A grading plan shall be prepared for the street areas along with the street improvement details in accordance with standards set forth in this chapter, and before buildings may be constructed a detailed land development plan shall be prepared showing the buildings and paved areas on each lot and the grading of each block and lot. The developer shall prepare a plan and grade for each subdivision or development in order to establish street grades, lot grades and floor elevations of buildings in proper relation to each other and to existing topography, as follows:
(a) Drainage Grading Plan.
(1) Preliminary grading and drainage plans shall be of approved appropriate scale on sheets not larger than thirty-six by thirty-six inches.
(2) Final grading and drainage plans shall be of approved appropriate scale on sheets not larger than thirty-six inches by thirty-six inches of India ink on linen or Milar.
(3) Erosion and Sedimentation Control Plan. The erosion and sedimentation plans shall be of approved appropriate scale on sheets not larger than thirty-six inches by thirty-six inches.
(4) Plats shall be 100 scale (1" = 100') or larger of India ink on linen or Milar eighteen inches by twenty-four inches.
(5) Hydraulic Calculations: Hydrologic calculations for all critical points within the system showing:
A. Tributary drainage areas within the subdivision shown on a map. Large areas outside the subdivision may be calculated using a U.S.G.S. Topo Map.
B. Design flow calculations listing times of concentration, intensity, and run-off coefficients.
(6) Hydraulic Design: Hydraulic design shall be shown by use of plan and profile of all drainage ways, conduits, and culverts, including a cross section of open channels showing design flow depth, sizes and types of conduits and culverts, drainage structures, and easement widths. Supporting calculations for downstream channel capacities as they affect overflow or backwater within the subdivision may be required. A list of the reference sources used for the hydrologic and hydraulic calculation should be included to aid in checking the calculations.
(7) Drainage Plans: When separate drainage plans are necessary, they should show the following information:
A. The same identification as the preliminary plat.
B. Boundaries and streets as on preliminary plat with some lot lines if they are necessary.
C. Existing drainage facilities with pertinent information.
D. Tributary areas with acreage (where scale will permit) with the streams, ditches, swamp, etc.
E. Acreage of large tributary areas given with a brief description of their location relative to the subdivision.
(8) Flood plains and high water levels.
(9) Proposed drainage facilities with pertinent data such as invert elevations.
(10) Drains or outlets to natural drainage courses.
(11) Any necessary drainage easements inside and outside the subdivision.
(b) Block Grading.
(1) The grading of blocks and lots shall be in accordance with the standards established by the standards of the Village. The plans may be based on any of the following grading systems:
(2) Where there is a ridge along rear lot lines and the lots drain to a rear yard drain, swale or ditch;
(3) Where parts of all lots drain to a swale or ditch along rear lot lines;
(4) Where there is a cross slope the drainage onto adjoining properties shall be skillfully controlled;
(5) Where the land is relatively flat and adequate drainage must be formed; or
(6) A variation of the above conditions.
(c) Grading of Lots.
(1) The floor elevation of each building shall be established in proper relation to the surrounding grade, the driveway and the street.
(2) The lot shall be graded so that water drains away from each building at a minimum grade of two percent (2%).
(3) Surface drainage swales shall have a minimum grade of five-tenths percent (0.5%) and be designed so that surface water will drain into a storm sewer, drain inlet or natural drainage way.
(4) The minimum grades of driveways shall be four-tenths percent (0.4%) and a maximum of fifteen percent (15%). Grading shall be adjusted so there will be no abrupt grades in the front yards and alongside lot lines.
(5) The grades of earth terraces shall not exceed two and one-half to one.
(6) If a masonry retaining wall exceeds three feet in height, a hedge, fence or railing shall be provided.
(d) Right of Way Grading.
(1) All walks and driveways shall be constructed or reconstructed to conform to the grade on the right of way where the grade has been established. The surface of all walks shall have a transverse slope of one-fourth inch to one- half inch per foot with the low side nearest to the curb line.
(2) Whenever permission is requested and granted to construct or reconstruct a walk where the surface of such walk has a transverse slope of a rate of more than one-half inch to the foot, the permit shall be granted and received only on the condition that Council may at any time thereafter order such walks to be reconstructed to the established grade of the right of way, entirely at the expense of the abutting property owner.
(3) In all cases where sidewalks cross a driveway or runway, the full width of the sidewalk shall conform to the established grade of the sidewalk adjoining both sides of such driveway or runway, unless permission has been first obtained from the Mayor or his/her designee. However, in all cases no less than a three-foot width of sidewalk shall conform to the grade of the sidewalks adjoining both sides of the driveway or runway.
(4) Upon a right of way where the grade has been established but where the street has not been improved by paving or grading to such grade, walks shall be constructed in conformity with the established grade or as specified in the legislation providing for the construction or reconstruction of such walks, driveways and curb openings. However, when walks are ordered by Council or are constructed or reconstructed without such order by the owner of property abutting on a right of way where no grade is established, such walks may be constructed or reconstructed at such levels and inclinations as may be prescribed by the Street Superintendent. When such permission is requested of and granted by the Street Superintendent to construct or reconstruct a walk on such right of way, it shall be granted and the walk shall be constructed or reconstructed only on condition that when a grade is established, such walk shall be removed and reconstructed to the grade which may thereafter be established by the Street Superintendent for such street, entirely at the expense of the owner of the property abutting on such street.
(5) Whenever a sidewalk is reconstructed to a grade that does not meet the grade of adjacent existing walks, the person constructing the new sidewalk shall construct a ramp to eliminate any stub toes or grade inequality. The materials, workmanship and character of the ramp shall be as determined by the Street Superintendent.
(e) Grading of Streets. Streets shall be related appropriately to the topography:
(1) A subdivision shall be planned so that as many lots as possible will be above the street grade. On irregular topography, streets shall be designed to avoid extensive cuts and fills and to comply with grading standards hereinafter established for private driveways and yards as well as for the streets. Streets approximately parallel to contour lines shall be adjusted so that the lots on one side of the street will not be excessively below the street grade.
(2) Grades of streets shall not exceed ten percent (10%) for local streets, seven percent (7%) for secondary streets and six percent (6%) for major streets. However, in no case may streets be constructed with grades that, in the professional opinion of the Village Engineer, create a substantial danger to the public safety. Street grades shall be not less than four-tenths percent (0.4%) in order to provide adequate surface drainage, provided, however, approval may be requested to permit a minimum of twenty-five hundredths percent (0.25%) where necessary because of topographic or other conditions.
(3) Street grades shall conform as closely as practicable to the original topography. All changes in grade shall be connected by vertical curves of sufficient length to provide a smooth transition and clear visibility for vehicular operations. A rate of change of grade of three or four percent (3% or 4%) per 100 feet is the maximum recommended to give at least 100 feet of sight distance. Streets shall level off to a grade not exceeding three percent (3%) for a distance of not less than 100 feet from each side of an intersection. (Ord. 2014-19. Passed 8-21-14.)