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HomeMy WebLinkAbout5D Water System Comprehensive Plan Report Phone 952.447.9800 / Fax 952.447.4245 / www.cityofpriorlake.com 4646 Dakota Street SE Prior Lake, MN 55372 CITY COUNCIL AGENDA REPORT MEETING DATE: MARCH 4, 2019 AGENDA #: 5D PREPARED BY: JASON WEDEL, PUBLIC WORKS DIRECTOR/CITY ENGINEER PRESENTED BY: JASON WEDEL AGENDA ITEM: CONSIDER APPROVAL OF A RESOLUTION APPROVING THE WATER SYSTEM PLAN CHAPTER OF THE CITY’S 2040 COMPREHENSIVE PLAN UPDATE GOAL AREA AND OBJECTIVE: Environmental Stewardship & Recreation 1. Provide clean and safe drinking water for the community and protect drinking water sources. DISCUSSION: Introduction The City is in the process of updating the 2040 Comprehensive Plan. The Comprehensive Plan is a compilation of policy statements, goals, standards and maps for guiding the physical, social and economic development, both private and public, of the City of Prior Lake. Included in the Comprehensive Plan is a Water System Plan Chapter. History The purpose of the Water System Plan is to evaluate and update the City’s water system plan. This plan evaluates future design considerations with regards to water system planning and infrastructure as well as current and future water demands. The existing facilities and infrastructure are reviewed as well as future improvements are analyzed to determine how future development will impact average day and maximum day pressures along with maximum day fire flows based on the City’s future land use planning. Current Circumstances The City currently meets its water needs using seven (7) municipal wells and purchasing water from the Shakopee Mdewakanton Sioux Community (SMSC). The Water System Plan looks at the City’s future land use as well as the population projections to determine what additional improvements will be necessary to serve the City and meet all the various demands. The primary demands that are analyzed are the average day demand, the maximum day demand, storage and fire flow. Utilizing the proposed land use map and the current Met Council population projections for Prior Lake, a model was created to determine the future improvements that will be necessary to meet the City’s future demands. The results of the updated Water System Plan indicate that the City is well prepared for future development. No additional wells will be necessary to meet the City’s long-term water needs. The recent agreement between the City and the SMSC and construction of a joint water treatment plant is a key component to meeting the future water needs of the City. That agreement provides 1.5 Million Gallons of water per Day (MGD) to the City in perpetuity. The City does have the ability to add one more well to supply water to the City’s existing water treatment plant in the event it becomes more efficient to do so. There is a need to continue the implementation of the City’s trunk watermain infrastructure into the undeveloped portions of the City. These improvements consist of oversized watermains and are typically constructed as property develops. They are funded through the collection of trunk water fees as part of the development contracts the City enters into with developers. This combination of water supply and trunk watermain infrastructure will allow the City to meet the long- term average day and maximum day demands. The Water System Plan also confirmed that the City has sufficient existing storage to meet all future demands. It is recommended that the City have enough storage to meet or exceed the average day demand. At full build out, including the portions of Spring Lake Township that are included the Orderly Annexation Agreement, the City’s existing storage is sufficient to exceed the future average day demand. This is accomplished through the storage that is currently available at both of the City’s water towers as well as the below ground storage at the water treatment plant. Fire flow is the final demand that was reviewed as part of the Water System Plan Update. When a fire occurs, the use of water by the fire department in that location can be very taxing on the overall water system. It is important to not only supply the amount of water that is needed to extinguish the fire, but it is also important that the high fire flows do not result in the creation of a negative water pressure on adjacent properties which could result in contamination of the system. The results of the model indicate that the City’s system will meet the fire flow requirements if the trunk watermain infrastructure is completed as proposed. Overall, the City of Prior Lake is well situated to meet the water needs of the community both now and into the future. Subsection 1108.804 of Prior Lake City Code states, the Planning Commission shall review all requests for an amendment to the Comprehensive Plan or the Comprehensive Plan Land Use Map at a public hearing and shall report its findings and recommendations to the City Council. The Prior Lake Planning Commission held a public hearing on the Water System Plan on February 25, 2019 and on a vote of 5-0 recommended the City Council approve a resolution approving the water system plan chapter of the City’s 2040 Comprehensive Plan update. ISSUES: One area that is part of the Water System Plan is a discussion on water conservation. The City currently has a two-tiered billing rate for water consumption. The objective of the tiered billing rate is to charge a lower rate for water used to meet daily needs such as drinking, bathing, and doing laundry. The higher tier is for water use associated with washing cars, filling swimming pools, and irrigation. The maximum day demand is over three times the amount that is used on an average day and it is primarily due to irrigation. The City currently charges $4.81 per 1,000 gallons for the first 25,000 gallons and $6.63 per 1,000 gallons for anything above 25,000 gallons. It is anticipated that the City will initiate a utility rate study in the next year or two to evaluate the existing tiered rates to determine if they are accomplishing the goal of reducing the maximum day demand. The study would also look at the possibility of adding a third tier or other options for encouraging water conservation. ALTERNATIVES: 1. Motion and a second, as part of the Consent Agenda, to approve a resolution approving the Water System Plan. 2. Remove this item from the Consent Agenda for additional discussion. RECOMMENDED MOTION: ATTACHMENT: Alternative #1 1. Water System Plan Update 4646 Dakota Street SE Prior Lake, MN 55372 RESOLUTION 19-___ A RESOLUTION APPROVING THE WATER SYSTEM PLAN CHAPTER OF THE CITY’S 2040 COMPREHENSIVE PLAN UPDATE Motion By: Second By: WHEREAS, Minnesota Statutes section 473.864 requires each local governmental unit to review and, if necessary, amend its entire comprehensive plan and its fiscal devices and official controls at least once every ten years to ensure its comprehensive plan conforms to metropolitan system plans and ensure its fiscal devices and official controls do not conflict with the comprehensive plan or permit activities that conflict with metropolitan system plans; and WHEREAS, the City Council of the City of Prior Lake authorized the review and update of its Comprehensive Plan; and WHEREAS, the City of Prior Lake 2040 Comprehensive Plan Update is a planning tool intended to guide the future growth and development of the City of Prior Lake in a manner that conforms with metropolitan system plans and complies with the Metropolitan Land Planning Act and other applicable planning statutes; and WHEREAS, WHEREAS, WHEREAS, WHEREAS, the 2040 Comprehensive Plan Update includes a chapter on the Water System Plan; and the purpose of the Water System Plan is to evaluate future design considerations with regards to water system planning and infrastructure as well as current and future water demands, review of the existing facilities and infrastructure, as well as analysis of future improvements to determine how future development will impact average day and maximum day pressures along with maximum day fire flows based on the City’s future land use planning; and the Prior Lake Planning Commission held a public hearing to review the Water System Plan on February 25, 2019 and on a vote of 5-0 recommended the City Council approve a resolution approving the water system plan chapter of the City’s 2040 Comprehensive Plan update; and the Water System Plan shows the City of Prior Lake is well situated to meet the water needs of the community both now and into the future. NOW THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF PRIOR LAKE, MINNESOTA as follows: 1. The recitals set forth above are incorporated herein. 2. The City Manager is hereby authorized to submit the Water System Plan Chapter of the City’s 2040 Comprehensive Plan Update to the Metropolitan Council. Passed and adopted by the Prior Lake City Council this 4th day of March 2019. 