(A) When required by the Director of Public Works, the applicant shall submit hydrology and hydraulic calculations and drainage area maps to determine the quantity of runoff generated by or tributary to the city, and its effects on the site or upon upstream or downstream properties. Erosion and sediment transfer studies, and other supporting data may be required.
(B) Limits of inundation on the subject property during condition of specified storm frequencies may be required to be delineated on the grading plan, along with the submittal of supporting calculations.
(1) Properties of one acre or greater in size shall be designed to retain the 100-year, 24-hour, duration storm on site. Such properties shall retain this duration storm on site or provide a drainage system to convey the drainage to an acceptable retention site as determined by the Director of Public Works. Such a drainage system shall include a provision to fully address disposal of nuisance water to the satisfaction of the Director of Public Works.
(2) Properties of less than one acre in size shall incorporate retention and drainage systems and/or properties approved by the Director of Public Works; such approval shall not be unreasonably withheld.
(C) The civil engineer responsible for preparation of the plans shall also certify that the building pads to be created through any proposed grading, are free from inundation from runoff from specified storms, and to provide floodplain elevations, and widths, sheet flow depths, floodway elevation and widths, and any other data required by the Director of Public Works, or by any applicable county, state or federal flood protection or insurance program or requirement.
(D) The civil engineer or applicant may also be required to prepare and submit, suitable studies and data regarding percolation and permeability characteristics of the soils and their suitability for the use of septic tanks ground water hydrology studies, data, and tests regarding the quantity and quality of ground water which can be produced from properties not served by water systems, and its adequacy for domestic and agricultural use and for fire protection.
(Ord. 1449, passed 10-19-05)