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Chapter 07 Sewer
City of Chanhassen 2040 Comprehensive Plan147 Chapter 7Sewer City of Chanhassen 2040 Comprehensive Plan148 7.1 | Executive Summary The City of Chanhassen’s Comprehensive Sanitary Sewer System Plan (plan) is intended to be an update to the city’s previous Comprehensive Sewer Plan dated 2008 and to assist the City of Chanhassen in meeting its short-term and long-term sanitary sewer needs. The plan is also intended to serve as an inventory of the city’s existing sanitary sewer facilities and an updated guide for completing the future sanitary sewer trunk system improvements. The city is divided into eight major sanitary sewer service areas or districts as shown in Figure 3.2 in Appendix A. For the purpose of sanitary sewer planning, these major districts are further divided into sub-districts based on both lift station and gravity sewer service areas as shown in Figure 3.3 in Appendix A. Each sub-district contributes wastewater flow to the sanitary sewer collection system dependent upon a variety of parameters. These parameters include but are not limited to land use, population density, wastewater generation rates, development restrictions, wetlands and dedicated green space. Approximate future trunk facility locations were determined based on the topography of undeveloped areas. An objective to planning the trunk sanitary sewer system is to minimize the number of trunk lift stations, while keeping the maximum depth of gravity sewers to realistic depths. The existing and proposed system layout is also shown on Figure 3.4 in Appendix A. The system layout is general in nature and exact pipe alignments and lift station locations will be deter-mined by the actual conditions at the time of final design. It is important that the general overall concept and sizing plan is utilized to assure an economical and adequate future system. A 22-year capital improvement plan (CIP) was developed for the completion of the trunk system. These trunk fa- cilities include all gravity sewer mains for each sub-district, lift stations and force mains. The CIP includes costs for each trunk improvement project; however, the approximate trunk costs do not include the cost of installing lateral sewers for development. The cost for lateral improvements would be funded directly through assessments to the development or redevelopment. The following table summarizes the proposed 22-year CIP and associated costs: 7 | Sewer City of Chanhassen 2040 Comprehensive Plan149 FIGURE 7.1 | Capital Improvement Plan Summary Improvement Description Extended Cost 2018 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $150,000 Lift Station #18,26 $90,000 Subtotal $440,000 2019 Inflow and Infiltration Abatement $200,000 2010 MUSA Lift Station $1,900,000 Sanitary Sewer Replacement $50,000 Lift Station #16 $45,000 Subtotal $2,195,000 2020 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $250,000 Lift Station #22 $55,000 Subtotal $505,000 2021 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $50,000 Lift Station #2,17 $90,000 Subtotal $340,000 2022 Lower Bluff Creek Trunk Sanitary Sewer $14,720,200 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $250,000 Lift Station #13 $45,000 Subtotal $15,215,200 2023 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $50,000 Lift Station #1,20 $120,000 Subtotal $370,000 2024 Inflow and Infiltration Abatement $200,000 Sanitary Sewer Replacement $150,000 Lift Station #7 $50,000 Subtotal $400,000 2025 -2030 2026-2030 Sanitary Sewer I/I Rehabilitation $1,000,000 2026-2030 Sanitary Sewer Reconstruction Program $850,000 Lift Station No. Improvements $455,000 Subtotal $2,305,000 2031 -2035 2031-2035 Sanitary Sewer I/I Rehabilitation $1,000,000 2031-2035 Sanitary Reconstruction Program $650,000 Lift Station No. Improvements $330,000 Subtotal $1,980,000 2036 -2040 2036-2040 Sanitary Sewer I/I Rehabilitation $1,000,000 2036-2040 Sanitary Reconstruction Program $850,000 Lift Station No. Improvements $800,000 Subtotal $2,650,000 Total Capital Improvements Plan Costs $26,400,200 »Costs are for budgeting purposes only, and are subject to change as projects are studied, designed and constructed. »Project Costs include 10% for construction contingency and 25% indirect costs where applicable. »Costs are estimated based on 2017 construction costs. City of Chanhassen 2040 Comprehensive Plan150 7.2 | Introduction Purpose The purpose of this study is to provide the city with an updated plan to serve future development and to identify existing system facilities and deficiencies. Scope The scope of this study includes population and sanitary sewer flow projections for the City of Chanhassen through the year 2040. The potential 2040 service area was defined as areas that can be feasibly served by sanitary sewer in the future and was based on the current land use plan prepared for the city’s comprehensive plan. The 2040 ser- vice area for the city is considered to be the full build-out of the current city limits. Based on the 2040 service area, sanitary sewer districts and sub-districts were defined. Existing and future sanitary sewer flow rates were calculated for each sub-district based on the respective land uses. Projected sanitary sewer flow rates were used to analyze the existing trunk system capacity and size future trunk system facilities. Future trunk improvements were defined with the intention that the trunk system would serve the 2040 service area. An approximate layout of potential trunk system improvements along with an opinion of probable cost is provided. Future improvements were prioritized and incorporated into a capital improvement program (CIP) based on an approximate phasing plan provided by the city staff. Data Available In preparing this report, the following sources of information were utilized: »Existing Sanitary Sewer GIS Information »Sanitary Sewer As-builts »City of Chanhassen Comprehensive Sewer Policy Plan, dated November 2008, prepared by WSB & Associates »City of Chanhassen Infiltration and Inflow Reduction Plan, dated June 12, 2006, prepared by WSB & Associates »County Road 61 Corridor Plan, dated December 2, 2014, prepared by SRF Group in association with Hoisington Koegler Group »2040 Thrive MSP Water Resources Policy Plan Existing City Sanitary Sewer System Overall Sanitary Sewer Service Area Typically, sanitary sewer systems consist of two elements: collection and treatment. Collection systems include sewer services, trunk sewer pipes, manholes, lift stations and forcemains which collect the sewer flows from private resident, commercial and industrial properties within a city. There are various locations throughout the city where Chanhassen’s collection system connects to another city’s system. These interconnections are addressed through service agreements. No such agreements have been entered into since 2008. Treatment systems include the biologi- cal or chemical treatment in order to remove targeted contaminants from the wastewater. The City of Chanhassen’s existing sanitary sewer system is a collection system only. The Metropolitan Council Environmental Services (MCES) provides treatment for Chanhassen’s entire sanitary sewer flows. MCES is also re- sponsible for major trunk facilities conveying wastewater across city boundaries to regional treatment facilities. All wastewater flows from the City of Chanhassen enter the MCES interceptor system and is conveyed to the MCES Blue Lake Wastewater Treatment Plant (WWTP) located in the City of Shakopee, just north of Highway 101. City of Chanhassen 2040 Comprehensive Plan151 The sanitary sewer service area is defined as the area from which wastewater flows are collected by the city’s regional system. The existing serviced area within the City of Chanhassen is comprised of approximately 10,600 gross acres which includes the lakes, open park land and road right-of-ways. This service area is shown in Figure 3.2. (Appendix A). Sanitary sewer service districts were developed within the city boundaries based on gravity service and lift station service areas. The existing serviced area has been developed within several districts, many of which are not fully developed. Gravity Sanitary Sewer The City of Chanhassen gravity sanitary sewer system consists of 6- to 36-inch diameter vitrified clay pipe (VCP), acrylonitrile butadiene styrene (ABS), reinforced concrete pipe (RCP), ductile iron pipe (DIP) and polyvinyl chlo- ride (PVC) plastic sewer pipe. The original sanitary sewer system for the area southwest of Lotus Lake was con- structed in the 1950s and consisted of two lift stations. Following the initial construction, a majority of the system was constructed in the 1970s. The existing gravity sanitary sewer system appears to be in good overall condition; however, limited televising inspections have found root penetrations at joints, cracked pipe, leaking manholes and castings, as well as mineral deposits. In recent years, the City of Chanhassen has been identified as having excessive infiltration and inflow (I/I) by MCES. The city is currently included on the MCES “List of Communities with Observed Excess I/I, June 30, 2006.” The city was also assessed a surcharge by MCES according to the adopted MCES 2007 Surcharge Policy. The City of Chanhassen developed an Infiltration and Inflow Reduction Plan dated June 12, 2006 which identified a number of gravity sanitary sewer improvements to reduce the amount of I/I entering the city’s system. The gravity sanitary sewers are directed to several MCES interceptors described in Section 4 that convey wastewa- ter to the Blue Lake WWTP. The existing gravity sanitary sewer trunk mains (8-inch diameter and larger) and the MCES interceptor are shown on Figure 3.0. (Appendix A) Lift Stations The City of Chanhassen sanitary sewer system consists of 31 lift stations ranging from a small 16 gallons per minute (gpm) grinder station to a large 1,448 gpm lift station. The lift station capacities vary depending on size of service area. The locations of the existing lift stations are shown on Figure 3.0 (Appendix A) and the following table summarizes capacity information for each of the lift stations: City of Chanhassen 2040 Comprehensive Plan152 General Lift Station Information General Sewer Shed Information Lift Station Area Year Constructed Approx. Length of Forcemain Pumping Capacity (gpm) Control Panel Age Pump Age Length of pipe (ft) Approx. Number of Manholes Approx. Number of Services 1 1967 5,486 103 1999 2003 3,610 20 40 2 1967 1,420 353 2005 2005 18,287 100 293 3 1971 1,200 860 2008 2008 33,617 164 413 4 1971 882 560 2008 2008 18,559 96 191 5 1971 1,175 325 2008 2008 22,843 105 271 6 1971/1990 400 198 2008 2002 13,997 97 154 7 1971/2000 1,365 370 1999 2006/ 2015 14,499 68 159 8 1971 425 76 2008 2008 470 3 6 9 1975 1,104 288 2008 2008 7,398 43 85 10 1975 1,726 905 2013 2013 51,313 286 827 11 1975 893 126 2011 2005/ 2006 4,254 19 39 12 1975 959 304 2008 2008/ 2007 9,287 56 106 13 1975 2,336 95 1999 2005/ 2000 6,322 34 73 14 1975 485 101 2008 2005/ 2000 663 5 7 15 1975 1,352 136 2006 2006 6,294 37 53 16 1975 174 64 2010 2010/ 2009 755 7 9 17 1977/1993 2,477 956 1996 1996 26,389 153 412 18 1977/1993 1,360 99 1996 2007 5,802 35 61 19 1982 1,590 89 2007 2007 2,874 17 39 20 1985 1,383 16 1986 2004/ 2014 1,393 6 18 21 1985 571 123 2015 2015 5,937 37 88 22 1985/1990 1,600 202 1987 2008/ 1987 2,556 12 7 23 1988 2,775 73 2016 2016 782 3 1 24 1991 1,917 1,448 2010 2010/ 2009 114,733 632 2,850 25 1991 1,460 143 1993 1993 6,920 45 81 26 1991 1,304 396 1993 1998 18,685 100 246 27 1992 676 382 2006 2006 10,789 75 166 28 1994 591 78 1997 1997 762 7 9 29 1993 696 226 1997 1997 1,116 5 7 30 2004 1,128 264 2004 2004 2,163 16 17 31 2006 757 82 2006 2006 1,481 11 28 FIGURE 7.2 | Existing Lift Station Information City of Chanhassen 2040 Comprehensive Plan153 Existing System Analysis and Deficiencies A SewerCAD computer model was developed in 2006 to verify existing system’s capacity to convey existing sys- tem wastewater flows to the MCES collection system. Existing system as-built information was used to develop the model and determine system capacity. Average day and peak flows were calculated by determining the existing developed area in each district, area of each existing land use, number of existing units and assuming a flow generat- ed for each land use. The model was calibrated by reducing the flow generated for each land use until the total system flow matched sewer flows metered by MCES. The existing system model includes the following parameters: »Existing