2 VOTE Briggs Thompson Burkart Braid Erickson Aye ☐ ☐ ☐ ☐ ☐ Nay ☐ ☐ ☐ ☐ ☐ Abstain ☐ ☐ ☐ ☐ ☐ Absent ☐ ☐ ☐ ☐ ☐ ______________________________ Michael Plante, City Manager June 2018 Water System Plan Update Prior Lake, Minnesota Bolton & Menk Project No. T21.113723 Submitted by: Bolton & Menk, Inc. 12224 Nicollet Ave Burnsville, MN 55337 P: 507-625-4171 F: 507-625-4177 Prepared by: Bolton & Menk, Inc. Certification Water System Plan Update | T21.113723 Certification Water System Plan Update for Prior Lake, Minnesota BMI Project No.: T21.113723 June 2018 I hereby certify that this plan, specification or report was prepared by me or under my direct supervision, and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. By: Seth A. Peterson, P.E. License No. 26468 Date: June 20, 2018 Prepared by: Bolton & Menk, Inc. Table of Contents Water System Plan Update ǀ T21.113723 Table of Contents I. EXECUTIVE SUMMARY ........................................................................................................... 1 II. WATER SYSTEM DESIGN CRITERIA ......................................................................................... 3 Prepared by: Bolton & Menk, Inc. Table of Contents Water System Plan Update ǀ T21.113723 Figures Figure 2.1: Average and Maximum Day Demand Trends ................................................................ 6 Figure 2.2: Prior Lake Water Use by Category ................................................................................. 7 Figure 3.1: Existing Water Distribution System ............................................................................ 14 Figure 3.2: Existing Average Daily Pressure ................................................................................... 20 Figure 3.3: Existing Maximum Day Pressure .................................................................................. 21 Figure 3.4: Existing Maximum Day Fire Flow ................................................................................. 25 Figure 3.5: Existing Average Day Hydraulic Grade Line ................................................................. 26 Figure 3.6: Existing Maximum Day Hydraulic Grade Line .............................................................. 27 Figure 5.1: Anticipated Water Distribution System ....................................................................... 40 Figure 5.2: Projected Average Daily Pressure ................................................................................ 41 Figure 5.3: Projected Maximum Daily Pressure ............................................................................. 42 Figure 5.4: Projected Maximum Day Fire Flow .............................................................................. 43 Figure 5.5: Projected Average Day Hydraulic Grade Line .............................................................. 44 Figure 5.6: Projected Maximum Day Hydraulic Grade Line ........................................................... 45 Tables Table 2.1: Historical Water Demand ................................................................................................ 4 Table 2.2: Average Seasonal Water Demands ................................................................................. 8 Table 2.3: Water Demand Forecast ................................................................................................. 9 Table 2.4: Storage Capacity Requirements .................................................................................... 11 Table 3.1: Prior Lake Well Information ......................................................................................... 13 Table 3.2: Prior Lake Well Pumping Capacity to WTF .................................................................... 15 Table 3.3: Prior Lake Well Pumping and SMSC Capacity ............................................................... 16 Table 3.4: Water Storage Facilities Summary ................................................................................ 23 Table 3.5: Needed Fire Flows for Residential Homes .................................................................... 24 Table 3.6: Well Water Quality ........................................................................................................ 28 Table 3.7: Iron and Manganese Removal ...................................................................................... 29 Table 6.1: Future Watermain Costs ............................................................................................... 48 Table 6.2: Cost and Implementation Schedule .............................................................................. 49 Appendix Appendix A: Existing and Future Land Use Maps Appendix B: Well Hydrographs Prepared by: Bolton & Menk, Inc. EXECUTIVE SUMMARY Water System Plan Update ǀ T21.113723 Page 1 I. EXECUTIVE SUMMARY The purpose of this plan is to evaluate and update the City of Prior Lake’s water system plan. This plan will evaluate future design considerations with regards to water system planning and infrastructure, as well as current and future water demands. The existing facilities and infrastructure are discussed along with the condition of the facilities. Future improvements are discussed in this report with the intent of updating the water model to reflect how future improvements will impact average day and maximum day pressures along with maximum day fire flows in newly developed areas based on the City’s future land use planning. The design period for this report is 20 years, yielding a design year of 2037. Future projections for water usage are based on Metropolitan Council population projections and the 2005 through 2016 historical water usage for the City of Prior Lake. Historically, from 2005 to 2016, the City of Prior Lake saw an increase in population served of 16.5%, from 21,395 in 2005 to 25,616 in 2016. Population is a driving factor in water demands and the per capita demand for a community. Historically for Prior Lake, the residential demand and total per capita demands have averaged 70 and 95.3 gallons per capita per day (gpcd) from 2005 through 2016, respectively. Average day demand has remained relatively consistent over the 10-year historical period. The historical average of the average day demand is 2.20 MGD. Maximum day demand has seen a more significant decline since 2005. Two major peaks occurred in 2007 and 2012, which correspond to years with drought and thus increased water usage for activities like lawn irrigation. In 2007, the maximum day demand was 7.03 MGD, while in 2012 the maximum day demand reached 6.61 MGD. Overall, the maximum day demand shows a steadily decreasing demand. The average maximum day demand over the previous 10 years is 5.58 MGD. Evaluation of the categorical water usage indicates that residential water accounts for 76% of the total water used. Irrigation accounts for the second largest use category with 10% of the total water. The City water usage is third at 5% of the total water usage. Commercial water use comes in fourth at 4% of the total water, followed by unaccounted for water (3%) and lastly institutional water (2%). Water demand projections indicate that by the design year of 2037, the average day demand is expected to be 2.82 Million Gallons per Day (MGD) with a maximum day demand of 6.68 MGD. The current Water Treatment Facility (WTF) is designed to handle 7.5 MGD, which is sufficient for Prepared by: Bolton & Menk, Inc. EXECUTIVE SUMMARY Water System Plan Update ǀ T21.113723 Page 2 current and projected demands. Water storage is another important factor in evaluation of the infrastructure. Currently, there is adequate storage for current demands and no new facilities are needed at this time. Analysis of the storage capacity for future demands indicates that by the design year of 2037, there will be a surplus in storage capacity of approximately 430,000 gallons. AWWA recommends that the storage capacity be equal to or greater than the average day demands. With a storage capacity of 3.25 million gallons (MG), Prior Lake exceeds this recommendation. Water supply for Prior Lake is from 7 municipal wells and from two interconnections. The City has two interconnections, one with the Shakopee Mdewakanton Sioux Community (SMSC) and one from the City of Savage. With these two interconnections, the City is provided with a sufficient water supply. However, if these two interconnections are not included, the addition of well 10 is required by 2033 to maintain a firm well capacity (capacity with the largest well out of service) greater than the maximum day demand. Historical water model figures, which are found in Section 3 of this report, were used to evaluate the distribution system to ensure it has adequate pressures and fire flows. The water model indicates that the City maintains a pressure of greater than 30 – 40 psi throughout the system at average and maximum day flows. It is recommended by Ten States Standards to maintain at least 35 psi in the system at any one time. The City currently exceeds this recommendation. The City currently has fire flows that exceed 3,500 gallons per minute (gpm) throughout a majority of the City. The Insurance Service Office (ISO) has recommendations for fire flows based in residential areas. Using these recommendations, the City of Prior Lake was determined to have exceeded the recommended fire flows. Future improvements are based on the future land use map found in Appendix A. The updated water model figures include maps showing: future improvements and infrastructure, average day pressure, maximum day pressure, and maximum day fire flows. The goal for the water model update was to evaluate how future development will affect the pressures and fire flows throughout the system and to determine what new infrastructure and watermains are required to maintain 40 – 50 psi at average day flows throughout the future land use areas. The main improvements to the system include looping new watermains and extending existing watermains to maintain adequate pressure. Future capital improvements along with preliminary costs are presented at the end of this report. This report should be continually updated and modified as the City of Prior Lakes’ water system changes and as water demands change through the design year of 2037. Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 3 II. WATER SYSTEM DESIGN CRITERIA Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 4 in Appendix A. The future land use map indicates that there is sufficient land to meet the anticipated growth needs for the City of Prior Lake through 2037. Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 5 Residential per capita demand is calculated based on the volume of water used by residential customers. The majority of water used within the City is for residential use and is discussed below. The residential per capita demand has averaged 70.0 gallons per capita per day (gpcd) from 2005 through 2016. Typically, it is desirable to maintain a residential demand less than 75 gpcd. Prior Lake’s conservation utility billing and educational efforts will help to keep the residential demand below this threshold. The total per capita demand averages 95.3 gallons per capita per day (gpcd) from 2005 through 2016. When the data from 2011 through 2016 is evaluated, the average day demand is 87 gpcd. This decrease in average per capita demand reflects water conservation measures the City has been implementing for the last several years. The per capita demand had a peak in 2012 due to a relatively moderate drought that occurred that year. This peak does not represent the trend in per capita demand and is considered an outlier in the data set from 2011 through 2016. Future water usage was based on the 2001 through 2016 average per capita demand. Overall, per capita demand shows a decreasing trend over the last 10 years as water conservation measures were implemented and education about water conservation becomes more public and easier to find. Starting in 2014, the City began purchasing water from SMSC. Based on the data in Table 2.1, when the City began purchasing water, the total per capita demand decreased from the previous year’s demands. This could also be attributed to increased rainfall in the Metropolitan region during those years. Average day demand has remained relatively consistent over the 10-year historical period. The historical average of the average day demand is 2.20 MGD. Similar to the per capita demand, 2012 saw a slight peak in average day demand due to drought conditions that persisted during the summer months. Overall, there have not been any major fluctuations in average day demand. However, the demand has slightly decreased since 2012, which could be represented by increased precipitation and efforts by the City to implement water conservation techniques and programs. Maximum day demand has seen a more significant decline since 2005. Two major peaks occurred in 2007 and 2012, which correspond to years with drought and reduced precipitation. In 2007, the maximum day demand was 7.03 MGD, while in 2012, the maximum day demand was 6.61. Overall, the maximum day demand shows a steadily decreasing demand. The average maximum day demand over the previous 10 years is 5.58 MGD. As the demand continues to decrease, this drives the peaking factor down Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 6 since the max day demand becomes closer to the average day demand. The most significant decrease in max day demand occurred from 2012 to 2016, which is similar to the average day demand and the total per capita demand over the same timeframe. Maximum day demands are most likely decreasing due to the implementation of water conservation measures and education about conserving water being more easily accessible to customers. Figure 2.1 represents the trends in average and maximum day demands from 2005 through 2016. Figure 2.1: Average and Maximum Day Demand Trends 2. Water Use by Category One way to analyze water consumption and historical demands is to observe who uses the water. Categorizing water use within a community can provide insight on where to prioritize water conservation efforts and provides valuable information when making future water demand projections. The average water consumption by category for residential, commercial, industrial, and other uses is shows in Figure 2.2. 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 2004 2006 2008 2010 2012 2014 2016Demand (MGD)Average Day Demand Max Day Demand Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 7 Figure 2.2: Prior Lake Water Use by Category As discussed above, residential water usage is the largest category in the City of Prior Lake. The land use promotes residential development driving the water use up in this category. There is limited commercial and industrial development in Prior Lake making these water use categories much smaller than the residential demand. The residential demand consists of typical household uses including lawn and garden watering, flushing toilets and taking showers, running washing machines, cooking, cleaning, and all other household water uses. As shown in Table 2.1, the residential per capita demand is 70.0 gpcd and according to Figure 2.2, residential water accounts for 76% of the total water. Irrigation accounts for the second largest use category with 10% of the total water. The City water usage is third at 5% of the total water usage. This category includes water used by the City for hydrant flushing, ice-skating rinks, vehicle washing, backwashing at the Water Treatment Facility and any other water used by the City for daily operations. Commercial water use comes in fourth at 4% of the total water, followed by unaccounted for water (3%) and lastly institutional water (2%). 3. Seasonal Water Use Seasonal water use was evaluated for Prior Lake with results found in Table 2.2. The table shows total volume of water used in the summer months compared to the winter months. For the purpose of this evaluation, summer months were considered May through September and winter months were October through April. Residential 76% Commercial 4% Institutional 2% City Water 5% Irrigation 10% Unaccounted For 3% Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 8 Table 2.2: Average Seasonal Water Demands Year Population Summer Usage (MG) Winter Usage (MG) Summer Per Capita Demand (gpcd) Winter Per Capita Demand (gpcd) 2005 21,395 406 298 52.0 38.2 2006 21,542 515 311 65.6 39.6 2007 22,111 580 312 71.9 38.6 2008 22,917 532 314 63.6 37.5 2009 23,335 561 317 65.9 37.3 2010 22,796 430 341 51.7 41.0 2011 23,010 474 338 56.4 40.2 2012 23,385 579 331 67.8 38.8 2013 24,223 499 320 56.5 36.2 2014 24,911 422 316 46.5 34.7 2015 24,732 409 322 45.3 35.7 2016 25,616 457 316 48.9 33.8 Average 489 320 57.7 36.7 Results indicate that summer demand is on average 33% greater than winter demands. This is evident by looking at the total water usage between the seasons and by looking at the summer per capita demand versus the winter per capita demand. One key reason for larger summer demands is lawn irrigation. Lawn irrigation is commonly a large water use category during summer months that can drive up the total volume of water used during that season. Conserving water with respect to lawn irrigation is discussed in Section 4 of this report. The purpose of evaluating seasonal demands is to determine if the City has sufficient infrastructure to handle peak demands. As indicated in Table 2.1, historical maximum day demands are commonly above 5.5 MGD. Evaluating seasonal demands will ensure that consideration is given for planning future improvements to handle the seasonal variations in water demand. The winter usage provides a good baseline water usage while summer water usage provides key design details that should be considered with future planning. Based on the above table, the City has sufficient infrastructure to handle peak summer month flows. However, as the population continues to grow and housing with lawn irrigation expands, this will drive up the summer demands to a point where additional infrastructure may need to be discussed. 