§ 161.09 Storm Water Management Plan Requirements

The Storm Water Management Plan or each development subject to this chapter must:

1. Be prepared by a licensed professional engineer.

2. Indicate whether storm water will be managed on-site or off-site and, if on-site, the general location and type of BMPs, with clear citation to the Iowa Storm Water Management Manual.

3. Include a signed and dated certification under penalty of perjury by the preparer of the storm water management plan that it complies with all of the requirements of this chapter and the Iowa Storm Water Management Manual, meets the submittal requirements outlined in the Iowa Storm Water Management Manual, is designed to achieve the City storm water standards, and that the City is entitled to rely upon the certification as due diligence on the part of the City.

4. Include a scaled map indicating the location of existing and proposed buildings, roads, parking areas, utilities, structural storm water management and sediment and erosion BMPs.

5. Include a map showing the proposed land use with a tabulation of the percentage of surface areas to be adapted to various uses, drainage patterns, location of utilities, roads, and easements and the limits of clearing and grading.

6. Include a topographic base map, consisting of an appropriately scaled topographic base map of the site which extends an appropriate distance beyond the limits of the proposed development and indicates existing surface water drainage, including (but not limited to) streams, ponds, culverts, ditches and wetlands; current land use including all existing structures; location of utilities, roads and easements and significant natural and manmade features not otherwise shown.

7. Include hydrologic and hydraulic design calculations for the pre-development and post-development conditions for the design storms specified in the Iowa Storm Water 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 Storm Water 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 storm water 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 storm water BMPs, including detailed maintenance and repair procedures to ensure their continued efficient function. These plans must identify the parts for components of a storm water 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 storm water 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 storm water 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.