# COMAR Title 27 — Critical Area Commission for the Chesapeake and Atlantic Coastal Bays

## Subtitle 01 — Criteria for Local Critical Area Program Development

### Chapter 11 — Directives for Updating Critical Area Maps

#### Regulation .04 Mapping Methodology for the Assessment of Physical Features.

*COMAR 27.01.11.04*

A. Using the source information under Regulation .03 of this chapter, the Department and the Commission shall digitize the shoreline and the  landward boundary of a tidal wetland.

B. The Department and the Commission shall determine the location of the shoreline by remote sensing and an evaluation of:

  (1) The location of vertical shoreline structures;

  (2) The location of water at the time of image capture;

  (3) An estimate of the high tide limit, based on photo interpretation and collateral data; and

  (4) On sandy beaches, the location of a debris line or the wettest land.

C. Except for a structural shoreline stabilization measure that is located offshore, the Department and the Commission shall map the shoreline:

  (1) At the landward edge of a bulkhead;

  (2) At the midpoint between the waterline and the upland edge of a revetment;

  (3) Around the landward edge of a man-made groin or jetty that is at least 30 feet in width; and

  (4) Along the shoreline when a man-made groin or jetty is less than 30 feet in width.

D. Except for a living shoreline or a mudflat, the Department and the Commission shall map the following land features as upland:

  (1) An upland island surrounded by open water;

  (2) An upland area surrounded by a tidal wetland if the upland area:

    (a) Was mapped as upland on the 1972 tidal wetlands maps and is at least one acre in size; or

    (b) Except for a duckblind or a water-dependent facility or activity under COMAR 27.01.03, is developed with a legally authorized improvement; and

  (3) A dredged material containment facility surrounded by open water that is part of a State-sponsored restoration project with conservation and habitat protection as essential elements of its operation.

E. A local jurisdiction may not construe the mapping of an area as a wetland or an upland to affect the allowable density or the number of development rights of that newly mapped area as part of a map update, except in accordance with written requirements and procedures in a local jurisdiction’s Critical Area program.

F. A local jurisdiction may include within the Critical Area land located more than 1,000 feet from tidal waters or tidal wetlands if the newly included area is:

  (1) Completely surrounded by Critical Area land and is:

    (a) Up to one acre in size and adjoins an intensely developed area or a limited development area, by which the designation of the newly included area becomes an intensely developed area or a limited development area;

    (b) Up to two acres in size and adjoins a resource conservation area, by which the designation of the newly included area becomes a resource conservation area; or

    (c) Greater than the acreage limits in §F(1)(a) and (b) of this regulation if:

      (i) A local jurisdiction proposes alternative mapping standards; and

      (ii) The alternative standards are approved by the Commission; or

  (2) An environmentally sensitive area contiguous to the Critical Area that is approved by the Commission.

G. The Department and the Commission, in collaboration with a local jurisdiction, shall maintain the Critical Area layer of the Statewide Base Map.

H. Each map of the Critical Area layer of the Statewide Base Map shall include:

  (1) A State-determined shoreline;

  (2) A State-determined landward boundary of tidal wetlands;

  (3) A digitally generated, georeferenced 1,000-foot Critical Area boundary; and

  (4) Land newly included within the Critical Area under §F of this regulation.