sewer mains – 10-inch diameter and larger »Existing trunk lift stations »Existing trunk main flows (MCES) Figure 7.3 illustrates the remaining pipe capacity resulting from the 2006 analysis trunk mains. Modeling results in- dicated two sections (of 23 sections) of the 36-inch trunk main parallel to the MCES interceptor flowing east along the north side of Lake Susan near Highway 101 exceeded capacity as shown on Figure 7.3. The model indicated a slight surcharge at the manholes in the two sections where existing flows exceeded capacity; however, the capacity of the overall trunk system is adequate. The MCES Lake Ann interceptor exhibited a few sections exceeding capacity; however, MCES is responsible for monitoring flows and determining deficiencies for this main. Figure 7.3 shows all trunk lift stations (with influence lines greater than 10-inches diameter) with the exception of Lift Station No. 7 exhibit adequate capacity. The figure below shows existing lift station pump capacity and existing peak inflow information. FIGURE 7.3 | Existing Trunk Lift Station Analysis On-site Disposal Systems There are several areas within the City of Chanhassen that are currently on septic systems. Some of these areas are developed with one or two acre lots that could be developed or subdivided with sanitary sewer service. Figure 3.6 in Appendix A presents the lots which currently utilize septic systems. The areas are primarily located in the districts Lift Station Area Pumping Capacity (gpm) Existing Peak Flow (gpm) Remaining Capacity (gpm) 1 103 38 65 3 594 544 50 4 560 229 331 6 198 130 68 7 135 145 -10 10 905 609 296 12 100 88 12 24 1,448 725 723 26 396 339 57 City of Chanhassen 2040 Comprehensive Plan154 south of the Highway 212 corridor. The remaining existing septic systems are scattered throughout the remainder of the city in areas with larger lots. There are currently 378 Subsurface Sewage Treatment Systems (SSTS) in the community with 370 serving residential and eight serving commercial/industrial uses. Chapter 19, Article IV of the Chanhassen City Code addresses SSTS, which provides regulation for the design and maintenance of SSTS. The city adopts by reference and incorporates Carver County’s “Subsurface Sewage Treatment Systems Purpose, Intent, and Authority” subject to the amendments set forth in our code. These regulations implement and enforce MPCA 7080 standards. Link to Chapter 19 Article IV of the Chanhassen City Code is: https://library.municode.com/mn/chanhassen/codes/ code_of_ordinances?nodeId=CICO_CH19WASESEDI_ARTIVSUSETRSY SSTS are required to be pumped every three years. A compliance report must be completed upon the sale of a home that is served by SSTS, unless one has been completed within the last three years. MCES SANITARY SEWER SYSTEM The majority of the wastewater generated from the City of Chanhassen is conveyed to one of two MCES interceptor sewers, identified as the Shorewood Interceptor (7017) and the Lake Ann Interceptor (7138). Shorewood Interceptor The Shorewood Interceptor is a combination forcemain and gravity sewer interceptor, which begins at the MCES L21 Lift Station near Lake Virginia and flows eastward through Shorewood, Excelsior, Greenwood and Tonka Bay. There are four extensions of the Shorewood Interceptor, which extend southward to the north boundary of Chanhassen (information obtained from the 2006 Comprehensive Sewer Policy Plan). »Shorewood interceptor extension 7017-1 is a 15-inch diameter RCP gravity flow sewer extending northeasterly from the Chanhassen boundary at Washta Bay Road along Pleasant Avenue to the northwest side of Mary Lake in Shorewood to the major interceptor. »Shorewood interceptor extension 7017-2 is a 9-inch diameter PVC forcemain that extends from the Chanhassen boundary at Chaska Road to the west shore of Galpin Lake in Shorewood to the major interceptor. »Shorewood interceptor extension 7017-3 is a combined gravity and forcemain facility that flows north from the Chanhassen boundary along Christmas Lake Road through a 15-inch diameter RCP to a lift station, then through a 9-inch diameter PVC pipe and an 8-inch diameter DIP to the major interceptor. »Shorewood interceptor extension 7017-4 is a 12-inch diameter RCP gravity flow sewer extends between Christmas Lake and Silver Lake from the Chanhassen boundary to the Shorewood Interceptor. Wastewater generated from the northern area, the area on the north side of Lake Lucy, and the area around the north and west sides of the Lake Minnewashta area flow north to the Shorewood Interceptor and is ultimately treated at the Blue Lake Wastewater Treatment Facility in Shakopee. Lake Ann Interceptor The Lake Ann Interceptor (7138) is an MCES sewer that serves Chanhassen in the Bluff Creek, Rice Marsh Lake, Lake Susan, Lake Ann, Lotus Lake, Lake Lucy and Lake Riley vicinity. The Lake Ann Interceptor sewer system was constructed in three phases and was completed in 1988. The interceptor extends southeast, beginning at Trunk Highway 41 near the north City limits and approximately 4.5 miles to the Red Rock Interceptor at the Chanhassen/ Eden Prairie border. The city’s Lake Ann trunk sewer is parallel to the MCES trunk sewer between the Red Rock Interceptor and Highway 5. The Red Rock Interceptor starts at the termination of the Lake Ann Interceptor and continues southeasterly through Eden Prairie where it discharges into the Purgatory Creek Interceptor and eventually to the Blue Lake Wastewater Treatment Facility in Shakopee. City of Chanhassen 2040 Comprehensive Plan155 Land Use Designation Abbreviation Residential – Large Lot RLL Residential –Low Density RLD Residential – Medium Density RMD Residential –High Density RHD Commercial C Office O Office/Industrial O/I Parks/Open Space P/OS Public/Semi-Public P/SP Mixed M Agricultural A During the 2007 SewerCAD model analysis for the existing City of Chanhassen sanitary sewer system and as discussed previously, the MCES Lake Ann interceptor exhibited a few sections exceeding capacity; however, MCES is responsible for monitoring flows and determining deficiencies for this main. 7.3 | Land Use Land Use Breakdown The current land use plan for the City of Chanhassen is shown in Chapter 2, Figure 2-10. This plan was developed by the city and separates the planning area into eleven (11) different land use categories. Land use is a critical factor in determining future sanitary sewers alignments and sizes due to the fact that different land uses generate different wastewater flow rates. The following table presents the current city land use breakdown and the associated abbreviations: FIGURE 7.4 | Land Use Summary Existing Developed and Developable Areas The area within the City of Chanhassen’s planning area is approximately 21 square miles or 13,700 acres. The exist- ing area within Chanhassen with sewer service is approximately 16.6 square miles or 10,600 gross acres. For sewer planning purposes, land that is not served by sanitary sewer is considered not developed and not all of this acreage is considered developable. Undevelopable land use categories include open space and water. Existing developed and undevelopable areas were subtracted to obtain developable acreage. Developable acres are shown on Figure 3.1, (Appendix A) along with the existing sewer service area. This is identified as “Gross” Devel- opable Acreage because it includes roads and common or public/park areas potentially included in developments. Roads, common areas and parks typically consume 25% to 30% of the gross area within a development. GROWTH PROJECTIONS Projected Residential Growth Historical growth data for the study area from the Minnesota State Demographer’s office is included on Figure 7.5. The City of Chanhassen exhibited stable growth between 1900 and 1960; however, it grew exponentially between 1960 and 2000 with approximately 73% growth between 1990 and 2000. City of Chanhassen 2040 Comprehensive Plan156 FIGURE 7.5 | Historical Census Data Figure 7.6 below shows the assumed residential population growth and sewered population through the year 2040 from the 2040 Thrive MSP Water Resources Policy Plan. Based on the data provided below, there would be an approximately 16% to 19% growth in population every 10 years. It is assumed that as development occurs, sanitary sewer service will be extended to the new development. Sanitary sewer service will also be extended to current large lot developments based on need such as failing septic systems. Sanitary sewer service would only be extended to new developments and existing large lot developments that have been incorporated into the MUSA area. Year Population Total Households Employees 1970 4,839 1,349 900 1980 6,351 2,075 2,102 1990 11,732 4,016 6,105 2000 20,321 6,914 9,350 2010 22,952 8,679 10,905 2020 2030 2040 Total Population 26,700 31,700 37,100 Sewered Population 25,660 30,660 36,060 Unsewered Population 2,400 2,400 2,400 Total Households 10,000 11,900 14,000 Sewered Households*9,620 11,520 13,620 Unsewered Households 800 800 700 Total Employees 15,600 17,000 18,400 Sewered Employees 15,400 16,800 18,200 Unsewered Employees 200 200 200 FIGURE 7.6 | 2040 Thrive MSP Water Resources Policy Plan Population Projections *Note: In TAZ 386 there are 18 properties where the homes empty into a holding tank at the back of the home, which then connect to a public sanitary sewer within West 96th Street to Lift Station 20. These properties are included in the sewered household category. City of Chanhassen 2040 Comprehensive Plan157 Projected Non-Residential Growth Non-residential customers are located in the following land use areas: Commercial, Office, Office/Industrial, Industrial, Mixed Use, Parks/Open Land and Public/Semi Public. Tracking the exact acreage developed each year for the preceding land uses is difficult; however, it is possible to track the number of total non-residential connections based on water use records. Typically, the above land use categories are grouped into two water use types, commercial and industrial. Since it is not possible to relate land use categories to water use records, the previously listed land use categories have been grouped together as non-residential for determining growth rates. To project future non-residential growth, some trends over the past few years can be analyzed. Figure 7.7 illustrates the growth in non-residential water connections over the past ten years, and the percentage of non-residential connections relative to residential connections for the City of Chanhassen water system. Year Non- residential connections Non- residential annual growth Residential connections Residential annual growth Percent non- residential connections 2007 251 6,545 3.69% 2008 345 37.45% 6,931 5.90% 4.74% 2009 342 -0.87%7,019 1.27% 4.65% 2010 431 26.02% 7,145 1.80% 5.69% 2011 426 -1.16%7,229 1.18% 5.56% 2012 382 -10.33%7,310 1.12% 4.97% 2013 341 -10.73%7,530 3.01% 4.33% 2014 292 -14.37%7,612 1.09% 3.69% 2015 295 1.03% 7,780 2.21% 3.65% 2016 296 0.34% 7,904 1.59% 3.61% Average 4.46% Year Population Residential Connections Non-Residential Connections 2016 24,951 7,904 296 2020 26,700 9,200 373 2030 31,700 11,100 450 2040 37,100 13,300 539 FIGURE 7.7 | Non-Residential Historical Growth FIGURE 7.8 | Non-Residential Growth Projections Historically there is a correlation in the ratio of non-residential to residential connections. The ratio has averaged 4.05% over the last five years. Based on a ratio of non-residential to residential connections of 4.05%, Fig- ure 7.8 was developed to project future non-residential connection growth in a similar fashion to Figure 7.6 projecting future population. Existing Wastewater Flows Future sanitary sewer flows, in conjunction with available slope, govern the capacity of sanitary sewers. To deter- mine future sanitary flows, existing water demand and MCES recommendations were considered. MCES typically estimates 274 gpd/connection or 75 gallons per capita per day (gpcd) for residential estimates and 800 gallons per acre per day (gpad) for non-residential developments. Total existing city wastewater flows are not measured for individual users; the total flows are only measured by MCES at the city flow meter for the entire City of Chanhassen. Wastewater flows are therefore not categorized by land use type. However, the City of Chanhassen does collect water demand data. Water demand data by customer type for 2010-2016 is shown below in Figure 7.9. The actual annual wastewater generated is also shown in the fol- lowing table, along with the percent of wastewater generated per actual gallons