This article is adopted under the authority
granted by §§ 61.34(1), 61.354 and 62.234, Wis. Stats.
The purpose of this article is to promote the
public health, safety and general welfare of this community and to
diminish threats to the environment by:
A. Establishing procedures to control the adverse impacts
of stormwater runoff and assure and protect the adequacy of existing
drainage facilities to store and convey stormwater;
B. Promoting the attainment and maintenance of surface
and ground water quality;
C. Minimizing the damages to public and private property,
the dangers to public health and safety and the inconveniences and
inefficiencies caused by poor surface drainage and flooding;
D. Reducing the adverse impacts of new land use development
and redevelopment on the quantity and quality of stormwater runoff;
and
E. Reducing stream channel erosion and sedimentation.
It is the intent of this article to achieve
the aforestated purpose by requiring the preparation and implementation
of duly approved site-specific stormwater management plans for sites
proposed to be developed or redeveloped and properties proposed to
be divided or subdivided and for logical subwatershed areas containing
such sites or properties. All discharges of stormwater shall be made
in a manner consistent with approved site-specific stormwater management
plans, and all land development and redevelopment activities are intended
to include stormwater management facilities and measures set forth
in the approved plans. Where the Village has prepared and adopted
a stormwater management system plan encompassing the site proposed
to be developed or redeveloped or property proposed to be subdivided,
the site-specific plan required shall be consistent with the system
plan.
It is not intended by this article to repeal,
abrogate, annul, impair or interfere with any existing easements,
covenants, deed restrictions, agreements, ordinances, rules, regulations
or permits previously adopted or issued pursuant to laws. However,
wherever this article imposes greater restrictions, the provisions
of this article shall govern.
In their interpretation and application, the
provisions of this article shall be held to be minimum requirements
and shall be liberally construed in favor of the Village and shall
not be deemed a limitation or repeal of any other power granted by
the Wisconsin Statutes.
This article shall be known as, referred to
or cited as the "Stormwater Management Ordinance, Village of Elm Grove,
Wisconsin."
The definitions as used in this article are
as follows:
AGRICULTURAL ACTIVITIES
The planting, growing, cultivating and harvesting of crops,
including sod; growing and tending of gardens and trees; harvesting
of trees; and pasturing or yarding of livestock.
DETENTION FACILITY
A structure designed to temporarily store stormwater runoff
for later release in order to delay and reduce peak flow rates and
pollutant concentrations. The most common detention facilities include
dry basins, and wet ponds where appropriate may also be used for detention
storage, as well as vehicular parking lots, depressed landscaped areas,
rooftops and underground storage chambers.
GROSS AGGREGATE AREA
The total area, in square feet, of all land located within
the interior property boundary containing a proposed land development,
redevelopment or property subdivision activity.
HYPSOMETRY
Those parts of a map which represent, usually by contour
lines, the physical distance of the surface of the earth above a specified
reference surface.
INFILTRATION
The process by which rainfall or surface runoff percolates
or penetrates into the underling soil.
OFF SITE
Located outside the exterior property boundaries described
in the permit application for a proposed land development or redevelopment
activity or outside the exterior boundaries of a proposed property
subdivision.
ON SITE
Located within the exterior property boundaries described
in the permit application for a proposed land development or redevelopment
or within the exterior boundaries of a proposed property subdivision.
PLANIMETRY
Those parts of a map which represent the horizontal location
and extent of man-made and natural features.
POST-DEVELOPMENT AND REDEVELOPMENT CONDITION
The extent and distribution of land cover and stormwater
management facilities and measures anticipated to occur under conditions
of full site development, redevelopment or property subdivision that
will influence stormwater runoff and infiltration.
PROPERTY SUBDIVISION
A division of a lot, parcel or tract of land by the owner thereof or the owner's agent for the purpose of sale or building development and redevelopment where the act of division creates a number of parcels or building sites of a minimum size, as defined in Chapter
305, Land Division.
RETENTION FACILITY
A storage structure designed to reduce or eliminate the surface
discharge of stormwater through evaporation and infiltration. Wet
ponds are the most common type of retention storage, although wet
ponds may also be used for detention storage.
