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HomeMy WebLinkAboutItem 04Comprehensive Water Plan Update Lakeville, Minnesota SEHNo. LAKEV 123875 August 9, 2013 Comp Water Plan 2013 Aug 7.docx August 9, 2013 RE:Comprehensive Water Plan Update Lakeville, Minnesota SEH No. LAKEV 123875 Mr. Christopher Petree Public Works Director City of Lakeville 18400 Ipava Avenue Dear Mr. Petree: Enclosed please find the Comprehensive Water Plan Update for the City of Lakeville, Minnesota. The primary emphasis of this study was to plan for future water system facilities required to serve areas of anticipated growth in the City. These facilities included wells, water storage, and trunk water main. The existing computer model of the water distribution system was updated and used for the analysis. The system was evaluated with respect to pressure, flow, pipe friction, and fire flow availability. Extended period simulations were also used to analyze system operations. We greatly appreciate the help provided by City staff. As always, it has been a pleasure working with the City. The staff’s experience and knowledge of the system and cooperative spirit proved very helpful in creating and calibrating the model. We will be available to review this report with you at your request. If you have any questions, please call me at 612.618.9075. Sincerely, John D. Chlebeck, PE Project Manager ah c:\projects\lakeville water system plan update\report\final\comp water plan 2013 aug 7.docx Comprehensive Water Plan Update Lakeville, Minnesota SEH No. LAKEV 123875 August 9, 2013 I hereby certify that this 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. JohnD. Chlebeck, PE Date:August 7, 2013Lic. No.:47125 Reviewed by: Miles JensenAugust 7, 2013 Date Short Elliott Hendrickson Inc. 3535 Vadnais Center Drive St. Paul, MN 55110-5196 651.490.2000 Executive Summary This report serves as support for the current capital improvement planning process being completed by the City of Lakeville. The focus of the report is to analyze existing water utility facilities, and to anticipate future system needs based on anticipated growth within the City. This report is an update on the last Comprehensive Water Plan completed in 2008. The analysis at that time incorporated growth projections that have since seen significant revision. In addition, the plan for water system facilities to serve future growth has been refined from a perspective of maximizing the use of existing infrastructure, optimizing service to future water system customers, and minimizing future capital costs where possible. The Lakeville water system consists of infrastructure components that perform supply, treatment, storage and distribution functions. This study evaluates system needs in each category (with the exception of water treatment) to meet existing and projected water use. Water treatment is dealt with in greater detail in a separate water treatment plant facility evaluation that is being completed concurrently with this Comprehensive Water Plan Update. Existing facilities include: 17 water supply wells pumping from bedrock aquifers with a total supply capacity of 22 million gallons per day (MGD) One central water treatment facility including gravity filtration for iron and manganese removal One below grade concrete water storage reservoir (clearwell) with a capacity of 3.1 million gallons (MG) located at the water treatment facility, including a high service pumping facility that pumps from the clearwell to the distribution system Five elevated water storage tanks located on the distribution system with a total useable capacity of 4.75 MG Approximately 300 miles of cast iron and ductile iron water distribution mains ranging in size from 6 inches to 36 inches in diameter Three distinct pressure zones including a Normal Zone that is supplied from the water treatment plant, and two reduced pressure zones that serve lower elevations through pressure reducing valves (PRVs) located on the distribution system Many water system facilities are designed by industry standard to meet maximum daily demands reliably. Maximum daily water use on the Lakeville water system has ranged from 13.2 MGD to 20.4 MGD over the previous five years. The amount of water use varies with population and land use patterns, as well as with environmental factors such as precipitation and temperature. Often peak water use is driven by summer irrigation demand. The population for Lakeville in 2012 is estimated at 57,048. The population is projected to increase to an ultimate level of approximately 88,800 between 2030 and 2035 by current estimates. This results in a projected maximum daily water use of potentially 31.435 MGD. New development is expected to drive much of the increase in population and water use in Lakeville. This report includes recommendations for infrastructure improvements to reliably serve projected new development and corresponding increases in water demand. Recommended improvements in this report include: Ten new water supply wells One new elevated water storage tank Trunk distribution mains to serve new development Comprehensive Water Plan UpdateLAKEV 123875 City of Lakeville Table of Contents Letter of Transmittal Certification Page Executive Summary Table of Contents Page 1.0Introduction.............................................................................................................1 2.0Existing System......................................................................................................3 2.1Existing Facilities..............................................................................................3 2.2Water Demands................................................................................................7 2.3Demand Distribution.........................................................................................7 3.0Hydraulic Analysis of the Distribution System.....................................................9 3.1Computer Model Setup and Calibration............................................................9 3.2System Pressures............................................................................................9 3.3Pipe Velocities and Friction Loss....................................................................12 3.4Extended Period Simulation...........................................................................12 3.5Current Available Fire Flow............................................................................14 4.0Expansion Areas and Projected Demands..........................................................15 4.1Area Served...................................................................................................15 4.2Elevations Served...........................................................................................15 4.3Population Trends..........................................................................................15 4.4Projected Growth............................................................................................18 4.5Land Use Based Demand Projections............................................................19 5.0Recommendations................................................................................................21 5.1Water Supply Wells........................................................................................21 5.1.1Ipava Avenue Transmission Main.......................................................22 5.2Storage...........................................................................................................25 5.2.1Elevated Storage Location..................................................................26 5.3Trunk Water Main...........................................................................................33 5.4Distribution System Back-Pressure with Expansion of High Service Pumping Facilities......................................................................................................... 33 5.5System Pressures After Improvements...........................................................34 5.6Available Fire Flows After Improvements........................................................34 6.0Capital Improvement Plan....................................................................................38 6.1Estimated Cost of Water System Improvements.............................................38 6.1.1Trunk Water Main Oversize Costs.......................................................39 6.1.2Wells...................................................................................................39 6.1.3Elevated Water Storage Tank.............................................................39 6.1.4Raw Water Transmission Lines...........................................................39 6.1.5Water Treatment Facility Improvements..............................................39 6.2Capital Improvement Plan Timeline................................................................39 6.3Trigger Chart..................................................................................................40 Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage i Table of Contents (Continued) List of Tables Table 1 – Existing Pressure Zones......................................................................................1 Table 2 – Existing Well Supply Facilities.............................................................................3 Table 3 – Existing Storage Facilities....................................................................................4 Table 4 – Water Demand History........................................................................................7 Table 5 – Recommended Single-Family Residential Fire Flows........................................14 Table 6 – Population and Household Trends.....................................................................18 Table 7 – Metropolitan Council Population Projections......................................................18 Table 8 – Population-Based Demand Projections.............................................................19 Table 9 – Land Use-Based Demand Projections...............................................................20 Table 10 – Well Construction Schedule.............................................................................22 Table 11 - Elevated Storage Needs...................................................................................26 Table 12 – Existing High Service Pump Controls as Modeled...........................................27 Table 13 – Modified Maximum Day High Service Pump Controls as Modeled...................28 Table 14 - Modified Average Day High Service Pump Controls as Modeled......................28 Table 15 – Trunk Water Main Extensions..........................................................................38 Table 16 – Water Supply and Storage Facilities................................................................38 Table 17 – Raw Water Transmission Main........................................................................38 Table 18 – Capital Improvement Plan Timeline................................................................. 