of water used. From the information provided, the wastewater generated during the years 2010 to 2016 ranged from 58% to 83% of the actual water usage. City of Chanhassen 2040 Comprehensive Plan158 FIGURE 7.9 | Water Demand By Customer Category FIGURE 7.10 | Historic Wastewater to Water Consumption Percentages Customer Category 2010 2011 2012 2013 2014 2015 2016 Residential (1,000 Gal)689,522 738,107 863,567 764,214 672,717 667,903 630,530 Commercial (1,000 Gal)165,669 180,144 176,868 161,122 147,411 138,082 112,660 Industrial (1,000 Gal)97,806 120,152 107,630 94,111 86,864 84,117 62,132 Other1 (1,000 Gal)21,456 19,744 29,005 22,948 22,257 20,890 107,052 Total (1,000 Gal)974,456 1,058,147 1,177,070 1,042,395 929,249 910,992 912,374 Wastewater Flow (1,000 Gal)2 757,900 784,200 652,800 725,600 721,800 620,200 753,500 % of Wastewater to Water Usage 78%74%55%70% 78% 68% 83% Average Water Demand (MGD)2.7 2.9 3.1 2.9 2.5 2.5 2.6 Average Wastewater Flow (MGD) 2.1 2.1 1.8 2.0 2.0 1.7 2.1 »The other water usage category includes institutions, schools and parks. »The total annual wastewater flow was provided by MCES and based on the flows that the City of Chanhassen was billed for. The industry standard design for water consumption is 100 gallons per person per day and for sewer it’s 75 gallons per person per day which accounts for losses occurring largely due to lawn watering; therefore for communities that do not have excessive I/I, the average wastewater flow is approximately 75% of the water demand. Figure 7.10 sum-marizes the wastewater to water consumption since 2000. As the City of Chanhassen continues to implement the I/I reduction plan, it is expected that the percent of wastewater flow to water demand will decrease and will become consistent with other communities that currently do not have excessive I/I. Year Wastewater to Water Consumption 2000 94% 2001 102% 2002 120% 2003 89% 2004 108% 2005 100% 2006 66% 2007 83% 2008 74% 2009 65% 2010 78% 2011 74% 2012 55% 2013 70% 2014 78% 2015 68% 2016 83% City of Chanhassen 2040 Comprehensive Plan159 FIGURE 7.10| Historic Wastewater to Water Consumption Percentages FIGURE 7.11 | Wastewater Flow Calculation Assumptions Land Use Abbreviation Land Use Description Units/Acre Gallons/Acre/Day RLL Residential – Large Lot 1 274 RLD Residential – Low Density 3 822 RMD Residential – Medium Density 7 1,918 RHD Residential – High Density 12 3,288 C Commercial -800 O Office -800 O/I Office/Industrial -800 P/OP Parks/Open Space -100 P/SP Public/Semi-Public -800 M Mixed -800 Residential Flow Rates To determine the residential flow generation rates in gallons per gross acre, several factors were reviewed and several assumptions made. As discussed previously, MCES typically uses 75 gpcd. Based on the residential water use from Figure 7.9 and the actual percentages of wastewater to water usage, Figure 7.12 indicates that the average Chanhassen residential wastewater flow is below 75 gpcd. FIGURE 7.12 | Historical Residential Wastewater Flow Rates Year Residential Connections Estimated Population Served1 Persons per Connection Residential Water Use (gal/day) Actual Percent of Wastewater to Water Usage Estimated Residential Wastewater Flow (gal/day) Average Residential Wastewater Flow per Connection (gal/day) Average Residential Wastewater Flow per Person (gal/day) 2010 7,145 22,157 3.10 1,889,101 78%1,473,499 206.2 66.5 2011 7,229 22,384 3.10 2,022,211 74%1,496,436 207.0 66.9 2012 7,310 22,689 3.10 2,365,937 55%1,301,265 178.0 57.4 2013 7,530 23,159 3.08 2,093,737 70%1,465,616 194.6 63.3 2014 7,612 23,593 3.10 1,843,060 78%1,437,587 188.9 60.9 2015 7,780 23,860 3.07 1,829,871 68% 1,244,312 159.9 52.2 2016 7,904 24,156 3.06 1,727,479 83%1,433,808 181.4 59.4 Average 188.0 60.9 »Estimated population served per City of Chanhassen Planning Department. Assumes unsewered population is approximately 795. Non-Residential Flow Rates Non-residential wastewater generators consist of Commercial, Office, Office/Industrial, Industrial, Mixed Use and Public/Semi Public land uses. As discussed previously, it is not possible to separate land use areas based on water use records. Therefore, existing wastewater flows were developed based on the water usage records and allocating the remaining water demand flows to each non-residential acre. Water demand was used because it can be sepa- rated by non-residential and residential use based on provided data. Verifying water usage records and applying the MCES assumption for non-residential users of 800 gpd is a reasonable assumptions for overall planning. It is possible a large user could develop within the system; therefore, some laterals may need to be increased in size at the time of construction. The cost to install larger laterals has not been accounted for as a part of this plan. These developments would need to be reviewed on a case-by-case basis as the development occurs. This table presents a number of assumptions utilized during the development of this report to calculate existing wastewater flows by actual developed units and future flows by number of units per acre and/or gallons per day per acre: City of Chanhassen 2040 Comprehensive Plan160 Peak Flow Factors The sanitary sewer collection system must be capable of handling not only average flows, but also the anticipated peak flows. These peak flows can be expressed as a variable ratio applied to average flow rates. This variable ratio, called the peak flow factor, has been found to decrease as the average flow increases. The peak flow factors applied in this study were based on typical MCES supplied peaking factors. They are generally considered conservative, and are widely used for planning in municipalities throughout the twin cities metropolitan area. Appendix B lists the peaking factors used for this study. Infiltration and Inflow (I/I) Infiltration is clear water that enters the sanitary sewer system through defects in the sewer pipes, joints, manholes and service laterals. Water that enters the sewer system from cross connections with storm sewer, sump pumps, roof drains or manhole covers is considered inflow. The city defines certain inflow as a form of illicit discharge, defined by City Code of Ordinances Sec. 19-44. Section 19-44 does not allow for certain types of cross connections by prohibiting direct or indirect discharges from roof drains, sump pumps, unauthorized swimming pool discharges, cistern overflow pipes or other surface drain connections to the sanitary sewer system. Any such connection found contributing to this inflow shall be disconnected and the piping removed in accordance with the ordinance. The quantity of I/I entering a wastewater collection system can be estimated utilizing flow data obtained from meters, such as the meters MCES has in place to monitor the city’s sanitary flows. By taking the city’s base flows, calculated as daily flows during winter months, and comparing them to the city’s average daily flows, the amount of I/I collected in the city’s system can be estimated. Based on available MCES flow data, the contribution of I/I to Chanhassen’s overall wastewater flow is approximately 13% from 2000-2017, as seen from Figure 7-13, with a peak of approximately 35%. Water from inflow and infiltration can consume available capacity in the wastewater collection system and increase the hydraulic load on the treatment facility. In extreme cases, the added hydraulic load can cause bypasses or overflows of raw wastewater. This extra hydraulic load also necessitates larger capacity collection and treatment components, which results in increased capital, operation and maintenance, and replacement costs. As sewer systems age and deteriorate, I/I can become an increasing problem. Therefore, it is important that I/I be reduced whenever it is cost effective to do so. The MCES has established wastewater flow goals for each community discharging wastewater into the Metropoli- tan Disposal System (MDS) based on average day flows and allowable peaking factors. These enforced wastewater flow goals are aimed at reducing excessive I/I within the city’s sanitary sewer system and also the MCES interceptor system. In February 2006, MCES adopted an I/I Surcharge Program which requires communities within the MCES service area to reduce or minimize excessive I/I over a period of five years. In the case that communities exceed the wastewater flow goals set by MCES during the five-year surcharge period, the community will be assessed a sur- charge for flows above the goal. The City of Chanhassen was identified by the MCES as having excessive I/I during the development of the I/I Surcharge Program. As part of the MCES surcharge program, the City of Chanhassen has the ability to recover the imposed surcharges by investing in the repair and maintenance of the city sanitary sewer system rather than paying surcharge amount directly to MCES. City of Chanhassen 2040 Comprehensive Plan161 This is done by taking official steps to reduce excess I/I through planned city (or private) fund expenditures that meet MCES requirements. The investments into the sanitary sewer system are added up over a 5 year work plan period, and at the end of the 5 year work plan if the total amount invested into the system are equal to the surcharge amount, then the surcharge is considered paid. Between 2009 and 2018 the City of Chanhassen spent over $994,000 on I&I reduction on efforts such as sani- tary sewer lining, installation of I&I barriers, replacement of sanitary sewer and sanitary sewer televising. In the summer of 2006, the city completed an I/I study to assess the city’s sanitary sewer I/I and implemented the I/I reduction program in response to the MCES program. Previous to the 2006 study, the city conducted a sump pump inspection program in the late 1990s in an effort to eliminate illicit discharges, which focused primarily on homes built prior to 1970 (24% of homes in Chanhassen) and conducted a feasibility report for a sewage flow monitoring program in 2002 aimed at achieving fair and equitable allocations of the wastewater treatment costs provided by MCES. Since 2006, the city has completed inspections, repairs and upgrades to the public sanitary sewer system with the goal of reducing I/I. The city on average has invested approximately $200,000 a year into I/I abatement programs, and will continue to do so as seen from the 2019-2023 CIP in Figure 7-1. While many improvements have been installed in the city’s public sanitary sewer system, MCES metering and city lift station run time data shows that certain areas of the sanitary sewer system are still experiencing I/I issues. This is why it is important for the city to continue investing in I/I abatement. Also, MCES has stated that up to 80% of I/I can originate from private property connections (illicit discharge, unmaintained systems, etc.). Thus, the city is conducting a similar study to that performed in 2006 which focuses more heavily on the impact private property connections have on the city’s overall I/I issue, and evaluates mitigation options if a private I/I issue exists. Consultant engineering services have been contracted for this study which will include: performing sewershed data review and providing a means for the collection of flow data (i.e. metering); preparation of a report that summarizes the findings of the sewershed review and flow data collected, including identifying critical areas contributing to I/I; and providing recommendations to remediate infiltration and inflow issues for both private side and public contributions. The final report will be completed in November 2019. The city will adjust its I/I abatement efforts and future planning based on the report’s findings, along with continuing public education and outreach on the importance of the issue and ways the public can help address I/I. FIGURE 7.14 | Historic Wastewater to Water Consumption Percentages The City of Chanhassen has completed inspections, repairs, and upgrades to the public sanitary system. In 2019, the city’s I&I Study will be updated in an effort to quantify and locate remaining sources of I&I. Year Wastewater to Water Consumption Year Wastewater to Water Consumption Year Wastewater to Water Consumption 2000 94%2007 83%2012 55% 2001 102%2008 74%2013 70% 2002 120%2009 65%2014 78% 2003 89%2010 78%2015 68% 2004 108%2011 74%2016 83% 2005 100%Average 75%Average 71% 2006 66% Average 95% FIGURE 7.13 | Infiltration and Inflow Calculations Year Average Daily Flow (Million Gallons) Base Flow (Million Gallons) Yearly I/I Contribution 2012 1.459 1.368 6% 2013 1.630 