05.01 - Storm Water Management Utility

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Memo April 30, 2008 Page 2of3 property damage, maintenance costs, etc. as well as showing visitors and possible future residents/business owners that the City tends to its infrastructure. While many times the benefits of storm drainage improvements are not noticed because they are underground, these are the types of services provided. 9. It is not uncommon — when a City implements a storm water management utility and starts billing separately for it, versus burying it in their general tax levy - for residents to expect a storm sewer inlet in their front yard. Not everyone will get, or need, storm sewer in his or her front yard. However, these same residents will most likely drive, walk, or shop in areas of town that have some kind of storm water management improvement, which is paid for via their monthly storm water management utility fees. 10. For the above services, a fee needs to be charged. 11 . The approach for setting the fee is to first group the parcels in the City into categories with relatively similar impervious characteristics. Impervious areas, such as roofs and driving areas, cause more runoff than the pervious areas of a parcel, such as grassed areas. Trying to calculate the runoff from every individual parcel would be too expensive a process. Thus, properties are grouped into these similar categories. The number of categories used depends on how complex one wants to get. Some Cities use 4 categories while some use over 10 categories. 12. The following 4 categories were originally set up for Pequot Lakes: Vacant (fields, empty lots, parks) - Basically 0% impervious Residential ("average" 1/3 acre lot) - About 25% to 30% impervious Medium Density Non-residential * - About 55% to 60% impervious Heavy Density Non-residential * - About 70% and higher impervious * I believe it is referred to as Commercial, Industrial & Institutional in the original Ordinance. We can adjust the descriptor as necessary. 13. After these categories were determined, we performed hydrologic and hydraulic engineering calculations based on the amount of runoff each category generated for a certain size rainfall event compared to the runoff from a typical residential parcel. The reason the comparison is made to a typical, or average, residential parcel is that in most cities, as in Pequot Lakes, the residential category makes up the majority of the parcels. The resulting factors are called Residential Equivalency Factors, or REF's.