Current through Register Vol. 49, No. 13, September 23, 2024
Subpart
1.
In general.
In addition to compliance with the general standards in part
6115.0200, subparts 2 to 5, specific requirements shall be met for the
activities described in subparts 2 to 7.
Subp. 2.
Excavations for beach
development.
The existing site conditions will not provide a suitable
beach using a sand blanket alone. When the proposal includes the installation
of a beach sand blanket, the area to be excavated shall be consistent with the
criteria for filling under part 6115.0190, subparts 2 to 5. The depth of
excavation needed to reach a suitable beach stratum shall be the minimum depth
necessary considering anticipated site maintenance and reasonable water depths
for a beach.
Subp. 3.
Waterbasin excavations.
Excavations for improvement or enhancement of hydrologic and
biologic conditions in all, or large portions of waterbasins:
A. A public need for the excavation has been
established by local governmental resolution specifying the public interests to
be improved or enhanced, except where the project is state sponsored.
B. The proposed project is intended to
achieve one or more of the following public purposes:
(1) to improve navigation, swimming, and
other recreational uses;
(2) to
reduce winter fish-kill potential;
(3) sediment removal to eliminate a source of
nutrients and/or contaminants.
C. The proposed excavation is part of an
overall improvement or enhancement project based upon adequate background and
field test data for which a comprehensive plan is submitted at the time of
application detailing all of the following:
(1) Objectives to be accomplished, and an
analysis of any alternative means considered to meet the objectives and the
rationale for selecting excavation.
(2) Sufficient soil boring and bottom
sampling data to evaluate sediment quality and bottom "seal" conditions. Where
excavation is proposed on a waterbasin that is perched on an impervious
stratum, soil borings must show that the proposed excavation will not rupture
the impervious stratum.
(3) The
methods, uses, and locations to be employed in excavating and disposing of
excavated material consistent with the provisions of parts 6115.0190 to
6115.0192.
(4) Existing water
quality data and provision for future water quality monitoring including any
water returned to the waterbasin during the removal of excavated
materials.
(5) A timetable which
indicates anticipated yearly excavation areas and volumes of materials to be
removed, plus the selected disposal methods, uses, and deposition locations for
each excavation period.
(6) A
detailed description of proposed excavation and disposal equipment and
facilities, including, where applicable, the length of discharge pipe purchased
or available for the project and the pumping characteristics of the
equipment.
Subp.
4.
Excavations for navigation-related purposes.
Excavations for navigation-related purposes:
A. Access channels from shorelines for
recreational craft. Excavations for accesses from shorelines to reach navigable
depths shall not be allowed if access could reasonably be obtained through use
of a dock to reach navigable depths, and prevalent wind, wave, and current
conditions would not impair reasonable access to reach navigable depths.
When shoreline conditions and wind, wave, and current
conditions preclude access to navigable depths, excavations for navigational
access shall be allowed provided the access channel shall not exceed four feet
in depth, more than 15 feet in bottom width, and will not extend to an offshore
water depth greater than four feet.
B. Other navigational channels. Excavations
shall be limited to the minimum depth and width necessary to allow reasonable
use of anticipated watercraft.
Excavations to provide maintenance of navigational channel
projects shall be limited to the length, width, and depth dimensions of the
original channel.
Subp.
5.
Harbors and boat slips.
Harbors and boat slips:
A. Excavations for development of offshore or
inland harbors or boat slips for the mooring of more than 25 watercraft or
watercraft larger than 20 feet in length shall be restricted to those waters
which have the following characteristics:
(1)
waterbasins having areas of 1,000 acres or more;
(2) watercourses which are used for
commercial or industrial navigational purposes.
B. Excavations for development of offshore
harbors serving fewer than 25 watercraft shall be limited to those water areas
where the location of the proposed offshore harbor would not create
unreasonable obstructions to public use and navigation on the water involved.
Unreasonable obstructions include any development which would result in threats
to public health, safety, or welfare.
C. Excavations for development of private
inland harbors or boat slips serving fewer than 25 watercraft or watercraft
less than 20 feet in length shall be limited to those waters where:
(1) prevalent wind, wave, or current
conditions along the shoreline where excavation is proposed are of a magnitude
and frequency which precludes the use and maintenance of docks to moor
watercraft. Determinations of magnitude and frequency which would inhibit use
of docks shall be based on supporting facts including:
(a) the character of the water involved and
its shoreline in relation to exposure to severe wind, wave, or current actions
and the configuration and area of the water;
(b) the frequency of occurrence of storms
producing severe winds and waves based on climatological data for the area;
and
(c) the average number of days
during each month of the navigational season when the shoreline is affected by
severe winds, waves, or currents;
(2) the presence of lake bed and bank
conditions would preclude the use and maintenance of docks and the conditions
of the site and the number, type, or size of watercraft intended to be moored
would preclude the development and use of on-land facilities, such as rollers,
winch and track systems, sliderails, or other facilities which could be used to
haul watercraft out of the water for on-land storage; or
(3) the proposed site is located in an area
of the water body where offshore mooring or excavations or extensive dock
development would create unreasonable obstructions to public use and navigation
of the water body.
