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<br />City of Gem Lake Comprehensive Plan GEMLK 140643 <br />Page 60 <br />Table 7-2 – Projected Sanitary Flows (MGD) <br />2010 (actual) 2020 2030 2040 <br />0.02 0.03 0.03 0.03 <br /> <br />There are no public or privately-owned Community Wastewater Systems other than the <br />indicated 106 individual SSTS remaining in operation in the City. <br /> <br />7.2.2 Existing System Model Analysis <br />7.2.2.1 Methodology <br />InfoSWMM, a product from Innovyze, is a wastewater modeling and management <br />software application, fully integrated with ArcGIS. InfoSWMM Suite 14.5 and ArcGIS v. <br />10.2.2 was used to model the sanitary sewer system of Gem Lake. InfoSWMM is a <br />comprehensive hydrologic, hydraulic, and water quality simulation model software that <br />operates through ArcGIS. It is intended for use modeling urban stormwater and <br />wastewater collection systems. InfoSWMM uses the Environmental Protection Agency <br />(EPA) SWMM software that was developed by the EPA in a joint effort with CDM, Inc. It <br />is an internationally used software that is used for planning, analysis and design related <br />to stormwater runoff, combined and sanitary sewers, and other drainage systems in <br />urban areas as well as applications in non-urban areas <br />The City’s existing sewer structure data and as-built information from the City’s sewer <br />construction plan sheets were compiled into a GIS database to configure the model. The <br />model was then used to evaluate current and future sewer capacities and required <br />system improvements. <br />For the purpose of the analysis, the original sub-sewersheds from the previous <br />comprehensive plan were maintained and are shown on Figure 7-1. <br />7.2.2.2 Dry Weather Analysis <br />Dry weather flow (DWF) values used in the model were determined by assigning each <br />parcel a wastewater flow rate from the land use loading rates. Those flows were <br />compared to previously established land use loading rates. The following table 7-3 shows <br />sanitary sewer loading rates used in the 2030 Comprehensive Plan and the changes that <br />were made in the 2040 Comprehensive Plan, to calibrate Gem Lake flow to what has <br />been metered by MCES. Wastewater flows were summed and added to the nearest <br />manhole in the existing system. <br />Table 7-3 – Sewer Allocation Forecasts <br />Existing Land Use 2030 <br />Comprehensive <br />Plan <br />GPD/AC <br />2040 Comprehensive Plan <br />GPD/AC <br />Mixed Use 1237.5 600 <br />Open Space 0 0 <br />Public/Institutional 500 500 <br />Recreational Open Space 0 0