Prior to the adoption of Ord. 2007-05 on 04/25/2007, Section 16.58.400 read as follows.

Storm drainage ~~damage~~ facilities shall be constructed in order to ~~properly maintain~~ convey and retain storm water on the site based on the rainfall design volume and peak discharge ~~depth of 0.75 inches per hour.~~ in accordance with a 24 hour storm duration with a 100 year return period. Calculations shall be based on standard engineering methods, or if computer modeling is used, Natural Resource Conservation Service (Soil Conservation Service) methods TR-20 or TR-55 using a type II rainfall distribution curve. Rainfall depths used shall be in accordance with National Atmospheric & Oceanic Administration estimates for the Vernal airport. Conveyance shall be designed and constructed in such a fashion as to prevent private property and infrastructure from being damaged during the storm event. Such storm drainage facilities shall be installed in accordance to City standards as directed by the City Engineer, the Department of Environmental Quality and the local health department.

1. The drainage system shall be designed to consider the drainage basin as an whole and shall accommodate not only runoff from the subdivision area but also, where applicable, the system shall be designed to accommodate the runoff from those areas adjacent upstream from the subdivision itself, as well as its effects on lands downstream. Multifamily and commercial subdivisions shall have retention facilities for storm water runoff incorporated entirely within the boundary of each lot.

3. All appropriate designs, details and dimensions needed to clearly explain proposed construction materials and elevations shall be included in the drainage plans. (PZSC § 03-28-006(7))(Ord. No. 96-08, Amended, 03/20/96)