40 Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage ii Table of Contents (Continued) List of Figures Figure 1 – Current Available Service Area...........................................................................2 Figure 2 – Existing Water Supply System............................................................................5 Figure 3 – Existing Water Distribution System.....................................................................6 Figure 4 – Typical Residential Demand Distribution Graph..................................................8 Figure 5 – Existing Average Day Pressures......................................................................10 Figure 6 – Existing Peak Hour Pressures..........................................................................11 Figure 7 – Extended Period Simulation Results for the Existing System............................13 Figure 8 – Maximum Day Available Fire Flows..................................................................16 Figure 9 – Ultimate Distribution System.............................................................................17 Figure 10 – Hydraulic Analysis of Raw Water Transmission Main on Ipava Avenue..........23 Figure 11 – Ultimate Raw Water Supply System...............................................................24 Figure 12 – Extended Period Simulation Results for the Future Tower at Cherryview Park30 Figure 13 – Extended Period Simulation Results for the Future Towerat Highview Ave. and 190th St................................................................................................31 Figure 14 – Extended Period Simulation Results with Modified Piping to New Tower........32 Figure 15 – Distribution System Hydraulic Impacts from Added High Service Pumping....33 Figure 16 – Ultimate Average Day Pressures....................................................................35 Figure 17 – Ultimate Peak Hour Pressures.......................................................................36 Figure 18 – Ultimate Available Fire Flow...........................................................................37 Figure 19 – Water System Capital Improvement Trigger Chart.........................................41 List of Appendices Appendix ARaw Water System Analysis Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage iii August 2013 Comprehensive Water Plan Update Prepared for City of Lakeville 1.0Introduction The Lakeville water distribution system serves most of the businesses and residents within the city limits of Lakeville. There are some properties served by individual or private community wells. This is especially true for areas identified for future expansion. Other areas of the City are supplied with water by the City of Burnsville. The current available service area of the water distribution system is represented in Figure 1. The Lakeville water distribution system currently consists of 17 wells, one water treatment plant, one below-ground storage reservoir, one at-grade storage standpipe, four elevated storage tanks, and approximately 300 miles of water distribution piping. The system is based on three pressure zones as listed in Table 1. Table 1–Existing Pressure Zones Static Pressure Pressure ZoneTower OverflowElevations Served Range(psi) Normal Zone1230949 to 117026 to 122 Valley Park1121919 to 102044 to 88 Air Lake1109939 to 98752 to 74 Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 1 Legend Pressure Zone 160thStW Air Lake 161stStW Valley Park / CMF Normal Pressure Zone 165thStW 170thStW 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 05/31/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Service PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 1 Lakeville, Minnesota Source: City of Lakeville Areas www.sehinc.com 2.0Existing System 2.1Existing Facilities Water is supplied to the City of Lakeville’s water system from 17 wells that draw from the Prairie du Chien-Jordan and Franconia-Ironton-Galesville aquifers. The total operating capacity of the City’s wells is 15,350 gpm (22.10 MGD), with a firm supply operating capacity of 14,250 gpm (20.52 MGD). Firm capacity is defined as the system capacity minus the capacity of the largest pump. This is the capacity that can be provided consistently, even during maintenance when one well pump might be out of service. Supply and storage system components are listed in Tables 2 and 3. The well capacities listed in Table 2 indicate an operating supply capacity that is less than the design capacity of each well. This is due to the interaction of the wells when pumped simultaneously. During peak summer operating conditions, the well production rates are reduced by interference- related drawdown. Table 2–Existing Well Supply Facilities Facility Design Supply Operating Supply Operating Supply Treated NameCapacity (gpm)Capacity (gpm)Capacity (MGD) Well 2Yes9008501.22 Well 3***No1,3001,0001.44 Well 4Yes1,2501,0001.44 Well 6Yes1,2001,0001.44 Well 7***No1,20000.00 Well 8Yes1,5801,0001.44 Well 9Yes1,4501,0001.44 Well 10Yes1,4001,0001.44 Well 11Yes1,3001,0001.44 Well 12Yes1,4001,0001.44 Well 13Yes1,4001,0001.44 Well 14Yes1,5501,0001.44 Well 15Yes1,5001,0001.44 Well 16Yes1,5001,0001.44 Well 17Yes1,4001,0001.44 Well 18**Yes6004000.58 Well 19Yes1,3001,1001.58 Total22,23015,35022.10 Firm Capacity14,25020.52 **Well 18, completed in the Franconia-Ironton-Galesville Aquifer, will be utilized to the largest extent possible to reduce pumping from Prairie du Chien -Jordan Aquifer. ***Wells 3 and 7 are designated for emergency use only; Well 7 is taken out of capacity calculation due to potential interference with private wells Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 3 Table 3–Existing Storage Facilities Facility NameOverflow TypeStorage Usable * ElevationCapacity (MG)Storage (MG) Clearwell1069Ground3.13.1 Airlake1109Hydropillar0.50.5 Fairfield1230Hydropillar0.750.75 North Park1230Spheroid1.01.0 Dakota Heights1230Standpipe2.01.0 Valley Park 1121Composite1.51.5 Composite Total8.857.85 Total Elevated4.75 * Usable storage at Dakota Heights is shown as 1.0 since pressures in the area are below 35 psi static when it is full. Homes in this area typically are on booster pumps/tank systems which the City participates 50/50 on cost. A map of the water supply system, including locations of wells and the water treatment plant that supply the City, is shown in Figure 2. The water treatment plant for the City of Lakeville provides iron and manganese removal through a gravity filtration system. The design capacity of the filters is 20 MGD, with room for expansion to 30 MGD with four additional filter cells. A filter loading study was recently conducted, indicating that the loading rate on the existing filters could safely be increased to 26.5 MGD. Filtered water is stored in a below-grade clearwell prior to pumping into the distribution system at the high service pumping station. The high service pumping station contains four pumps currently, including two pumps with 4 MGD (2825 gpm) design capacity, one pump with 8 MGD (5700 gpm) design capacity, and one pump with 14 MGD (8300 gpm) design capacity. The existing firm pumping capacity of the facility is 16 MGD (11,350 gpm), with the largest pump out of service. The Lakeville water distribution system is comprised of water mains ranging in size from 6 inches to 30 inches in diameter. There are five gravity-operated water storage tanks on the distribution system, in addition to the below-grade water storage clearwell at the water treatment facility. Distribution facilities, including water mains, storage tanks, and pressure reducing valves, are mapped in Figure 3. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 4 162ndStW Legend Future PDCJ Well 165thStW 165thStW Future FIG Well Well 4 Existing Well Well 2 WTP Existing Transmission Mains 170thStW Diameter (in) Well 17 Well 19 6 8 10 Well 13 12 16 20 Well 11 JurelCt Well 6 24 30 Well 14 Well 12 Well 10 Well 8 Well 18 185thStW Well 9 Well 16 190thStW Well 15 01,0002,0004,000 Feet 195thStW This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/04/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Raw Water PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 2 Source: City of Lakeville Lakeville, Minnesota Supply System www.sehinc.com Legend PRV 160thStW Tank 161stStW WTP Existing Mains 165thStW Diameter (in) 6 8 170thStW NorthPark 10 12 16 18 ValleyParkComposite 20 24 DakotaHeights 30 36 Reduced Pressure Zone Air Lake Valley Park / CMF 190thStW 195thStW 195thStW 202ndStW Fairfield 210thStW AirLake 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 05/31/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Distribution PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 3 Lakeville, Minnesota Source: City of Lakeville System www.sehinc.com 2.2Water Demands The Lakeville water utility records indicate that in 2012, the average daily (AD) water demand for the complete system was 6.9 MG (4,792 gpm). The maximum day (MD) demand for 2012 was 18.9 MGD (13,125 gpm). Water demands from the period of 2007 - 2012 are summarized in Table 4. The highest maximum day demand rate was experienced in 2007 at 20.4 MGD. It is thought that conservation activities, as well as a downturn in the housing market, are contributing factors to the reduction in demand since 2007. Table 4–Water Demand History Maximum Average Average Per Maximum Peaking Day Per Population Day Capita Day YearFactor Capita EstimateDemand Demand Demand (MD/AD)Demand (MGD)(gpcd)(MGD) (gpcd) 200753,8297.213420.42.8379 200854,3286.712320.23.0372 200955,7726.611817.12.6307 201055,9545.810413.22.3236 201156,5346.311115.02.4265 201257,0486.912118.92.7331 2.3Demand Distribution Water demands are variable throughout the day and the season. The heaviest demand conditions typically occur during a MD demand scenario in the summer, when outdoor water use is at its highest level. Over the course of a given day, water uses often follow a diurnal demand distribution. Figure 4 represents a typical demand distribution graph for residential water use. Commercial and industrial uses are usually more constrained and predictable. The residential demand graph depicts low water demand during the late evening and early morning periods. As the morning progresses, there is an increase in demand as automatic sprinkler systems are operated in conjunction with increased home water use. During late morning to early afternoon there is a slight recovery prior to a second peak use in the early evening. Most water systems are designed to meet the maximum daily demand rate with supply facilities such as wells, treatment processes, and high service pumping facilities. Storage reservoirs are used to supplement the supply of treated water during the peak usage hours within each day. During lower usage periods, the system is able to produce water in excess of the demand. This excess is used to fill the storage reservoirs. When the demand rate exceeds the production rate, the stored water in the reservoirs is used to make up for the deficit. Based on accounts of utility operations staff in Lakeville, the demand distribution in Lakeville may have a higher peak in the morning than in the evening, due to the predominance of automatic sprinkler systems in the city. The storage tanks in Lakeville are also observed to lose a greater quantity of water during the morning peak use period. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 7 Figure 4 – Typical Residential Demand Distribution Graph 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 12:00 AM2:00 AM4:00 AM6:00 AM8:00 AM10:00 AM12:00 PM2:00 PM4:00 PM6:00 PM8:00 PM10:00 PM12:00 AM TIME OF DAY Taken from AWWA M32, Computer Modeling of Water Distribution Systems, 2005, American Water Works Association Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 8 3.0Hydraulic Analysis of the Distribution System 3.1Computer Model Setup and Calibration The computer model was originally constructed during an earlier water system comprehensive planning process. SEH refined the model in the last Comprehensive Water Plan in 2008, and conducted calibration at that time. For this plan update, five hydrant flow tests were conducted to supplement earlier calibration data and verify model calibration. InfoWater by Innovyze was used for this analysis. All utility owned pipes 6 inches in diameter and larger were included in the original model. Current utility distribution system mapping in GIS was used for this plan update to make the model reflect current system conditions. The demands were updated based on historic pumping data. Elevation data were assigned to the model using 2-foot contour information supplied by the City, based on available LIDAR. Demands were assigned to model junction nodes based on historical demands as recorded by the utility. Demands were assigned evenly across the system, and later adjusted in order to calibrate the extended period simulation results to system operations as recorded by the utility’s SCADA system. 