4. Projected Population and Water Use Historic water use (average and maximum day demands) and population projections Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 9 can be utilized to help make future water projections. It is also important to consider changing trends in the amount of growth expected in the industrial and commercial sectors. These consumers can use large volumes of water for process and general operation of industry. Expansions of this sector can greatly influence future water demands. Historically, the City of Prior Lake does not have a large industrial or commercial water demand. Based on 2016 data, the largest commercial or industrial water user required only 0.4% of the total annual water delivered to the distribution system. There are no known anticipated large volume water users planning on locating in Prior Lake. Commercial and industrial use is anticipated to follow historical trends and grow as population increases. Residential demand will drive future water projections. The future demand forecast is shown in Table 2.3. Table 2.3: Water Demand Forecast Year Projected Total Population (1) Projected Population Served Projected Total Per Capita Water Demand (GPCD) Projected Average Daily Demand (MGD) Projected Maximum Daily Demand (MGD) (2) 2016 25,616 25,616 83 2.12 4.52 2017 25,941 25,941 87 2.25 5.43 2018 26,266 26,266 87 2.28 5.50 2019 26,591 26,591 87 2.31 5.57 2020 26,916 26,916 87 2.34 5.64 2021 27,241 27,241 87 2.37 5.70 2022 27,566 27,566 87 2.39 5.77 2023 27,891 27,891 87 2.42 5.84 2024 28,216 28,216 87 2.45 5.91 2025 28,541 28,541 87 2.48 5.98 2030 30,166 30,166 87 2.62 6.29 2037 (3) 32,441 32,441 87 2.82 6.68 2040 33,416 33,416 87 2.90 6.82 (1) Total Population Projections based on Metropolitan Council population projections (2) Peaking Factor based on historical data (3) Design Year Water demand projections in Table 2.3 were based on historical trends and the increase in population. Metropolitan Council System Statements were used to for population projections through 2040. It is assumed that the projected service population will equal the projected total population as all future residents will be required to connect to the City’s distribution system. Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 10 The historical total per capita demand from 2011 through 2016 (excluding 2012) of 87 gallons per capita per day (gpcd) was used to make water demand projections through 2040. This excludes 2012, which was a dry year, which led increased water usage and a much higher per capita demand over the previous two years and following four years. It can be acceptable to omit years with extreme drought or extreme precipitation as outliers as they can skew the data and make future projections unrealistic. Based on historical trends in per capita demand and future population projections, it is likely that the total per capita demand will remain consistent around 87 gpcd through 2040. The reason 2011 through 2016 data was used (excluding 2012) was that the City has implemented water conservation measures over the last several years and the per capita demand reflects those efforts. It is important to consider these water conservation measures when making projections as they can help make accurate projections with regards to the City’s plan of conserving water and reducing per capita demands. The projected average day demand was calculated by multiplying the projected total per capita demand of 87 gpcd by the projected service area population. The projected average day demand shows a slightly increasing demand because the average day demand is calculated based on population. As the population increases and the per capita demand remains constant, the average day demand will slightly increase. By the design year of 2037, a projected average day demand of 2.82 MGD is expected. The projected maximum day demand was calculated by multiplying the average day demand by a peaking factor. The peaking factor used to calculate the projected maximum day demand is the average peaking factor from 2011 through 2016 of 2.41. This peaking factor was used to project maximum day demands up to 2030. Ten States Standards has recommendations for peaking factors using an empirical equation that calculates peaking factors based on a communities population. Based on Ten States Standards recommendations, as the population increases, the peaking factor will decrease. Therefore, as Prior Lakes’ population continues to increase, they should theoretically see a decreasing peaking factor. Using Ten States Standards recommendations, the peaking factor for 2030 and 2040 are 2.40 and 2.35 respectively. Reducing the peaking factor also accounts for improved technology and more water efficient appliances and water conservation programs that may be implemented in the City. Using these criteria, a projected maximum day demand of 6.68 MG is projected in the design year of 2037. Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 11 5. Future Water Storage Requirements AWWA recommends that the storage capacity should equal or exceed average day demands. Considerations for improving storage capacity are based on the existing infrastructure and the ability to maintain a storage capacity equal to or greater than the future water use projections found above. Table 2.4 presents the future storage capacity requirements necessary for Prior Lake. Table 2.4: Storage Capacity Requirements Year Service Area Population Average Day (GPD) Existing Elevated Storage (gallons) Existing Ground Storage (gallons) Storage Excess/Deficit (Gallons) 2016 25,616 2,117,797 1,750,000 1,500,000 1,132,203 2017 25,941 2,253,084 1,750,000 1,500,000 996,916 2018 26,266 2,281,311 1,750,000 1,500,000 968,689 2019 26,591 2,309,539 1,750,000 1,500,000 940,461 2020 26,916 2,337,767 1,750,000 1,500,000 912,233 2021 27,241 2,365,994 1,750,000 1,500,000 884,006 2022 27,566 2,394,222 1,750,000 1,500,000 855,778 2023 27,891 2,422,449 1,750,000 1,500,000 827,551 2024 28,216 2,450,677 1,750,000 1,500,000 799,323 2025 28,541 2,478,905 1,750,000 1,500,000 771,095 2030 30,166 2,620,043 1,750,000 1,500,000 629,957 2037 (1) 32,441 2,817,636 1,750,000 1,500,000 432,364 2040 33,416 2,902,319 1,750,000 1,500,000 347,681 (1) Design Year Based on the table above, by the design year of 2037, an excess storage capacity of 432,000 gallons is expected. There is adequate storage capacity through the design year of 2037 and beyond. The existing ground storage is included in the capacity because a backup generate is located at the site which can run pumps to convey water into the distribution system during a power failure. Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA Water System Plan Update ǀ T21.113723 Page 12 being acceptable during emergency withdrawals for short durations. 2. Pressure Requirements Water pressures are subject to individual preference. What some may view as adequate pressure may be viewed as too much or too little pressure. Municipalities are challenged with balancing pressure with demand and capacity of the system along with conservation of water. Typically, higher pressures equate to higher flow rates, but increases the volume of water lost through crack and broken pipes. Ten States Standards recommends the minimum working pressure in the distribution system should be 35 psi with normal working pressures ranging from 60 – 80 psi. The Minnesota Department of Health (MDH) along with Ten States Standards requires the system to maintain a minimum pressure of at least 20 psi at ground level at all points in the distribution system under all flow conditions. This ensures that there is adequate water pressure in the event of a long-term power failure or during an emergency. The City of Prior Lake desires to have at least 40 – 50 psi in the distribution system for normal operation. Future consideration should be given to new developments to maintain pressures greater than 40 – 50 psi. 3. Water Distribution Model The water model for Prior Lake was updated for this report to show the impacts of future improvements to the system. Future improvements are discussed in Section 5 of this report. The model was updated based on future zoning within the City of Prior Lake. The projected water model including an updated anticipated distribution system map, anticipated average and maximum day pressure maps, and an anticipated maximum day fire flow map are provided in Section 5. The improvements relate to improving fire flow where possible and adding new watermain into areas that are slated for future development. The water model should be used as a tool to evaluate if additional infrastructure is required in the distribution system. Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 13 III. