A preapplication conference shall be held with the Township
Superintendent and/or his designee prior to the submittal of a stormwater
management plan. The purpose of the preapplication conference is to
provide information and guidance that will assist the proprietor in
preparing the required plan.
A.
Clarity of plan presentation.
(1)
Through maps, illustrations, reports, and calculations, the stormwater
management plan shall display the required information in a clear
and logical sequence.
(2)
Information submitted to the Township on a site plan or tentative
preliminary subdivision plat or condominium may be used to meet the
requirements of this section, provided that a written statement identifying
the applicable data is provided.[1]
(3)
The stormwater management plan must be sufficiently detailed to specify
the type, location, and size of stormwater management and erosion
control facilities, using preliminary calculations. Detailed construction
drawings are not required at the stormwater management plan review
stage.
(4)
If it is proposed to develop a parcel in two or more phases, the
stormwater management plan shall be prepared and submitted for the
total project unless a variation has been approved by the Township
Board.
B.
Plan preparation. The stormwater management plan shall be prepared
by a registered civil engineer, registered landscape architect, registered
surveyor, and/or registered architect. Other persons and professionals
may assist in the preparation of the plan.
C.
Scale for mapping. The stormwater management plan shall be drawn
to a scale of at least one inch equal to 50 feet for property less
than three acres and one inch equal to 100 feet for property three
acres or more in size.
D.
Required information; identification and description. The following
information is required for all stormwater management plans:
(1)
Proprietor's name, address and telephone number.
(2)
Name of the township, city or village where residing.
(3)
Date (month, day, year) including revisions.
(4)
Title block, scale, and North point.
(5)
Name of planner, architect, engineer, surveyor, wetland specialist,
landscape architect, and/or other technical experts who have prepared
or assisted in the preparation of the stormwater management plan.
(6)
Existing lot lines, building lines, structures, parking areas, etc.,
on the parcel and within 100 feet of the site.
(7)
Proposed lot lines, property lines, and all structures, parking areas,
etc., within the site and within 100 feet of the site.
(8)
Zoning classification of petitioner's parcel and all abutting
parcels.
E.
Required information; existing conditions. The following information
describing existing site conditions is required:
(1)
A site location and vicinity map at a scale of not less than one
inch equal to 2,000 feet which shows watercourses, wetlands, topography,
and other features relevant to stormwater management. United States
Geological Survey quadrangle map information may be submitted to meet
this requirement. The approximate boundaries of the small watershed
within which the site is located shall be delineated (maps available
for reference at the Township offices).
(3)
Designation of soils with a high infiltration rate, including soil
map units 14B, 14C, 15B, 15C, 15E, 35A, 62B, 62C, and 63A, as shown
on the soil survey maps of the county, published by the United States
Soil Conservation Service.
(4)
Location and flow direction of all watercourses (including lakes,
ponds, creeks, and streams) on the site, including permanent and intermittent
features, as indicated on aerial photographs or United States Geological
Survey topographic quadrangle maps, and verified through field survey.
Elevations shall be indicated, referenced to a North American Vertical
Datum (NAVD 88) as bench mark.[3]
(5)
Location of wetlands, based upon the National Wetland Inventory Maps
(available for reference in the Township offices) and verified by
field survey.
(6)
Location of the one-hundred-year floodplain for all watercourses.
(7)
Outlet points and associated drainage area boundaries.
(8)
Preliminary engineering analysis of the existing peak rate of discharge
from the site.
(9)
Entry points where stormwater runoff and watercourses enter the site
from off-site locations, with arrows indicating the direction of the
flow.
(10)
Location of existing storm drains, ditches, basins, and other
stormwater management facilities.
F.
Required information; proposed conditions. The following information
describing the site after the proposed alteration or development is
required:
(1)
Proposed changes to the land surface and existing vegetative cover,
including delineation of areas to be cut and filled. Final contours
at two-foot contour intervals shall be provided.
(2)
A plan and timetable for the staging of site grading and preparation
activities.
(3)
General description and proposed location of temporary and permanent
soil erosion control facilities and measures, including but not limited
to sediment traps, sediment basins, diversion structures, stone filters
around storm drain inlets, berms with filter fabric, straw bale berms,
seeding and vegetative cover.