3.2System Pressures Average Day (AD) pressures are depicted by pressure districts in Figure 5. The existing system pressures for an AD demand scenario range from 24 to 121 psi. The minimum working pressure as stated in Ten States Standards is 35 psi. Pressures are typically lower than this near the Dakota Heights Tank where elevations are the highest in the City limits. Homes in this area typically have in-home booster pumps/tanks to increase the pressure to an acceptable range. The City’s current policy is to participate 50/50 in cost sharing to furnish and install these booster pumps/tanks. The pressures calculated for a peak hour (PH) simulation are represented in Figure 6. The change in water pressure between AD and PH demands varies over the distribution system. The largest pressure variations observed in the model were approximately 15 psi in the northeastern portion of the distribution system Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 9 Legend Static Pressure (psi) 160thStW 0 - 10 161stStW 11 - 20 21 - 30 165thStW 31 - 40 41 - 50 51 - 60 170thStW 61 - 70 71 - 80 81 - 90 91 - 100 101 - 110 111 - 120 121 - 130 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Average Day PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 5 Lakeville, Minnesota Source: City of Lakeville Pressures www.sehinc.com Legend Static Pressure (psi) 160thStW 0 - 10 161stStW 11 - 20 21 - 30 165thStW 31 - 40 41 - 50 51 - 60 170thStW 61 - 70 71 - 80 81 - 90 91 - 100 101 - 110 111 - 120 121 - 130 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Peak Hour PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 6 Lakeville, Minnesota Source: City of Lakeville Pressures www.sehinc.com 3.3Pipe Velocities and Friction Loss Pipe segments are considered potentially deficient, or most-limiting, if they have the following conditions: Velocities greater than 5 ft/s; and Head losses greater than 10 ft/1000 ft. Velocities in pipe segments are acceptable up to about 10 ft/s during emergency or extreme demand conditions of short duration. As velocities increase, pipe friction increases and problems with water hammer occur. This is especially true in systems with higher pressures. We have checked the system for locations where velocities and head losses meet the above stated conditions. There are several locations where pipe velocities exceed 5 ft/s. The majority of these locations are near the water treatment plant as the high service pumps are operating at peak capacity. In addition, several locations throughout the distribution system where inconsistent sizing creates bottlenecks were also apparent. These bottlenecks also results in head losses greater than 10 ft/1000 ft. 3.4Extended Period Simulation An extended period simulation (EPS) was setup in the model to check the system operation during several consecutive days of maximum day demands. The primary purpose of this simulation was to check for cumulative system imbalances that are not evident in standard simulations. Tower and system supply placement and the sizes of distribution system pipe contribute to imbalances. They also contribute to a reduced storage-replenishment rate and the ability to refill the towers at night during low demand periods. We have simulated a 72-hour period with three consecutive maximum day (MD) demand conditions. The model utilizes demand pattern curves to adjust demand over the course of a day to approximate variations in water use. Controls were set up on the high service pumps at the water treatment plant to turn the pumps on and off based on water tower levels. The existing controls for the high service pumps were entered into the model during the last Comprehensive Water Plan, and are presented in Table 12, in Section 5.2.1. The expected water surface elevations during EPS analysis indicated that there is imbalance in the system under peak conditions. During simulated consecutive maximum day events, the North Park Tank drains quicker than the Dakota Heights Tank. At times there is as much as a five to ten foot difference in hydraulic grade lines. This imbalance is thought to be caused by high peak demands in the northeastern portion of the distribution system. The City has installed modulating valves at the water treatment plant that are designed to direct more flow toward the North Park tank. Under peak demands, these valves have been used to throttle plant effluent going to the west and south, which in turn directs more flow north along Ipava Avenue. Modeling results also seem to indicate a lag in the filling of the Fairfield tower under peak demand conditions. Depending on the level of demand on the south end of the system, the Fairfield tower may also have water levels that are lower than Dakota Heights under peak demand conditions. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 12 Figure 7 – Extended Period Simulation Results for the Existing System Existing System - Existing Controls - MD EPS 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 1,200.00 North Park HGL Dakota Heights HGL 1,195.00 Fairfield HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Existing System - Existing Controls - AD EPS 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 1,200.00 North Park HGL 1,195.00 Dakota Heights HGL Fairfield HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Figure 7 depicts tank water elevation fluctuations as modeled during two different EPS scenarios for the existing system. The firstgraph depicts tank water elevations under maximum day (MD) demands. The second graph depicts tank water elevations under average day (AD) demands. Under AD demand conditions, the towers are balanced well, and there are no difficulties encountered in filling the tanks. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 13 As demands continue to increase on the system as projected, the system imbalances will tend to be exacerbated. This will be offset by additional trunk main construction to some degree. The analysis of tank hydraulic balance for the ultimate distribution system is discussed in more detail in Section 5.2.1, as it relates to the location of future elevated storage. 3.5Current Available Fire Flow The modeled fire flows were run up to a maximum of 3,500 gpm. The computer model indicates that higher flows are available in some areas, but at some point they become unrealistic because there are not enough hydrants or fire equipment to deliver such high rates. The minimum fire flow available at any given point in a system should not be less than 500 gpm at a residual pressure of 20 psi. This represents the amount of water required to provide for two standard hose streams on a fire in a typical residential area for single-family residential dwellings with spacing between 31 to 100 feet. The distance between buildings and the corresponding fire flow is summarized in Table 5. Table 5–Recommended Single-Family Residential Fire Flows Distance Between Needed Fire Buildings (feet)Flow (gpm) More than 100500 31-100750 11-301000 Less than 111500 The needed fire flow for commercial and industrial buildings, according to ISO, is based on several characteristics of individual buildings such as: Type of construction Type of business that is using the property and materials stored Proximity and characteristics of nearby properties Presence or absence of a fire sprinkler system, and design of sprinkler system While the minimum available fire flow for residential buildings with greater than 100 feet between them should be at or above 500 gpm, typically more available flow is needed. Needed fire flow can approach 10,000 gpm for some properties. It is not realistic for a water distribution system to provide that amount of water for fire protection in most cases. Therefore, those properties would need other fire protection systems to augment the water from the distribution system. ISO does expect communities to provide up to 3500 gpm for 3 hours where needed fire flow is in excess of 3500 gpm. The community’s fire insurance rating can be impacted for providing less than this where needed. These flow rates are usually necessary for high density or industrial properties. The computed fire flows for the current distribution system are represented in Figure 8. They are represented by fire flow districts in gallons per minute. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 14 4.0Expansion Areas and Projected Demands 4.1Area Served The Comprehensive Water Plan of 2008 considered MUSA planned expansion areas and timelines that represented the development projections at that time. The recent economic recession and housing market retreat have forced a reconsideration of growth projections for Lakeville. The City is currently in the beginning stages of developing a comprehensive land use plan. Preliminary information from that plan, along with population projections previously developed by the Metropolitan Council for Lakeville, were considered for the projection of future water demands that will drive water utility infrastructure investment. It is understood that land development is currently increasing in the east-central portion of the city (bounded by Dodd Boulevard on the west and north, Lakeville Boulevard on the south, and the municipal boundary on the east). Preliminary land use planning includes commercial and medium to high density residential development along the Cedar Avenue corridor between Lakeville Boulevard and Dodd Boulevard. Outside of that corridor, it is expected that development will be mostly low to medium density residential. Though there are other areas for future development to the west, south, and northeast of the current water utility service area, the vast majority of growth and water system expansion is expected to occur in the east-central area as defined above. 4.2Elevations Served The expansion service areas shown in Figure 9 include land with elevations ranging from 930 to 1180. This elevation range will likely require service from both the normal and reduced pressure zones. A portion of the expansion area west of I-35 is unable to be served by the existing normal pressure zone. Higher elevations in that location will result in pressures below recommended levels. If this area is served in the future, a small boosted pressure zone including pumping station and a small storage facility would be recommended. Service to this area is not planned for the foreseeable future. 4.3Population Trends The population of the City of Lakeville has increased rapidly over the past forty years. Population and household trends are shown in Table 6. The most recent weak housing market has resulted in a reduction in growth since 2008. City staff have reported that there is evidence that development may be on an increasing trend again, with an increase in subdivision requests. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 15 Legend Available Fire Flow at 20 psi Residual (gpm) 160thStW 0 - 500 161stStW 501 - 1000 1001 - 1500 165thStW 1501 - 2000 2001 - 2500 2501 - 3000 170thStW 3001 - 3500 > 3500 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Existing COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Maximum Day PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 8 Lakeville, Minnesota Source: City of Lakeville Available Fire Flow www.sehinc.com Legend PRV 160thStW 161stStW Tank WTP Existing Mains 165thStW Diameter (in) 6 170thStW 8 NorthPark 10 12 16 18 ValleyParkComposite 20 DakotaHeights 24 30 36 Future Trunk Mains Diameter (in) 12 16 20 24 FutureElevatedWater 195thStW Reduced Pressure Zone StorageTankLocation Air Lake Valley Park / CMF 202ndStW 207thStW Fairfield 210thStW AirLake 215thSt 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Ultimate COMPREHENSIVE WATER PLAN UPDATE Print Date: 05/31/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Distribution PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 9 Lakeville, Minnesota Source: City of Lakeville System www.sehinc.com Table 6–Populationand Household Trends Annual Growth YearPopulationHouseholds Rate (%) 19707,1961,883 198014,7904,3377.5% 199024,8547,8515.3% 200043,12813,6095.7% 201055,95418,6832.6% The population estimate for 2012 was recently released by the Metropolitan Council, at 57,048. With an average annual population increase of 547 between 2010 and 2012, that is an average annual growth rate of 1.0%. 