(A) The calculation of slope used in determining whether an area is to be classified as a hillside subdivision shall be determined in accordance with the following criteria and formula.
(B) The proposed subdivision, or portion thereof, seeking classification as a hillside subdivision shall be delineated on a preliminary plat of the property. The plat shall contain contour lines of the property at intervals not exceeding five feet. The plat and contour lines shall be prepared by a registered surveyor or registered engineer.
(C) The formula for determining the percent of slope is as follows.
S = .0023 x I x L
A
(D) In the equation, “S” is the percent of slope, “.0023” is a conversion factor of square feet to acres, “I” is the contour interval (or the distance between adjacent contour lines within the subject parcel), and “A” is the area in acres of the subject parcel.
(1) Step 1. Determine “I”, the contour interval, by examining the map or measuring the interval, using the key on the map.
(2) Step 2. Determine “L”, the total length of the contour lines within the subject area, by tracing each line with a planimeter and converting to feet on the basis of the map’s scale.
(3) Step 3. Determine “A”, area (in acres) from the development plans or permit application.
(4) Step 4. Determine the slope, “S”, by inserting the appropriate numbers in the equation.
(Prior Code, Ch. 12 Art. V § 502)