12.01 - Storm Drainage Utility Fee

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Pequot Lakes Storm Drainage Utility The approach is to take a certain size rainfall event and determine the resulting average runoff generated from different types, groups, or categories of properties. Trying to calculate the runoff from every individual parcel would be too expensive a process. Thus, properties are grouped into 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. The categories are based on the amount of impervious area on an average parcel in that category. Impervious areas cause more runoff than the pervious areas of a parcel. The following categories have been set up for Pequot Lakes: 1. Vacant (fields, empty lots, parks): Basically 0% impervious 2. Residential ("average" 1/3 acre lot): About 25% - 30% impervious 3. Medium Density Non-residential ': About 55% - 60% impervious 4. Heavy Density Non-residential *: About 70% and higher impervious * I believe it was previously referred to as Commercial/Industrial. Non-residential is a better descriptor as Commercial/Industrial does not cover the range that could fall into this category. In most Cities, as in Pequot Lakes, the residential category makes up the majority of the parcels. After the categories were determined, a factor was assigned to each category based on the amount of runoff it generates as compared to a typical residential parcel. This factor is called a Residential Equivalency Factor, or REF. Following are the REF's calculated for each category: 1. Vacant: 0.2 2. Residential: 1.0 3. Medium Density Non-residential: 2.3 4. Heavy Density Non-residential: 4.0 The monthly charge for each parcel is then determined by the following formula: Area of parcel in acres x REF x monthly rate Page 2 of 4 C:\My Documents\City Clerk\Storm Drainage Utility\Storm Drainage Utility Explanation-Aug 4 2005.doc