4.4Projected Growth Table 7 summarizes population projections from the Metropolitan Council for the City of Lakeville. These forecasts were adopted by the Metropolitan Council as part of the 2030 Regional Development Framework. Table 7–Metropolitan Council Population Projections Average Density Average YearPopulationEmployeesHouseholds(People / Annual Growth Household)Rate (%) 202078,40022,94528,4002.763.4 203088,80027,38733,5002.651.3 Based on the developable land in Lakeville currently, it is thought that the 2030 projected population of 88,800 is representative of ultimate build-out and saturated development. The City’s Economic Development department estimates that the Metropolitan Council population projections are possibly overly aggressive. A 2% growth rate may be more reflective of near-term growth. For the purposes of this study, we have examined a range of potential growth bounded by the Metropolitan Council projections on the high end, and a 2% growth rate on the low end. Based on the population projection range, water demands are projected in Table 8. These demand projections are based on an assumed average day per capita demand rate of 118 gallons per capita per day (gpcd), which is an average of the prior 10 years, after eliminating the highest and lowest outliers. The maximum day demand is projected using a peaking factor (maximum day demand to average day demand ratio) of 3.0, which is the highest of the previous five years. The projected demand rates represent a high water use year for the projected population, and likely a summer with low rainfall. Using a relatively high demand projection rate, though within reason, is good practice for infrastructure planning. A capital improvement plan based on such projections will allow for the City to reliably meet the future demands of the water system. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 18 Table 8–Population-Based Demand Projections Projected Projected Projected Projected Average Day Maximum Day Projected Projected Average Maximum Demand - Demand - Population - Population Day Day Year Metropolitan Metropolitan Metropolitan - 2% Demand - Demand - Council Council CouncilGrowth2%Growth 2% Growth Population Population (MGD)(MGD) (MGD)(MGD) 201464,9327.66222.98659,3767.00621.019 201567,1777.92723.78160,5767.14821.444 201669,4228.19224.57561,7997.29221.877 201771,6668.45725.37063,0487.44022.319 201873,9118.72126.16464,3217.59022.770 201976,1558.98626.95965,6217.74323.230 202078,4009.25127.75466,9467.90023.699 202179,4409.37428.12268,2998.05924.178 202280,4809.49728.49069,6798.22224.666 202381,5209.61928.85871,0868.38825.165 202482,5609.74229.22672,5228.55825.673 202583,6009.86529.59473,9878.73026.191 202684,6409.98829.96375,4828.90726.721 202785,68010.11030.33177,0079.08727.260 202886,72010.23330.69978,5629.27027.811 202987,76010.35631.06780,1499.45828.373 203088,80010.47831.43581,7699.64928.946 203188,80010.47831.43583,4209.84429.531 203288,80010.47831.43585,10610.04230.127 203388,80010.47831.43586,82510.24530.736 203488,80010.47831.43588,57910.45231.357 203588,80010.47831.43588,80010.47831.435 4.5Land Use Based Demand Projections Due to the uncertainty with growth projections and water use projections, it is useful to estimate future water system demands from multiple perspectives to find a range of potential outcomes. In addition to the population-based method used in the previous section, projected land uses were also examined for this plan, and water demands projected based on an assumed unit demand per area for varying land uses. The method used is summarized in Table 9. Since the City is currently in the process of developing a land use plan, the values in Table 9 for acreage for each category of development are estimated. The unit demands for each type of development are typical values, and were chosen here to match the City’s current water and sewer planning documents. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 19 Table 9–Land Use-Based Demand Projections Average Units Persons Unit Unit Day Area per per Demand Demand (ac)Demand AcreUnit(gpd/Person)(gpd/ac) (MGD) Cedar Ave Commercial801,2000.096 Cedar Ave MD / HD Residential49072.561001,7920.878 South Office Park4901,2000.588 South Light Industrial1051,2000.126 West Commercial701,2000.084 West LD Residential14033.161009480.133 West MD / HD Residential14072.561001,7920.251 Rural / Open Space2,000-- Remainder -Low Density 3,38033.161009483.205 Residential Estimated Total -Added Average Day Demand through Ultimate Development5.360 2011 Average Day Demand6.143 Projected Average Day Demand through Ultimate Development11.503 Projected Maximum Day Demand through Ultimate Development (Assumes a Maximum 34.510 Day Peaking Factor of 3.0) Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 20 5.0Recommendations With future development, Lakeville will require additional supply, storage and trunk water main to meet the water supply needs of its residents and businesses. Water treatment capacity may need to be expanded in the future as well. A concurrent study is underway to evaluate the capacity of the existing water treatment facility. This section evaluates the capacity of water supply and distribution facilities based on current and projected water demands. The proposed distribution system layout for the ultimate service area was presented in Figure 9. 5.1Water Supply Wells A community’s water supply capacity is sized to meet maximum day demands reliably. The industry standard is to provide enough pumping capacity to meet the maximum day demand rate with the largest pump out of service (i.e. firm capacity). Current well supply capacity in Lakeville is 22.1 MGD, and the firm pumping capacity is 20.5 MGD. Maximum day demands reached a peak of 20.4 MGD in 2007. That rate has fluctuated since then, but could reach thatlevel with the right environmental conditions to drive up water use. Based upon the peak demand projections in Table 8, the 2007 level of per capita use combined with the current population could drive demand above the current firm well supply capacity. For that reason, additional capacity is recommended in the near future. It is understood that the City is planning to initiate a well project this year. If growth continues at the projected rate, additional wells will be needed as indicated in Table 10. Figure 11 shows the proposed locations of future wells. A study was conducted as part of this plan update to review potential locations for future wells along the Dodd Blvd. corridor. That study is attached in Appendix A. It included a review of hydrogeologic conditions and raw water transmission capacity. The findings indicate that the aquifer and transmission main should support 2-3 additional wells along that corridor. There are potential well interference issues, and transmission main friction losses that limit development beyond that. The current plan is to construct additional future wells in the east central portion of the city, extending a second raw water transmission main to transport water back to the existing water treatment facility. The long range water system capital improvement plan set forth in this plan includes this assumption. As the need for the transmission main, and those additional wells, becomes more imminent, it is recommended that an aquifer pumping test be conducted in the vicinity of proposed new wells to assess the local aquifer properties in more detail. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 21 Table 10–Well Construction Schedule YearProjected Maximum Firm Capacity Future Well Day Demand (MGD)(MGD)Operating 201422.98623.4Wells 20, 21 201523.78125.416Wells 22, 23 201624.57525.416 201725.37026.568Wells 24, 25 201826.16426.568 201926.95928.008Well 26 202027.75428.008 202128.12229.448Well 27 202228.49029.448 202328.85829.448 202429.22630.888Well 28 202529.59430.888 202629.96330.888 202730.33130.888 202830.69930.888 202931.06732.328Well 29 203031.43532.328 203131.43532.328 203231.43532.328 203331.43532.328 203431.43532.328 203531.43532.328 5.1.1Ipava Avenue Transmission Main The City would also like to investigate additional wells along the transmission main that runs north from the water treatment plant along Ipava Avenue, in order to maximize the use of existing transmission main infrastructure prior to constructing new transmission mains to serve new well fields. There is a potential for well interference and restrictions in existing transmission main capacity with additional well pumping along the corridor. There are two locations that have been identified as potential sites for new wells. One is the current site of Well 17, at Steve Michaud Park. The other is the current site of Well 11, at Eastview Elementary School. The hydraulic model of the raw water system was used to analyze the effect on backpressure at the wells with the addition of new wells pumping into the existing transmission line. Figure 10 provides the results of the hydraulic analysis. The first well simulated in each modeling scenario was a Jordan well with an estimated capacity of 1000 gpm. The second well simulated was a FIG well with an estimated capacity of 400 gpm. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 22 Figure 10 – Hydraulic Analysis of Raw Water Transmission Main on Ipava Avenue The hydraulic model indicates that one additional well pumping at 1000 gpm at Michaud Park adds approximately 30 feet of head on the existing well pump there. A second 400 gpm well at that location adds an additional 15 - 20 feet of head. The pump operation curve for Well 17 should be examined to evaluate the potential effect on that pump. It is possible that interference and/or frictional back pressure on the pump could significantly reduce its capacity or cause the pump to operate outside of the manufacturer’s recommended operating conditions. Additional well pumping at the Eastview Elementary site is expected to have a lesser impact on backpressure in the transmission main. The modeling results predict approximately 10 feet of additional head with one additional well pumping at 1000 gpm. A second additional well at the site pumping 400 gpm adds approximately 5 feet of additional head. Interference related drawdown is also expected at either site with the addition of a Jordan well. A FIG well is not expected to interfere with the existing Jordan wells. Based on the analysis presented in the Raw Water System Analysis in Appendix A, the interference drawdown is estimated to be approximately 10 feet if the second well is spaced 1000 feet from the existing well. Spacing of less than 1000 feet is not recommended for a Jordan well. A test well is highly recommended at either location prior to proceeding with a production well. This would allow closer examination of potential interference before investing in production well construction. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 23 Legend 165thStW Future PDCJ Well Well 4 Future FIG Well Well 2 Existing Well 170thStW WTP Future Transmission Mains Well 17 Well 25 Well 19 Diameter (in) 12 16 Well 13 24 Well 20 Existing Transmission Mains Diameter (in) Well 22 Well 21 6 Well 11 Well 23 JurelCt Well 6 Well 24 8 10 Well 14 12 Well 12 Well 10 Well 8 Well 18 185thStW Well 9 16 20 24 Well 16 Well 26 Well 29 Well 27Well 28 30 190thStW Well 15 195thStW 01,0002,0004,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. 199thStW Project: LAKEV 123875 Ultimate COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/04/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Raw Water PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 11 Source: City of Lakeville Lakeville, Minnesota Supply System www.sehinc.com Given the potential for interference and transmission main limitations, it is recommended that additional analysis be conducted prior to proceeding with any well construction that would utilize the existing transmission main on Ipava Avenue. This includes a review of well pump performance curves, field testing of well pump performance, and test wells to examine aquifer performance characteristics. For planning purposes, it is assumed in this study that one additional FIG well and one additional Jordan well may be constructed at the Eastview Elementary site. One additional FIG well is shown at the Michaud Park site. If an additional FIG well turns out to be viable at this site, it could allow the City to utilize existing raw water transmission main infrastructure and provide time to construct a new transmission main on the east side of the water treatment plant. 