Issue link: https://geospatial.trimble.com/en/resources/i/1415420
august 2019 csengineermag.com 41 The Intensity Development Factor adds a land use component by allocating cost based on the percentage of impervious area relative to the entire parcel size. This system recognizes that stormwater from a farm house on 20 acres has a different impact than a house in a densely populated neighborhood. These land use categories can be broad, difficult to implement and even more difficult to explain to the public. The Residential Equivalent Factor (REF) uses a highly-scientific approach to determining stormwater impacts from each parcel. For each parcel, REF con- siders soil types, land use and ground slope to predict the expected amount of stormwater discharge for a given storm intensity. While this approach is arguably the most exact, performing these calculations for each property is very time-consuming and explaining this to the public is a significant chal- lenge. Regardless of the rate structure selected, it may be viable to consider offering a credit program that can reduce the stormwater fee for install- ing or conducting practices that reduce stormwater runoff or improve stormwater quality. These are generally referred to as Best Manage- ment Practices (BMP's). Each municipality will have to decide who is eligible for credits and the amount of reduction for a given BMP. Some municipalities offer credits to only non-residential properties as a means to limit the complexity of managing the credit program. Finally, a robust public education program is essential for gaining public and stakeholder approval. This should include involving key stakeholders early in the process. Key stakeholders may include elected officials, non-profits, schools / universities and the business community. Typically, these are the properties that will be seeing the larger stormwater bills. Getting their input early will help them plan for this and will provide valuable feedback for moving forward. Managing stormwater quality is yet another unfunded mandate from the EPA. The cost for capital and operations will have to be paid for at the local level, whether it's via taxes or a stormwater fee. Once the public understands this, and that a stormwater fee can be applied equally among all property owners, then there is general acceptance. Residents want to know that the fees they pay are going toward the intended projects. A stormwater fee is one way to ensure that happens. Practices that reduce stormwater runoff or improve stormwater quality can be used as credits to reduce stormwater fees. Michael Schober MICHAEL A. SCHOBER, PE, BCEE, T&M Associates. Mr. Schober has over 33 years of experience in the field of water resource engineering. He has been involved in dozens of water, wastewater and stormwater projects and has worked with municipalities and authorities to develop stormwater utilities. He has a BS, Civil Engineering, from Villanova University.