Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
General requirement.
The standards and guidelines in this part must be followed in
wetland creation and restoration efforts to ensure adequate replacement of
wetland function and value.
In evaluating a proposed replacement or banking plan
application, the local government unit must determine that the plan will
adequately replace the public value of wetlands lost. If the local government
unit determines that the proposed replacement is not likely to result in
adequate replacement of function and public value, the local government must
either require modifications necessary to obtain adequate replacement or deny
the application.
Subp. 2.
Design requirements.
A. The
standards in this subpart must be met for all replacement wetlands unless the
local government unit, with concurrence of the technical evaluation panel,
determines that a standard is clearly not appropriate.
B. Water control structures must be
constructed using specifications provided in the Minnesota Wetland Restoration
Guide or their equivalent. Control structures may be subject to the Department
of Natural Resources dam safety regulations.
C. Best management practices must be
established and maintained at the replacement site as necessary to protect the
replacement wetland and other waterbodies. Erosion control measures must be
employed during construction and until permanent ground cover is
established.
D. Native, noninvasive
vegetation must be established in restored and created wetlands. Each
replacement or banking plan must include a vegetation establishment and
management plan. The vegetation establishment and management plan must include
a goal of, and specific provisions for, establishing plant communities that
correspond to the hydrology and landscape position of the replacement site. If
the replacement wetland is seeded or planted, the seed or planting stock should
be from native, noninvasive species in accordance with the Minnesota Wetland
Restoration Guide. In evaluating the vegetation establishment and management
plan, the local government unit must determine that implementation of the plan
is likely to result in establishment of the appropriate native, noninvasive
vegetation within the monitoring period. During the monitoring period, the
applicant must take reasonable steps to control invasion by any nonnative or
invasive species.
E. The bottom
contours of created types 3, 4, and 5 wetlands must provide a variety of water
depths, comparable to natural wetlands in the vicinity of the replacement, and
be consistent with part
8420.0522, subpart 5.
F. The edge of created or graded wetlands
must be comparable to other naturally occurring wetlands of similar hydrologic
condition and landscape position in the major watershed. Sideslopes of created
wetlands, graded portions of restored wetlands, and graded buffer strips, must
not be steeper than 8:1, eight feet horizontally for every one foot vertically,
or flatter, unless the technical evaluation panel concurs that steeper slopes
are acceptable based on the surrounding landscape and the characteristics of
other naturally occurring wetlands in the vicinity. Sideslopes of 10:1 to 15:1
are preferred.
G. Treatment of
runoff before discharge to replacement areas is required to improve
sustainability and minimize degradation of the wetland over time. The
replacement area must be physically separated from any water quality treatment
system. "Treatment of runoff" under this part means:
(1) any part of a storm water treatment
system needed to comply with water quality treatment requirements of state or
local storm water permits or ordinances, provided the treatment system is
physically separated from the replacement wetland; or
(2) when water quality treatment is not
required by state or local permits or ordinances, the installation of
appropriate best management practices, to the extent practicable and feasible,
to protect long-term wetland function.
H. For projects that contain elements that
include dams, dikes, or other impoundment features, the construction plans must
be designed, overseen, and certified by a registered professional
engineer.
Subp. 3.
Design considerations.
The following replacement wetland design elements must be
considered for replacement wetlands and incorporated to the extent practicable
and feasible:
A. restored wetlands
should emulate the hydrology and vegetation of the presettlement wetland
condition;
B. expanded buffers
should be incorporated into the design of replacement wetlands in areas where
there is a high potential for erosion and the buffer will improve slope
stability or when necessary to provide wildlife habitat corridor connections
with other wetlands or habitats;
C.
measures should be taken to manage hydraulic bounce as indicated in the
guidance document under part
8420.0112, item N; and
D. for all restored wetlands where the
original organic substrate has been stripped away and for all created wetlands,
the organic substrate must be sufficient to establish a functioning wetland and
to accomplish the goals of the replacement or banking plan. When feasible,
organic soil used for backfill should be salvaged from the impacted wetland for
utilization in the replacement wetland. Organic soil for backfill from wetlands
dominated by nonnative or invasive species should be avoided.