5.2Storage To determine the water storage needs of a community, average daily demands, peak demands, and emergency needs must be considered. Table 11 shows the calculations used to determine future water storage volume requirements for Lakeville. Water storage facilities should be capable of supplying the desired rate of fire flow for the required length of time during peak demands when the water system is already impacted by other uses and with the largest supply pump out of service. The calculations in Table 11 assume that maximum day demands are occurring on the system, storage volume is reduced by peak demands greater than firm supply pumping rate (i.e. equalization storage is expended), and the highest-capacity high service pump is out of service. There is an assumption that the firm well capacity is equal to or greater than the firm pumping capacity at the water treatment facility. It should be noted that the calculation is examining elevated storage capacity only, since the storage capacity at the water treatment plant is accounted for by the firm high service pumping rate that draws from the below-grade clearwell. Because there are multiple pressure zones in Lakeville served by elevated storage, it is important to evaluate the needs of each zone separately. In the case of Lakeville, two of the elevated storage tanks are in reduced pressure zones (Air Lake and the CMF Composite). Water from these tanks is not available to serve the needs of the normal pressure zone. Table 11 indicates that there could be a shortage of elevated storage capacity to meet current needs of the normal pressure zone. The water demands used for current needs are those projected for 2013 based on population as discussed in Section 4 of this report. Ultimately, the calculations in Table 11 indicate a need for an additional 1.5 million gallons of elevated storage to serve the normal pressure zone. This could be constructed instages, or as a single tank. There would be significant cost savings by constructing a single tank with 1.5 million gallons in capacity. Storage need in the reduced pressure zones (Air Lake and Valley Park) is more a function of flow distribution than capacity, therefore individual calculations similar to those in Table 11 are not included for these zones. The reduced zones are served by multiple PRVs with ample capacity to maintain water levels in the Air Lake and Valley Park tanks provided there is enough storage on the system as a whole. The storage tanks on the high zone are capable of serving the reduced zones as well. The presence of elevated storage in these zones helps to control PRV operation and to provide a local reservoir of water for fire demands. The current Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 25 storage capacity in the reduced zones is sufficient to serve these functions through ultimate build-out of the water distribution system. Table 11-Elevated Storage Needs 2013 Projected Ultimate Normal Zone Normal Zone DemandDevelopment2013Ultimate A Average Daily Water Use in gpd7,000,00010,478,4004,900,000 7,335,000 B Maximum / Average Day Ratio3.03.03.03.0 Maximum Day Water Use in gpd C (A x B)21,000,00031,435,20014,700,00022,005,000 D Maximum Day Water Use in gpm14,58321,83010,20815,281 Firm Pumping Supply Capacity in E gpm*11,00022,0006,625 15,451 F ISO Design Fire Fighting Rate in gpm3,5003,5003,5003,500 G Fire Fighting Duration in Hours3333 Design Fire Fighting Volume in gal. H (F x G x 60min/hour)630,000630,000630,000630,000 Total Coincident Demand in gpm I (D + F)18,08325,33013,70818,781 Required Draft from Storage in gpm J (I-E)7,0833,3307,0833,330 Adjusted Fire Fighting Storage in gal K (G x 60 min/hr x J)1,275,000599,4001,275,000599,445 Equalization Storage in gal L (D x 225)**3,281,2504,911,7502,296,8753,438,281 M Total Storage Need in gal (K + L)4,556,2505,511,1503,571,8754,037,726 N Existing Elevated Storage in gallons4,750,0002,750,000 * Firm pumping capacity represents treatment facility high service pumping capacity with largest pump out of service. Calculations for Main Zone storage use firm pumping capacity of high service pumps minus estimated demand to reduced pressure zones. **Equalization storage volume based on estimated water use in excess of maximum day demand rate over the course of the maximum day. Estimated here based on typical diurnal demand curve peaking. Constructing too much storage capacity on a system can be problematic if it creates excessive water residence times on the distribution system - especially during low demand periods. However, the average day for Lakeville is currently in excess of the projected ultimate storage need for the community. Because of this, water residence times are not expected to exceed recommended values as water in the towers can be turned over on a daily basis with current operations. It is recommended that an additional 1.5 MG storage tank be constructed to serve the main pressure zone in the near future. Given the time it takes for planning, design, bidding, and construction, the earliest a new elevated water storage tank could be online is likely 2016. It is placed on the capital improvement plan later in this report as such. 5.2.1Elevated Storage Location In addition to overall storage capacity, storage location becomes important for the hydraulic operation of the distribution system. For example, if storage is located too far from properties with high fire flow needs, the distribution system would need to be sized excessively in order to get the high flow rates from the storage location to the point of use. Elevated storage tanks Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 26 also are often designed to balance hydraulically on the overall distribution system under peak operating demands. This is the case in Lakeville, where the water levels in one tank (Dakota Heights) is used to control operation of the high service pumps at the water treatment facility. The other elevated tanks are filled and drained based on their hydraulic connectivity to the high service pumps and the Dakota Heights standpipe. As discussed in Section 3.4, under high demand conditions, the water levels in the North Park and Fairfield tanks are observed to drop below the level of the Dakota Heights tank. Because they are separated from the high service pumps and the Dakota Heights tank by piping with frictional resistance, it is not possible to fill the more remote tanks as quickly when demands are high on the system. Additional pumping tends to fill the Dakota Heights tank first. Adding pumping capacity would therefore tend to overflow Dakota Heights before filling the more remote tanks. For this reason, the hydraulic balance of a future elevated tank on the normal pressure zone should be taken into consideration. A location for the new tank should be chosen where possible to allow equalization of water levels without having to size water mains excessively. Two alternate locations for anelevated tank were evaluated from a hydraulic standpoint - for hydraulic balance and the transmission of fire flows. A potential location for a new tower was identified in Cherryview Park, located near the intersection of Dodd Blvd. and 175th St. A water tower at this location was modeled under existing system demands with existing distribution facilities, as well as with ultimate projected demands and distribution facilities. A second location near the intersection of Highview Ave. and 190th St. was modeled in the existing system and ultimate system scenarios to evaluate the difference in system hydraulic balance between the two locations. The modeling analysis for each location included extended period simulation (EPS) under varying system conditions. The model utilizes demand pattern curves to adjust demand over the course of a day to approximate variations in water use. Controls were set up on the high service pumps at the water treatment plant to turn the pumps on and off based on water tower levels. The existing controls for the high service pumps were entered into the model during the last Comprehensive Water Plan, and are represented in Table 12. For the purposes of this analysis, it was assumed that Wells 3 and 7 remained off. Because the greatest system imbalances occur under peak demand conditions, the EPS analyses were run under both average day and maximum day demand conditions on the system. It was assumed for all maximum day conditions that the control points were modified to maintain water levels in the tanks near full to avoid any severe tank draining events. The controls used in the model for this purpose are shown in Table 13. Table 12–Existing High Service Pump Controls as Modeled Hydraulic Design HSP Controlling Hydraulic Corresponding Corresponding Grade Capacity No.TowerGrade OnLevel OnLevel Off Off(gpm) 1Dakota Heights1212501220585700 2Dakota Heights1222601227652825 3Dakota Heights1224621229672825 4Dakota Heights1226641229678300 Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 27 Table 13–Modified Maximum Day High Service Pump Controls as Modeled Design HSP Hydraulic Corresponding Hydraulic Correspondin Controlling TowerCapacity No.Grade OnLevel OnGrade Offg Level Off (gpm) 1Dakota Heights1226641229675700 2Dakota Heights1226641229672825 3Dakota Heights1226641229672825 4Dakota Heights1226641229678300 Similarly, controls for average day demand conditions were modified to allow fluctuation in tank water levels to achieve tank turn-over and prevent water stagnation. The modified average day controls are listed in Table 14. In an EPS analysis, the computer model generates results over time for system conditions such as flow rates, pressures, pump status, and tower water levels. The EPS was run for three consecutive days under maximum day demands and average day demands to observe how the water tower levels are predicted to fluctuate. The results of the EPS analysis of each location with the existing distribution system / demands, and with the ultimate planned distribution system / demands, are shown in Figures 12 and 13. The results in Figure 12 indicate that the Cherryview Park location is hydraulically disconnected from Dakota Heights and the water treatment plant. Under existing system maximum day demands, the Cherryview Park tank lags the Dakota Heights tank by as much as 15 feet during high demand conditions. This is further exacerbated under the ultimate maximum day demand conditions. Under average day demand conditions, all of the tanks equalize relatively well. Table 14-Modified Average Day High Service Pump Controls as Modeled Hydraulic Design HSP Corresponding Hydraulic Corresponding Grade Capacity Controlling Tower No.Grade OnLevel OnLevel Off Off(gpm) 1Dakota Heights1205431229675700 2Dakota Heights1210481229672825 3Dakota Heights1210481229672825 4Dakota Heights1215531229678300 The Highview and 190th Street location has a much greater hydraulic connection to Dakota Heights and the water treatment plant, as indicated in Figure 13. For the existing system maximum day demand scenario, with high service pump controls modified to keep the tanks near full, a tank at the proposed location is observed to fill and remain full during the course of the simulation. The tank fills quickly due to its proximity to the water treatment plant high service pumps, and drains slowly due to its distance from system demands. The model indicates that this situation can be fixed if the piping is in place between the water tower and the existing distribution system along 190th Street, and between 190th Street and 195th Street east of Dodd Blvd., as shown in