SITE
The entire area of proposed land development, redevelopment
or property subdivision.
SITE-SPECIFIC STORMWATER MANAGEMENT PLAN
A plan that identifies what actions should be taken to reduce
stormwater quantity and pollutant loads from land development, redevelopment
or property subdivision activities to levels meeting the purpose and
intent of this article.
STORMWATER MANAGEMENT SYSTEM PLAN
A plan developed to address stormwater drainage and nonpoint
source pollution control problems under both existing and planned
conditions within a logical planning area, such as on a watershed
or subwatershed, and which meets the purpose and intent of this article.
STORMWATER RUNOFF
That portion of the precipitation falling during a rainfall
event or that portion of snow melt that runs off the surface of the
land and into the natural or artificial drainage system.
SUBDIVIDE OR SUBDIVISION
The development, redevelopment or any form of property division which affects property satisfying any of the dimensional or other criteria in §
325-31 of this article.
WETLAND
An area where the groundwater elevation is at, near or above
the land surface, characterized by both hydric soils and the presence
of hydrophytic plants. For the purpose of this article, a wetland
shall have a minimum area of 2.5 acres. It should be noted that wetlands
having a smaller area than 2.5 acres may be regulated for other purposes
by the federal, state, county and municipal governments.
WETLAND FUNCTIONAL VALUE
The type, quality and significance of the ecological and
cultural benefits provided by wetland resources, such as flood storage,
water quality protection, groundwater recharge and discharge, shoreline
protection, fish and wildlife habitat, floral diversity, aesthetics,
recreation and education.
The jurisdiction of this article shall include
all lands or waters within the corporate limits of the Village of
Elm Grove.
This article applies to land use development,
redevelopment and property division or subdivision activities which
meet the following criteria:
A. Residential land use development, redevelopment or
property division or subdivision occurring within a gross aggregate
area of more than five acres;
B. Residential land use development or redevelopment
occurring within, or property division of, a gross aggregate area
of more than three acres, if 1.5 acres or more of impervious surfaces
are proposed;
C. Nonresidential land use development, redevelopment
or property division or subdivision occurring within a gross aggregate
area of more than 1.5 acres, if 0.5 acre or more of impervious surfaces
are proposed; and
D. Land use development, redevelopment or property division
or subdivision of any size area that in the opinion of the Village
Engineer is likely to result in stormwater runoff which exceeds the
safe capacity of existing drainage facilities or receiving watercourse;
which causes undue channel erosion; which increases surface water
pollution; or which endangers property or public health and safety.
The following development and redevelopment
activities are exempt from the requirement of this article:
A. Maintenance, alteration, improvement or use of an
existing structure which does not significantly affect the water quality
or hydrologic and hydraulic conditions of the surface water resources
of the subwatershed concerned as determined by the Village Engineer
in writing;
B. Maintenance activities undertaken by any federal,
state or municipal governmental agency;
C. Stormwater management facilities to be constructed
or measures to be undertaken by the Village when the Village Engineer
has determined that a stormwater management plan is not required;
and
D. Agricultural activities not associated with development
and redevelopment.
The Village Engineer may waive the requirements
of this article in part or in whole. A request for waiver shall be
submitted to the Village Engineer and shall include a narrative description
and drawings of the proposed development or redevelopment or subdivision
for which the waiver is being requested. The Village Engineer may
grant a waiver if the Village Engineer finds that:
A. The development or redevelopment or subdivision is
not likely to:
(1) Significantly increase or decrease the rate or volume
of stormwater runoff from the development, redevelopment or subdivision
site;
(2) Have a significant adverse impact on a wetland or
other environmentally sensitive area;
(3) Significantly contribute to the degradation of surface
or ground water quality; or
(4) Otherwise significantly impair attainment of the purpose
of this article; and
B. The applicable adopted stormwater management system
plan does not indicate the need for any site-specific stormwater management
measures on the site concerned.