(4)
Preliminary calculations of the effect of the development upon the
peak rate of discharge, and a preliminary determination of the amount
of detention storage required to limit the proposed discharge to the
existing levels.
(5)
General description and proposed location of all temporary and permanent
stormwater management facilities, including facilities for the conveyance,
infiltration, and/or storage of runoff. The anticipated benefits of
stormwater management facilities for water quality and/or flood control
shall be indicated.
(6)
Proposed outlet points and associated drainage area boundaries.
(7)
Proposed flow routes with directional arrows for stormwater runoff
from both the ten-year storm frequency event and the one-hundred-year
storm frequency event.
(8)
The receiving watercourses, drains, ditches, and/or basins for stormwater
runoff, whether located on site or off site.
(9)
Approximate location of easements to protect and provide access for
the maintenance of the primary and secondary drainage systems.
(10)
Expected alterations of wetlands, floodplains, and watercourses,
including expected changes in the type of vegetation and water level.
(11)
Preliminary listing of activities proposed to maintain stormwater
management and erosion control facilities.
A.
The stormwater management plan for each development and earth change required under § 364-5B shall be submitted to the Township Clerk.
B.
For developments subject to site plan review, the proprietor shall
submit a stormwater management plan to the Township Clerk at the time
that the site plan is submitted.
C.
For developments subject to subdivision plat or condominium review,
the proprietor shall submit a stormwater management plan to the Township
Clerk at the time that the tentative preliminary plat or condominium
is submitted.[1]
D.
For other earth changes or activities subject to stormwater management
plan requirements, the plan shall be submitted to the Township Clerk
before construction drawings are submitted.
E.
The stormwater management plan must be received at least three weeks
prior to a Planning Commission meeting in order to be reviewed at
that meeting.
F.
Compliance with the requirements of this chapter does not eliminate
the need for the proprietor to obtain permits and approvals from county
and state agencies. Such permits and approvals include, but are not
limited to, soil erosion permits from the County Water Resources Commissioner,
drainage approvals from the County Water Resources Commissioner, road
drainage approvals from the County Road Commission, wetlands permits
from the State Department of Environmental Quality, and dam construction
permits from the State Department of Environmental Quality.
G.
Compliance with the requirements of this chapter does not eliminate
the need for the proprietor to comply with other applicable Township
ordinances and regulations.
H.
No grading, site preparation, or removal of vegetative cover shall
take place without stormwater management plan approval and the installation
of erosion control facilities.
I.
If it becomes necessary to alter a development or earth change proposal
after the stormwater management plan has been approved, a revised
stormwater management plan may be submitted. All requirements and
standards for stormwater management plans (this article) shall apply.
A.
Planning Commission review.
(1)
The Planning Commission shall review stormwater management plans to assure compliance with the approval standards listed in § 364-12.
(2)
Engineered grading plans do not require Planning Commission review.
(3)
When the stormwater management plan appears on the Planning Commission's
agenda for the first time, it will be distributed to Township consultants
and staff.
(4)
If the Planning Commission determines that all required information
has not been received, the proprietor may request that the matter
be tabled to allow for the submittal of the required information.
(5)
A recommendation to the Township Board to approve, approve with conditions,
or deny approval shall be made at a regular Planning Commission meeting.
B.
Township Board review.
(1)
The stormwater management plan approval request shall be placed on
the Township Board agenda no sooner than 15 days after approval or
denial by the Planning Commission.
(2)
Following completion of its review of the stormwater management plan
and the Planning Commission's recommendations, the Township Board
shall approve or deny the proposed stormwater management plan, with
or without modifications.
The Township Board shall establish fees and escrow requirements
by resolution. Fees and escrow account payments shall be sufficient
to cover administrative and technical review costs anticipated to
be incurred by the Township including the costs of on-site inspections.
All developments and earth changes subject to review under the
requirements of this chapter shall be designed, constructed, and maintained
to prevent flooding and protect water quality. The particular facilities
and measures required on site shall reflect the natural features,
wetlands, and watercourses on the site; the potential for on-site
and off-site flooding, water pollution, and erosion; and the size
of the site.
A.
General standards for on-site and off-site stormwater management.