Figure 9. With this piping in place, a valve can be closed in the short term between the north-south main east of Dodd Blvd. and the existing distribution system connection point. This would force the flow of water to come from the Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 28 south, better balancing the new water tower with the existing system. The modeled tower levels under these conditions are shown in Figure 14. With ultimate system maximum day demands, the Highview and 190th Street location tends to track Dakota Heights closely, indicating good hydraulic balance. Therefore, a tank at this location will tend to become better balanced on the system as demands increase to the east. Based on the findings of the hydraulic analysis, a future elevated tank would be better situated hydraulically near the vicinity of Highview Avenue and 190th Street. The modeling shows potential challenges with tank operations at that location as discussed. These challenges can be overcome through a temporary valve closure on the proposed connecting trunk main, and are expected to correct over time with increasing demands to the east of the proposed tank location. The alternate location considered at Cherryview Park has limitations that are more difficult to overcome operationally, and that will be exacerbated over time as demands increase on the system. In addition to system hydraulics, there are other important considerations when selecting a site for an elevated water storage tank. Common considerations include the following: Ground elevation: higher ground elevation results in a less expensive and less intrusive elevated tank to reach the necessary hydraulic grade of the water level in the tank. Existing water main infrastructure that can be used to connect the tank hydraulically to the water system. Soil conditions: water tank foundations have high loadings, and poor soil conditions can result in significant soil correction requirements or deep foundations on piles - either of which could add significantly to the cost of the project. Airport structure height restrictions. Visual impact to neighbors and / or shadowing. Availability and cost of land. The first two of these items were examined as part of this study. The remaining items should be evaluated more thoroughly during preliminary design for the new water storage tank. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 29 Figure 12 – Extended Period Simulation Results for the Future Tower at Cherryview Park Tower at Cherryview - MD Modified Controls - MD EPS 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 North Park HGL 1,200.00 Dakota Heights HGL Fairfield HGL 1,195.00 Cherryview HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Tower at Cherryview- MD Modified Controls - 40 MGD HSP - Ultimate MD Demands / Trunk System 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 1,200.00 North Park HGL Dakota Heights HGL 1,195.00 Fairfield HGL Cherryview HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Tower at Cherryview - AD Modified Controls - Existing System AD Demands 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 North Park HGL 1,205.00 Dakota Heights HGL 1,200.00 Fairfield HGL Cherryview HGL 1,195.00 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 30 Figure 13 – Extended Period Simulation Results for the Future Tower at Highview Ave. and 190th St. Tower at Highview / 190th - MD Modified Controls - Existing System MD Demands 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 North Park HGL 1,200.00 Dakota Heights HGL 1,195.00 Fairfield HGL Highview HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Tower at Highview / 190th - MD Modified Controls - 40 MGD HSP - Ultimate MD Demands / Trunk System 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 North Park HGL 1,200.00 Dakota Heights HGL Fairfield HGL 1,195.00 Highview HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Tower at Highview / 190th - AD Modified Controls - Existing System AD Demands 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 North Park HGL 1,200.00 Dakota Heights HGL Fairfield HGL 1,195.00 Highview HGL 1,190.00 0 10 20 30 40 50 60 70 Time of Simulation (hr) Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 31 Figure 14 – Extended Period Simulation Results with Modified Piping to New Tower Tower at Highview / 190th - MD Modified Controls - MD EPS 1,235.00 1,230.00 1,225.00 1,220.00 1,215.00 1,210.00 1,205.00 North Park HGL 1,200.00 Dakota Heights HGL Fairfield HGL 1,195.00 Highview HGL 1,190.00 0 10 20 30 40 50 60 70 80 Time of Simulation (hr) Ground elevation is an important factor as the height of the storage tank structure is determined by the system hydraulic grade and the ground elevation. To function on the normal pressure zone, the overflow hydraulic grade of the new tank needs to be set at 1230 feet. The ground elevation at Cherryview Park is approximately 1020 feet. This results in a tower height of at least 210 feet. This is a very tall structure, which adds to the cost and the visual impact to the surrounding neighborhood. By comparison, the site near Highview and 190th St. has a ground elevation of approximately 1090, resulting in a tower that is 140 feet tall. The estimated cost impact of additional structure height for a water tower is approximately $10k to $15k per foot. Therefore, the Cherryview Park location could add $1M in construction cost to the project. Given that system hydraulics and ground elevation favor the site near Highview and 190th Street, it is recommended that this site be further investigated for the construction of an elevated water storage facility. Given the difficulties posed by the Cherryview Park site, it is recommended that the City abandon that site for an elevated tank in the normal pressure zone. If property is identified in the area of Highview and 190th Street, further investigation is recommended prior to final design for the tank. To further evaluate the chosen site, soil borings are recommended along with a geotechnical review of the soils at the site. This will help to evaluate foundation requirements for the tank, and allow further refinement of the estimated project cost. This could be conducted as part of preliminary design for the new tank. In addition to the geotechnical review, a review of the site for FAA clearances should be conducted and the permitting process started as necessary to construct the tower at the chosen location. It is also common to have “virtual reality imaging” (VRI) of the new tower at the site completed, along with a shadow study, to gain public acceptance of the project. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 32 5.3Trunk Water Main As development progresses into the expansion areas, a trunk water main system must be constructed to deliver adequate flows for various conditions including emergency fire flow. The majority of trunk water main improvements identified are outside of the existing service area and should be constructed as development occurs. Figure 9 presented the proposed preliminary routing of trunk water mains to serve future development areas. Actual main routing will depend on a variety of local factors as individual projects progress. This map should be seen as a recommendation for the general hydraulic capacity of the distribution system as it is extended to serve new development. Generally speaking, the trunk main layout is comprised of a gridded network of 24-inch, 16-inch, and 12-inch diameter water mains. 5.4Distribution System Back-Pressure with Expansion of High Service Pumping Facilities Based on the analysis of the Water Treatment Facility Expansion Study that is being completed concurrent with this study, additional pumping capacity at the water treatment plant will be added over the course of the next 20 - 30 years. A hydraulic modeling analysis was conducted to evaluate the impact of additional high service pumping on distribution system pressures, which in turn impacts the performance of the high service pumps. The hydraulic grade at the plant was calculated with incremental pumping increases to evaluate changes. The calculations were performed in the hydraulic model under maximum day conditions with high service pump flow rates as indicated in Figure 15. The pump performance curves for the existing high service pumps should be reviewed to evaluate the impact to pump performance given these expected hydraulic conditions. Figure 15 – Distribution System Hydraulic Impacts from Added High Service Pumping 1,350.00 1,300.00 1,250.00 1,200.00 1,150.00 1,100.00 Ground Elevation HGL - Existing HSPs 1 & 2 at 10,000 gpm 1,050.00 HGL - Existing HSPs 1, 2, & 3 at 13,000 gpm HGL - Ultimate HSPs at 23,000 gpm HGL - Ultimate HSPs at 28,000 gpm 1,000.00 0 1000 2000 3000 4000 5000 Distance from WTP (ft) Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 33 5.5System Pressures After Improvements The future average day system pressures after all recommended improvements are represented in Figure 16. Peak hour pressures are shown in Figure 17. The modeling results indicate that the trunk main capacities as modeled will allow the distribution of flow under projected peak hour demands without significant losses due to friction. In addition, the division into pressure zones of the future expansion area in the east- central portion of the city was designed to maintain static system pressures within acceptable operating ranges where possible. The average day and peak hour conditions represent a range of expected typical operating pressures. 5.6Available Fire Flows After Improvements The future available fire flows under maximum day demands are represented in Figure 18. These flows represent the future expected available fire flows with all recommended system improvements. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 34 Legend Static Pressure (psi) 160thStW 0 - 10 161stStW 11 - 20 21 - 30 165thStW 31 - 40 41 - 50 51 - 60 170thStW 61 - 70 71 - 80 81 - 90 91 - 100 101 - 110 111 - 120 121 - 130 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Ultimate System COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Average Day PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 16 Lakeville, Minnesota Source: City of Lakeville www.sehinc.com Pressures Legend Static Pressure (psi) 160thStW 0 - 10 161stStW 11 - 20 21 - 30 165thStW 31 - 40 41 - 50 51 - 60 170thStW 61 - 70 71 - 80 81 - 90 91 - 100 101 - 110 111 - 120 121 - 130 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Ultimate System COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Peak Hour PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 17 Lakeville, Minnesota Source: City of Lakeville www.sehinc.com Pressures Legend Available Fire Flow at 20 psi Residual (gpm) 160thStW 0 - 500 161stStW 501 - 1000 1001 - 1500 165thStW 1501 - 2000 2001 - 2500 2501 - 3000 170thStW 3001 - 3500 > 3500 190thStW 195thStW 195thStW 202ndStW 210thStW 02,0004,0008,000 Feet This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Project: LAKEV 123875 Ultimate System COMPREHENSIVE WATER PLAN UPDATE Print Date: 06/25/2013 3535 VADNAIS CENTER DR. Figure ST. PAUL, MN 55110 Maximum Day PHONE: (651) 490-2000 Map by: JDC FAX: (888) 908-8166 Projection: Dakota County TF: (800) 325-2055 18 Lakeville, Minnesota Source: City of Lakeville www.sehinc.com Available Fire Flow 6.0Capital Improvement Plan One of the main objectives of this study was to develop a long-range Capital Improvement Plan (CIP) for water system facilities. The CIP provides information on the anticipated cost and timing of future improvements. 