D.
The width and length of boat slips shall not exceed 150 percent of the width
and length of the anticipated watercraft and all authorized boat slips shall be
oriented to maximize the degree of wave protection.
E. Excavations for development of inland
harbors shall be limited to those waters described in item C and shall meet the
following additional requirements:
(1)
Requirements applicable to all commercial and industrial inland harbors:
(a) The mooring area of the harbor shall be
compactly shaped in order to minimize the surface area excavated in relation to
the number of mooring spaces to be provided and shall be located at an adequate
distance from the shoreline to provide wave protection and prevent
breakthrough.
(b) No branch or
connecting channels shall be permitted extending laterally outward from
authorized inland excavations.
(c)
If practical, a "dogleg" shall be incorporated in the approach channel located
between the mooring area and the shoreline to minimize visual impact from the
water body and promote wave dissipation.
(d) The excavation shall not extend more than
200 feet inland from the public water unless evidence is provided to show that
greater distances are required because of the dimensions of the watercraft to
be moored.
(e) The methods, use,
and deposition locations to be employed in disposing of excavated materials
shall be consistent with the provisions of part 6115.0200, subpart 5, item
B.
(2) An application
for a permit shall contain plans, maps, and supporting data regarding proposed
excavation site soil borings, ground water levels and characteristics, water
quality, topography, drainage, and vegetation which shall substantiate that the
proposed project must be reasonable and practical based upon geologic and
hydrologic conditions including:
(a) quantity
and quality of stream flow and local drainage at the proposed project
site;
(b) water stagnancy problems
including the capability of being flushed or drained;
(c) interference with stream flow or
longshore drift;
(d) type of soil
strata and underground formations in the project vicinity;
(e) protection of the water body itself in
terms of reduced water supply, increased seepage or drainage, pollution,
increased flooding, and other adverse hydrological impacts;
(f) adequate entrance openings;
(g) ample turning radius;
(h) adequate depth and size for the
anticipated watercraft usage;
(i)
adequate reduction of wave heights in mooring areas;
(j) proper harbor shape to reduce wave
resonance;
(k) need for and
feasibility of maintenance dredging;
(l) adequate height of perimeter
wall;
(m) need for wave absorbers
within the harbor; and
(n) bank
stabilization by appropriate erosion control measures.
(3) Additional requirements applicable to
specific types of harbors. Private inland harbors serving two or more single
family residential riparian lots shall, if practical, be located along the
mutual boundary of properties to be served.
Private inland harbors for proposed multifamily or cluster
developments, residential planned unit developments, or for resorts,
campgrounds, or other commercial purposes. The development plan shall be
approved by the local governmental unit. The permit shall be of the
title-registration type including a provision that the individual waterfront
lots in the development have priority rights to the available mooring spaces
thus obviating issuance of future permits for individual harbors for these
lots. The harbor shall be appropriately sized, consistent with the number of
watercraft to be served. For residential and commercial planned unit
developments, the number of mooring spaces to be permitted shall be consistent
with part 6120.3800.
Public inland harbor projects must be justified by:
(a) a public need for the proposed inland
harbor established by local governmental resolution specifying public interests
to be enhanced;
(b) the harbor
shall be appropriately sized consistent with the demand for mooring facilities
in the area and the number of watercraft to be served;
(c) the harbor shall be available for use by
the general public; and
(d) the
harbor may extend more than 200 feet inland provided the plans minimize the
total length by which the public water is proposed to be extended in keeping
with the number of watercraft to be served and the topography.
Subp. 6.
Excavations for fish and wildlife habitat improvement.
Excavation to restore or improve fish and wildlife habitat
require plans showing the nature and degree of habitat to be benefited, and
information showing that the project will not create other adverse effects such
as flooding, erosion, sedimentation, or navigational obstructions.
Excavations in trout streams officially designated by the
commissioner shall be allowed only if:
A. the amount, method, and location of the
excavation will not result in increased water temperatures, cause excessive
sedimentation in the stream, or destruction of fish habitat; and
B. there is no other feasible or practical
alternative other than excavation.
Subp. 7.
Excavations in public
watercourses.
Except as noted in part 6115.0200, subpart 4, a permit shall
be required for any excavation in a public watercourse and shall be subject to
the following specific requirements in addition to the general requirements of
part 6115.0200, subparts 2 to 5:
A.
The watercourse capacity shall be sufficient to adequately convey normal
runoff.