1.352 17% 2014 1.624 1.303 20% 2015 1.395 1.154 17% 2016 1.715 1.481 14% 2017 1.724 1.613 6% AVERAGE 13% City of Chanhassen 2040 Comprehensive Plan162 Potential sources of I/I within the city include: sanitary sewer manholes, laterals and services and sump pump and draintile connections to sanitary sewer services. Every year, a portion of public sanitary sewer infrastructure, manholes and laterals is inspected and the necessary repairs are made. Section 19-44 of the City Code, is used to enforce the city’s I/I policies with regards to private sewer infrastructure and can be found in Appendix C. Public Sanitary Sewer and Manholes Annually, the city reviews the condition of a portion of the public infrastructure, televising the sewer pipe and inspecting manholes. The sections chosen include pipe and manholes within the next year’s street improvement project and areas that have been identified as high potential for I/I, such as pipe located next to a surface water feature. Issues identified are repaired or replaced. Examples of repair work includes installing I/I barriers and gasketed manhole covers, chemical grout and short lining. Typically, the city reconstructs approximately one mile of streets in even-numbered years based on the condition of the street, water main and sanitary sewer. In odd-numbered years, the city rehabilitates between three and six miles of streets. It is the city’s policy to install drain tile throughout street reconstruction projects and in select areas in rehabilitation projects. Drain tile desaturates the street subgrade, reducing the groundwater available for infiltration into the sanitary sewer system. The drain tile also provides homeowners an option to connect their sump pump discharge which reduces inflow into the sanitary sewer system. Private Sewer Services Public sewer televising includes a visual of the service wye. As of 2014, the city offers residents within street project areas the opportunity to have their sanitary sewer service from the home to the public sewer televised. Participation is voluntary and is intended to identify services that are a source of I/I or are in need of other repairs. This service will continue to be offered to residents within street improvement project areas. Private Sump Pump and Drain Tile Illicit Connections According to information provided by the Metropolitan Council, prior to 1969 the Plumbing Code allowed sump pumps to discharge into the sanitary sewer and perimeter drain tile was permitted to be directly connected to the sanitary sewer service. According to the 2016 records, there were 733 buildings within the city that were built in or before 1969; the remaining 8,097 homes within Chanhassen were built after 1969. Of the homes built before 1969, 62% of the service wyes and 1% of the service laterals have been televised. Figure 3.7 in Appendix A shows the properties which contain buildings constructed in or before 1969. In an effort to reduce the number of illicit discharges (inflow) to the sanitary system, the city inspected 924 homes as part of the Sump Pump Inspection Program in 1996: 84% of homes were in compliance, meaning their sump pump was not connected to the sanitary sewer. Throughout the next seven years, the city reinspected the non-compliant properties to ensure that the sump pump discharge was disconnected from the sanitary sewer. More detailed information including specific projects and associated costs are included in the prepared I/I reduction plan. Total annual costs for I/I reduction efforts are included in the overall sanitary sewer Capital Improvements Plan prepared with this comprehensive study. A copy of the detailed I/I Capital Improvements Plan from the I/I reduction plan is included in Appendix C. The clearwater flow from residential uses is estimated using the data presented in Figure 7.12. Design assumptions for sewer discharge is 75 gallons per person per day and 100 gallons per person per day for water consumption, or sewer discharge is 75% of water consumption. Using this rationale wastewater flow in excess of 75% is an estimation of clearwater flow and is summarized in Figure 7.15. City of Chanhassen 2040 Comprehensive Plan163 Year Actual Percent of Wastewater to Water Usage Amount Above 75% Threshold Estimated Residential Wastewater Flow (gal/day) Estimated Clearwater Flow (gal/day) 2010 78%3%1,473,499 44,205 2011 74%-1,496,436 - 2012 55%-1,301,265 - 2013 70%-1,465,616 - 2014 78%3%1,437,587 43,128 2015 68%-1,244,312 - 2016 83%8%1,433,808 114,705 FIGURE 7.15 | Historical Residential Wastewater Flow Rates 7.4 | Sanitary Sewer Districts To develop the future sanitary sewer trunk system, the ultimate potential service area was divided into major service areas or districts and then those major service districts were divided into sub-districts. Generally the selection of these areas is governed by existing topography and/or other existing features such as roadways. The ultimate potential service area for Chanhassen is divided into eight major sanitary sewer districts: Minnewashta (MW), Bluff Creek (BC), Lake Ann (LA), Lake Lucy (LC), North (NO), Lotus Lake (LL), Lake Riley (LR) and Lower Bluff Creek (LB). Figures 7.16 and Figures 3.2 and 3.3 in Appendix A show the major sanitary sewer districts and the sub-districts. The existing and projected flows for each sanitary sewer district is presented in Figure 7.21. The existing flows not- ed in Figure 7.21 are higher than the sewer flow rates provided by the Metropolitan Council. The difference between calculated and realized sewer flows can be attributed to the fact that properties within each land type can contain undevelopable acreage such as wetland, storm water features or steep slopes which cannot be readily deleted from the property area. Minnewashta District (MW) The Minnewashta (MW) Sewer District includes the area around the south, west and north sides of Lake Minnewashta. There are approximately 1,200 acres of developed land consisting of low density residential and commercial uses, including approximately 40 acres of single family residential land within the City of Victoria. The district also includes park/open space and significant acreage of public/semi-public land within the Minnesota Landscape Arboretum property. Approximately 20 acres of low density residential developable land remains within the MW Sewer District. The MW Sewer District is subdivided into seven sub-districts. The flows from the MW district are collected by several sewer lines ranging in size from 8-inch to 10-inch pipe. There are six lift stations that service the MW Sewer District as summarized in Figure 7.17. City of Chanhassen 2040 Comprehensive Plan164 FIGURE 7.16 | Sanitary Sewer Districts City of Chanhassen 2040 Comprehensive Plan165 FIGURE 7.17 | Summary of Lift Stations within the Minnewashta Subdistricts Subdistrict Serviced by Discharges to MW 1 Lift Station 3 MCES Shorewood Interceptor Sewer (7017) MW 2 Lift Station 28 MW 3 MW 3 Lift Station 7 MW 1 MW 4 Lift Station 6 MW 3 MW 5 n/a*n/a MW 6 Lift Station 8 MW 7 MW 7 Lift Station 4 MCES Shorewood Interceptor Sewer (7017) Bluff Creek District (BC) The Bluff Creek (BC) Sewer District includes the area from the east side of Lake Minnewashta and extends southeasterly along the Chanhassen/Chaska border to the Highway 212 corridor. There are approximately 1,250 acres of developed land and 400 acres of developable land within the BC Sewer District. The BC District is partially developed with a combination of low and medium density residential, large lot residential, parks/open space, public/semi-public and office/industrial properties. The BC Sewer District is subdivided into 11 sub-districts. The wastewater generated is collected by gravity sewers ranging from 8-inches to 21-inches diameter. There are three lift stations within the BC Sewer District: Lift Stations 19, 24 and 26. Lift Station No. 19 serves the BC-2 sub-district and Lift Station No. 26 serves the BC-3 sub-district. All of the wastewater from the BC sub-districts flows to Lift Station 24, where it is then pumped north to an 18-inch trunk sewer in the Lake Ann Sewer District Lake Ann District (LA) The Lake Ann District (LA) Sewer District includes the area that runs through the central part of Chanhassen. There are approximately 1,656 acres of existing developed land and 295 acres of developable land within the LA Sewer District. The LA District is sub-divided into 11 sub-districts. The majority of the sub-districts have been developed but there will still be need for lateral sewer lines as LA-4, -5 and -6 are sub-districts that are not fully developed. The LA District consists of low, medium and high density residential properties as well as large lots, park/open space, public/semi-public and office industrial areas. The wastewater generated in the LA District is collected by gravity sewers ranging from 8-inches to 36 inches in diameter. There are five existing lift stations within the LA Sewer District: Lift Stations 23, 27, 29, 30 and 31. Lift Station No 23 is a small station within the LA-4 sub-district that serves Lake Ann Park and discharges to Lake Susan Sub District 11. Lift Station No. 27 serves the LA-7 sub-district and discharges to LA-6. Lift Station No. 29 was constructed to serve approximately nine large lots in the southern part of LA-3 sub-district; however, its use has been very minimal, as it only services one home at this time. Lift Station 30 serves the LA-9 sub-district and dis- charges to LA-8. Lift Station 31 serves approximately 28 single family lots in the southern part of LA-3 sub-district. The MCES Lake Ann Interceptor runs southeast through the center of the LA Sewer District. The city’s major trunk line, which ranges in size from 21-inches in diameter to 36-inches in diameter, parallels the MCES Lake Ann Inter- ceptor from State Highway 5 to near Market Boulevard, where it discharges into the Lake Ann Interceptor. *There is currently no collection system that serves sub-district MW-5, which contains the Minnesota Landscape Arboretum research fields and natural areas. City of Chanhassen 2040 Comprehensive Plan166 Lake Lucy District (LC) The Lake Lucy (LC) Sanitary Sewer District is located around the north side of Lake Lucy. The LC District is not subdivided in to sub-districts due to its size. There is approximately 91 acres of existing developed land within the LC District, which is all low density residential. A 10 acre parcel in the southwest corner of the LC District may further subdivide in the future. Sanitary sewers 8-inches in diameter collect the wastewater and direct it to Lift Station No. 25. Lift Station No. 25 is the only lift station within the LC District, which collects the entirety of wastewater generated and pumps the wastewater to the North District North District (NO) The North District (NO) is located along the north border of the city and extends east from the Minnewashta District to the eastern border of the city. The NO District also includes the area along the northeast side of Lotus Lake and is fully developed. There is approximately 725 acres of existing developed land within the NO Sewer District. The existing de- velopment within the NO District consists of low density residential, park/open space and public/semi-public uses. This district also includes approximately 17 acres of low density residential within the City of Shorewood. The only properties that may be developed in the future are low density residential lots that lie within sub-districts NO-7 and NO-8. The NO District is subdivided into 12 sub-districts. The wastewater generated is collected by gravity sewers ranging in size from 8-inches to 15-inches in diameter. There are six lift stations within the NO District and include Lift Stations 5, 13, 14, 15, 16 and 21. Lotus Lake District (LL) The Lotus Lake District (LL) is located along the western and southern sides of Lotus Lake and is divided into 10 sub-districts. Most of the area within the LL District is developed and is composed of low and high density residential, parks/open space, public/semi-public, office/industrial and commercial properties. There is approximately 925 acres of developed land within the LL Sewer District. Sub-district LL-3 has approximately eight acres of developable low density residential land. LL-7 has one 1.2 acre commercial property that is possible for redevelopment. The wastewater generated is collected by gravity sewers ranging in size from 8-inches to 21-inches in diameter. There are seven lift stations within the LL District and include Lift Stations 1, 2, 9, 