Agenda - Council - 02/12/2008 - Laserfiche WebLink

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ri U • CASE 96 REVIEW COMPREHENSIVE SURFACE WATER MANAGEMENT PLAN By: Leonard Linton, Civil Engineer II Background: The City is required to revise their Comprehensive Plan in 2008. One portion of the plan is the Comprehensive Surface Water Management Plan. The current plan was created in 1980 and revised in 1987. The plan for the Southeast quadrant of the City was updated in 1997 and 2002. Significant development has occurred since the plan was first created. A request for proposals was sent out in 2007. The City. Council approved the selection of Bolton & Menk, Inc. to prepare the updated Surface Water Management Plan. Staff has reviewed and commented on several drafts during the preparation of the plan. The comments have been incorporated into the current version. The major components of the plan include: 1. Coordination of the plan with the Municipal Separate Stonn Sewer System (MS4) permit that the City has been operating under since 2003. 2. Review current ordinances and recommend updates to conform with the MS4 permit and new state laws. 3. Preparation of a Capital Improvement Plan for storm water management. 4. Completion of the Wetland Functions and Values assessment started in 2007 with adoption of the Wetland Buffer Ordinance. 5. Completion of a City wide storm water model. The report is rather large; however, it is divided into three parts. The first part is the Surface Water Management Plan text. The second part is tables and maps for the stonm water model. The last third is the Wetland Management Plan. There is an Executive Summary on page 2 that introduces the report and the history behind the need for a Surface Water Management Plan. Bolton & Menk, hic. has prepared a letter that highlights the significant points of the plan. The report and letter are included in the packet. The goals and policies are found on pages 27-35. _Staff is prepared to discuss the new additions and modifications of existing policies. One significant change is a recommendation to require additional rate reduction and incorporation of infiltration practices in all new developments. We currently limit stormwater runoff rates to pre -development rates; the new recommendation is to make the limit 75% of the pre -development rate. The justification for the change is the first paragraph in the attached letter and is included in the report. , Figures 11— 24 are from the modeling software and show the condition of the ponds for a 100 -year event or pipe capacity for a 10 -year storm. The ponds that pose a potential threat to structures may need further investigation and could be candidates for future CIP projects if improvements are warranted. The pipes that are flowing full may also need investigation and improvement. Staff proposes using the letter as an outline for committee discussion. • Funding Source: -219-