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\A_113723_ExistingWatermain_11x17.mxd | Date Saved: 3/16/2018 10:40:32 AMWater Modeling City of Prior Lake Figure 3.1: Existing Water Distibution System March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 15 One way to evaluate the pumping capacity and the ability of the wells to meet maximum day demands, it to evaluate the total and firm well capacities. The total well capacity is the total capacity of all the wells pumping together to supply water. The firm well capacity is the pumping capacity of all the wells without the largest producing well in service. Typically, firm well capacity is used to measure whether or not there is enough supply to meet demands. If the firm well capacity is not greater than or equal to the maximum day demand, then there is insufficient water supply to provide enough water to meet demands. Table 3.2 presents the total and firm well capacities for the Prior Lake wells based on pumping for 20 hours per day or 24 hours per day. Using 20 hours per day for well pumping is typical, as it allows for pump maintenance, partial aquifer recharge, and pump cycling based on elevated storage tank levels. Pumping for 24 hours represents an emergency in which the City is trying to supplement an extremely large demand by running the wells constantly. Table 3.2: Prior Lake Well Pumping Capacity to WTF Item 20-Hour Pumping (1) 24-Hour Pumping (1) Firm Capacity Total Capacity Firm Capacity Total Capacity Well Capacity (gpm) 4,200 5,400 4,200 5,400 Well Capacity (MGD) 5.04 6.48 6.05 7.78 (1) Firm and Total Capacities do not include Well No. 6 as this well is available for emergency use only 2. Interconnections To supplement water supply and to make up for deficits in pumping capacity during maximum day demands, the City of Prior Lake has agreements with the Shakopee Mdewakanton Sioux Community (SMSC) and with the City of Savage to purchase water to supplement the City’s water supply. The agreement with Savage allows the City to use up to 1 million gallons of water per day. The current agreement between SMSC and Prior Lake allows Prior Lake to purchase up to 2.2 million gallons of water per day. As the population of SMSC grows and water use increases, the total volume of water the City can utilize decreases to 1.5 million gallons. However, the City will always be able to use up to 1.5 million gallons of water per day in the future from SMSC per the agreement. Table 3.3 shows the total capacity including the amounts available from SMSC. Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 16 Table 3.3: Prior Lake Well Pumping and SMSC Capacity Item 20-Hour Pumping (1) 24-Hour Pumping (1) Firm Capacity Total Capacity Firm Capacity Total Capacity Well Capacity (MGD) 5.04 6.48 6.05 7.78 SMSC Capacity (MGD) 1.5 1.5 2.2 2.2 Total Capacity (MGD) 6.54 7.98 8.25 9.98 (1) Firm and Total Capacities do not include Well No. 6 as this well is available for emergency use only The City began using the interconnection with SMSC in 2014. Since then, they have purchased 159, 231, and 270 million gallons of water in 2014, 2015, and 2016, respectively. The interconnections with SMSC and Savage have helped provide a supplemental water source to meet the City’s maximum day demands. 3. Impacts on Aquifer Pumping Levels The City of Prior Lake monitors their supply wells with their SCADA system. The SCADA system collects readings on the well water levels every 15 minutes. The data that is collected can be used to view trends in the water levels to adjust the well to optimize pumping or to determine if there is an issue with the supply in the well. The resulting well hydrographs are presented in Appendix B. It is important to note that the data is presented as the monthly average well water level. The hydrographs shows that well water levels are either stable or show an increasing trend. An increasing trend means that the water levels are rising over the monitoring period. Based on the hydrographs, wells 3, 5, 6, 7, and 9 show stable trends in water levels. Even though the well water levels appears to fluctuate significantly through the monitoring period, as can be seen for Well No. 7, the overall trend remains stable. Wells 4 and 8 show an increasing trend in water levels over the monitoring period. One piece of data that can be collected from the hydrographs is the feet of fluctuation of the water levels. Observing the seasonal variation of water level can help determine if there are times of the year when a well has limitations or if there is an issue if pumping capacity becomes limited. Overall, none of the wells for Prior Lake fluctuate significantly. During the drought in 2012, it can be seen that almost all wells have a significant drop in water level elevation. 2012 was the summer that put extreme stress on the water system as peak day demands became very large. Even with the higher Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 17 than normal usage in 2012, the well water levels recovered to previous levels within the next couple of years. Prior Lake’s wells appear to be stable with no significant concerns over water levels at each well. Gaps in the data indicate a time when the SCADA measurement system was not properly calibrated or it was non-functional. Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 18 highways. These pipes convey large volumes of water throughout the City until smaller lateral pipes (less than 16 inch) convey water in neighborhoods. The majority of watermain in the City ranges from 6 inch to 10 inch. The watermains are looped within the City as to not have a dead end pipe, which could create water quality concerns. The watermains loop around and connect so the water flows in a path. Parts of the system do have branched systems that are not looped. Consideration should be given to looping larger diameter watermains with future expansion. Extending watermain to future developments and providing looping can help with maintaining adequate system pressure. Hydrant flushing is an important maintenance activity to clean out dead end watermains. The City has been proactive in performing hydrant flushes on critical watermains. The water distribution-piping network has been well maintained and will continue to serve the customers of Prior Lake. 2. Pressure Service Areas Prior Lake is served by a single pressure service area from two elevated storage tanks and one reservoir at the WTF. Four (4) Pressure Reducing Valves (PRV’s) on the northern edge of town help by regulating pressures in neighborhoods whom could otherwise have extremely high or low pressures. There are two booster stations in the City. One serves one area in the northwestern side of town near the Wilds golf course and the other serves the Summit Preserve area just north of Co. Rd. 42 and east of Co. Rd. 18. 3. System Pressures As discussed above, the City of Prior Lake is served by a single pressure service area. Both elevated towers and the ground reservoir serve the entire City. Figure 3.2 presents the existing average day pressures throughout the distribution system. Based on the figure, a majority of the City has pressures greater than 50 psi. Around the lake, (typically areas with the lowest elevation) pressures are in excess of 70 psi. This covers the downtown area of Prior Lake as well. Areas on the far southern and western areas of the City have pressures that dip down into the 40 – 50 psi range. Only areas that are near the city limits have pressures in the 30 – 40 psi range. However, development is limited in these areas. The area around the Wilds golf course has pressures ranging from 50 – 70 psi. The system appears to have adequate pressures to supply water at average day demands throughout the City. Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 19 Figure 3.3 presents the existing system maximum day pressure. This is the pressure throughout the system during maximum day demands. When compared to Figure 3.2, the maximum day pressures slightly decrease throughout the City. Areas around the lake (typically the lowest portions of the City) maintain a similar system pressure around 70 – 80 psi (within 10 psi of average day pressures). The greatest impacts during maximum day are on the South side of the City where in some neighborhoods pressures drop from 70 – 80 psi down to 50 – 60 psi. The downtown area of Prior Lake still maintains adequate pressures during max day demands with pressures ranging from 50 – 70 psi. Even though these are impacted the most, the system pressure is still adequate throughout the City. Figure 3.5 shows the existing Hydraulic Grade Line (HGL) throughout the City as indicated by the model. The HGL is consistent between 1,000 – 1,200 feet for a majority of the City. On the outskirts of town, in areas where development is limited, the HGL begins to decrease. This is due to less water infrastructure in these areas and the limited development. The majority of the City maintains a sufficient HGL according to the water model. Figure 3.6 indicates that the HGL ranges from 950 – 1,200 feet during maximum day demands. Again, on the western and southern edges of the City where development is limited and there is less infrastructure, the HGL begins to decrease in elevation. Even still, the majority of the area in City limits maintains an adequate HGL during maximum day demands. !