Final Report Water Distribution System Master Plan...System Master Plan project to create a...

Final Report Water Distribution System

Master Plan

Submitted to

Forsyth County Water and Sewer Department

Draft December 2007 Final March 2008

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Contents

Contents ............................................................................................................................................... ii 1 Introduction .................................................................................................................................. 1-1 2 System Review ............................................................................................................................. 2-1

2.1 High Zone................................................................................................................... 2-4 2.2 Super High Zone ....................................................................................................... 2-5 2.3 Low Zone.................................................................................................................... 2-5

3 Population and Water Demand Projections............................................................................ 3-1 3.1 Population Projections.............................................................................................. 3-1 3.2 Existing Demands ..................................................................................................... 3-2 3.3 Projected Water Demands ....................................................................................... 3-3

4 Water Distribution System Model Development.................................................................. 4-1 4.1 GIS Integration........................................................................................................... 4-1 4.2 GIS Data Import to H2OMap .................................................................................. 4-2 4.3 Skeletonization .......................................................................................................... 4-2 4.4 City of Cumming Model .......................................................................................... 4-2 4.5 Demand Diurnal Curves .......................................................................................... 4-4 4.6 Point Demands .......................................................................................................... 4-4

5 Optimized Solution for 2025...................................................................................................... 5-1 5.1 Optimization Scope................................................................................................... 5-1 5.2 Optimization Results ................................................................................................ 5-2 5.3 Fire-flow Demand Verification ............................................................................. 5-11 5.4 Water Quality Verification..................................................................................... 5-11

6 Capital Improvement Plan ......................................................................................................... 6-1 6.1 Recommended Pipeline Improvements................................................................. 6-1 6.2 Recommended Storage Improvements.................................................................. 6-5 6.3 Recommended Pump Station Improvements ....................................................... 6-6 6.4 Recommended Pressure Zone................................................................................. 6-7 6.5 Annual Implementation Cost .................................................................................. 6-7

7 Conclusions................................................................................................................................... 7-1

II

WASTER DISTRIBUTION SYSTEM MASTER PLAN CONTENTS

Tables

1-1 Project Tasks and Reports .................................................................................................... 1-1 2-1 Water Source Maximum Capacity...................................................................................... 2-3 2-2 Active Small Water Systems in Forsyth County .............................................................. 2-4 3-1 Projected Population in Forsyth County ........................................................................... 3-1 3-2 Connected Population in Forsyth County Service Area................................................. 3-2 3-3 Average and Maximum Day Demands ............................................................................. 3-3 4-1 GIS Input Data for Hydraulic Model Development........................................................ 4-1 4-2 Top Twelve Water Users ...................................................................................................... 4-5 5-1 Final Solution Cost Breakdown......................................................................................... 5-10 6-1 Summary of CIP Pipelines for 2010, 2015, and 2025.......................................................6-2 6-2 Cost Estimates for Recommended Pipeline Improvements in Year 2010.................... 6-3 6-3 Cost Estimates and Scheduling for Recommended Storage Tank Improvements .... 6-6 6-4 Cost Estimates for Recommended Pump Station Improvements................................. 6-7

Figures

2-1 Water Distribution System................................................................................................... 2-2 2-2 Pressure Zone Interconnection............................................................................................ 2-6 4-1 Skeletonized Water Distribution System Hydraulic Model........................................... 4-3 5-1 Pipelines of Optimized Solution for 2010, 2015 and 2025............................................... 5-3 5-2 Pipeline Diameter Sizes of Optimized Solution for 2010...............................................5-4 5-3 Pipeline Diameter Sizes of Optimized Solution for 2015...............................................5-5 5-4 Pipeline Diameter Sizes of Optimized Solution for 2025...............................................5-6 5-5 Pressure Zone Options and City/County Connections.................................................5-7 5-6 Final Solution Pump Station Layout.................................................................................5-8 5-7 Final Solution Storage Layout ...........................................................................................5-9

Appendices

A Forsyth County Population and Water Needs B Demand Node Development Report with Diurnal Curves C System Operation Summary TM D Field Testing Plan E Design Data Summary Report F Interim Solutions Report G Final Solutions Report H Final Report I Project Maps for Pipeline Improvements in 2010

III

Acronyms and Abbreviations

ADD average daily demand

CIP Capital Improvement Plan

DIP ductile iron pipe

FCWSD Forsyth County Water and Sewer Department

fps feet per second

GA genetic algorithm

GIS geographic information system

LF linear feet

MDD pressure reducing valve

MG million gallons

mgd million gallons per day

NPV net present value

PS pump station

PRV pressure reducing valve

psi pounds per square inch

PVC polyvinyl chloride

TM technical memorandum

VFD variable frequency drive

WRF Water Reclamation Facility

WTP water treatment plan

IV

WASTER DISTRIBUTION SYSTEM MASTER PLAN ACRONYMS AND ABBREVIATIONS


V

SECTION 1

Introduction

The Forsyth County Water and Sewer Department (FCWSD) initiated the Water Distribution System Master Plan project to create a calibrated dynamic hydraulic and water quality model of its distribution system that would be used as a decision analysis tool for existing and future improvements. The model was coupled with optimization techniques to develop a cost-efficient, optimal, and defensible Capital Improvement Plan (CIP). This plan facilitates FCWSD’s preparation for meeting future growth and associated operational changes in the most cost-efficient manner.