The site-specific stormwater management plan
required by this article shall meet the following requirements:
A. General.
(1) The stormwater management plan shall be prepared by
a registered professional engineer and shall contain all of the information
required to evaluate the adequacy of the plan and the probable impacts
of implementation of the plan on the quality and quantity of stormwater
discharges, on existing drainage facilities and on surface and ground
water quality. The plan shall contain the name, address and telephone
number of the owner or developer of the site concerned, of the registered
professional engineer preparing the plan, of the person responsible
for installation of the stormwater management facilities recommended
in the plan and of the person responsible for the maintenance of those
facilities.
(2) The plan shall consist of narrative descriptions and
explanations; maps, charts and graphs; tables; photographs; supporting
calculations; and references to recognized engineering text and manuals
as may be necessary to provide a clear and concise description of
the plan. The sources of maps and data presented in the plan shall
be identified.
B. Existing site conditions. The plan shall include a
map and description of the existing conditions of the site concerned,
including:
(1) A map of the site at a scale of one inch equals 100
feet or larger showing the property boundaries referenced to the United
States Public Land Survey System or to a lot and block of a recorded
subdivision plat and the topography of the site, including contours
shown at an interval of two feet or less, together with such spot
elevations as may be necessary; the contours and spot elevations shall
be referenced to the National Geodetic Vertical Datum of 1929;
(2) The hydrologic and hydraulic characteristics of the
site, including drainage flow paths and directions of flow onto, through
and out of the site; related drainage basin boundaries; times of concentration;
and rates and volumes of flow;
(3) The location of areas where stormwater may collect
or percolate into the ground;
(4) Groundwater elevations referred to the National Geodetic
Vertical Datum of 1929;
(5) Soils by hydrologic group;
(6) Cover type and condition;
(7) Location and extent of impervious surfaces, including
type and condition of the surfaces;
(8) Locations and outlines of all buildings or other structures;
(9) Location of all receiving bodies of surface water
on or adjacent to the site into which stormwater flows;
(10)
Location and extent of the one-hundred-year
recurrence interval flood hazard area associated with any perennial
stream or watercourse on or adjacent to the site;
(11)
Information regarding current water quality
objectives and current water quality conditions in any perennial watercourses
located on or adjacent to the site;
(12)
Locations of points of discharge of stormwater
runoff from adjacent tributary areas together with the size of those
areas expressed in acres;
(13)
Locations, sizes and elevations of all existing
storm sewers, channels, ditches, detention or retention ponds or other
engineered drainage facilities on or adjacent to the site, the elevations
being referred to the National Geodetic Datum of 1929; and
(14)
Locations of any existing water supply wells
and wellhead protection areas.
C. Proposed post-development and redevelopment site conditions.
The plan shall describe the alterations proposed to be made to the
site and the resulting proposed post-development and redevelopment
conditions. The description shall include:
(1) Proposed changes in the planimetry of the site and
in the hypsometry of the site by contours having the same contour
interval and referred to the same datum as used to present the hypsometry
of the existing site conditions;
(2) The location and outline of all proposed buildings
or other structures;
(3) Changes in the location, extent and type of impervious
surfaces;
(4) The location and extent of areas where vegetation
is to be disturbed or planted;
(5) Changes in the drainage flow paths into, through and
out of the site and related changes in drainage basin boundaries;
(6) The location, elevations and sizes of all proposed
minor and major stormwater management facilities; the former, including
all storm sewers and inlets, and the later, including curbed roadways,
roadway ditches, culverts, storage facilities and interconnected flow
paths, all elevations being referred to the National Geodetic Vertical
Datum of 1929;
(7) Any changes to lakes, streams, watercourses or wetlands
on or adjacent to the site concerned; and
(8) The location and widths of required public rights-of-way
or easements existing or needed to accommodate the recommended stormwater
management facilities. Any needed improvements to existing facilities
shall also be shown in detail.