6.1Estimated Cost of Water System Improvements The estimated costs of future trunk water main extensions, storage and well facilities, and raw water main are shown in Tables 15, 16, and 17 respectively. Costs for future water treatment facility improvements are being provided separately in a concurrent facility plan completed by Black and Veatch. Table 15–Trunk Water Main Extensions Trunk Oversize Total Trunk Diameter (in)Length (ft) Cost ($/ft)Oversize Cost 1283,42810$834,000 1644,36630$1,331,000 201,32050$66,000 246,26370$438,000 Total Trunk Oversize Estimated Cost$2,669,000 Estimated Cost per Year if All Constructed Between 2014 and $157,000 2030 Table 16–Water Supply and Storage Facilities YearConstruction ActivityEstimated Project Cost 2014Well 20, Well 21$1,400,000 2015Well 22, Well 23$1,400,000 20161.5 MG Main Zone Elevated Storage Tank$3,000,000 2017Well 24, Well 25$1,400,000 2019Well 26$700,000 2021Well 27$700,000 2024Well 28$700,000 2029Well 29$700,000 Total Estimated Costs for Water Supply and Storage $10,000,000 Facilities Table 17–Raw Water Transmission Main Total Raw Water Diameter Unit Cost YearWell ServedLength (ft)Transmission Main (in)($/ft) Cost 2015Wells 26 / 27243,000$130$390,000 2019Wells 26 / 27245,745$130$746,850 2024Well 28162,700$90$243,000 2029Well 29162,400$90$216,000 Total Estimated Costs for Raw Water Transmission Main$1,595,850 Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 38 The cost estimates are reported in 2013 dollars. The costs can be related to the value of the Engineering News Record (ENR) Index for Construction Costs (U.S. 20 City Average 1913 = 100) of approximately 9542 (June 2013). Future changes in this index can be used as a preliminary gauge of cost changes in the proposed facilities. It should be noted that costs for water system equipment such as elevated water storage tanks and wells can fluctuate over time to a greater degree than the overall construction cost index. Therefore, engineering judgment should be employed when adjusting and refining these costs, as the related improvements become part of the City’s active short-range capital improvement plan. 6.1.1Trunk Water Main Oversize Costs Right-of-way costs that may be related to the final construction are not included. Trunk facilities are defined as all pipes greater than 8 inches in diameter. The City’s cost, oversize cost, is only a part of the total cost and is defined by the difference in cost between the actual improvement and a residential equivalent improvement (defined as an 8-inch water main of equal length). 6.1.2Wells Estimates for well construction include a test well, production well construction, pump and motor installation, pitless unit installation, on site water main, hydrant, paving, meter vault, electrical and controls. The value also includes an estimate for engineering and administrative costs. 6.1.3Elevated Water Storage Tank The cost presented is representative of current costs for an elevated steel or composite single pedestal tank with 1.5 million gallons in storage capacity. A tank height of 160 feet is assumed, based on a ground elevation of 1070 ft. and an overflow elevation of 1230 ft. The estimate includes associated site work. The value also includes an estimate for engineering and administrative costs. 6.1.4Raw Water Transmission Lines Right-of-way costs that may be related to the final construction are not included. The transmission line costs also do not include well site main installation as those costs are addressed in the individual well cost estimates. The value includes an estimate for engineering and administrative costs. 6.1.5Water Treatment Facility Improvements Planning and cost estimates for future water treatment facility improvements are not included in this report as they are being addressed in a concurrent facility plan completed by Black and Veatch. 6.2Capital Improvement Plan Timeline Table 18 summarizes estimated annual costs (in 2013 dollars) for the recommended future improvements. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 39 Table 18–Capital Improvement Plan Timeline Raw Water 1.5 MG Trunk Main YearTransmission Elevated WellTotal Extension MainStorage Tank 2014$157,000$1,400,000$1,557,000 2015$157,000$1,400,000$1,557,000 2016$157,000$3,000,000$3,157,000 2017$157,000$1,400,000$1,557,000 2018$157,000$157,000 2019$157,000$1,136,850$700,000$1,993,850 2020$157,000$157,000 2021$157,000$700,000$857,000 2022$157,000$157,000 2023$157,000$700,000$857,000 2024$157,000$243,000$400,000 2025$157,000$157,000 2026$157,000$700,000$857,000 2027$157,000$157,000 2028$157,000$157,000 2029$157,000$216,000$373,000 2030$157,000$157,000 6.3Trigger Chart The timing of future water improvements will be influenced by a number of parameters. Items such as development pressure in specific areas, aging facilities and/or facilities which are undersized, availability of funds, etc. all play a role in the timing of future improvements. Because of the factors involved, it is difficult to accurately predict the timing of future improvements, especially those which may occur far into the future. A trigger chart is presented in Figure 19, which correlates well and storage improvements to system demands. Future capital improvement planning can thus be tied to actual system demands and the timeline adjusted as necessary. Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 40 Figure 19 – Water System Capital Improvement Trigger Chart 40.000 35.000 30.000 25.000 Projected Average Day Demand - Metropolitan Council Population (MGD) 20.000 Projected Average Day Demand - 2% Growth (MGD) Projected Maximum Day Demand - Metropolitan Council Population (MGD) 1.5 MG Projected Maximum Day Demand - 2% Growth (MGD) Elevated 15.000 Firm Capacity (MGD) Storage Total Capacity (MGD) Tank 10.000 5.000 0.000 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035 2037 Year Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 41 Appendix A Raw Water System Analysis Comprehensive Water Plan UpdateLAKEV 123875 City of LakevillePage 42 MEMORANDUM TO:Zach Johnson, Chris Petree, Ken Seuer FROM: John Chlebeck DATE: August 5, 2013 RE:Raw Water System Analysis SEH No. LAKEV 123875 14.00 The raw water supply system, including wells and transmission main, for Wells 4, 2, 19, 14, 12, 10, and 18 was analyzed for capacity to add additional wells to the line. This included a review of existing aquifer data and pumping test data to make an estimate of well interference and well spacing requirements for future wells to be constructed in the Jordan Aquifer. In addition, a computer hydraulic model of the supply and transmission system was constructed to look at potential limitations on the existing transmission line in its ability to convey additional flow from future wells. Hydrogeologic Data Review Existing data was reviewed to assess aquifer capacity and potential interference from future Wells 20, 21, and 22 at locations along the transmission line between Well 19 and Well 14. This included a review of the Dakota County Geologic Atlas, along with pump testing information from Wells 12, 14, and 19. The pump test data allowed for an estimate of aquifer transmissivity. The data was also used to develop functions for drawdown vs. time pumped and drawdown vs. distance from the pumped well. Figure 1shows drawdown estimates as a function of distance from a typical well in that part of the Jordan aquifer. The curve represents drawdown at 1000 hours of continuous pump time at 1200 gpm, and is based on the pump test data from Well 19. This shows some level of influence between the wells. To relate this to Lakeville's wells, the proposed Well 21 location is about 1800 ft from Well 14. Therefore, the new well is estimated to draw down Well 14 by approximately 7-8 feet when pumping at 1200 gpm for 1000 hours. This will have some impact on the capacity of Well 14, and should be looked at in more detailbefore the new well is drilled at that location. The pump setting for Well 14 appears to be at 300 ft. below ground surface (according to the well log). The current pumping water level in the well is in the range of 180 - 210 ft below ground surface. Therefore, there doesn't appear to be a risk of drawing down the aquifer to a point that is critical to pump operation. However, the extra drawdown will reduce suction pressure on the pump and thus cause the pump to operate at lower capacity. It has been report by City staff that the wells do experience greater drawdown during summer months when relatively high volumes are pumped from the Jordan aquifer. This agrees with the findings of this analysis, and drawdown at existing wells can be expected to be increased with the addition of new Jordan wells. This should be accounted for during design of new wells, and the impact on existing wells should also be examined more closely before constructing new Jordan wells. Short Elliott Hendrickson Inc., 3535 Vadnais Center Drive, St. Paul, MN 55110-5196 SEH is an equal opportunity employer | www.sehinc.com | 651.490.2000 | 800.325.2055 | 888.908.8166 fax Raw Water System Analysis August 5, 2013 Page 2 Figure 1 - Estimated Drawdown with Distance from Pumping Well It should be noted that this analysis is based on pumping tests using the pumping well as the observation well. It is recommended to have at least one non-pumping observation well for a pumping test that is used to estimate aquifer properties. The transmissivity calculated from the pumping test data falls in the middle of the range of expected values for the area, based on the Dakota County Geologic Atlas. Therefore, the results are considered a reasonable estimate for planning purposes. Transmission System Hydraulic Analysis The hydraulic analysis of the raw water line that runs along Dodd Blvd. was the second part of this analysis. A model of the raw water system was constructed to look at the effects on transmission main headloss, velocity, and hydraulic grade from adding additional wells to this line. The results are shown in Figure 2. Raw Water System Analysis August 5, 2013 Page 3 Figure 2 - Hydraulic Grade Impact from New Wells The figure shows the impact to hydraulic grade (pressure) along the line with the addition of future wells. The current hydraulic grade was calculated assuming Wells 4, 2, 19, 14, 12, 10, and 18 are pumping into the line at their design capacities, and that the line discharges to the water treatment plant at approximately ground elevation (1089 ft MSL). This is probably a conservative analysis as all of those wells are not likely to operate at their design capacitiessimultaneously. The hydraulic analysis shows that there is likely to be an impact to the hydraulic grade in that transmission line from the added pumping of Wells 20, 21, and 22. Each of these new wells was assumed to have a design capacity of 1200 gpm. With the addition of each well to the model, the hydraulic grade upstream of the proposed well locations is increased by 5-10 feet. This will result in an additional 5-10 feet of back-pressure on the wells, which will also tend to decrease the production capacity of the wells. The impact is expected to be greatest to Wells 4, 2, and 19. Wells that are closer to the water treatment plant will have less impact. Figure 3 shows the impact to hydraulic grade if all wells are operatingat 1000 gpm (except Well 18 at 600 gpm). This may be closer to the actual hydraulic impact from simultaneous pumping of the wells since it is reported that the wells operate at lower rates during the summer when they are pumped simultaneously. This is a result of both aquifer drawdown and system backpressure on the well pumps. Raw Water System Analysis August 5, 2013 Page 4 Figure 3 - Hydraulic Grade Impact with Reduced Pumping Rates at Wells The reason for the increased hydraulic grade in the transmission main is the increased head loss caused by increased flow in the line. Figures 4, 5, and 6 (attached) indicate velocities in the transmission main under varying pumping conditions. Generally, velocities up to 10 feet per second are acceptable in a transmission main. However, increased velocity will result in additional frictional head losses that will increase back pressure on the existing well pumps and cause a reduction is production capacity. Preliminary Wellhead Protection Areas for Wells 20, 21, and 22 It is recommended during the site selection for a new well to evaluate potential contaminant sources around the well site and other potential risks associated with well use. Figure 7 shows preliminary wellhead protection areas around the proposed locations for Wells 20, 21, and 22. Based on the confined nature of the aquifer, estimated well pumping rates, and