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~ Water Ouality -Developments must incorporate effective non-point ~' <br />source pollution reduction BMPs to achieve 90°/n and/or 40% total <br />suspended solids removal from the runoff venerated by a NURP water <br />quality storm (2 5" rainfalll Runoff volume reduction requirement may <br />be considered and included in the calculations showinv compliance with <br />achievinv the 90% TSS and/or 40°/n TSS removal requirement. Water <br />quality calculations documentation and/or water quality modeliny shall <br />be submitted to yeti compliance with the standard. <br />3 Runoff rate control - h~droloyic calculations - A hvdrog_raph method <br />based on sound hydroloyic theory shall be used to analyze runoff for the <br />desiPn or analysis of flows and water levels.. <br />~ o....,. CF ..,.«e ..,.«tr..l .1 ~~~,... ot~...lor.ie _ Riinnff ratee fnr tha nrnnncrrt <br />100-year critical storm events and runoff rates may be restricted to less <br />than the existinv rates when the capacity of downstream conveyance <br />stems is limited. <br />5. Outlets -Discharges from new construction sites tnust have a stable <br />outlet capable of carrying designed flow at anon-erosive velocity. <br />Outlet design must consider flow capacity and flow duration. This ' <br />requirement applies to both the site outlet and the ultimate outlet Co <br />stormwater conveyance or waterbody. <br />6. Pond Requirements -For all projects creating more than one acre of <br />impervious surface, pending shall be required. At a minimum all pond <br />design specifications shall conform to the current it -and~NPDES ,-- <br />constructionpermitrequirements [n_addition the following-are_required;-_,>, <br />;'.'., <br />a. f{ bench shall be provided starting at the normal water level and .--.-_-_-'" ' <br />ending 1 foot below normal water level with side slopes no less <br />than 10 feet horizontal to 1 fooC vertical (10:1) for safety <br />a. ponsiderations._, - - - ... <br />a. Pond side slopes shall noC exceed 4 feeC horizontal to 1 foot vertical <br />(4.1) without approval of the City. <br />Fnrmatted: Bullets and Numbering <br />Formatted: Bullets and Numbering <br />Formatted: Bullets and Numbering <br />Deleted: <)pMinimize impervious <br />surface area and maximiu infil[rntion <br />-The project shall use existing nanual <br />drainage ways and vegetated soil surfaces <br />to convey, store, filter, and stain <br />stormwater runoff before discharge into <br />public waters or a stormwater conveyance <br />sysmm (penvanGn pool areas of wet <br />ponds tend to lose infiltration capuity <br />wtd will not be accepted as an infhration <br />practioo). Th¢ applica~rt shall limit the <br />impervious suffaw of the developed situ <br />or subdivision by incorporating the <br />following design considerations, <br />cmrsistent with zoning, snbdivision, artd <br />PUD requirmncntsal <br /><q>Narrowing svect widths <br /><#>Reducing parking lot spaccQ <br /><U>Sidewalk locations¶ <br /><#>GSp>Reducing setbacks atd <br />drivcwayst <br /><R>Maximizing open space while <br />incorporating smaller lot sixes to <br />conserve natnral areas and reduce the <br />amount of smnnwater runoff generated at <br />the site¶ <br /><#>Using landscaping and soils to treat <br />and infilhate stormwater mnoff 7 <br /><%>Bliminate curb and gutter where <br />practicable, mtd use vegetated swales or <br />equivalentP <br /><I{>LOOk for vegem[ed areas that can <br />filter sheet Flow, rmnoving sediment and <br />other pollutants, and increasing the time <br />of concenvation <br /><U>Disconnec[ impervious areas' by <br />allowing nmo(f Crom small impervious <br />areas to be directed to pervious areas <br />whore it pan be infiltret¢d or Gltor¢d.¶ <br />dPAil nmotr from downspouts, <br />driveways and otherimpervious at ra <br />Formatted: Bullets and Numbering <br />Deleted: version of the approved <br />Community Design Manual <br />Deleted: the current requirements <br />found in the <br />~';~ Deleted: <br />Deleted: All stormwater ponds shall be <br />provided with a forebay area to provide <br />for the senlement of fine sand sized <br />All public and private owned stormwater management racu¢les <br />shall provide an unobstructed access math (minimum of 10 feed <br />gable of supporting li>;ht truck traffic during normal weather for <br />the purpose of conductiny ins affections of the facility and <br />maintenance thereof No private stormwater facility may be . <br />anaroved unless an easement is provided to the City allowiny <br />access for maintenance and inspection Maintenance avreements <br />before durine and after development are also required <br />Deleted: Pond side slopes shall not <br />exceed 4 feet horizontal to 1 foot vertical <br />(4:1)and should. provide a bench just at J <br />tl,¢ <br />Deleted: considerations.Q <br />'; Deleted: All pnblic and private owned <br />stormwater managenunt facditics shall <br />provide an unobstmged access path <br />(minimwn of 20 feet) capable of ~5] <br />Formatted: Bullets and Numbering <br />