Resolutions-2012-33

CITY OF TIFFIN, IOWA, RESOLUTION NO. 2012 -33 A RESOLUTION APPROVING CHANGES IN TIFFIN DESIGN STANDARD SECTION 9. 13 STORM WATER MANAGEMENT FACILITIES WHEREAS, the City of Tiffin, wishes to amend the Tiffin Design Standards Section 9. 13 regarding storm water management facilities by repealing the existing section and adopting the following in its place; WHEREAS, Section 9. 13 Storm -Water Management Facilities will now read as follows: D. Location Criteria: 1. Storm water retention and management facilities will not be deeded to or maintained by the City unless the City makes a specific agreement with the developer to undertake ownership or management. 2. Storm water detention is not allowed within any front or side yard setbacks, required by building code, or within 25 feet from the estimated back building line. 3. Regional storm water management facilities are encouraged and may be required. 4. Required storm water management facilities that are of sufficient size may be deeded to and maintained by the City. The conditions for City ownership will be reviewed on a case by case basis. E. Design considerations 1. Dry- bottom detention facilities must be oversized by 10% to help offset anticipated sedimentation prior to total watershed development. 2. Maximum side slopes of dry bottom facilities will not exceed 3: 5: 1. Maximum side slopes from the point of normal water level to a point 20 feet land side and 20 feet water side must be 9: 1. The maximum rip -rap slope be increased to 3 feet. 3. Low flow pipes are required to convey low flows from storm sewer outlets to the detention facility outlet structure. Low flow pipes must be a minimum of 12 inches in diameter unless it can be shown that the bottom of the detention facility will remain dry. Low flow pipes shall must be slotted and bedded in freely draining aggregate. Alternate methods of subsurface drainage may be proposed. 4. Wet detention ponds must include erosion stone rip -rap. 5. All detention facilities must be graded such that all areas to have grass will be in mowing condition. 6. Wet detention ponds must have minimum pool depth of 10 feet for at least 25% of the permanent pool area. Upon completion of the pond, the owner must stock the pond with appropriate bass, bluegill, and catfish combination. Owner may contact DNR fisheries for fish stocking.