10, 11, 12 and 22. Lake Riley District (LR) The Lake Riley District (LR) is located around the north, west and south sides of Lake Riley. There are approximately 485 acres of developed land and 40 acres of developable land within the LR Sewer District. The potential future devel- opment within the LR District is around the US Highway 212 corridor and Great Plains Boulevard. The developed ar- eas consist of low and high density residential, large lots, park/open space and mixed use properties. Sub-districts LR-3 and LR-4 have areas of potential low and medium density residential as well as mixed use developable properties. The LR District is subdivided into five sub-districts. The wastewater is collected by gravity sewers ranging in size from 8-inches to 36-inches in diameter. There are two lift stations within the LR District and include Lift Station 17 and 18. Lower Bluff Creek District (LB) The LB District is located south of Lyman Boulevard between Powers Boulevard and Great Plains Boulevard, and between Pioneer Trail and the southern city limits. This area within the district is partially developed with very little city sewer service. There is a strong possibility for redevelopment, namely along the Highway 212 corridor, as well as the Bluff Creek Golf Course. There are approximately 610 acres of developed land and 1,000 acres of developable land within the LB Sewer District. City of Chanhassen 2040 Comprehensive Plan167 The LB District is subdivided into five sub-districts. An 8-inch sanitary extends along 96th Street to Lift Station No. 20 and serves the existing developed lots within LB - 4. Lift Station No. 20 pumps wastewater through a forcemain that runs north along Great Plains Boulevard that discharges to the Lake Riley District. There is also an existing 15-inch and 18-inch trunk sewer line that was constructed along Pioneer Trail and Powers Boulevard; however, this existing trunk sewer does not serve any development at this time. Development of the land within this sewer district and future densities is contingent upon the installation of a lift station and forcemain to bring the sewage to the 21- inch sewer main at Great Plains Boulevard and Lyman Boulevard. The lots within sub-district LB-2 are served by an existing 8-inch diameter sewer that discharges to the Eden Prairie sewer system. Sub-district LB-1 is proposed to have low, large lot and high density residential and office, parks/open space and office industrial properties. The area encompassed in sub-district LB-3 is currently large lot development with area for future residential low density development. Sub-district LB-5 is primarily undeveloped. There are large lots located on Homestead Lane and Flintlock Trail but there is no sewer service. Eight-inch sanitary sewer would be required to convey the flows from these existing lots and potentially from the proposed lift station in LB-4. The northern portion of LB-5 is proposed for low density and large lot residential, office and parks/open space. 7.5 | Future Sanitary Sewer System Wastewater Flow Projections Wastewater flow projections were generated for each sanitary sewer district and corresponding sub-districts based on the gross developable acreage available, anticipated land uses and wastewater flow generation rates. The waste- water flow generation rates for the various land uses found in Figure 7.11 of this report were used to project the future wastewater flows for the service area. The total district existing average and peak flows and also the ultimate 2040 average and peak flows were calculated using the actual development for existing flows and the projected land use for ultimate flows. Estimated peak hour flows are not totaled as the peaking factor is dependent upon the average day flow rate. Summing the projected peak hour flow rates would produce a flow rate higher than the peak hour flow rate for the entire city; therefore, the peak hour flows are calculated by multiplying the total average flows by the MCES peaking factor. Figure 7.21 presents the existing and projected 2040 flows for each sanitary sewer district. FIGURE 7.18 | Breakdown of Growth by Interceptor 2020 2030 2040 Interceptor House Pop Employ House Pop Employ House Pop Employ Lake Ann 8,215 21,205 14,957 10,066 26,172 16,351 12,091 31,330 17,708 Shorewood 1,405 4,025 443 1,454 4,104 449 1,529 4,345 492 City of Chanhassen 2040 Comprehensive Plan168 FIGURE 7.19 | 2040 Wastewater Flow Projections to MCES Interceptors FIGURE 7.20 | Sewer Capacities 12 inch or Larger Pipes Lyman B lv d (C.R.18) Lyman Blvd (C.R.18) P ion e e r Trail (C R 14) (C R 6 1 )F l y in g C lo u d D riv ePowersBlvd(C.R.17)AudubonRoad(C.R.15)State Hig h w ay 101Hwy101GreatPlainsBlvd Hwy 101Gr e at Pl ainsBlvdStat e H w y 5 State H w y 5 Arboretum Boulevard Highway 41GalpinBlvd.(C.R.117)State H w y 5 State Hw y 7 Hazeltine Blvd (Hwy 41)Chanhassen Rd. Hwy. 101AudubonRoad(C R 6 1 )F l y in g C l o u d D rMinnewashtaPkwyGalpinBlvd(C.R.19)£¤212 £¤212 £¤212 PowersBlvd(C.R.17Bl u f f C r e e k D rBluffCreekBlvd"""" " """""""Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä MCES Interceptor 7017-4Average Flow = 0.03 MGDPeak Hourly Flow = 0.12 MGD MCES Interceptor 7017-2 Average Flow = 0.07 MGD Peak Hourly Flow = 0.27 MGD MCES Interceptor 7017Average Flow = 0.23 MGDPeak Hourly Flow = 594 gpm (LS 3) MCES Interceptor 7017-1 Average Flow = 0.04 MGD Peak Hourly Flow = 560 gpm (LS 4) MCES Interceptor 7017-3 Average Flow = 0.09 MGD Peak Hourly Flow = 0.34 MGD MCES Int. 7016 via Eden Prairie Average Flow = 0.09 MGD Peak Hourly Flow = 0.36 MGD MCES Interceptor 8253-327 Average Flow = 0.03 MGD Peak Hourly Flow = 0.10 MGD MCES Interceptor 8253-327Average Flow = 0.07 MGDPeak Hourly Flow = 0.29 MGD MCES Interceptor 8253-327Average Flow = 0.22 MGDPeak Hourly Flow = 0.84 MGD MCES Interceptor 7138Average Flow = 1.51 MGDPeak Hourly Flow = 4.37 MGD MCES Interceptor 7025-1Average Flow = 0.05 MGDPeak Hourly Flow = 0.19 MGD MCES Interceptor 7025-1Average Flow = 0.02 MGDPeak Hourly Flow = 0.08 MGD MCES Interceptor 7138 Average Flow = 0.02 MGD Peak Hourly Flow = 0.07 MGD MCES Interceptor 7025-1 Average Flow = 0.21 MGD Peak Hourly Flow = 0.82 MGD MCES Interceptor 7025-1Average Flow = 0.17 MGDPeak Hourly Flow = 0.65 MGD MCES Interceptor 7138Average Flow = 0.01 MGDPeak Hourly Flow = 0.03 MGD MCES Interceptor 8253-328Average Flow = 1.32 MGDPeak Hourly Flow = 3.96 MGD MCES Interceptor 8253-328Average Flow = 0.11 MGDPeak Hourly Flow = 0.43 MGD7017 7017-26-TB-661 701 77017 8253-32871388253-3277025-1Document Path: K:\010994-000\GIS\Maps\SanitarySewer_MCESInterceptor.mxd Date Saved: 7/31/2019 10:25:21 AM Legend Xä Lift Station Forcemain "Gravity Main "MCES Interceptor City Boundary 2040 Wastewater Flow Projections SewerCAD Model Update & Analysis City of Chanhassen, MN 0 4,000Feet¯1 inch = 4,000 feet City of Chanhassen 2040 Comprehensive Plan169 FIGURE 7.21 | 2040 Wastewater Flows Per Sewer District FIGURE 7.22 | Wastewater Growth Forecasts ( Household and Employment) by Sewer District Sanitary Sewer District Existing Average Day Flow (MGD) Existing Peak Hour Flow (MGD) 2040 Average Day Projected Flow (MGD) 2040 Peak Hour Projected Flow (MGD) Minnewashta (MW)0.150 0.589 0.310 1.126 Bluff Creek (BC)0.718 2.370 1.017 3.153 Lake Ann (LA)0.681 2.25 1.114 3.45 Lake Lucy (LC)0.019 0.074 0.027 0.106 North (NO)0.316 1.137 0.363 1.308 Lotus Lake (LL)0.595 2.02 0.642 2.18 Lake Riley (LR)0.222 0.843 0.383 1.377 Lower Bluff Creek (LB)0.015 0.061 1.192 3.696 Total System 2.716 7.333 5.051 12.122 Households Households HouseholdsEmploymentEmployment Employment Minnewashta 709 403 743 437 770 475 Bluff Creek 2,394 2,447 2,832 4,532 3,356 5,501 Lake Ann 2,138 7,077 2,308 6,576 2,725 6,646 Lake Lucy 112 - 146 - 195 - Lake Riley 1,197 172 1,506 222 1,555 209 Lotus Lake 1,857 4,762 1,915 4,235 1,949 3,985 Lower Bluff Creek 348 580 1,071 900 1,827 1,405 Northern 1,245 158 1,380 98 1,622 179 TOTAL 10,000 15,600 11,900 17,000 14,000 18,400 2020 2030 2040 »The sum of the existing peak hour flow does not equal the sum of the peak discharges from each district since the peaking factor decreases as the average flow increases. »Peaking factors were taken from MCES factors included in Appendix B. Future Trunk Sanitary Sewer System Analysis The 2007 SewerCAD model developed for the analysis of the existing sanitary system flows was utilized to determine the ability of the existing trunk sanitary system to convey future wastewater flows. Future trunk mains and lift stations will be extended to accommodate future development, which in turn will increase the flows conveyed to the existing trunk system. The trunk sewer system has not been extended since 2007, therefore an updated analyses was not done. Proposed flows were entered into the model and results indicated a reduction in remaining capacity throughout the system, primarily in the Lower Bluff Creek District. Figure 7.3 presents the remaining sewer capacity taking into account proposed future flows. The two sections of the 36-inch trunk main parallel to the MCES interceptor flowing east along the north side of Lake Susan near Highway 101 that exceeded capacity in the existing flow model re- mained the only two sections exceeding capacity in the future system model. Similar to the existing system model, the MCES interceptor exhibited a few sections exceeding capacity; however, MCES is responsible for monitoring flows and determining deficiencies for this main. The City of Victoria future flows conveyed through the MCES interceptor were not included in the model to analyze future capacities in the MCES Lake Ann interceptor. All existing trunk lift stations with the exception of Lift Station Nos. 7 exhibit adequate pumping capacity to serve future development. Figure 7.23 below shows existing lift station pump capacity and existing peak inflow. City of Chanhassen 2040 Comprehensive Plan170 Lift Station Area Existing Pumping Capacity (gpm) Existing Peak Hour Inflow (gpm) Estimated Future Peak Hour Inflow (gpm) Remaining Pumping Capacity (gpm) 4 560 229 21 310 5 325 69 44 212 7 135 145 4 -14 10 905 609 19 277 17 956 77 425 454 18 99 20 371 -292 19 89 20 23 46 24 1,448 725 407 316 25 143 22 22 99 26 396 339 55 2 30 264 30 149 85 FIGURE 7.23 | Future Trunk Lift Station Analysis Lift stations 17, 18, 19 and 30 may need to be upgraded if existing large lot residential properties in subdistricts LR-1 (will flow to LS 17, then LS 19), BC-10 and LA-9 (respectively) are rezoned to low or medium density and serviced by municipal sanitary sewer. A feasibility report would need to be completed to determine the sewer impacts to the existing lift stations. Typically if development impacts from up-zoning are identified, upgrades to existing infrastructure are paid for by the developer or land owner(s). Future Trunk Sanitary Sewer System Minnewashta District (MW) Additional trunk sanitary sewer main improvements will not be necessary to serve the identified future development within the Minnewashta Sewer District. The properties remaining for development are located near trunk and lateral facilities and remaining capacity within the existing facilities is sufficient for estimat- ed peak flows at full build-out. The 2030 Comprehensive Plan addressed the possibility of serving the northeast portion of Victoria through the Minnewashta District. Subsequently, the City of Victoria further examined this service connection and opted to service this area via a future lift station and force main that connect to the Met Council interceptor. Lift Station No. 7 may need to be increased in capacity in the future. Currently, Lift Station No. 28 has a capacity of 100 gpm, with an estimated 25 gpm of existing peak flow. Both of these lift stations would need to have the capacity increased if undeveloped property in Victoria to the west of these lift stations where to development and sanitary sewer service connected to the City of Chanhassen sewer system. The estimated future peak flow from the Victoria development area totals 160 gpm (0.2302 MGD). Bluff Creek District (BC) Improvements to the existing lateral and trunk sanitary sewer system will be required to provide service to currently undeveloped properties as well as existing properties that do not have city service. Several of the sub-districts will require improvements to service the developable areas. Sub-district BC-1: Requires an 8-inch trunk line to service a public/semi-public piece of land with the addition of a lift station to pump the wastewater to BC-4. Sub-district BC-2: Contains a nine acre parcel that can be