(1)
Stormwater management conveyance, storage and infiltration measures
and facilities shall be designed to prevent flood hazards and water
pollution related to stormwater runoff and soil erosion from the proposed
development.
(2)
Stormwater from upstream and off-site locations shall be conveyed
around or through the site, or stored on site.
(3)
A primary drainage system which manages runoff from storms up to
a ten-year-frequency storm event shall be provided.
(4)
A secondary drainage system, such as an overland flow routing system
to manage runoff from storms up to a one-hundred-year-frequency storm
event shall be provided (secondary drainage system).
(5)
Every detention basin shall control the release of stormwater for
the ten-year- and one-hundred-year-frequency storm events. For the
ten-year-frequency storm event, the peak rate of discharge shall not
exceed 0.2 cubic foot per second per acre. For the one-hundred-year-frequency
storm event, the runoff rate shall not exceed the predevelopment rate.
(6)
Unless otherwise approved, stormwater runoff shall be conveyed through
swales and vegetated buffer strips so as to decrease runoff velocity,
allow for natural infiltration, allow suspended sediment particles
to settle, and to remove pollutants.
(7)
Alterations to natural drainage patterns shall not create flooding
or water pollution for adjacent or downstream property owners.
(8)
Watercourses shall not be dredged, cleared of vegetation, deepened,
widened, straightened, stabilized or otherwise altered without applicable
permits or approvals from the Township Board and the State Department
of Environmental Quality. If the watercourse is a designated county
drain, approval from the County Water Resources Commissioner shall
also be obtained.
(9)
No modifications of major watercourses shall be permitted when the
primary purpose is to increase the flow capacity of the watercourse.
(10)
Discharge of runoff from any site which may contain oil, grease,
toxic chemicals, or other polluting materials is prohibited unless
measures to reduce and trap pollutants meet the requirements of the
State Department of Environmental Quality and the Township, based
upon professionally accepted principles.
(11)
Drainage systems shall be designed to protect public health
and safety and to be visually attractive.
B.
Soil erosion control.
(1)
Cutting, filling and grading shall be minimized and the natural topography
of the site shall be preserved to the maximum feasible extent, except
where specific findings demonstrate that major alterations will still
meet the purposes and requirements of this chapter.
(2)
All development and other earth changes shall be designed, constructed
and completed in such a manner that the exposed area of any disturbed
land is limited to the shortest possible period of time.
(3)
Soil erosion control measures shall be installed between the disturbed
area and any watercourses (including rivers, streams, creeks, lakes,
ponds and other watercourses), wetlands, or roadways on or near the
site.
(4)
Sediment resulting from accelerated soil erosion shall be removed
from runoff water before it leaves the site of the development or
earth change.
(5)
Temporary and permanent soil erosion control measures designed and
constructed for the conveyance of water around, through or away from
the development or earth change area shall be designed to limit the
water flow to a nonerosive velocity.
(6)
Temporary soil erosion control measures shall be removed after permanent
soil erosion control measures have been implemented. All developments
and earth change areas shall be stabilized with permanent soil erosion
control measures.
(7)
If lakes, ponds, rivers, creeks, streams or other watercourses and
wetlands are located on or near the site, erosion control measures
which trap sediment shall be provided. Straw bale berms may be used
as temporary stormwater diversion structures but will not be considered
sufficient by themselves for trapping sediment on site. The use of
sediment basins, sediment traps, filter fabric, and rock filters in
lieu of straw bale berms shall be strongly encouraged. Other measures
may be required if reasonably determined to be necessary to protect
a watercourse or wetland.
(8)
When it is not possible to permanently stabilize a disturbed area
after an earth change has been completed or where significant earth
change activity ceases, temporary soil erosion control measures shall
be implemented within 30 calendar days.
(9)
Permanent soil erosion control measures for all slopes, channels,
ditches, or any disturbed land area shall be completed within 15 calendar
days after final grading or the final earth change has been completed.
All temporary soil erosion control measures shall be maintained until
permanent soil erosion control measures are implemented.
(10)
Vegetated buffer strips shall be created or retained along the
edges of all lakes, ponds, creeks, streams, other watercourses, and
wetlands, when reasonably determined to be necessary to protect the
watercourse.
