A. A drainage plan prepared, signed and sealed by a registered professional shall include, at a minimum, a description of the property, description of the drainage basin disturbed by the development, methods and assumptions of the registered professional, and results for culvert locations, culvert outlet controls, drainage easements, ditch section and ditch lining.

B. The design of any drainage structures or reservoirs shall be sufficient to carry surface water runoff from spring melt and/or 10-year rainstorm events which may result from present or projected development.

C. All structures for erosion/runoff control shall be designed by the subdivider in compliance with the applicable state and federal statutes and regulations.

D. Minimum roadway culvert size for drainage shall be 18-inch diameter corrugated metal pipe or equal with at least a one percent drainage grade through the culvert. In areas where the natural drainage is one percent or less, the minimum drainage grade through the culvert may be reduced to three-tenths of one percent, or as allowed by the Borough engineer.

E. Minimum roadway culvert size for water equalization shall be 12-inch diameter when approved by the Borough engineer. (Ord. 2005-33 § 15, 2006; Ord. 2005-10 § 2, 2005. 2004 Code § 17.60.180.)