D. Anticipated impacts. The plan shall contain a description
of the following anticipated impacts of stormwater runoff from the
proposed development, redevelopment or property subdivision as managed
by the facilities and measures recommended in the plan:
(1) Increases or decreases in the rates and volumes of
stormwater runoff;
(2) Changes in the locations and conveyance capacities
of points of discharge of stormwater from and to the site concerned;
(3) Adequacy of receiving storm sewer, engineered stormwater
management facility or watercourse to convey or store the anticipated
peak rate of stormwater discharge from the site concerned, giving
due consideration to existing flows;
(4) Changes in the location and extent of the one-hundred-year
recurrence interval flood hazard area of any perennial watercourse
location within or through, or adjacent to, the site concerned;
(5) Changes in the quality of receiving wetlands and bodies
of surface water;
(6) Changes in groundwater elevations referred to National
Geodetic Vertical Datum of 1929; and
(7) Impacts on municipal wellhead protection areas.
E. Proposed stormwater management facilities and measures.
The plan shall include a definitive description of the stormwater
management facilities and measures proposed to be used for the control
of the quantity and quality of the anticipated stormwater runoff from
the proposed development, redevelopment or property subdivision. The
measures and descriptions may include:
(1) For detention and retention facilities: locations,
areas, depths, volumes, inlet and outlet configurations and elevation
of the bottoms and of key inlet and outlet control structures, all
elevations being referred to National Geodetic Vertical Datum of 1929;
(2) For conveyance facilities: locations of inlets and
manholes and associated rim and invert elevations and pipe sizes;
locations, elevations and cross sections of ditches, swales and channels;
and culvert sizes, inlet and outlet configurations and elevations,
all elevations being referred to National Geodetic Vertical Datum
of 1929;
(3) Areas to be used for percolation into the groundwater
reservoir;
(4) Provisions for the control of erosion and sedimentation,
including control of off-site impacts; and
(5) Measures to abate any potential pollution of surface
and ground waters.
F. Hydrologic computations. The plan shall include computations
of peak flow rates and discharge volumes for the two-year, ten-year
and one-hundred-year recurrence interval rainfall events for each
point of discharge into and out of the site concerned under existing
and planned development and redevelopment conditions. The data shall
include times of concentration to key junctions in flow paths and
to points of discharge into and out of the site.
G. Construction schedule and costs. The plan shall include
a schedule for the construction of the recommended stormwater management
facilities and estimates of attendant capital and operation and maintenance
costs.
The site-specific stormwater management system
plan required under the provisions of this article shall be designed
in accordance with good engineering practice. The specific methods
to be used in the calculation of peak rates of discharge, volumes
and water quality conditions and of the hydraulic capacities of storage
and conveyance facilities shall be left to the judgment of the professional
engineer preparing the plan, subject, however, to the approval of
the Village Engineer. The site-specific stormwater management system
shall be designed such that the natural topography and land cover,
including such features as high-quality woodlands, wetlands, swales,
natural depressions, native soil infiltration capacity and natural
groundwater recharge areas, are protected and preserved to the maximum
extent practicable.
The stormwater management facilities and measures
required to serve land use development, redevelopment and property
subdivision activities subject to this article shall be designed to
meet the following minimum standards:
A. Stormwater discharges shall be treated to achieve
the levels of pollutant removals specified in the adopted Village
stormwater management system plan. Unless otherwise specified in the
above-noted plans, stormwater management measures shall be designed
with the general goal of removing, on an average annual basis, 80%
of the suspended solids load that may be expected in the absence of
control. To achieve this level of removal, the stormwater management
measures shall be designed to accommodate, at a minimum, the runoff
volume resulting from 1.5 inches of rainfall.
B. Discharge of urban stormwater pollutants to wetlands
shall be minimized to the extent practicable. Significant degradation
of wetland functional values due to stormwater pollutant loading shall
be avoided.
C. Stormwater discharges shall be pretreated prior to
infiltration to prolong maintenance of the infiltration capacity and
to prevent discharge of stormwater pollutants and concentrations that
would result in exceeding groundwater quality standards established
by the Wisconsin Department of Natural Resources.