C.
Stormwater storage and infiltration facilities.
(1)
Stormwater storage and/or infiltration facilities which protect water
quality and minimize flooding shall be required for all developments.
Storage facilities may include, but are not limited to, detention
basins, retention basins, infiltration trenches, swales with check
dams, and other facilities.
(2)
All detention basins shall be designed to maximize the ability of the basin to hold and trap sediment. The types of basins listed in this Subsection C(2) meet Township requirements. The following types of basins are listed in order of preference, with the most desirable listed first:
(a)
Infiltration facilities, provided that soils and groundwater
conditions are suitable.
(b)
Detention basins with a fixed minimum water elevation between
runoff event (wet basins). Wet basins which serve to trap soil particles
on site are preferable to dry basins.
(c)
Detention basins which hold stormwater from the one-year storm
event for more than 24 hours before completely draining to become
a dry basin (extended detention). Dry basins without extended detention
shall not be permitted.
(3)
Detention and retention basins shall be designed to hold runoff from
a one-hundred-year-frequency storm event. Basins shall be permanently
stabilized to minimize erosion.
(4)
Retention and detention basins shall have an overflow system. If
the overflow system cannot discharge to a creek, lake or wetland without
causing flooding on adjacent or downstream properties, then the basin
shall be designed to hold stormwater runoff from two back-to-back
one-hundred-year-frequency storm events.
(5)
Unless a variation is approved by the Township Board (See Article IV of this chapter.), detention and retention basins with banks sloping more than one on five (vertical to horizontal) shall not be permitted.
(6)
Detention basins and associated berms and landscaping shall be designed
to protect public safety and to be visually attractive.
(7)
Constructed detention basins shall not be a part of a platted subdivision
lot, but shall be provided in platted outlots or open space areas.
D.
Discharge of stormwater runoff to wetlands.
(1)
Stormwater runoff discharged to wetlands must be diffused to nonerosive
velocities before it reaches the wetland.
(2)
Wetlands may be used for stormwater detention if the following conditions
are met:
(a)
The wetland storage or detention area is set back at least 100
feet from the edge of any lake or stream.
(b)
The wetland does not have significant wildlife habitat or ecological
values which would likely be impaired or destroyed.
(c)
The wetland has sufficient holding capacity for stormwater,
based upon calculations prepared by the proprietor and reviewed and
approved by the Township Engineer.
(d)
Adequate on-site soil erosion control is provided to protect
the natural functioning of the wetland.
(3)
During the construction phase of development, adequate erosion control
and protection of wetlands shall be provided as required, including
such things as:
(a)
One or more sediment traps or soil settling basins located in
upland locations; and/or
(b)
Open-water sediment traps within or adjacent to wetlands, provided
that the proposal meets the wetland protection requirements of the
State Department of Environmental Quality and the Township for wetlands
alteration.
A.
Waiver option. In lieu of on-site stormwater detention, the use of
off-site stormwater conveyance, infiltration, and/or detention areas
may be proposed. In such cases, the proprietor shall request a waiver
of the requirements for on-site stormwater detention. This waiver
option does not allow for changes in requirements for on-site erosion
control. Off-site stormwater management areas may be shared with other
landowners, provided that maintenance agreements have been approved
by the Township Board and recorded.
B.
Review by Planning Commission and Township Board. The Planning Commission
shall review the waiver request and shall make a recommendation to
the Township Board. The final decision on a waiver request shall be
made by the Township Board.
C.
Stormwater management plan submittal. The waiver request shall be
submitted with a stormwater management plan as provided in this article,
including proposed stormwater management and erosion control measures,
on site and off site.
D.
Applicable standards. In addition to the stormwater management standards
specified in this article, the proprietor must demonstrate and provide
assurances for the following:
(1)
Stormwater flows and management controls shall not result in excessive
stream channel erosion on site or off site;
(2)
High-value or unique wetlands and natural areas shall not be significantly
altered by stormwater flows on site or off site;
(3)
Soil erosion shall be managed off site as well as on site;
(4)
Off-site stormwater facilities shall be protected through appropriate
easements; and
(5)
Adequate provision and agreements for maintenance of stormwater management
facilities shall be made.
