A. The grading plan shall contain the following information:
1. A vicinity map showing the location of the work;
2. The property line boundary of the site;
3. All existing improvements on and adjacent to the property;
4. The existing and proposed contours of the site. The minimum contour interval shall be one foot or less for slopes five percent or flatter, and five feet or less for slopes steeper than five percent. The contour interval shall be small enough to clearly show the drainage pattern of the site;
5. The existing and proposed drainage;
6. The extent and manner of the cutting of trees and the clearing of vegetation, the disposal of same, and the measures to be taken for the protection of undisturbed trees and vegetation, unless this information is shown on an erosion and sediment control plan;
7. Any other information required by the director of public services.
B. Runoff calculations must be submitted with the grading plan.
1. Maximum runoff shall be computed using the rational method. The rainfall intensity-duration cure contained in the Pinole 5-year Facility Plan, Dated 1975, or a similar curve approved by the director of public services shall be used in the computation.
2. Runoff design shall accommodate the full and anticipated future development within the drainage area.
3. Drainage channels having a drainage area of four square miles or more shall be designed to contain a fifty year frequency of occurrence runoff. Drainage channels having a drainage area of less than four square miles and more than one square mile shall be designed to contain a twenty-five year frequency of occurrence runoff. Drainage channels having a drainage area of one square mile or less shall be designed to contain a ten year frequency of occurrence runoff.
C. The maximum size of each sheet of the grading plan shall be twenty-four inches by forty inches.
D. The scale of the grading plan shall be an engineering scale large enough to show clearly all details, but not less than one inch equals one hundred feet.
E. The details of any drainage structures or retaining walls must be shown on the grading plan.
F. Specifications describing proposed construction methods and materials to be used must be submitted with the grading plan.
G. The grading plan must be signed by a registered civil engineer and must be prepared under his or her direction.
H. An estimate of the cost of accomplishing the work described and delineated on the grading plan and the permit must be submitted in a form which is acceptable to the director of public services. (Ord. 486 (part), 1986).