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\B_113723_ExistingAverageDailyPressure_11x17.mxd | Date Saved: 3/15/2018 11:16:03 AMWater Modeling City of Prior Lake Figure 3.2: Existing Average Daily Pressure March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Average Daily Pressure 20 - 30 psi 30 - 40 psi 40 - 50 psi 50 - 60 psi 60 - 70 psi 70 - 80 psi 80 - 90 psi 90 - 100 psi 100 - 110 psi 110 - 120 psi City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\C_113723_ExistingMaxDayPressure_11x17.mxd | Date Saved: 3/15/2018 11:15:04 AMWater Modeling City of Prior Lake Figure 3.3: Existing Maximum Day Pressure March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Maximum Day Pressure 20 - 30 psi 30 - 40 psi 40 - 50 psi 50 - 60 psi 60 - 70 psi 70 - 80 psi 80 - 90 psi 90 - 100 psi 100 - 110 psi 110 - 120 psi City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 22 Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 23 capacity. A summary of the storage facilities is presented in Table 3.4. Table 3.4: Water Storage Facilities Summary Structure Name Location Type of Storage Structure Year Constructed Primary Material Storage Capacity (Gallons) South Tower Tower St. SE Elevated storage 1973 Steel 750,000 North Tower Cedarwood St. SE Elevated storage 1986 Steel 1,000,000 WTP Clearwell 16335 Itasca Ave. SE Ground storage 2009 Concrete 1,500,000 Total 3,250,000 AWWA recommends that the storage capacity should equal or exceed the average day demand. Based on the historical data provided in Table 2.1, the current storage capacity is adequate for current average day demands. Using Table 2.4, the analysis of storage capacity, and the future average day projections, by 2025 there is an estimated average day demand of 2.48 MGD yielding a surplus storage capacity of 770,000 gallons. Looking at 2030, the projected average day demand is 2.62 yielding a surplus in storage of 630,000 gallons. By the design year of 2037, an excess of 430,000 gallons of storage capacity is expected. There is adequate storage capacity for the City of Prior Lake through the design year. Both elevated towers are in good condition and have several more years of useful life remaining. 2. Minimum Use One way to evaluate the adequacy of storage capacity is to evaluate the minimum use to see if there is sufficient turnover of water during winter months to prevent freezing in the storage facilities. A good rule is to allow water to turnover every couple of days in the winter. Currently, the average day demand averages approximately 2.22 MGD. Utilizing the full storage capacity of 3.25 MG, the water turnover is about every 1.5 days. Using the future demands, by 2037 the average day demand is anticipated to be 2.82 MGD, yielding a turnover every 1.15 days (if no extra storage facility is constructed). Based on this simple analysis, there is a good storage supply and water turnover in the City to prevent water from freezing in the towers during winter months. 3. Existing Fire Demand Requirements Water modeling can be used to evaluate available fire flows in a City. This can be beneficial for planning purposes when evaluating distribution system improvements. The guide for determining required fire flows is developed by the Insurance Service Office (ISO). When designing future improvements, it is important to account for Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 24 needed fire flows. The needed fire flow differs between structures and building types such as residential, commercial, or industrial. For single-family homes, the following table should be considered for needed fire flows. Table 3.5: Needed Fire Flows for Residential Homes Distance Between Buildings (ft) Fire Flow (gpm) More than 100 500 31 - 100 750 – 1,000 11 - 30 1,001 - 1500 Less than 11 1,501 – 2,000 Continuous 2,500 Commercial and industrial needed fire flows are determined on an individual basis by evaluating the occupancy area, communication factor, exposure factor, and if a sprinkler system is installed. Typically, most systems require only 500 – 1,000 gpm of needed fire flow if a sprinkler system is installed and up to 500 gpm of additional flow if a sprinkler system is not installed. Figure 3.4 presents the City of Prior Lakes’ existing maximum day fire flows. As can be seen on the map below, a majority of the City has a fire flow greater than 3,500 gpm. Areas with less flow are found on the end runs of watermains and along runs with smaller diameter watermains. The lowest available fire flow according to the model in Figure 3.4 is between 1,000 and 1,500 gpm. Small areas around the north end of Lower Prior Lake have the lowest available fire flow. These areas are on the end of the smaller diameter watermains. However, these areas still have sufficient fire flows based on the discussion and table above. Overall, the City of Prior Lake has sufficient fire flow protection. !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\D_113723_MaxFireflow_11x17.mxd | Date Saved: 3/15/2018 11:13:34 AMWater Modeling City of Prior Lake Figure 3.4: Existing Maximum Day Fire Flow March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Available Fireflow 0 - 500 gpm 500 - 1000 gpm 1000 - 1500 gpm 1500 - 2000 gpm 2000 - 2500 gpm 2500 - 3000 gpm 3000 - 3500 gpm 3500 + gpm City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\E_113723_ExistAvgDayHydGradeLine_11x17.mxd | Date Saved: 3/15/2018 1:58:24 PMWater Modeling City of Prior Lake Figure 3.5: Existing Average Daily Demand - Hydraulic Grade Line March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Existing Average Daily Demand - HGL 600-800 ft 800-1,000 ft 1,000-1,200 ft City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I !(!(!(!(UT UT 3P 3P "¬! "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\F_113723_ExistMaxDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 10:55:53 AMWater Modeling City of Prior Lake Figure 3.6: Existing Maximum Daily Demand– Hydraulic Grade Line March 2018 Legend !Ø Wells "¬!Booster Stations !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Existing Maximum Daily Demand - HGL 200 - 450 ft 200 - 450 ft 450 - 700 ft 700 - 950 ft 950 - 1,200 ft City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 28 Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 29 WTF is very effective at removing iron and manganese levels to below the National Secondary Drinking Water Standards. Table 3.7 represents the average iron and manganese concentrations and loads that enter the WTF and the average effluent concentrations and loads leaving the WTF. Table 3.7: Iron and Manganese Removal Raw/Treated Constituent Average Concentration (mg/L) Mass Load (lbs./day) Raw Iron 0.22 3.92 Treated Iron 0.01 0.27 Raw Manganese 0.53 9.62 Treated Manganese 0.03 0.63 On average, 9.62 lbs/day of manganese enters the WTF in the raw water supply. The manganese load in the effluent is 0.63 lbs/day, approximately two times the load of iron leaving the filters. The mass loadings were calculated based on the average daily flow from the last six years (2010 – 2016) of 2.17 MGD. Effluent iron concentrations average 0.01 mg/L and effluent manganese concentrations average 0.03 mg/L. Overall, the filter achieves a 93% removal of iron and 93% removal of manganese producing an effluent water quality higher than the standards set in the Secondary Drinking Water Standards. a) Fluoridation Fluoride is added to the treated water before it is sent into the distribution system. Fluoride is added to aide in cavity protection for customers and prevents tooth decay. b) Chlorination The City disinfects the supply water using chlorine as a primary disinfectant. The City uses free chlorine as the source of chlorine. This is achieved by breakpoint chlorination where chlorine is added at a specific dose which oxidizes all of the natural or added ammonia in the water until all that is left is the free chlorine molecules. This type of disinfection provides a stable and powerful disinfectant that inactivates organisms in the water and provides a suitable residual in the distribution system. 3. Current Drinking Water Standards The City follows all of the enforcement standards set forth in the Environmental Protection Agency’s National Primary Drinking Water Standards. These standards are Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE Water System Plan Update ǀ T21.113723 Page 30 enforceable limits that each public water supply system must adhere to and provide annual updates to the public. Prior Lake accomplishes this in the annual drinking water report. 