(a) Responsibility. The Village is not responsible for providing drainage facilities on private property for the management of stormwater on the private property. It shall be the responsibility of the property owner to maintain private stormwater facilities serving the property and to prevent or correct the accumulation of debris, which interferes with the drainage or stormwater management function of the system. All developments and earth changes subject to review under the requirements of this chapter shall be designed, constructed, and maintained to control runoff, prevent flooding and protect water quality. The particular facilities and measures required onsite shall reflect the natural features, wetland, and watercourses on the site; the potential for onsite and offsite flooding, water pollution, and erosion; and the size of the site.
(b) General Standards for Onsite and Offsite Stormwater Management.
(1) Stormwater facilities shall be designed to prevent flood hazards and water pollution related to stormwater runoff, soil erosion and channel erosion from the proposed earth change.
(2) Existing stormwater from upstream and offsite locations shall be conveyed around or through the site, or stored onsite.
(3) Every stormwater facility shall control the release of stormwater in accordance with the design standards adopted by Village Council resolution.
(4) Unless otherwise approved, stormwater runoff shall be conveyed through swales and vegetated buffer strips so as to decrease runoff velocity, allow for natural infiltration and passive storage, allow suspended sediment particles to settle, and to remove pollutants.
(5) Alterations to natural drainage patterns shall not increase runoff, create flooding or water pollution for adjacent or downstream property owners.
(6) Cutting, filling, and grading shall be minimized and the natural topography of the site shall be preserved to the maximum extent practicable, except where specific findings demonstrate that major alterations will still meet the purposes and requirements of this chapter.
(7) Grading of lands at locations that are adjacent to or near lands, streets, alleys, sidewalks, or other public or private property shall be done in a manner to protect the property from settling, cracking or sustaining other damage.
(8) All development and other earth changes shall be designed, constructed, and completed so that the exposed area of any disturbed land is limited to the shortest possible period of time.
(9) Damage to public utilities or services and damage to or impairment of any water body on or near the location of any water body shall be prevented.
(10) Natural wetlands shall be maintained to the maximum extent practicable.
(11) Increased offsite release of stormwater shall be minimized to the maximum extent practicable. Therefore, the volume of stormwater shall be managed and stored to the maximum extent practicable.
(12) The increased volume of water discharged due to earth changes and/or development of the site shall not create adverse impacts to property owners and watercourses. These adverse impacts may include, but are not limited to flooding, excessive soil saturation, crop damage, erosion, and/or degradation in water quality or habitat.
(13) Discharges or flows from firefighting activities to the Village's storm sewer system are not prohibited, provided, however, that they must be addressed if they are identified as significant sources of pollution to the waters of the State of Michigan.
(14) If identified as a significant contributor of pollutants to the Village's storm sewer system, the following categories of non-stormwater discharges or flows shall be prohibited:
A. Water line flushing and discharges from potable water sources;
B. Landscape irrigation runoff, lawn watering runoff, and irrigation waters;
C. Diverted stream flows and flows from riparian habitats and wetlands;
D. Rising groundwaters and springs;
E. Uncontaminated groundwater infiltration and seepage;
F. Uncontaminated pumped groundwater, except for groundwater cleanups specifically authorized by NPDES permits;
G. Foundation drains, water from crawl space pumps, footing drains, and basement sump pumps;
H. Air conditioning condensation;
I. Waters from noncommercial car washing;
J. Street wash water; and
K. Dechlorinated swimming pool water from single, two, or three family residences. (A swimming pool operated by the permittee shall not be discharged to a separate storm sewer or to surface waters of the state without NPDES permit authorization from EGLE.)
(c) Stormwater Facilities. The types of stormwater facilities are listed in order of preference, with the most desirable listed first.
(1) Infiltration Facilities. This chapter encourages the use of infiltration systems as a part of stormwater management plan design. Stormwater storage and/or infiltration facilities, which protect water quality and minimize flooding, shall be designed to meet the standards of this chapter. Storage facilities may include, but are not limited to, detention basins, retention basins, infiltration trenches, swales with check dams, bioretention structures and other facilities and/or BMP's proposed by the applicant. It shall be the responsibility of the applicant to demonstrate that all proposed facilities meet the intent, goals, and standards of this chapter. As the rate of percolation/infiltration of water into the soil column varies depending on the soil type, the type of infiltration system used may be site specific. Stormwater management plan designers shall consider soil permeability when designing storm water infiltration components of a management system. The site developer shall attempt to minimize compaction of soil, which decreases infiltration and groundwater recharge and contributes to increased stormwater runoff.
(2) Stormwater Storage Facilities. All detention and/or retention basins shall be designed to meet the standards of this chapter. The types of basins are listed in order of preference, with the most desirable listed first:
A. Wet basins, or detention basins with a fixed minimum water elevation between runoff events. Wet basins, which serve to trap soil particles onsite, are preferable to dry basins.
B. Detention basins, which detain the first flush of an event and attenuate its release over an extended period.
C. Extended detention basins, which hold stormwater from a less frequent storm event over an extended period before completely draining to become a dry basin. Dry basins without extended detention shall not be permitted.
D. Detention and/or retention basins shall be designed to hold runoff from a 100-year frequency storm event. Basins shall be permanently stabilized to minimize erosion. Detention and/or retention 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 back-to-back 100-year storm events.
E. Detention and/or retention basins and associated berms and landscaping shall be designed to protect public safety and to be visually attractive.
F. Detention and/or retention basins shall be provided in platted outlots, common areas or open space areas.
(Ord. 154. Passed 10-12-11; Ord. 154A-1. Passed 7-14-21.)