D. Stormwater detention, retention and infiltration facilities
shall not be located closer than allowed by applicable sections of
the Wisconsin Administrative Code. The stormwater management plan
shall show all wells within the following areas: 100 feet from a well
serving a private water system; or 1,200 feet from a well serving
a municipal or a community/subdivision water supply system; or within
the wellhead protection areas of a well serving a municipal or a community/subdivision
water supply system, if such a protection area has been delineated.
Copies of any variances to the Administrative Code obtained from the
state must be furnished to the Village prior to the start of construction.
E. In the design of the stormwater facilities and measures,
due consideration shall be given to the design criteria and standards
set forth in the Wisconsin Stormwater Manual prepared and published
by the Wisconsin Department of Natural Resources and as may be revised
from time to time.
Stormwater detention and retention control facilities
included in the stormwater management system plan required under this
article shall be designed in conformance with the adopted Village
stormwater management system plan.
The Village Engineer may establish stormwater
management requirements either more or less stringent than those set
forth in this article provided that the Village Engineer finds that
one or more of the following conditions applies:
A. A higher level of quality in the stormwater discharge
is required to protect sensitive environmental resources.
B. A higher level of protection from ponding or flooding
is required to protect the public health and safety.
C. Provisions are available to manage the stormwater
runoff by off-site facilities, provided that all of the following
conditions are met for the off-site facilities: the facilities are
in place; the facilities are adequately sized to provide a level of
stormwater runoff control equal to or greater than that which would
be afforded by on-site facilities and measures meeting the requirements
of this article; and a legal entity exists that is responsible for
the maintenance of the facilities.
An irrevocable letter of credit of sufficient duration or certified check shall accompany the plan to guarantee implementation of the proposed stormwater management measures recommended in the plan. The amount of the guaranty shall be based upon the estimated initial construction costs and shall be for 125% of those costs. Upon completion of the recommended measures and submittal of the as-built plan required under §
325-44D(5) of this article, any portion of the guaranty not utilized shall be released or returned.
If the Village Engineer at any time finds that
the stormwater management measures constructed in accordance with
the system plan are not being properly maintained or if they are altered
in any way from the location, configuration and capacity of the measures
specified in the approved plan, the Village Zoning Administrator,
upon the recommendation of the Village Engineer, shall issue an order
to the owner to undertake the needed maintenance or repair. In the
event of noncompliance by the owner within 10 calendar days of actual
service of the order or the taking of an appeal, the Village may seek
an injunction to compel action by the owner. The cost of such legal
enforcement action for maintenance shall be levied as a special charge
pursuant to § 66.60(16), Wis. Stats., against the property
concerned. The special charge shall be collectible in the manner as
provided in § 66.60(16) and (17), Wis. Stats.
The following shall be deemed to constitute
public nuisances and may be prosecuted as such by the Village and
may be enforced by injunction:
A. Any development, redevelopment or property subdivision
that is commenced without an approved stormwater management plan as
required by this article;
B. Any stormwater drainage facility which is not constructed
in accordance with the stormwater management plan required under this
article;
C. Any drainage facility not maintained in accordance with §
325-41 of this article; and
D. Any activity which adversely impacts on surface or
ground water quality.
When the Village Engineer finds that a willful
violation of the provisions of this article exists, the Village Engineer
shall inform the Zoning Administrator, who may order the owner of
the site concerned to correct the violation by issuing a notice of
violation or stop-work order.
A. Any person who commences any site improvements without
an approved plan as required by this article may be required to restore
the land to its original condition within a period of 30 days.
B. If the owner fails to take corrective action after
being noticed, the Village may take all steps necessary to correct
the violation, including but not limited to using Village forces or
engaging contractors after obtaining an injunction in the absence
of consent of the owner.
C. If the owner concerned has filed an irrevocable letter of credit or certified check under §
325-40 of this article, the appropriate guaranty shall be drawn upon.
D. If the owner has not filed an irrevocable letter of
credit or certified check the cost shall be levied as a special charge
against the property concerned under § 66.60(16), Wis. Stats.
E. Any person who does not comply with the provisions
of this article shall be subject to a forfeiture of not less than
$100 and not more than $1,000 for each offense, together with the
costs of prosecution. Each day a violation exists shall be deemed
to constitute a separate offense.