4. Proposed Drinking Water Standards With the current WTF treating for iron and manganese and removals below the National Secondary Drinking Water Standards, the City is sending treated water into the distribution system that is safe and sustainable for customer use in the City. The City will continue to monitor water quality per Federal and State regulations. Prepared by: Bolton & Menk, Inc. WATER CONSERVATION Water System Plan Update ǀ T21.113723 Page 31 IV. WATER CONSERVATION Prepared by: Bolton & Menk, Inc. WATER CONSERVATION Water System Plan Update ǀ T21.113723 Page 32 than they may be otherwise warranted. If a City is treating this water that may mean expansion or addition of the Water Treatment Facility (WTF), just to keep up with these demands. With an average of 76% of water going to residential use, lawn irrigation can play a major role in the seasonal demand for this customer category. Currently, the City has sufficient water supply with the interconnections to keep with the maximum day demands and seasonal water use. However, if future water use continues to grow without any sort of water conservation measure to limit irrigation, Prior Lake may be required to add Well 10 sooner than anticipated. Reduction of lawn irrigation to help control demands is typically accomplished through odd- even day or even time-of-day watering restrictions. Prior Lake currently has an ordinance for odd-even day watering that has helped reduce peak day and seasonal demands. The City has also been proactive in implementing a tiered rate structure that bills more for higher water usage. This has helped reduce water usage over the past few years as is evident in Table 2.1 (Historical Demands). The City currently bills water customers on a bi-monthly basis. The City should consider monthly billing as a method to help with conservation as customers will see and track their usage more frequently and have a chance to make changes on usage more quickly. This would require additional time by the City to put together customer bills and possibly reconfiguration of the City’s billing system/software. The water rate system is a two-tier system for usage rates. The City should consider adding a third, higher rate on high usage. Many other communities have a three-tier system with the higher tier targeting those high usage customers. Reducing water lost in the system is accomplished through leak detection and annual water audits. The City currently performs a leak detection on a third of the City each year. This means that every three years the entire City will have updated leak detection results. It is important to use the leak detection information yearly for Capital Improvement Planning to target areas where the volume of water lost in the system is greatest. Water losses can also be targeted by installing new enhanced meters and repairing and recalibrating current meters. Water conservation is a key factor in reducing water use. Conservation measures typically involve education along with an incentive and regulation to encourage water conservation. While some of these measures such as: billing inserts on water conservation or rebates for installing a water efficient appliance or grant programs for adding rain barrels, can help with Prepared by: Bolton & Menk, Inc. WATER CONSERVATION Water System Plan Update ǀ T21.113723 Page 33 reducing water use, they will not completely eliminate the need for additional wells or water storage. However, they could delay the implementation of the infrastructure or reduce the total future required capacity. Prepared by: Bolton & Menk, Inc. WATER CONSERVATION Water System Plan Update ǀ T21.113723 Page 34 The City evaluates water rates on a yearly basis and updates them as necessary. The latest rate adjustment was made in January of 2017. Prepared by: Bolton & Menk, Inc. WATER CONSERVATION Water System Plan Update ǀ T21.113723 Page 35 system somewhere, which results in lost revenue. Overall, Prior Lake has a lower percentage of unaccounted for water and they have implemented and maintained a quality leak detection program. These efforts should help track water losses to keep them at a minimum. Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 36 V. RECOMMENDED FUTURE IMPROVEMENTS Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 37 Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 38 include extending the 16-inch watermain that currently terminates north of highway 13, along highway 13 to the southwest. This new 16-inch watermain would serve the areas that the future land use map in Appendix A depicts as primarily industrial and urban low-density residential land use. Looping this new 16-inch watermain through these sections will provide adequate flows and pressures to these areas. In addition, extending the 20” watermain that is currently installed up to the intersection of Marschall Rd. at Belmont Ave. NW, to the west and south along Marschall Rd., will provide adequate flows and the ability to loop watermain through these areas. Additionally, more loops can be created depending on how the development in these areas progresses. Some ideas for additional loops include adding 8-inch loops through residential neighborhoods and extending 10-inch or 12-inch watermains through industrial developments. The new 16-inch watermain would be connected to the existing watermain that runs around the north end of Upper Prior Lake. On the north side of the City, the projected land use is a mix of urban low-density to urban high-density housing with additional industrial land throughout. To best serve this area, the existing 16-inch watermain that runs along County Road 42 can be extended into the northwest corner of the City. This loop would serve the projected residential demand. Additionally, to help maintain adequate flows and pressure, the 16-inch watermain from the SMSC WTP, would be extended North along County Road 82 and ultimately connect to the 16-inch watermain on County Road 42. To meet demands in the north-central section of the City, the existing 12-inch watermain running along County Road 21 would be extended east and west to serve the projected residential and industrial areas. A new 12-inch watermain would also be extended north along Pike Lake Trail NE to the City limits. This 12-inch line would also have an 8-inch line running to the east. Several pressure-reducing valves are required in this scenario to help even out the pressures. The additional loops created pockets of low or high pressures that are regulated by using the PRV’s. Average day pressures throughout the City are depicted in Figure 5.2. With the addition of the new watermain loops to serve the future development areas, the City can expect to maintain an average day pressure ranging from 70 – 90 psi in the western section of the City. The pressures here would be adequate for future residential and industrial development as depicted in the future land use map in Appendix A. Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 39 In the north section of the City, average daily pressures in the new land use areas range from 70 – 90 psi with some areas having pressures in the 50 – 60 psi range. As noted above, this area has several PRV’s added. The PRV’s were added to isolate the Summit Preserve development and allow the new booster station to increase the pressure, and to control pressures in the areas between County Roads 18 and 21. These PRV’s help to maintain the pressures above 70 psi for a majority of the area. Figure 5.5 indicates that the Hydraulic Grade Line (HGL) throughout the City will remain constant between 800 – 1,200 feet with the watermain additions shown in Figure 5.1. This is adequate for future average day demands. Maximum day pressures using the updated water model are found in Figure 5.3. In the western section of the City, maximum day pressures ranging from 60 – 80 psi can be expected. A majority of this area depicted in Figure 5.3 will have a pressure of approximately 70 psi. In the northern section of the City, maximum day pressures drop to around 50 psi west of County Road 21, but the majority of the area still maintains pressures greater than 50 psi. Based on Figures 5.2 and 5.3, with the addition of new watermain loops, the City can expect to maintain average day and maximum day pressures greater than 50 psi in all areas. Figure 5.6 indicates that the HGL throughout the City will be constant in a majority of the City between 1,160 – 1,220 feet. Areas on the North side of the City can expect to have a HGL between 1,100 – 1,160 feet. The change in HGL is due to the elevation change in the topography. Overall, the HGL is adequate for future maximum day demands. 2. Fire Flow Based on the current model, a majority of Prior Lake has a fire flow greater than 3,500 gpm, with the lowest modeled fire flow of 500 gpm in small areas around Lower Prior Lake. The lowest fire flows are in areas with dead end watermains. However, these areas are directly adjacent to, or are surrounded by areas with fire flows greater than 3,500 gpm. Overall, the City already has fire flows that exceed recommendations found in Table 3.4 above. The addition of new watermain will still help increase the available fire flow in areas around the City limits and in all future development areas. The additional watermains increased the projected maximum day fire flows to greater than 3,500 gpm in all future land use areas. This indicates that the looping and sizing of watermains was adequate to provide sufficient fire flow to meet the criteria set up in Table 3.4. !