(B) Applicability of site runoff storage requirements (detention).
(1) All developments shall comply with the site runoff storage requirements provided in § 55.023 of this subchapter in which:
(a) More than two single-family structures or one two-family structure are to be constructed on a site five or more acres in size;
(b) Multi-family or nonresidential land use is to be constructed on a site more than one acre in size;
(c) Existing multi-family or nonresidential land uses on a site one acre or more in size, on which new development after the effective date of this chapter in the aggregate exceeds 25,000 square feet;
(d) Roadway developments in rights-of-way under the ownership or control of a unit of local governments when the contiguous area of new roadway construction (excluding previously paved areas) exceeds two acres; and
(e) The developer of a commercial or industrial redevelopment may request that a fee-in-lieu of detention be approved provided that all of the following are demonstrated to the sole satisfaction of the Administrator:
1. The drainage plan will not increase existing flood damages; and
2. The drainage plan provides a net benefit in water quality compared to the existing development.
(2) The Administrator shall determine the appropriate fee to be collected as defined in § 55.215, and his or her decision in the matter shall be considered final.
(C) Exemptions from site runoff storage requirements (detention). Site run-off storage is not required under the following circumstances:
(1) Direct discharge industrial sites; and/or
(2) Non-industrial direct discharge sites 160 acres or less having the following minimum river frontage:
Site Area | Required Frontage |
0—2 acres | 50 feet |
Up to 5 acres | 100 feet |
Up to 10 acres | 150 feet |
Up to 40 acres | 200 feet |
Up to 80 acres | 350 feet |
Up to 160 acres | 500 feet |
(3) In solar farm developments, the solar panels will be considered "disconnected" and therefore pervious, if the following criteria are met:
(a) Groundcover vegetation must be maintained in good condition in those areas receiving disconnected runoff, specifically the area under and between the rows of panels. Typically this maintenance is no different than other lawn or landscaped areas. However, care should be taken to avoid soil compaction in these areas.
(b) The total proposed impervious area on the surface of the ground must be less than 25,000 square feet. The total impervious must include any gravel, pavement, asphalt, concrete, panel posts, and so on.
(c) The open space between panels must be equal to or greater than the width of the row of panels. The runoff must sheet flow onto and across the vegetated area to maintain the disconnection. Sheet flow is optimal on sites with gradual slopes (<5%). Level spreaders, terraces, or berms may be used to maintain sheet flow conditions if the average slope is steeper than 5% and <10%. Installations on slopes >10% will require a detailed engineering study to demonstrate the safe and non-erosive conveyance of runoff to the property line or downstream storm water management practice.
(Res. 02-441, passed 10-17-2002; Res. 02-495, passed 11-21-2002; Res. 04-87, passed 3-17-2004; Ord. 22-24, passed 2-25-2022)