(A) As used in this section, the following terms shall means:
(1) "DETENTION." Facilities designed to hold runoff while gradually releasing it at an allowable discharge.
(2) "RETENTION." Facilities designed to hold water for a substantial period of time and releasing it through evaporation, plant transpiration or infiltration into the soil.
(3) "HYDROLOGIC RESPONSE." The manner and means by which storm and surface water collects on the property and is conveyed from that property, and which is a function dependent upon a number of interacting factors, including, but not limited to, topography, vegetation, geologic conditions, soil moisture conditions and ground water conditions. The principal measures of the hydrologic system may be stated in terms of total runoff volume, as a percentage of total precipitation which runs off, or in terms of the peak rate of flow generated by a storm of given duration, intensity or frequency.
(B) Some properties, due to their unique topography or geology, or due to the construction and maintenance of storm water control or detention facilities, may have a hydrologic response substantially similar to properties with lesser amounts of impervious surface.
(C) Any Class B property owner who has installed an approved on-site "retention" or "detention" facility may apply for an adjustment of equivalent service units applied to that specific parcel. Provided that the resulting adjustment will be commensurate with the facility's mitigating effects on runoff and provided that no property's service charge adjustment results in a rate which is less than the fee paid by single family residential property. Applications shall be made on forms supplied by the city.
(D) The city may adjust the drainage utility charge for the properties based on hydrologic data submitted by the property owner or his agent which demonstrates a hydrologic response substantially similar to that of a property with a lesser amount of impervious surface. This data will include as a minimum:
(1) The site's approved drainage plan.
(2) Hydrologic analyses for the property.
(3) Facility design specifications.
(4) Maximum discharge rate physically possible.
(5) Current flows into the facility and the amount of impervious area designed to be serviced by the facility.
(6) The amount of impervious surface on the property if different from the city’s measurement.
(E) All adjustment will remain in effect as long as:
(1) The property owner has obtained the permits required by the city and the facility has been constructed in compliance with all approved plans.
(2) The property owner remains responsible for all costs of operation and maintenance of the facility.
(3) The city will have access to the facility for purposes of inspection its compliance with design, maintenance and operating standards.
(F) Detention credit will be based upon the Criteria and Calculation contained in Exhibit "A" which is attached hereto and incorporated herein.
(Ord. O-27-92, passed 9-22-92; Am. Ord. O-09-03, passed 5-13-03; Am. Ord. O-20-03, passed 9-2-03)