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Analytical Process and Elements <br />Finally, each proposed stormwater retrofit practice was added individually to the "existing conditions" <br />model and pollutant reductions were estimated. Because neither a detailed design of each practice nor <br />in-depth site investigation was completed, a generalized design for each practice was used. Whenever <br />possible, site -specific parameters were included. Design parameters were modified to obtain various <br />levels of treatment. It is worth noting that each practice was modeled individually, and the benefits of <br />projects may not be additive, especially if serving the same area (i.e. treatment train effects). Reported <br />treatment levels are dependent upon optimal site selection and sizing. Additional information on the <br />WinSLAMM models can be found in Appendix A. <br />Cost estimating is essential for the comparison and ranking of projects, development of work plans, <br />and pursuit of grants and other funds. All estimates were developed using 2016 dollars. Costs <br />throughout this report were estimated using a multitude of sources. Costs were derived from The <br />Center for Watershed Protection's Urban Subwatershed Restoration Manuals (Schueler & Kitchell, 2005 <br />and Schueler et al. 2007) and recent installation costs and cost estimates provided to the ACD by <br />personal contacts. Cost estimates were annualized costs that incorporated the elements listed below <br />over a 30-year period. <br />Project promotion and administration includes local staff efforts to reach out to landowners, <br />administer related grants, and complete necessary administrative tasks. <br />De si n includes site surveying, engineering, and construction oversight. <br />Land or easement acquisition cover the cost of purchasing property or the cost of obtaining <br />necessary utility and access easements from landowners. <br />Construction calculations are project specific and may include all or some of the following; <br />grading, erosion control, vegetation management, structures, mobilization, traffic control, <br />equipment, soil disposal, and rock or other materials. <br />Maintenance includes annual inspections and minor site remediation such as vegetation <br />management, structural outlet repair and cleaning, and washout repair. <br />In cases where promotion to landowners is important, such as rain gardens, those costs were included <br />as well. In cases where multiple, similar projects are proposed in the same locality, promotion and <br />administration costs were estimated using a non -linear relationship that accounted for savings with <br />scale. Design assistance from an engineer is assumed for practices in -line with the stormwater <br />conveyance system, involving complex stormwater treatment interactions, or posing a risk for upstream <br />flooding. It should be understood that no site -specific construction investigations were done as part of <br />this stormwater retrofit analysis, and therefore cost estimates account for only general site <br />considerations. <br />Project ranking is essential to identify which projects may be pursued to achieve water quality <br />goals. Project ranking tables are presented based on cost per pound of TP removed and cost per 1,000 <br />pounds of TSS removed. <br />Project selection involves considerations other than project ranking, including but not limited to <br />total cost, treatment train effects, social acceptability, and political feasibility. <br />City of Ramsey Stormwater Retrofit Analysis <br />