All earthen dikes shall be constructed and maintained as follows:
A. The minimum height of all earthen dikes shall be two feet.
B. Earthen dikes three feet or more in height shall have a flat section at the top or crown of the dike not less than two feet wide.
C. The sloped wall of the dike shall be consistent with the angle of repose of the material of which the walls are constructed, provided that all slopes shall be flat and no slope shall have a gradient steeper than a one foot rise in a two foot horizontal measurement. Diked slope walls shall not be stepped at less than three foot intervals.
D. Prior to surfacing of the earthen dike, the subgrade shall be thoroughly cleaned of organic base material and compacted sufficiently to ensure the stability of side slopes and to withstand a full hydrostatic head. The subgrade shall be trimmed before, during, and after compaction, as necessary to make the subgrade surface smooth and uniform and to give the completed structure the required grade and cross section. Where vegetation is present, the subgrade shall be treated with a soil sterilant to protect against weeds.
E. A firm aggregate foundation base shall be compacted and shaped to a uniform smooth surface, consistent with subsection (D) of this section. Aggregate base may consist of crushed stone, rock, gravel, natural or manufactured sand, or a similar material, as accepted by the department, provided that at least fifty percent of the combined aggregate is rock or gravel.
F. Asphaltic surfacing on all earthen dikes shall be required. Surfacing shall be impervious, prevent leaching through pavement, and shall be stable enough to support a full hydrostatic head. Pavement surface shall be maintained impervious, free from holes and cracks.
G. The top (crests) and bottom edges (toes) of all dike slopes shall be designed so that they will not be damaged by water runoff and to prevent surface runoff from seeping into subgrade under the asphalt boating. The toe embankment should be curved to eliminate possible surfacing weaknesses at critical points. If the embankment toe cannot be curved, a wedge should be placed and compacted to ensure water tightness at the toe.
(Ord. 90-08-1074 § 4 (part))