underline-strikeout version of the final draft ordinance - Pima County ...

For May 4, 2010 BOS HearingTHIS THE CLERK OF THE BOARD FORMAT!!!Chapter 16.48RUNOFF DETENTION SYSTEMSSections:16.48.010 Runoff reduction required when-Specifications adopted.16.48.020 Balanced and critical basins-Development conditions.16.48.030 Structural flood control measures.16.48.040 Fee in lieu of detention requirements.16.48.050 Maps of balanced and critical basins.16.48.010Runoff reduction required when-Specifications adopted.Any new development with residential densities of 3 or more units per acre, or any residentialdevelopment larger than 1 acre that has a density of 6 units per developed acre, as well as allproposed commercial and industrial developments greater than 1 acre in size shall provide somemethod of peak or volumetric runoff reduction, unless fees in lieu of detention are proposedpursuant to 16.48.040 and approved by the Chief Engineer. The amount of reduction is stipulatedwithin the Storm Wwater Detention/Retention Manual. The peak runoff reduction should beprovided through detention of storm water and storm water harvesting for supplementalirrigation, where possible. The Storm Wwater Detention/Retention Manual, approved for use bythe Board, or other applicable engineering standards for storm water control and/or storm waterharvesting that is approved by the Chief Engineer shall be used for design. as of the effectivedate of this title, is made a part of this title. Any revisions to the Storm WwaterRetention/Detention Manual will be reviewed by the Flood Control District AdvisoryCommittee, prior to adoption by the Board as updated design standards for detention/retention.(Ord. 2010 FC-1; Ord. 2005 FC-2 § 2 (part), 2005; Ord. 1999 FC-1 § 1 (part), 1999; Ord. 1988FC-2 Art. 14 (part), 1988)16.48.020Balanced and critical basins-Development conditions.A. Balanced and critical drainage basins are watersheds that have been identified by the ChiefEngineer as unsuitable for increased development because of the high probability of increasedflooding with development and the potential for flooding of existing improvements or property.Critical and balanced basins may be developed further only upon the incorporation of adequatedetention systems or flood control facilities, as reviewed and approved by the Chief Engineer.Drainage basins that have not previously been identified as unsuitable for additional urbandevelopment, shall be considered to be balanced basins, but upon study by the Chief Engineer,may be subject to the critical basin provisions of this chapter. These detention systems or floodcontrol facilities shall be incorporated into any and all future basin-development proposals,regardless of size or land-use density, unless fees in lieu of detention are proposed pursuant to16.48.040 and approved by the Chief Engineer.B. Retention of storm water is not allowed without demonstrating that, over the long-term, theponded waters will not cause a nuisance or a vector problem. In lieu of threshold retention,County requirements will be based upon additional detention requirements for the 2-year storm,69