can then be generated
• Apply existing classifications
• Classify new areas
• Final analysis, quality control review, acreage
  calculations
• Final map prepared for local review and public
  input January 2009
• Talbot County mapping approximately 60 days
  behind Baltimore