The developer shall prepare a plan and grade each subdivision in order to establish street grades, lot grades, and floor elevations of buildings of proper relation to each other and to existing topography, as follows:
(a) Grading Plan. Subdivisions shall be planned to take advantage of the natural topography so as to minimize grading as set forth in Section 1163.02
. A grading plan shall be prepared for the street areas along with the street improvement details in accord with standards set forth in Section 1163.03
(k); 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.
(b) Block Grading. The grading of blocks and lots shall be in accord with the standards established by the Federal Housing Administration, Land Planning Bulletin No. 3, or standards of the City. The plans may be based on any of the following grading systems:
(1) Where there is a ridge along rear lot lines, and the lots drain to the streets,
(2) Where parts of all lots drain to a swale, or ditch along rear lot lines,
(3) Where there is a cross slope, the drainage onto adjoining properties shall be skillfully controlled,
(4) Where the land is relatively flat and adequate drainage must be formed,
(5) Or, a variation of the above conditions.
The grading of the roadway shall extend the full width of the right-of-way. Tree lawns shall be graded at a gradient of not less than 2 percent or more than 3 percent upward or downward from the curb to the sidewalk or property line.
(c) Lot Grading. The floor elevation of each building shall be established in proper relation to the surrounding grade, the driveway and the street. The lot shall be graded so that water drains away from each building at a minimum grade of 2 percent. Surface drainage swales shall have a minimum grade of 0.5 percent and be designed so that surface water will drain onto a driveway, a street gutter, storm sewer, drain inlet or natural drainage way. The minimum grades of driveways shall be 0.4 percent, and a maximum of 15 percent. Grading shall be adjusted so there will be no abrupt grades in the front yards and along side lot lines. The grades of earth terraces shall not exceed 2 1/2 to 1. If a masonry retaining wall exceeds three (3) feet in height, a hedge, fence or railing shall be provided.
(d) Top Soil and Trees. The Commission may require that top soil shall be stripped from the roadway and construction areas, piled separately but not removed from the site or used as spoil. It may also require that as many trees as can be reasonably utilized in the final development plan be retained, and the grading be adjusted to the existing grade as the trees.