redeveloped into low density residential with the future installation of an eight inch lateral. Sub-district BC-3: This area is fully developed, however several large lots in the Timberwood development are within this district and on a septic system. Future installation of eight inch lateral sanitary sewer will service these properties. Sub-district BC-4: Potential development of low density residential and public/semi-public land with the future installation of an eight inch lateral. Sub-district BC-5: Fully developed and will not require additional sewer installation. Sub-district BC-6: An 11 acre parcel was redeveloped to residential low density in 2017. The extension of an eight inch lateral from the existing stub within the southern portion of Fawn Hill Road served this parcel. City of Chanhassen 2040 Comprehensive Plan171 Sub-district BC-7: This area is fully developed. However, several large lots in the Timberwood development are within this district and on a septic system. Future installation of eight inch lateral sanitary sewer will service these properties. Sub-district BC-8: There is one undeveloped office industrial property within sub-district BC-8 that will require an 8-inch sanitary sewer line to tie into Chaska’s system or a new lift station to convey flow to Lift Station No. 24 Sub-district BC-9: Future installation of eight inch lateral sanitary sewer will service the properties on Sunridge Court, Audubon Road and Sunset Trail that are currently serviced by septic systems. The vacant land southwest of Lyman Boulevard and Powers Boulevard is guided for medium and high density residential, office and dual guided for commercial as part of the Avienda development pending the extension of eight or ten inch sanitary sewer that flows to Lift Station No. 24. Sub-district BC-10: This area is fully developed as large lot residential. All properties are currently on septic systems. Future improvements include installation of eight inch lateral sanitary sewer and a lift station that connects to the BC-2 system. Lake Ann (LA) Sub-districts LA-1, LA-2, LA-7, LA-8, LA-10 and LA-11 have developed to their full potential and are sufficiently serviced by the existing sewer systems. Subdistrict LA-3. The 19 acre property east of Audubon Road and south of Alisa Lane can be redeveloped into low density residential and serviced by the extension of eight inch lateral sanitary sewer that connects to the system within Alisa Lane and/or Stonefield Lane. Sub-district LA-4 also will require an 8-inch line to be extended from Coulter Boulevard to the north to service the future office-industrial property located west of McGlynn Drive. Sub-districts LA-5 and LA-6 are proposed to have large areas of development consisting of low, medium, and high density residential properties. Eight-inch sewer laterals will be needed to convey the wastewater from these sub-districts to the existing MCES Interceptor. LA-9 is fully developed, but there are some low density and large lot properties without sewer service. Eight-inch sanitary sewer would be used to connect to the existing sewer system should future connection be asked for by the residents. Lake Lucy (LC) Most of the LC District has sewer service, with the exception of approximately a 10 acre parcel south of Lake Lucy Road at Yosemite Avenue. Eight-inch laterals were stubbed to the property line when the area to the east developed. North District (NO) The only properties that may be developed in the future are low density residential lots and lie within sub-districts NO-7, NO-8 and NO-9. Additional sanitary sewer trunk lines would not be needed to serve these lots as there are sufficient facilities adjacent to the properties. Lotus Lake (LL) The majority of this district is fully developed. The potential future developments within sub-district LL-3 and extension of sanitary sewer to existing lots within LL-10 would be served by the existing trunk sanitary sewer system facilities. Eight inch laterals would be needed to accommodate these properties. Lake Riley (LR) Sub-district LR-1 is fully developed with large lots that will require a future eight-inch sanitary sewer and a lift station to pump the wastewater to sub-district LR-2. The proposed sewer would be needed if the residents requested City service, if the area redevelops, or if septic system failures lead to health or safety issues requiring centralized sanitary sewer service. Sub-districts LR-2 and LR-5 are fully developed are sufficiently serviced by the existing sewer systems. Sub-districts LR-3 and LR-4 are mostly developed and contain future low and medium density residential as well as mixed use properties. To serve future development within these sub-districts, eight inch laterals are proposed. City of Chanhassen 2040 Comprehensive Plan172 Lower Bluff District (LB) Sub-district LB-1 contains low density residential and large lot properties that will be serviced by eight-inch gravity sanitary sewer. In 2014, the “County Road 61 Corridor Plan” by SRF Consulting Group and Hoisington Koegler Group was finalized and included the trunk sanitary layout and estimated costs. The properties west of the Seminary Fen Scientific and Natural Area (SNA) will require eight-inch sanitary sewer to convey flow to a future lift station at the west- ern edge of the SNA. The remainder of Sub-District LB-1 will be serviced by eight-inch lateral. A future lift station at High- way 101 and County Road 61 will take all of the flow of LB-1 and pump it north along Highway 101 to LB-5. Sub-district LB-2 is fully developed and is serviced by eight inch sanitary sewer that connects to the City of Eden Prairie. Sub-district LB-3 consists of existing large lot development and future low density residential development. To service this area, eight-inch sanitary sewer and lift station just west of Deerbrook Drive will be required. Flow from this area will be discharged to LB-5. Sub-district LB-4 is fully developed as residential homes connected to the sanitary sewer via a “201 System”. The “201 Program” instituted by the Metropolitan Waste Control Commission (MWCC) based on Section 201 of the Fed- eral Water Pollution Control Act of 1972. The 201 Facilities Planning identified facilities that were required in order to achieve water quality requirements. As a result, Carver County led a project in the 1980s to install sanitary sewer along 96th Street to service the existing properties. The project was to correct the existing problems without providing sani- tary sewer facilities to accommodate additional growth in the area. The project was paid using federal and local funds; also, benefiting property owners were assessed. When this sewer was installed, the services were connected directly to the existing septic tanks instead of abandoning the septic tanks. The old septic tanks are a suspected source on infiltration into the sanitary sewer system. With the proposed sewer layout it may be feasible to abandon Lift Station No. 20 and route the flow west to the new lift station located along Powers Boulevard in LB-5. To reduce the amount of infiltration entering the city’s sanitary sewer system, when the new sewer is constructed, services should be installed directly to the homes and all septic tanks should be abandoned. Sub-district LB-5 is primarily undeveloped. There are large lots located on Homestead Lane and Flintlock Trail but there is no sewer service. To convey the flows from these existing lots and potentially from the proposed lift station in LB-4, eight-inch sanitary sewer would be required. The northern portion of LB-5 is proposed for low and medium density residential and office properties. These properties will require 8-inch trunk mains to carry the wastewater flow. A portion of LB-5 south of Highway 212 and east of Powers Boulevard may be rezoned from low density residential to office. The comprehensive plan assumes the land use will be low density residential as the sewer generation per acre is higher than that of office (822 versus 800 gpad). The Bluff Creek Golf Course may potentially be redeveloped into low density residential properties. Redevelopment of the Bluff Creek Golf Course may be required to convey the gravity sewer flows from the southern and eastern portions of the LB District. To service the existing properties on Delphinium Lane, Raspberry Hill, and Halla Nursery Drive West, eight-inch sanitary sewer will be needed. To convey the flow from the LB-1 -3 and -5 a 15-inch line will be need- ed. All of the LB-5 wastewater flows would be taken by gravity sewer to a proposed lift station north of Pioneer Trail and south east of the Highway 212/Powers Boulevard intersection. This proposed lift station would pump flows to the northeast along the Highway 212 and tie into an existing 21-inch sewer stub in LR-4 of the Lake Riley District. This lift station is critical in pumping all sewer south of Hwy. 212 to the MCES interceptor system. Alternative sewer alignments have been considered to service sub-district LB-3 and the portion of LB-5 south of Pioneer Trail. The alternative alignments, estimated cost (2016 dollars) and design considerations are included in Appendix D. City of Chanhassen 2040 Comprehensive Plan173 7.6 | Capital Improvement Program Analysis of Area South of Pioneer Boulevard The MUSA expansion area generally lies south of Pioneer Trail. Over the past 10 years, two studies have been performed to analyze utility extension to the area: the December, 2014 County Road 61 Corridor Plan by SRF Consulting Group, and the 2016 Kimley Horn Lower Bluff Creek District Sanitary Sewer Study. These studies are intended to serve as guiding documents; actual alignments will be established as development proposals are submitted. These studies are included in Appendix D. The Kimley Horn study included Option 2A, the trunk sewer alignment through the Bluff Creek Golf Course property, and four alternate alignments. Figure 3.4, Appendix A, depicts Option 2A as the future sewer align- ment, which is consistent with the previous comprehensive plan. Figure 7.24 includes a summary of only the estimated oversizing cost for trunk sewer and lift station costs to serve the sewer sub-districts south of Pioneer Boulevard. Figure 3.1 in Appendix A, details the existing MUSA area and the proposed MUSA expansion area. FIGURE 7.24 | Lift Station and Trunk Main Oversizing Cost for the MUSA Expansion Sewer Improvements Sewer Sub-District Utility Extension Cost LB – 5 Trunk Sewer, Lift Station & Forcemain $3,620,000 LB – 1 Trunk Sewer, Lift Station & Forcemain**$11,100,200 *Source: Kimley Horn & Associates for Option 2A **Source: County Road 61 Corridor Plan by SRF Consulting Group, Inc. in association with Hoisington Koegler Group, Inc. Alternative alignments for the LB-3 -4 and -5 subdistricts and the associated estimated costs are included in Appendix D. Lift Station Improvements As discussed in previous sections, the city owns and operates 31 lift stations, which require routine maintenance and upgrades. The expected service life of the controls and equipment in these lift stations is 20 years. Pumps and motors should be replaced at approximately 33,000 hours of use on an intermittent duty pump station. The city has routinely replaced and upgraded outdated pumping equipment and controls in many lift stations over the past several years. It is recommended that this program continue to prevent failure of older and outdated lift station equipment. This replacement program will need to continue over the next 20 years and beyond to keep all the lift stations run- ning efficiently with minimal maintenance and breakdowns. Replacement of outdated pumps and controls in the lift station should be scheduled as part of the city’s capital improvements program. Figure 7.26 presents a detailed capital improvement program in 5-year increments as a pro- posed schedule for upgrades to the city’s lift stations. These tables also include the recommended improvements to be made to each of the lift stations listed. This list of improvements is based on information obtained from city staff and from a site investigation of each lift station. New lift stations that are constructed will need to be incorporated into the lift station capital improvements schedule in the appropriate time period. Most costs include construction costs only and do not include administration, legal or engineering fees as the work would be completed in-house by city staff; however, larger projects may need to be outsourced for design. City of Chanhassen 2040 Comprehensive Plan174 FIGURE 7.25 | Lift