Packet: Tiffin City Council Work Session (09/15/2026)

CHAPTER 161 POST-CONSTRUCTION STORMWATER RUNOFF CONTROL 7. Include hydrologic and hydraulic design calculations for the pre-development and post-development conditions for the design storms specified in the Iowa Stormwater Management Manual. Such calculations must include: A. Description of the design storm frequency, intensity and duration; B. Time of concentration; C. Data on the increase in rate and volume of runoff for the design storms referenced in the Iowa Stormwater Management Manual; D. Soil curve numbers or runoff coefficients; E. Peak runoff rates and total volumes for each watershed area; F. Culvert capacities; G. Flow velocities; and H. Documentation of sources for all computation methods and field test results. 8. Include a soils report, if a stormwater BMP depends on the hydrologic properties of the soils. The soils report must be based on on-site boring or soil pit profiles. 9. Include a maintenance and repair plan for all stormwater BMPs, including detailed maintenance and repair procedures to ensure their continued efficient function. These plans must identify the parts for components of a stormwater BMP that need to be maintained and the equipment and skills or training necessary. Provisions for periodic review and evaluation of the effectiveness of the maintenance program and the need for revisions or additional maintenance procedures must be included in the plan. 10. Include a detailed landscaping plan for management of vegetation at the site after construction is finished, including the person responsible for the maintenance of vegetation at the site and what practices will be employed to ensure that adequate vegetation cover is preserved. The plan must be prepared by a qualified individual approved by the City, such as a registered landscape architect, wetland specialist, licensed engineer, landscape designer or by the soil and water conservation district. 11. Include proof of permanent recorded maintenance easements that will ensure access to all stormwater BMPs at the site for the purpose of inspection and repair. 12. Include proof of permanent recorded maintenance agreements binding on all subsequent landowners served by stormwater BMPs to ensure maintenance and repair in accordance with the specifications of this chapter. 13. Include copies of all other applicable environmental permits for the site. 14. Include any other information required by the City Engineer to ensure compliance with the requirements of this chapter. CODE OF ORDINANCES, TIFFIN, IOWA - 1430 -