B. The watercourse bottom
gradients shall be such that normal low flow velocities are nonerosive and the
sideslopes shall be graded such that bank slumping is not a hazard. Where
excavation will result in excessive bank erosion, energy dissipation
structures, channel and bank protection, or other engineering measures shall be
required.
C. The outlet shall be
adequate in that it:
(1) sufficiently conveys
the discharge waters from the area proposed for excavation;
(2) does not produce substantial increases in
downstream overbank flooding; and
(3) does not produce downstream erosion
hazards as a result of the watercourse excavation.
D. When projects involve widening or
straightening which alters the watercourse banks, all sideslopes which
contribute direct surface runoff into the authorized altered watercourse, and a
strip of land along both sides of the watercourse, one rod wide or to the top
of the spoil bank, whichever is the greater, shall be seeded and maintained in
permanent grasses. No mowing of this grassed strip shall be allowed until after
July 31 of each year.
E. The
alignment and slope of the excavated channel shall be such as to provide a
smooth transition between the existing and the excavated channel.
F. Disposal of excavated material from
channel excavation shall be consistent with part 6115.0200, subpart 5, except
where the original channel is allowed to be filled as part of the
project.
G. No significant increase
in flood damages will be permitted. Floodwater retardance structures may be
required to minimize any increase in flood damage.
H. The applicant shall submit the names and
addresses of landowners located immediately upstream, downstream, and adjacent
to any proposed watercourse alteration resulting from excavation. In addition,
the applicant shall submit the names and addresses of other landowners and
occupants that the commissioner, after reviewing the plans for the proposed
excavation, believes will have a substantial interest in the channel change or
will be substantially affected by the watercourse alteration.
I. The preferred alternative to widening,
deepening, or straightening a watercourse for control of flood waters is the
construction of water impoundment structures in upstream areas. Where
impoundments are infeasible, impractical, or would result in adverse effects on
health and safety or greater adverse environmental effects, the preferred
alternative is the construction of flood bypass channels to convey high
velocity flood flows.
Excavations in public watercourses for flood management
purposes shall be allowed only where an upstream impoundment or a flood bypass
channel is infeasible or impractical or excavation is the least damaging
environmentally.
Excavations for widening, deepening, or straightening
portions of watercourses shall be based on flood management plans which provide
details on the relationship of the proposed excavation to management of flood
flows for the entire watercourse and shall be consistent with state standards
and state approved local standards for floodplain management including maximum
use of nonstructural measures where feasible and practical.
J. Excavations shall be limited to the
minimum extent necessary to facilitate construction of the road crossing and
shall include provisions for adequate riprap or other bank protection measures
to protect altered banks from erosion.
K. Excavations for construction of sediment
traps or settling basins to control sedimentation and water quality shall be
based on plans approved by the Pollution Control Agency or the local soil and
water conservation district and shall be consistent with any state and local
standards, regulations, and requirements.
L. Watercourse channel excavations to restore
or improve fish and wildlife habitat shall require plans showing the nature and
degree of habitat to be benefited, and information showing that the project
will not create other adverse effects such as flooding, erosion, sedimentation,
or navigational obstructions.
M.
Watercourse channel excavations in trout streams officially designated by the
commissioner shall only be allowed if:
(1)
the amount, method, and location of the channel excavation will not result in
increased water temperatures, cause excessive sedimentation in the stream, or
destruction of fish habitat; and
(2) there is no other feasible or practical
alternative other than channel excavation.
N. The straightening or realignment of a
watercourse with a total drainage area, at its mouth, greater than five square
miles shall only be permitted where the project will not result in increased
downstream flooding, erosion, or sedimentation. Where it is proposed to
straighten or realign a watercourse with a total drainage area, at its mouth,
greater than five square miles, the applicant may be required to submit
appropriate hydraulic data. Such data may include:
(1) contributing watershed above the
project;
(2) data for the flood of
record;
(3) maximum observed high
water level;
(4) flow data, based
on the best available technology as follows:
(a) existing and proposed time of
concentration;
(b) existing and
proposed stage downstream;
(c)
existing and proposed mean velocity downstream;
(5) certification that the data was prepared
by a registered professional engineer.
O. The alteration of watercourses by
straightening or realigning channels to facilitate adjacent land use shall be
allowed only if the applicant provides evidence:
(1) that the alteration is reasonable,
practical, and will adequately protect public safety and welfare; and
(2) that the alteration will involve a
minimum of encroachment, change, or damage to the environment, particularly to
the ecological system of the waterway.
P. All other proposals for excavations in
public watercourses shall meet the general requirements of part 6115.0200,
subparts 2 to 5 and the specific requirements of subparts 2 to 6 and shall
require submission of supporting evidence as provided in items N and
O.