Station Capital Improvement Plan Lift Station Number Proposed Improvements Refurbish Control Panel1 New Controls and Control Panel2 New Pump3 New Concrete Top Slab & Hatch4 Wet Well Cleaning& Rehab5 Site Work6 Piping7 2018 26 ●●●●● 18 ●●●●●● 2019 16 ●●● 2020 22 ●●●●●● 2021 2 ●●● 17 ●● 2022 13 ●● 2023 1 ●● 20 ●●●●● 2024 7 ●●●● 2025 to 2030 6 ●●●● 9 ●●●● 10 ●●● 11 ● 12 ●●● 15 ●● 30 ●●●●● 31 ●●● 2031 to 2035 3 ●●● 8 ●●●● 14 ●●●● 19 ●●●● 27 ●●● 2036 to 2040 4 ●●● 5 ●●● 21 ●●● 23 ●●● 24 ●●● 25 ●●● 28 ●●● 29 ●●● 32 ●●● »1. Includes replacement of panel and replacement of outdated electrical components. »2. New controls and control panels are recommended for the lift stations that have panels that were installed in the 1980s and 1990s. »3. Pumps that are over 20 years old need to be replaced. »4. Includes replacement of sagging hatches or those without safety grates and replacement of the concrete top slab. »5. Includes cleaning, inspection and applying a protective coating to the wet wells at the time pumps are replaced. »6. Includes replacement of the bituminous driveways and regrading for proper drainage around the lift station. »7. Includes restraining discharge piping. City of Chanhassen 2040 Comprehensive Plan175 Lift Station Number 2018 to 2024 2025-2030 2031-2035 2036-2040 Total Lift Station Costs 1 $75,000 $75,000 2 $45,000 $45,000 3 $75,000 75,000 4 $75,000 $75,000 5 $75,000 $75,000 6 $45,000 $45,000 7 $50,000 $50,000 8 75,000 $75,000 9 $75,000 $75,000 10 $85,000 $85,000 11 $45,000 $45,000 12 $50,000 $50,000 13 $45,000 $45,000 14 $50,000 $50,000 15 $45,000 $45,000 16 $45,000 $45,000 17 $45,000 $45,000 18 $45,000 $45,000 19 $65,000 $65,000 20 $45,000 $45,000 21 $75,000 $75,000 22 $55,000 $55,000 23 $75,000 $75,000 24 $200,000 $200,000 25 $75,000 $75,000 26 $45,000 $45,000 27 $65,000 $65,000 28 $75,000 $75,000 29 $75,000 $75,000 30 $65,000 $65,000 31 $45,000 $45,000 32 $75,000 $75,000 Total Costs $495,000 $455,000 $330,000 $800,000 $2,080,000 FIGURE 7.26 | Lift Station Improvements »Costs are for budgeting purposes only, and are subject to change as projects are studied, designed and constructed. »Project Costs include 10% for construction contingency. »Costs are estimated based on 2017 construction costs. Capital Improvements Summary A Capital Improvement Plan based on estimated phasing of trunk sewer construction is presented in Figure 7.1. This figure includes trunk system improvements for service areas added, list station improvements and improvements for I/I reduction efforts. The projected 2040 sanitary sewer trunk system was broken down into improvements based on flow districts. The overall cost associated with these improvements over the next 22 years is approximately $22.5 million. These costs are based upon 2017 dollars. City of Chanhassen 2040 Comprehensive Plan176 Funding The city’s current sewer fee structure is provided in Appendix E. Fees consist of sewer user fees, trunk sewer fees and sewer access charges (SAC). Utility usage fees are charged to both residential and non-residential users based on the actual water usage metered during the winter months. The purpose of the user charges is to fund the operation, maintenance and replacement costs of existing collection systems. User charges are primarily based on the actual costs of operations, maintenance and replacement of all wastewater system facilities. Trunk and SAC fees provide a funding mechanism for construction of the major infrastructure improvements needed to serve growth. The City of Chanhassen has established that growth should be funded and paid for by those who are in need of the facilities. The development creating the need for additional sanitary sewer system improvements are expected to pay for new trunk facilities and expansion of existing facilities through trunk and SAC fees. Currently, the trunk sewer fees are a per unit cost at the time of development and the SAC fees are calculated based upon the Metro- politan Council’s SAC Procedure Manual, which assigns non-residential properties a SAC unit for office or industrial/ commercial buildings. Developments and redevelopments that currently are not serviced by the city’s sanitary sewer system must construct lateral sanitary service to the parcel. The design and installation costs of the lateral sanitary sewer shall be bore by the project developer. Goals and Policies The timing of future trunk sanitary sewer improvements will be influenced by several parameters including develop- ment pressures in specific areas, failing on-site septic systems, regulatory requirements, availability of funds, etc. As a result it is difficult to accurately predict the timing of future improvements especially those which may occur far into the future. Therefore, the Capital Improvement Program is intended to serve as a guide only for future fiscal planning and should be reviewed on a regular basis as more current planning and cost data becomes available. The following items are general policy guidelines to be considered when reviewing and/or revising the city’s fee structure: System Expansion (Orderly Development) Development shall occur in an orderly fashion. Properties that abut parcels served by municipal utilities will be consid- ered as the next feasible property for development. The city may limit development activities to selected areas. Petitions to expand in areas not already under development will be considered. Factors that will be considered include but are not limited to capacity in the MCES interceptor, capacity in the city’s collection system, economic factors including costs, number of developments under construction and the staff resources available to review the requested development. Leapfrogging Leapfrogging refers to the circumstance where certain parties want to develop an area not currently adjacent to the limits of the City of Chanhassen’s existing sewer system. The applicant wants to “leapfrog” over areas located adja- cent to the city’s existing services that would be the next logical area to be developed. In this circumstance, the City of Chanhassen could decide whether or not to approve such development. If approved, it is recommended that the inter- ested property owner pay for the entire cost of installing services to their property and resulting system upgrades. The developer shall be offered no credit or reimbursement for these costs. If development of the property that was “leap- frogged” is later initiated, payment of all trunk charges for the property will still be required regardless of the fact that the facilities were already installed before development occurred. City of Chanhassen 2040 Comprehensive Plan177 Overdepth and Oversizing The costs of additional depth shall be defined by differences in cost for the depth required by the development and the depth required for trunk facilities. Trunk oversizing as defined by the city and installed by the developer will be credited using the differential of pipe costs between the larger and the minimum pipe size required for the develop- ment. Bid pricing shall not be the sole determinate in defining a developer credit. The city shall determine if a credit will be given for a project. Lift Stations Trunk lift stations should be defined as those servicing more than one single development project. The trunk fees will pay for 100 percent of the cost of trunk lift stations. Lift stations that do not fit the definition for a trunk lift station are to be paid for by the developer. All lift stations shall be designed and constructed in accordance with city standards. The city will consider cost sharing for other lift stations if it is found that a particular lift station may be able to serve a greater area than the single development. The cost sharing shall include the oversizing or overdepth required to serve additional area and associated Supervisory Control and Data Acquisition (SCADA) system costs to establish the lift station on the city’s SCADA system. Existing Developed Unserviced Properties There are a number of existing developed areas that do not receive sewer and water service within the city limits. The trunk system has been designed to handle all existing developed unserviced properties within the city, but it is not the policy of the city to initiate a sewer extension project. If an individual property owner or group of neighbor- ing property owners would like city sanitary sewer services where it is not yet available, the city will review whether or not it is economically viable. Existing developed, unserviced residential properties will be assessed or required to pay connection fees as required by the City Code. Existing Non-Residential Unserviced Properties Existing unserviced commercial/industrial or other non-residential properties wishing to expand or hookup to municipal utilities shall be treated the same as new development and will be assessed or required to pay connection fees as required by the city. Interconnections As Chanhassen and its neighboring cities have grown, interconnections (inter-community service areas) and subsequent municipal wastewater charge agreements for receiving adjacent municipal wastewater flows have developed. The majority of Chanhassen’s municipal wastewater inter-community service areas with neighboring cities are to the north, as seen from Figure 7.27, with Shorewood and Eden Prairie. The City also has agreements with Victoria and Chaska. The communities reimburse each other for the municipal wastewater charges that each will incur by receiving flow from the adjacent community. City of Chanhassen 2040 Comprehensive Plan178 7.7 | Recommendations Based on the results and analysis of this study, it is recommended that the City of Chanhassen and the City Council, where applicable: »Adopt this report as the Comprehensive Sanitary Sewer Plan for the City of Chanhassen. »Review and update the CIP for trunk sanitary sewer facilities every year to reflect sewer improvement projects necessary for the next five year period. »Proceed with future sanitary sewer improvements in accordance with the initial 5-year capital improvement program. »Continue to reduce I/I to the existing collection system and maintain provisions for preventing I/I from entering the sanitary sewer system with new construction. 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Hwy. 101AudubonRoad(C R 6 1 )F ly in g C l o u d D rMinnewashtaPkwyGalpinBlvd(C.R.19)£¤212 £¤212 £¤212 PowersBlvd(C.R.17Bluff Creek DrBluffCreekBlvd""""""" " """Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä Xä LS 8 LS 1 LS 2 LS 9 LS 7 LS 5 LS 3 LS 4 LS 6 LS 23 LS 19 LS 15 LS 29 LS 17 LS 18 LS 22 LS 20 LS 26 LS 24 LS 13 LS 10 LS 31 LS 11 LS 30 LS 27 LS 25 LS 12 LS 16 LS 28 LS 14 LS 21 Legend Xä Lift Station MCES Interceptor Forcemain Trunk Gravity Main Diameter 10" 12" 15" 16" 18" 21" 24" 27" 36" City Boundary 1 inch = 3,200 feet 0 3,200Feet¯ SewerCAD Model Update & Analysis City of Chanhassen, MN Trunk Sanitary Sewer System Figure 3.0 City of Chanhassen 2040 Comprehensive Plan181 ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park Cathcart Park Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park P rairieK n o llPark PowerHillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park Carver Beach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum SugarbushPark Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake LS 8 LS 1 LS 2 LS 9 LS 7 LS 5 LS 3 LS 4 LS 6 LS 23 LS 19 LS 15 LS 29 LS 17 LS 18 LS 22 LS 20 LS 26 LS 24 LS 13 LS 10 LS 31 LS 11 LS 30 LS 27 LS 25 LS 12 LS 16 LS 28 LS 14 LS 21 LA-4 LB-1 LB-5 BC-9 MW-5 BC-1 LL-7 BC-8 LL-3 LA-6 LA-2 BC-3 BC-7 LR-4 LR-3 MW-1 LR-2 NO-8 BC-4 LB-3 LC-1 LR-5 MW-4 LR-1 LL-5 LA-3 MW-7 LA-7 LA-5BC-6 BC-5 NO-10 LA-11 NO-9 LB-4 NO-2 MW-3 NO-7 LA-9 LL-6 LA-10 LA-8 NO-5 NO-1 LL-1 LL-8 LB-2 NO-12 BC-2 LL-9 LA-1 LL-2 NO-4 LL-4 NO-11 BC-10 LL-10 BC-11 NO-6MW-6 ä Existing Lift Station Existing Sanitary Sewer Existing Force Main MCES Interceptor ä Future Lift Station Future Force Main Future Sanitary Sewer Sub Districts District Bluff Creek Lake Ann Lake Lucy Lake Riley Lotus Lake Lower Bluff Creek Minnewashta North Not to scale Ü Existing and Future Sanitary Sewer and Subdistricts Document Path: K:\2040 sewer\Separated_MXDs\Future_and_Existing_Sanitary_Sewer_and_Subdistricts.mxdDate: 9/11/2017 Figure 3.1Figure 3.1 City of Chanhassen 2040 Comprehensive Plan182 Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park CathcartPark Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park PrairieK n ollP a rk Power HillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park