A drainage system shall be designed and constructed by the subdivider to provide for the proper drainage of the surface water of the subdivision and the drainage area of which it is a part. To this end the subdivision shall be graded as required by Section 1173.01, Table 1, and the following requirements and methods shall be followed:
(a) Drainage Plan. Prior to the start of any construction of streets, the subdivider shall furnish a plot plan showing the slab or floor elevation of each house proposed to be constructed. He shall also show by the use of arrows how he proposes to surface drain each lot. The subdivider shall submit topographic maps showing the area to be drained with calculations prepared by a registered professional engineer in determining the proposed storm water collection system.
(b) Drainage Requirements: Grading. No final grading, sidewalk or pavement construction or installation of utilities shall be permitted in any proposed street until the final plat has been approved or conditionally approved. The subdivider shall grade each subdivision as specified in Section 1173.01
, Table 1, in order to establish street, block and lot grades in proper relation to each other to topography as follows:
(1) Street grading plan. A grading plan shall be prepared for the streets along with street improvement details. The grading of the roadway shall extend the full width of the right of way. Planting strips shall be graded at a gradient of one-half inch (½”) per foot from the curb to the sidewalk or property line.
(2) Block and lot grading.
A. Block grading shall be as follows: drainage into the streets or as specified by the City Engineer.
B. Lot grading shall be as follows: lots shall be graded so that water drains away from each building at a minimum grade of two percent. Surface drainage swales shall have a minimum grade of one percent (1%) and shall be designed so that surface water will drain into a driveway, street gutter, storm sewer, drain inlet or natural drainage way. The minimum grade of driveways shall be a minimum of four-tenths percent and a maximum of ten percent.
C. Engineered fill. All areas within the street right-of-way as well as all areas within the building area.,i.e., between the right-of-way line and the rear setback line of each lot, requiring fill, must first be completely stripped of all topsoil and vegetation prior to the placement of any fill. Additionally, all fill in these areas must be placed in accordance with the compacted fill specifications specified by the City Engineer.
(3) Topsoil. If grading results in the stripping of topsoil, the topsoil shall not be removed from the site or used as fill, but shall be saved and uniformly spread over the lots as grading is finished.
(4) Trees. As many trees as can be reasonably utilized in the final development plan shall be retained and the grading adjusted to the existing grade at the trees at the drip line.
(c) Drainage System Requirements. Grading of the subdivision, the road drainage system, and Off-road drainage systems shall be done with regard to the natural drainage of the area involved, and open ditches, conduits, catch basins, inlets and manholes of adequate size shall be constructed to provide for such drainage. The design criteria for the drainage systems shall be as approved by the City Engineer based on the Medina County Storm Water Management and Sediment Control Rules and Regulations.
(1) All watercourses or ditches with a design capacity not exceeding the capacity of a thirty-six inch concrete pipe shall be enclosed. Existing creeks or ditches constructed by the subdivider which exceed the above limit shall be constructed with a minimum fifteen-foot wide continuous earth roadway to provide access for maintenance equipment to all sections of the ditch. The ditch easement shall be wide enough to contain ditch slopes and roadway with ample clearance for the operation of maintenance equipment. Open ditches will have a side slope ratio of two to one and a minimum of a two-foot bottom width.
(2) No open ditch shall be constructed within 100 feet of the rear of a house, as measured from the house to the edge of the ditch easement.
(3) Any storm drainage courses carried along side lot lines shall be enclosed with approved pipe.
(4) Easements for drainage purposes shall be a minimum of fifteen feet in width. Where the watercourse is larger ( including retention and detention basins), easement widths shall be increased as determined by the City Engineer including any access easements. (See subsection (c)(2) hereof). Where watercourses cross plotted lots diagonally, the subdivider shall straighten such courses where practicable and shall substantially follow sublot lines. Easements shall be shown on the record plat and deeds and shall cover all existing or reconstructed watercourses.
(d) Protection of Drainage Systems. The subdivider shall adequately protect all ditches (roadways and watercourses) to the satisfaction of the City Engineer as follows:
(1) Any watercourse having a gradient in excess of two and one-half percent shall be enclosed with pipe with the necessary inlets and shall be piped to a storm sewer, if nearby, or otherwise to a natural watercourse. Where a street is of considerable length and of various gradients, a part of which requires storm sewers, the lengths between the storm sewers, even though less than two and one-half percent gradient, shall also be enclosed in pipe, when required by the City Engineer. Material and construction shall be in accordance with the specifications of the City Engineer. Watercourses or road gutters having a gradient of less than two and one-half percent but more than one and one-half percent shall be sodded or paved with brick, concrete, half tile or broken concrete slabs. All areas within the right of way not paved or sodded shall be fertilized and seeded.
(2) All adjoining land where the vegetation has been injured or destroyed or where the land is in need of protection to prevent erosion, deposits in the drainage facilities and/or unsightly conditions shall be restored and protected as directed by the City Engineer.
(3) In all cases, any drainage facilities within the subdivision shall be in a stable condition, free from either erosion or sedimentation and/or other debris.
(4) All trenches under the paved areas shall be backfilled with gravel or screenings, or thoroughly compacted earth in four-inch layers, loose measurement as required by the City Engineer.
(e) Pipe Policy. Pipe strength and materials along with joining materials shall be subject to the approval of the City Engineer.