estimated aquifer porosity, the preliminary wellhead protection area boundary is calculated to be a circle with a diameter of approximately 4500 ft., following recommended methods from the Minnesota Department of Health. There is one petroleum storage tank from the MPCA database that is within the preliminary wellhead protection area for future Well 22. This site is identified as Cherryview Elementary School. There are also some commercial small quantity hazardous waste generators along Dodd Blvd. within the preliminary wellhead protection area for Well 20. These include a CVS pharmacy, a medical clinic, and a Raw Water System Analysis August 5, 2013 Page 5 dental office. None of these are thought to be immediate threats to future wells in the locations shown, especially given the protected nature of the Jordan aquifer. There are 3 private wells located in close proximity to the future locations identified for Wells 21 and 22. These wells are all identifiedas St. Peter sandstone wells, and their well logs are attached to this document for reference. The St. Peter is known to have hydraulic connection with the Jordan aquifer in parts of Dakota County, though most commonly they are hydraulically separated by a shale layer at the base of the St. Peter formation. There is a possibility for some influence on the private wells from municipal pumping in the Jordan, however. The City should be prepared for that possibility. Better confirmation could be obtained during recommended test pumping prior to the construction of a new well in the area. Conclusions The analysis conducted for this study shows that future wells along the Dodd Blvd. raw water transmission main will create some level of impact to the existing wells. This impact includes drawdown from interference in nearby wells, and increased back-pressure from head loss in the transmission main. The degree of impact will be dependent on the simultaneous pumping rates in the existing and future wells. Itis possible that all of the wells, including future Wells 20, 21, and 22, could be operated around 1000 gpm with the existing pumps and motors. The specific pump curves shouldbe reviewed to get a more accurate estimate of how the pumps will respond to the increased discharge pressure and reduced suction pressure. This should be done during preliminary design of any future well to ensure that impacts to existing facilities are not prohibitive to achieving the planned capacity of the new well. The proposed location for Well 21 (as currently shown in the plans for water main construction along Dodd Blvd. planned for this year) is thought to be a viable location for a new municipal well. The alternate location discussed at our meeting on March 1 (in the SE quadrant of the Highview Ave. and Dodd Blvd. intersection) is also viable for development of a well. In fact, it is possible that wells could be constructed at both locations. The two sites are approximately 1000 feet apart, and there would be an interference effect between the two wells, but there is a strong likelihood that two municipal wells could be supported in the Jordan Aquifer at that location. For that reason, some consideration should be given to stubbing the raw water transmission main across Dodd Blvd. to the alternate well location during the planned reconstruction activities this year. There are apparent impacts to the existing wells with the addition of each new well along the transmission main. These impacts need to be evaluated in more detail prior to the construction of any new well. This evaluation should include aquifer test pumping at each location being considered, to evaluate interference with existing wells as well as local aquifer properties. In addition, a detailed review of existing well pump performance characteristics should be completed to provide a better estimate of the impacts that can be expected with greater pumping from the aquifer. jdc Attachment c:Miles Jensen, SEH c:\projects\lakeville water system plan update\report\final\appendix a - raw water system analysis.docx Legend 165TH ST W 165TH ST W Pipe DIAMETER 4 6 170TH ST W 8 10 12 16 174TH ST W 20 24 30 185TH ST W Feet 02,0004,000 Project: LAKEV 123532 Raw Water System Velocities - Existing Wells 3535 VADNAIS CENTER DR. Figure Print Date: 03/21/2013 ST. PAUL, MN 55110 PHONE: (651) 490-2000 Map by: John Chlebeck Water System Plan Update FAX: (651) 490-2150 4 Projection: Lambert Conical Ft WATTS: 800-325-2055 Source: City of Lakeville, SEH Inc. www.sehinc.com Lakeville, Minnesota This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Legend 165TH ST W 165TH ST W Pipe DIAMETER 4 6 170TH ST W 8 10 12 16 174TH ST W 20 24 30 185TH ST W Feet 02,0004,000 Project: LAKEV 123532 Raw Water System Velocities - Wells 20, 21, and 22 Added 3535 VADNAIS CENTER DR. Figure Print Date: 03/21/2013 ST. PAUL, MN 55110 PHONE: (651) 490-2000 Map by: John Chlebeck Water System Plan Update FAX: (651) 490-2150 5 Projection: Lambert Conical Ft WATTS: 800-325-2055 Source: City of Lakeville, SEH Inc. www.sehinc.com Lakeville, Minnesota This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. Legend 165th St W Pipe DIAMETER 6 8 10 12 170th St W 16 20 24 30 4.3 ft/s 185th St W Feet 02,0004,000 Project: LAKEV 123532 Raw Water System Velocities - Reduced Flow 3535 VADNAIS CENTER DR. Figure Print Date: 08/05/2013 ST. PAUL, MN 55110 PHONE: (651) 490-2000 Map by: John Chlebeck Water System Plan Update FAX: (651) 490-2150 6 Projection: Lambert Conical Ft WATTS: 800-325-2055 Source: City of Lakeville, SEH Inc. www.sehinc.com Lakeville, Minnesota This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. 170th St W Legend Pipe Well 25 Diameter 6 8 10  12 16 20   24 30 A A@ @ A @ Well 20 Preliminary Wellhead Protection Area A @ Municipal Wells Existing Well Future PDCJ Well A @ Future FIG Well Well 22  Well 21 MPCA WIMN Site  Feedlot  A @ Well 23 Hazardous Waste, Small to Minimal QG  Leak Site  Tank Site Well 14 4.3 ft/s A @ Well 12 Well 10 Feet 01,5003,000 Well 18 Project: LAKEV 123532 Preliminary Wellhead Protection Areas 3535 VADNAIS CENTER DR. Figure Print Date: 08/06/2013 ST. PAUL, MN 55110 PHONE: (651) 490-2000 Map by: John Chlebeck Water System Plan Update FAX: (651) 490-2150 7 Projection: Lambert Conical Ft WATTS: 800-325-2055 Source: City of Lakeville, SEH Inc. www.sehinc.com Lakeville, Minnesota This map is neither a legally recorded map nor a survey map and is not intended to be used as one. This map is a compilation of records, information, and data gathered from various sources listed on this map and is to be used for reference purposes only. SEH does not warrant that the Geographic Information System (GIS) Data used to prepare this map are error free, and SEH does not represent that the GIS Data can be used for navigational, tracking, or any other purpose requiring exacting measurement of distance or direction or precision in the depiction of geographic features. The user of this map acknowledges that SEH shall not be liable for any damages which arise out of the user's access or use of data provided. MINNESOTA DEPARTMENT OF HEALTH 1999/01/28 Unique No. 00251988Update Date WELL AND BORING RECORD County NameDakota1999/01/28 Entry Date Minnesota Statutes Chapter 1031 Well Depth Depth Completed Date Well Completed Township Name Township Range Dir Section Subsection ft.300ft. 300 11420W 8DDADCA Non-specified Rotary Well NameDrilling Method H130271 Well Hydrofractured? H130271Drilling Fluid Contact's Name YesNo Fromft. ft. to APPLE VALLEY MN Domestic Use Hole Diameter YesN Casing Drive Shoe? Casing Diameter Weight(lbs/ft) GEOLOGICAL MATERIAL COLOR HARDNESS FROM TO 5249in. toft GLACIAL DRIFG 0120 PLATTEVILLE FLOATER ? 120150 ST. PETER SANDSTONE 150248 ST. PETER SANDSTONE 248340 ft. Fromft. to340 Screen N249 Open Hole MakeType Land surface1999/01/28 Date Static Water Level130ft. from PUMPING LEVEL (below land surface) hrs. pumpingg.p.m. ft. after Well Head Completion Pitless adapter mfr Model Casing Protection 12 in. above grade At-grade(Environmental Wells and Borings ONLY) No Well grouted? Yes Grouting Information Nearest Known Source of Contamination type ft.direction Well disinfected upon completion?YesNo Not Installed Pump Date Installed Mfr name ModelVolts HP g.p.m Drop Pipe LengthCapacity ft. REMARKS, ELEVATION, SOURCE OF DATA, etc. Type WELL SEALING NO. H-130271. Any not in use and not sealed well(s) on property?No Yes GAMMA LOGGED 1-28-1999. No Yes Was a variance granted from the MDH for this Well? 1063 USGS Quad:Farmington Elevation: Lic. Or Reg. No.MGS Well CONTRACTOR CERTIFICATION Aquifer:OSTP Alt Id: License Business Name Report Copy Name of Driller HE-01205-06 (Rev. 9/96) MINNESOTA DEPARTMENT OF HEALTH 1991/08/14 Unique No. 00124316Update Date WELL AND BORING RECORD County NameDakota1990/03/30 Entry Date Minnesota Statutes Chapter 1031 Well Depth Depth Completed Date Well Completed Township Name Township Range Dir Section Subsection ft.255ft.1976/09/18 255 11420W 8DDDADA Well NameDrilling Method DAVID ERSTAD Well Hydrofractured? Drilling Fluid YesNo Fromft. ft. to Domestic Use Hole Diameter YesN Casing Drive Shoe? Casing Diameter Weight(lbs/ft) GEOLOGICAL MATERIAL COLOR HARDNESS FROM TO 4224in. toft SOIL BLACK 03 CLAY RED SOFT 37 CLAY YELLO SOFT 734 CLAY BLUE SOFT 34100 ft. Fromft. to255 Screen N224 Open Hole CLAY + GRAVEL BROW HARD 100126 MakeType CLAY YELLO SOFT 126134 GRAVEL BROW HARD 134153 SANDSTONE YELLO SOFT 153187 SANDSTONE GRAY SOFT 187224 Land surface1976/09/18 Date Static Water Level129ft. from SANDSTONE WHITE HARD 224255 PUMPING LEVEL (below land surface) hrs. pumpingg.p.m. 12915ft. after Well Head Completion Pitless adapter mfr Model Casing Protection 12 in. above grade At-grade(Environmental Wells and Borings ONLY) No Well grouted? Yes Grouting Information Nearest Known Source of Contamination type ft.direction 85SDF Well disinfected upon completion?YesNo Not Installed Pump Date Installed Y Mfr name FAIRBANKS MORSE Volts Model230 7511HP0.75 g.p.m Drop Pipe LengthCapacity ft.10 165 REMARKS, ELEVATION, SOURCE OF DATA, etc. Type S 18026 DODD BLVD. W. Any not in use and not sealed well(s) on property?No Yes No Yes Was a variance granted from the MDH for this Well? 1053 USGS Quad:Farmington Elevation: Lic. Or Reg. No.19163 Well CONTRACTOR CERTIFICATION Aquifer:OSTP Alt Id: License Business Name Report Copy Name of Driller HE-01205-06 (Rev. 9/96) MINNESOTA DEPARTMENT OF HEALTH 1991/08/14 Unique No. 00124319Update Date WELL AND BORING RECORD County NameDakota1990/03/30 Entry Date Minnesota Statutes Chapter 1031 Well Depth Depth Completed Date Well Completed Township Name Township Range Dir Section Subsection ft.255ft.1976/10/20 255 11420W 8DDDDAC Well NameDrilling Method ROBERT PUGH Well Hydrofractured? Drilling Fluid YesNo Fromft. ft. to Domestic Use Hole Diameter YesN Casing Drive Shoe? Casing Diameter Weight(lbs/ft) GEOLOGICAL MATERIAL COLOR HARDNESS FROM TO 4228in. toft CLAY YELLO SOFT 019 CLAY BLUE SOFT 19113 GRAVEL BROW HARD 113127 CLAY YELLO SOFT 127139 ft. Fromft. to255 Screen N228 Open Hole GRAVEL BROW HARD 139141 MakeType SAND BROW SOFT 141173 LIMESTONE YELLO SOFT 173174 GRAVEL FINE BROW SOFT 174194 SANDSTONE YELLO SOFT 194208 Land surface1976/10/20 Date Static Water Level129ft. from SANDSTONE GRAY SOFT 208216 PUMPING LEVEL (below land surface) hrs. pumpingg.p.m. 12915ft. after SANDSTONE WHITE SOFT 216228 Well Head Completion SANDSTONE WHITE HARD 228255 Pitless adapter mfr Model Casing Protection 12 in. above grade At-grade(Environmental Wells and Borings ONLY) No Well grouted? Yes Grouting Information Nearest Known Source of Contamination type ft.direction 87SDF S Well disinfected upon completion?YesNo Not Installed Pump Date Installed Y Mfr name FAIRBANKS MORSE Volts Model230 10014HP1 g.p.m Drop Pipe LengthCapacity ft.11 155 REMARKS, ELEVATION, SOURCE OF DATA, etc. Type S 17965 HIGHVIEW AVE. Any not in use and not sealed well(s) on property?No Yes No Yes Was a variance granted from the MDH for this Well? 1044 USGS Quad:Farmington Elevation: Lic. Or Reg. No.19163 Well CONTRACTOR CERTIFICATION Aquifer:OSTP Alt Id: License Business Name Report Copy Name of Driller HE-01205-06 (Rev. 9/96)