CarverBeach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum Sugarbush Park Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake Not to scale Ü Sanitary Sewer Districts Document Path: K:\2040 sewer\Separated_MXDs\Sanitary_Sewer_Districts.mxdDate: 9/11/2017 District Bluff Creek Lake Ann Lake Lucy Lake Riley Lotus Lake Lower Bluff Creek Minnewashta North Figure 3.2Figure 3.2 City of Chanhassen 2040 Comprehensive Plan183 Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park CathcartPark Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park PrairieK n ollP a rk Power HillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park CarverBeach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum Sugarbush Park Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake LA-4 LB-1 LB-5 BC-9 MW-5 BC-1 LL-7 BC-8 LL-3 LA-6 LA-2 BC-3 BC-7 LR-4 LR-3 MW-1 LR-2 NO-8 BC-4 LB-3 LC-1 LR-5 MW-4 LR-1 LL-5 LA-3 MW-7 LA-7 LA-5BC-6 BC-5 NO-10 LA-9 LA-11 NO-9 LB-4 NO-1 NO-2 MW-3 NO-7 LL-6 LA-10 LA-8 NO-5 LL-1 LL-8 LB-2 NO-12 BC-2 LL-9 LA-1 LL-2 NO-4 LL-4 NO-11 BC-10 LL-10 BC-11 NO-6MW-6 NO-3 MW-2 Not to scale Ü Sanitary Sewer Subdistricts Document Path: K:\2040 sewer\Separated_MXDs\Fig3.3_Sanitary_Sewer_Subdistricts.mxdDate: 9/11/2017 Sub Districts District Bluff Creek Lake Ann Lake Lucy Lake Riley Lotus Lake Lower Bluff Creek Minnewashta North Figure 3.3Figure 3.3 City of Chanhassen 2040 Comprehensive Plan184 ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park CathcartPark Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park P rairieK n o llPark Power HillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park CarverBeach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum Sugarbush Park Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake LS 8 LS 1 LS 2 LS 9 LS 7 LS 5 LS 3 LS 4 LS 6 LS 23 LS 19 LS 15 LS 29 LS 17 LS 18 LS 22 LS 20 LS 26 LS 24 LS 13 LS 10 LS 31 LS 11 LS 30 LS 27 LS 25 LS 12 LS 16 LS 28 LS 14 LS 21 ä Existing Lift Station Existing Sanitary Sewer Existing Force Main MCES Interceptor ä Future Lift Station Future Force Main Future Sanitary Sewer Not to scale Ü Existing and Future Sanitary Sewer Document Path: K:\2040 sewer\Separated_MXDs\Future_and_Existing_Sanitary_Sewer.mxdDate: 9/11/2017 Figure 3.4Figure 3.4 City of Chanhassen 2040 Comprehensive Plan185 Future Connections to Met Council Sanitary Sewer Interceptor Location Connection Type Estimated Date of Connection “Galpin Site” between Galpin Boulevard and Lake Ann 8” lateral connection to the interceptor Developer has submitted a plan for City Council review in 2019. “Gorra Property” between Lake Ann and Trunk Highway 5 8” lateral connection to the interceptor Unknown. Connection would be development-driven. No plans for development have been submitted to the City. Mid 2020’s City of Chanhassen 2040 Comprehensive Plan186 Not to scale Ü Existing On-Site Treatment Systems Document Path: K:\2040 sewer\Separated_MXDs\Existing_On_Site_Treatment_Systems.mxdDate: 9/11/2017 Figure 3.6 Figure 3.5 City of Chanhassen 2040 Comprehensive Plan187 ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä ä Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park CathcartPark Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park PrairieK n ollP ark PowerHillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park Carver Beach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum SugarbushPark Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake LS 8 LS 1 LS 2 LS 9 LS 7 LS 5 LS 3 LS 4 LS 6 LS 23 LS 19 LS 15 LS 29 LS 17 LS 18 LS 22 LS 20 LS 26 LS 24 LS 13 LS 10 LS 31 LS 11 LS 30 LS 27 LS 25 LS 12 LS 16 LS 28 LS 14 LS 21 ä Existing Lift Station Existing Sanitary Sewer Existing Force Main MCES Interceptor ä Future Lift Station Future Force Main Future Sanitary Sewer 2030 Landuse Type COMMERICAL OFFICE OFFICE INDUSTRIAL MIXED RESIDENTIAL LARGE LOT RESIDENTIAL LOW DENSITY RESIDENTIAL MEDIUM DENSITY RESIDENTIAL HIGH DENSITY AGRICULTURE PARKS OPEN SPACE PUBLIC SEMI PUBLIC Not to scale Ü Existing and Future Sanitary Sewer and 2040 Land Use Plan Document Path: K:\2040 sewer\Separated_MXDs\Future_and_Existing_Sewer_Landuse.mxdDate: 9/11/2017 Figure 5.1Figure 3.6 City of Chanhassen 2040 Comprehensive Plan188 Lake Ann Park Rice Marsh Lake Park North Lotus Lake ParkLake Minnewashta Regional Park (County Park)SunsetRidgeParkMeadow Green Park K e r b e r P o n d P a r k Lake Susan PreserveBluff Creek Preserve Park CathcartPark Hesse Farm Preserve Pheasant Hill Park CurryFarmsPark CityCenterParkStoneCreekPark RoundhousePark HermanFieldPark CarverBeachPlayground Park PrairieK n ollP ark PowerHillPark Chanhassen Hills Park BandimereHeightsPark Greenwood Shores Park Carver Beach Park Bluff Creek Golf Course Raguet Wildlife Management Area (WMA) MN Valley National Wildlife Refuge Minnesota Landscape Arboretum SugarbushPark Chanhassen Nature Preserve Minnesota Landscape Arboretum Park Pleasant ViewPreservePark Park Minnewashta Heights Park S Lotus Lake Park Bandimere Park Chanhassen Estates Park Lake Susan Park Seminary Fen Scientific and Natural Area (SNA) Park Riley Ridge Park Pioneer Pass Park Raguet Wildlife Management Area (WMA) Lotus Lake Lake Riley Lake Minnewashta Lake Lucy Rice Lake Lake Susan Lake Ann Lake Virginia Lake Harrison Rice Marsh Lake Clasen Lake Lake St Joe Christmas Lake Not to scale Ü Homes Built Before 1969 Document Path: K:\2040 sewer\Separated_MXDs\Homes_Built_Before_1969.mxdDate: 9/11/2017 Figure 7.1Figure 3.7 City of Chanhassen 2040 Comprehensive Plan189 APPENDIX B | MCES Design Peaking Factors City of Chanhassen 2040 Comprehensive Plan190 Average Flow (MGD) Peak Hourly Flow Factor Average Flow (MGD) Peak Hourly Flow Factor 0.00 to 0.11 4.0 1.90 to 2.29 2.8 0.12 to 0.18 3.9 2.30 to 2.89 2.7 0.19 to 0.23 3.8 2.90 to 3.49 2.6 0.24 to 0.29 3.7 3.50 to 4.19 2.5 0.30 to 0.39 3.6 4.20 to 5.09 2.4 0.40 to 0.49 3.5 2.10 to 6.39 2.3 0.50 to 0.64 3.4 6.40 to 7.99 2.2 0.65 to 0.79 3.3 8.00 to 10.39 2.1 0.80 to 0.99 3.2 10.0 to 13.49 2.0 1.00 to 1.19 3.1 13.50 to 17.99 1.9 1.20 to 1.49 3.0 18.00 to 29.99 1.8 1.50 to 1.89 2.9 Over 30.00 1.7 MCES Flow Variation Factors for Sewer Design City of Chanhassen 2040 Comprehensive Plan191 APPENDIX C | Infiltration and Inflow Policies and Reduction Capital Improvements Plan City of Chanhassen 2040 Comprehensive Plan192 City Code Section 19 - 44 Sec. 19-44. - Prohibited discharges into sanitary sewer system. »No person shall discharge or cause to be discharged any substance not requiring treatment or any substance not acceptable for discharge, as determined by the city or the Minnesota Pollution Control Agency, into the sanitary sewer system. Only sanitary sewage from approved plumbing fixtures may be discharged into the sanitary sewer system. »No person shall discharge or cause to be discharged, directly or indirectly, any stormwater, surface water, groundwater, roof runoff, subsurface drainage, or cooling water to any sanitary sewer. Any person having a roof drain, sump pump, unauthorized swimming pool discharge, cistern overflow pipe or surface drain connected and/or discharging into the sanitary sewer shall disconnect and remove any piping or system conveying such water to the sanitary sewer system. »All construction involving the installation of clear water sump pits shall include a sump pump with minimum size 1½ diameter dis charge pipe. The pipe attachment must be a rigid permanent type plumbing such as PVC or ABS plastic pipe with glued fittings, copper or galvanized pipe. All discharge piping shall be installed in accordance with the plumbing code. Discharge piping shall start at the sump pit and extend through the exterior of the building and terminate with not less than six inches of exposed pipe. Sump pump discharge location and flow shall be consistent with the approved development drainage plan for the lot. The discharge may not be pumped directly onto any public right-of-way unless approved by the city engineer or his designee. Any disconnects or openings in the sanitary sewer shall be closed and repaired in compliance with applicable codes. »Every person owning improved real estate that discharges into the city’s sanitary sewer system shall allow inspection by authorized city employees or its agents of all properties or structures connected to the sanitary sewer system to confirm there is no sump pump or other prohibited discharge into the sanitary sewer system. Any persons refusing to allow their property to be inspected shall immediately become subject to the surcharge as described in subsection (g) hereinafter. »Any owner of any property found to be in violation of this section shall make the necessary changes to comply with this section and such change shall be verified by authorized city employees or its agents. Any property or structure not inspected or not in compliance by May 1, 1994, shall, following notification from the city, comply within 14 calendar days or be subject to the surcharge as provided in subsection (g) hereinafter. »Upon verified compliance with this section, the city reserves the right to reinspect such property or structure at least annually to confirm continued compliance. Any property found not to be in compliance upon re-inspection or any person refusing to allow their property to be reinspected shall, following notification from the city, comply within 14 calendar days or be subject to the surcharge hereinafter provided for. »A surcharge of $100.00 per month is hereby imposed and shall be added to every sewer billing, to property owners who are found not in compliance with this section. The surcharge shall be added every month until the property is verified to be in compliance through the city’s inspection program. »The city council, upon recommendation of the city engineer, shall hear and decide requests for temporary waivers from the provisions of this section where strict enforcement would cause a threat to public safety because of circumstances unique to the individual property under consideration. Any request for a temporary waiver shall be submitted to the city engineer in writing. Upon approval of a temporary waiver from the provisions of this section, the property owner shall agree to pay an additional fee for sanitary sewer services based on the number of gallons discharged into the sanitary sewer system as estimated by the city engineer. »Violation of this section is a misdemeanor and each day that the violation continues is a separately prosecutable offense. The imposition of the surcharge shall not limit the city’s authority to prosecute the criminal violations, seek an injunction in district court ordering the person to disconnect the nonconforming connection to the sanitary sewer, or for the city to correct the violation and certify the costs of connection as an assessment against the property on which the connection was made. City of Chanhassen 2040 Comprehensive Plan193 APPENDIX D | Alternative Sanitary Sewer Service for the TH 101 and Pioneer Trail Area City of Chanhassen 2040 Comprehensive Plan194 ENGINEER'S OPINION OF PROBABLE COST - ALTERNATIVES SUMMARY Contract:CP PW285bb Owner:CITY OF CHANHASSEN Project:LOWER BLUFF CREEK DISTRICT SANITARY SEWER STUDY Date:Monday, June 6, 2016 Amount 3,620,000.00$ 3,780,000.00$ 5,520,000.00$ 4,040,000.00$ 2,390,000.00$ OPTION 5 Alternative OPTION 2A OPTION 2B OPTION 3A OPTION 3B City of Chanhassen 2040 Comprehensive Plan195 City of Chanhassen 2040 Comprehensive Plan196 City of Chanhassen 2040 Comprehensive Plan197 City of Chanhassen 2040 Comprehensive Plan198 City of Chanhassen 2040 Comprehensive Plan199 APPENDIX E | City of Chanhassen Sanitary Sewer Fee Structure City of Chanhassen 2040 Comprehensive Plan200 Residential based on winter quarter usage $4.64 per 1,000 gallons Commercial based on actual quarterly usage $4.64 per 1,000 gallons Minimum sewage charge per quarter (for amounts up to 6,000 gallons per quarter) $23.85 City of Chanhassen 2040 Comprehensive Plan201 Subdistrict Pipe diameter Min. Pipe Capacity (cfs) Ave (MGD)Peak (cfs) BC-2 0.009 BC-4 0.04 0.049 0.3 10"1.16 BC-2 0.009 BC-4 0.04 BC-5 0.075 0.124 0.75 12"1.68 BC-2 0.009 BC-4 0.04 BC-5 0.075 BC-6 0.075 0.199 1.17 15"3.04 BC-2 0.009 BC-3 0.111 BC-4 0.04 BC-5 0.075 BC-6 0.075 BC-7 0.119 BC-8 0.185 0.614 3.23 18"3.65 21"5.51 BC-9 0.151 0.91 12"1.68 15"3.04 21"5.51 BC-2 0.009 BC-3 0.111 BC-4 0.04 BC-5 0.075 BC-6 0.075 BC-7 0.119 BC-8 0.185 BC-9 0.151 0.765 3.91 18"21.6 (actual) BC-2 0.009 BC-3 0.111 BC-4 0.04 BC-5 0.075 BC-6 0.075 BC-7 0.119 Subdistrict Flows to Trunk Sewer* APPENDIX F | Trunk Sewer Capacity City of Chanhassen 2040 Comprehensive Plan202