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\G_113723_20Yr_Watermain_11x17.mxd | Date Saved: 3/15/2018 1:39:09 PMFigure 5.1: Anticipated Water Distribution System March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\H_113723_20yr_AverageDailyPressure_11x17.mxd | Date Saved: 3/16/2018 3:31:08 PMFigure 5.2: Projected Average Daily Pressure March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 Average Daily Pressure 20 - 30 psi 30 - 40 psi 40 - 50 psi 50 - 60 psi 60 - 70 psi 70 - 80 psi 80 - 90 psi 90 - 100 psi 100 - 110 psi 110 - 120 psi City Limits03,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\I_113723_20YrMaxDayPressure_11x17.mxd | Date Saved: 3/15/2018 1:36:09 PMFigure 5.3: Projected Maximum Day Pressure March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 Maximum Day Pressure 20 - 30 psi 30 - 40 psi 40 - 50 psi 50 - 60 psi 60 - 70 psi 70 - 80 psi 80 - 90 psi 90 - 100 psi 100 - 110 psi 110 - 120 psi City Limits03,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\J_113723_20yrMaxFireflow_11x17.mxd | Date Saved: 3/15/2018 1:25:56 PMFigure 5.4: Projected Maximum Day Fire Flow March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 Available Fire Flow 0 - 500 gpm 500 - 1000 gpm 1000 - 1500 gpm 1500 - 2000 gpm 2000 - 2500 gpm 2500 - 3000 gpm 3000 - 3500 gpm 3500 + gpm City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\K_113723_20yrAvgDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 4:14:16 PMFigure 5.5: Projected Average Daily Demand – Hydraulic Grade Line March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 Future Average Daily Demand - HGL 0 - 400 ft 400 - 800 ft 800 - 1,200 City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake !(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT UT 3P 3P "¬! !Ø !Ø !Ø!Ø !Ø!Ø !Ø Well No. 9 Well No. 8 Well No. 6 Well No. 5 Booster Station Tank No. 1 Tank No. 2 SMSC WTP WTP No. 1Well No. 7 Well No. 3 Well No. 4 Booster Station ?±A@ ?±A@ GÜWX GÜWX G±WX G±WX GuWX GrWX G¸WX GuWX GwWX GqWX GkWX Spring Lake PikeLake Rice Lake CampbellLake Geis Lake HowardLake Keup'sLake BuckLake O'Dowd Lake UpperPriorLake Lower PriorLake TholeLake Cleary Lake Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\L_113723_20yrMaxDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 11:19:15 AMFigure 5.6: Projected Maximum Daily Demand– Hydraulic Grade Line March 2018 Legend !(Proposed Valves !(Pressure Reducing Valves UT Elevated Storage Tanks 3P Water Plant !Ø Wells "¬!Booster Station Watermain Pipe Sizes 3 4 6 8 10 12 16 18 20 Future Watermain Pipes 8 10 12 16 20 Future Maximum Daily Demand - HGL 980 - 1,040 ft 1,040 - 1,100 ft 1,100 - 1,160 ft 1,160 - 1,220 ft 1,220 - 1,280 ft City Limits 0 3,200 FeetSource: Scott County, City of Prior Lake, MnGeo !I Water Modeling City of Prior Lake Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 46 Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS Water System Plan Update ǀ T21.113723 Page 47 adequate for current and future flows. However, the needed fire reserve plays a critical role in the needed storage capacity for a water system. Any type of progress that can be made, such as an ordinance requiring fire suppression systems in all new buildings, are important considerations that will help reduce the total volume of water required for fire flows and fire storage. Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS Water System Plan Update ǀ T21.113723 Page 48 VI. ECONOMIC ANALYSIS Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS Water System Plan Update ǀ T21.113723 Page 49 Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS Water System Plan Update ǀ T21.113723 Page 50 Prepared by: Bolton & Menk, Inc. Water System Plan Update ǀ T21.113723 Appendix A: Existing and Future Land Use Maps Map Document: \\METROSOUTH1\gis\PLAK\T42112823\ESRI\Pro\112823_StoryMap\112823_CompPlan_Boards_2.0.aprx\112823_Existing_Land_Use_11x17L Date Saved: 9/5/2017 3:26 PM2040 Comprehensive Plan City of Prior Lake, MN September 2017 Existing Land Use RevereWay160th Street Southeast Highwa y 13South170thStreetSouthwes t ConnellyParkway Highw a y 1 3 S o u t h EagleCree k Aven u e South e a stMarschall Road SouthMarschall Road SouthEagleCreekAvenueNortheastT u rnerD riveSo uthwest BooneAvenueSouthMysticLakeDriveNorthwestHighway 13 South158thStreetWest ValleyViewRoad CarriageHillsParkwayNortheast Texas AvenuePikeLakeT ra ilNortheastCounty Road 78 East 140thStreetNortheastChestnutBoulevardMcKennaRoad Townline AvenueF ranklinTrailSoutheast150th Street West Fairlawn AvenueMarschallRoad150thStreet Sout heast Eagle Cre e k A ve nu eFishPointRoadSoutheast SunrayBoulevardSouthwestFrem ontA venueN o rth w estPanama AvenueN or t hwood RoadNorthwe s t Egan Drive Wood Duck Trail CountryTrailWestOld Brick Yard Road154thStreetNorthwest LangfordBoulevard LangfordAvenueMarystownRoadC o untyRoad18150th Street WestJohnsonMemorialDrive 130thStreetWest Mystic Lake Drive SouthBaseline Avenue170th Street East County Road 14 CountyRoad42East CountyRoad21Count ry T ra i lEas tZumbro AvenueCounty Road 79170th Street West Ho wa r dLake RoadNort h west140thStreetNorthwest McColl Drive Scott County GIS Legend 0 ¼ Miles Source: Scott County, City of Prior Lake, MnGeo !I City Limits Scott County Parcels Existing Land Use (2017) Agricultural Commercial Golf Course Industrial Institutional Multifamily Open Water PUD Park, Recreational, or Preserve Public/Semi-Public R-O-W SMSC Single Family Attached Single Family Detached Undeveloped 160th Street Southeast MainAve n ue Sou thea s t Highway13SouthDuluthAvenueSoutheastEagle C reekAvenueSoutheast AnnaTrailSoutheas t FranklinTrailSoutheastDakot a S t r e e t S o u t h e a s t Pleasant Street Southeast ColoradoStreetSouth e a s t Scott County GIS Map Document: \\metrosouth1\gis\PLAK\T42112823\ESRI\Pro\112823_StoryMap\112823_CompPlan_Boards_2.0.aprx\112823_Future_Land_Use_11x17L Date Saved: 8/10/2017 12:21 PM2040 Comprehensive Plan City of Prior Lake, MN August 2017 Future Lane Use RevereWay160th Street Southeast Highwa y 13South170thStreetSouthwes t ConnellyParkway Highw a y 1 3 S o u t h EagleCree k Aven u e South e a stMarschall Road SouthMarschall Road SouthEagleCreekAvenueNortheastT u rnerD riveSo uthwest BooneAvenueSouthMysticLakeDriveNorthwestHighway 13 South158thStreetWest ValleyViewRoad CarriageHillsParkwayNortheast Texas AvenuePikeLakeT ra ilNortheastCounty Road 78 East 140thStreetNortheastChestnutBoulevardMcKennaRoad Townline AvenueF ranklinTrailSoutheast150th Street West Fairlawn AvenueMarschallRoad150thStreet Sout heast Eagle Cre e k A ve nu eFishPointRoadSoutheast SunrayBoulevardSouthwestFrem ontA venueN o rth w estPanama AvenueN or t hwood RoadNorthwe s t Egan Drive Wood Duck Trail CountryTrailWestOld Brick Yard Road154thStreetNorthwest LangfordBoulevard LangfordAvenueMarystownRoadC o untyRoad18150th Street WestJohnsonMemorialDrive 130thStreetWest Mystic Lake Drive SouthBaseline Avenue170th Street East County Road 14 CountyRoad42East CountyRoad21Count ry T ra i lEas tZumbro AvenueCounty Road 79170th Street West Ho wa r dLake RoadNort h west140thStreetNorthwest McColl Drive Scott County GIS Legend 0 ¼ Miles Source: Scott County, City of Prior Lake, MnGeo !I City Limits Scott County Parcels Residential Rural Density Urban Low Density Urban Medium Density Urban High Density Commercial Retail/General Business Town Center Mixed Use District Office/Industrial Business Office Park Planned Industrial Public Lake Public/Semi-Public Park, Recreational, or Preserve Right-of-Way Recreation & Open Space SMSC UEXA 160th Street Southeast MainAve n ue Sou thea s t Highway13SouthDuluthAvenueSoutheastEagle C reekAvenueSoutheast AnnaTrailSoutheas t FranklinTrailSoutheastDakot a S t r e e t S o u t h e a s t Pleasant Street Southeast ColoradoStreetSouth e a s t Scott County GIS Prepared by: Bolton & Menk, Inc. Water System Plan Update ǀ T21.113723 Appendix B: Well Hydrographs 840.00 845.00 850.00 855.00 860.00 865.00 870.00 875.00 880.00 885.00 Water Level Elevation (ft)Prior Lake Well No. 3 Water Elevation Well Water Elevation Static Water Level* *Note: Static water level measured on 4/14/1973 825.00 830.00 835.00 840.00 845.00 850.00 855.00 860.00 865.00 870.00 875.00 880.00 885.00 890.00 Water LEvel Elevation (ft)Prior Lake Well No. 4 Water Elevation Well Water Elevation Static Water Level* *Note: Static water level measured on 7/10/1995 700.00 725.00 750.00 775.00 800.00 825.00 850.00 875.00 900.00 925.00 Water Level Elevation (ft)Prior Lake Well No. 5 Water Elevation Static Water Level* *Note: Static water level measured on 4/6/1988 750.00 760.00 770.00 780.00 790.00 800.00 810.00 820.00 830.00 840.00 850.00 860.00 870.00 880.00 890.00 900.00 910.00 920.00 930.00 940.00 950.00 Water Level Elevation (ft)Prior Lake Well No. 6 Water Elevation Well Water Level Static Water Level* *Note: Static water level measured on 8/9/2001 740.00 760.00 780.00 800.00 820.00 840.00 860.00 880.00 900.00 Water Level Elevation (ft)Prior Lake Well No. 7 Water Elevation Well Water Level Static Water Level* *Note: Static water level measured on 4/14/2003 450.00 475.00 500.00 525.00 550.00 575.00 600.00 625.00 650.00 675.00 700.00 725.00 750.00 775.00 800.00 825.00 850.00 875.00 900.00 Water Level Elevation (ft)Prior Lake Well No. 8 Water Elevation Well Water Level Static Water Level* *Note: Static water level measured on 6/6/2006 450.00 475.00 500.00 525.00 550.00 575.00 600.00 625.00 650.00 675.00 700.00 725.00 750.00 775.00 800.00 825.00 850.00 875.00 900.00 Water Level Elevation (ft)Prior Lake Well No. 9 Water Elevation Well Water Level Static Water Level* *Note: Static water level measured on 10/12/2006 Prepared by: Bolton & Menk, Inc. Water System Plan Update ǀ T21.113723