2015-009 Council Ordinances - Laserfiche WebLink

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c. Conveyance system. Wherever possible untreated and treated stormwater runoff shall be conveyed in facilities open to the atmosphere (e.g. swales, vegetated buffer strips, energy - dissipating structures, and the like) rather than through enclosed pipes, so as to decrease runoff velocity, allow for natural infiltration, allow suspended sediment particles to settle, and to remove pollutants. d. Proposed development design shall: 1. Maintain or decrease runoff volume. 2. Decrease erosion and sedimentation. 3. Maintain or decrease flow frequency, duration, and peak runoff rates. 4. Increase infiltration (groundwater recharge) or filtration. 5. Maintain existing flow patterns. 6. Reduce time to peak flows by increasing the time of concentration to and through storm sewers. 7. Provide storage of stormwater runoff on site. 8. Avoid channel erosion. 9. The proposed project must not adversely affect water level off the site during or after construction. 10. The proposed activity may not reduce hydraulic efficiency of the drainage ways at any point up -gradient of the applicant's parcel boundary. e. Landlocked basins. A landlocked basin may be provided an outlet only if it: 1. Retains a hydrologic regime that complies with the requirements of the local governmental unit (LGU) responsible for administration of the Wetland Conservation Act (WCA); and 2. Provides sufficient dead storage volume to retain back to back 100 -year, 24-hour rainfalls and runoff; and 3. Does not create adverse downstream flooding or water quality conditions as a result of increased discharge rate or volume, or other factors. f. All plans shall be consistent with National Pollutant Discharge Elimination permit (NPDES) requirements, the Lino Lakes engineering design standards, the Lino Lakes stormwater design standards, and the filing or approval requirements of Rice Creek Watershed District, DRAFT ORD 09-15 CHAPTER 1011STORMWATER & ESC ORDINANCE.DOCX 16/29