Agenda Packets - 2003/02/10 - Laserfiche WebLink

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6 an ordinance that restricts the discharge of storm water into the City’s Municipal Sewer System: CHAPTER 907: MUNICIPAL SANITARY SEWER SYSTEM Section 907.06: STORM WATER: It shall be unlawful to discharge or cause to be discharged into the Municipal sewer system, either directly or indirectly, any roof, storm, surface or ground water of any type or kind or water discharged from any air conditioning unit or system. (1988 Code §71.07) However, in spite of this ordinance, the City suspects that there are numerous properties that continue to have unlawful connections to the sanitary sewer system. The Metropolitan Council Environmental Services charges the City for the use of the regional trunk sewer system based on the volume of flow the City contributes to it. In 2002, the City started to experience a dramatic increase in the sewer flow volumes, as much as 30% over the amount from just one-year prior. To understand the magnitude and significance of this increase consider: In 2002, the City paid $641,199.00 to Metropolitan Council Environmental Services. A 30% increase then represents an additional cost of over $192,000. In addition to the increased cost to the City, storm water discharge into the City sanitary sewer system also increases to probability that the system will flood and overload to such an extent as to cause significant and grave damage to the properties of a large number of City residents. In addition to other damage, flooding and overloading creates a hazard to health. What is the cause of the increased sewer flow? Staff suspects it is a direct result of inflow and infiltration of storm water into the system – otherwise known as I & I. Inflow is the direct discharge of storm water into the sewer system; infiltration is seeping into the system via cracks and openings. In the last few years, the Public Works Department has developed two programs to help address the infiltration problem. One program includes the televising of the entire sanitary sewer system, then developing a maintenance program whereby problem areas such as major leaking joints and cracks are sealed using and pipe slip lining system. Another program is to replace sewer manhole covers that allow storm water to seep in. Infiltration will always be present to some degree; however with the steps that have been implemented in recent years, there is little more the City can do at this time that would be cost effective to further address infiltration. Inflow, on the other hand, is a problem that Staff believes needs to addressed.