(a) Outlets. No subdivision shall be approved by the Planning and Zoning Board unless there is an adequate outlet for stormwater as determined by the Village Engineer. Generally it will be necessary to pipe storm water to an adequate watercourse, stream or existing storm system which has the capacity to accommodate the flow, or to utilize acceptable on-site water retention methods adequate to minimize excessive off-site stormwater flows
(b) Preservation of Natural Drainage Courses. No natural drainage course shall be altered and no fill, buildings or structures shall be located unless provision is made for the flow of surface water, in a manner satisfactory to the Village Engineer. An easement shall be provided on both sides of the existing surface drainage course adequate for the purpose of future widening, deepening, enclosing or otherwise improving said drainage course. If such drainage course crosses private property, easements must be obtained by the Owner/Developer for construction and future maintenance. These easements must be shown on the Construction Plans. A copy of the recorded easement shall be shown on the final plat or incorporated by reference to the volume and page number of the recorded easement
(c) Grades. All surface areas not covered by a hard surface improvement or stone shall be seeded or sodded and sloped to drain, according to the following:
(1) Grass areas shall have a minimum slope or grade of one percent (1.0%).
(2) Grass areas next to buildings shall slope away from the building at not less than five percent (5%) for a minimum of ten feet.
(3) Ditches or swales in grassed areas with a bottom slope or grade between two percent and seven percent (2-7%) shall be sodded.
(4) Ditches or swales with a bottom slope or grade greater than seven percent (7%) shall have a paved or stone gutter as required by the Village Engineer.
(5) Ditches or channels with a slope flatter than one percent (1.0%) shall have a paved bottom.
(d) Drainage Data.
(1) Stormwater management practices for proposed development shall conform with the design standards and requirements as set forth in the “Stormwater Design Manual” (Mid-Ohio Regional Planning Commission; June, 1977) as may be subsequently revised.
(2) The storm drainage system of a proposed subdivision shall be designed to flow full conveying the stormwater runoff generated by a two (2) year frequency storm. The system shall also be capable of accommodating a five (5) year frequency storm such that the hydraulic grade line does not exceed the top of any structure grade.
(3) A major storm flood routing path shall be designed for all developments. This route shall be a part of the required storm drainage system and designed to carry stormwater runoff from a storm with a frequency of not less than 100 years, without causing significant threat to property or public safety. Depth of flow shall not exceed six inches (6") above the curb. An easement must be dedicated for the protection and maintenance of this flood route.
(4) Drainage calculations shall be submitted along with a master drainage plan to the Zoning Inspector at the same time the construction drawings and/or Development Plan is submitted.
(e) Culverts. All culverts utilized in subdivisions shall have the appropriate headwalls and other structures and improvements to protect the facility, as determined by the Village Engineer. Such culverts shall be designed according to the most current Ohio Department of Transportation (ODOT) drainage design recommendations.
(Ord. 2000-14. Passed 7-24-00.)