This report presents a summary of the existing work to date on the project and a discussion of the phasing and timing of the capital projects that were determined to be beneficial to the system. Each of the tasks of the project are summarized in this report, but have been explained throughout the project in the form of a technical memorandum (TM) or report. Table 1-1 details the individual project tasks and the resulting reports from the work completed.

TABLE 1-1 Project Tasks and Reports Forsyth County, GA

Task No. Project Task Resulting Deliverable

1 Project Management Agenda and notes for all meetings Monthly progress report

2 Population and Water Demand Projections Updated Forsyth County Population and Water Needs Projections TM

3 Water Distribution System Hydraulic Model Development

GIS data needs request MWH Soft® H20Map Water™ software and training manuals Demand Node Development Report with diurnal curves System Operation Summary TM Model calibration demonstration Field Testing Plan

4 Water Quality Model Development Water quality model calibration demonstrationa

5 Water Distribution System Deficiencies

List of recommended fire flow locations in model Fire-Flow Deficiencies Analysis TM b

6 Water Distribution System Optimization

Design Data Summary Report Interim Solutions Report Final Solutions Report Final Report

7 Capital Improvement Plan Development

Draft Master Plan Report Final Master Plan Report Final PowerPoint Presentation Final H20 Map model

a The water quality model calibration will be submitted as a separate deliverable. b Deficiencies were identified during optimization task and, therefore, will be discussed in “Optimized Solutions” section. A TM discussing deficiencies related to fire flow will be submitted as a separate deliverable.

1-1

WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 1—INTRODUCTION


1-2

SECTION 2

System Review

Forsyth County is a rapidly growing area located approximately 40 miles northeast of downtown Atlanta along GA 400. The county encompasses 247 square miles. In 1987, Forsyth County and the City of Cumming established utility service boundaries for the provision of water and sewer services by each in the unincorporated areas of Forsyth County. The FCWSD’s service area encompasses approximately 80 percent of the County’s land area and excludes the service area in and around the City of Cumming. FCWSD’s service area is approximately 200 square miles and, at the end of December 2006, was serving approximately 35,202 residential, 1,787 commercial/industrial, and 2,890 senior citizen accounts (CH2M HILL, Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007). As of July 31, 2007, the connected population was estimated to be 112,233 based on the Chamber of Commerce’s median household size for Forsyth County of 2.68 people (CH2M HILL, Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007). Figure 2-1 presents the current water service area boundary for the FCWSD’s water system.

Potable water is generally supplied to FCWSD’s service area from the Forsyth County Water Treatment Plant (WTP) and from wholesale finished water purchased from the City of Cumming. Prior to April 2000, Forsyth County’s water supply was provided almost exclusively through wholesale purchases from the City of Cumming and Fulton County. Beginning in April 2000, the Forsyth County WTP was commissioned and the FCWSD began producing its own potable water. The WTP has a permitted treatment capacity of 16.73 million gallons per day (mgd) and receives raw surface water for treatment from Lake Lanier via a City of Cumming raw water intake. The agreement with the City of Cumming allows FCWSD to withdraw up to 16 mgd daily and a monthly average of 14 mgd from the raw water intake. Currently, the pumping and raw water piping configuration limits the amount of water conveyed to the Forsyth County WTP to approximately 14.5 mgd. Additional raw water intake improvements are required to supply the FCWSD’s full 16-mgd withdrawal capacity.

To supplement periods of high demands, FCWSD has agreed to continue purchasing finished water from the City of Cumming until May 26, 2012. The volume purchased will be at least equal to the total purchased from the City in the base year of 1999 (1,628,204,220 metered gallons). In 1998, Forsyth County’s contract with Fulton County was amended to allow the FCWSD to receive a monthly average of 5 mgd of treated water until April 2001, and 2 mgd thereafter. Cherokee County agreed to furnish water to FCWSD upon demand, with amounts and rates determined at the time of the demand. Presently, nominal amounts of water are purchased from Fulton County and Cherokee County (CH2M HILL, Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007). Altogether, the water sources in the FCWSD’s service area have a maximum annual average capacity of 23 mgd. Table 2-1 shows the maximum available production from these sources for both current and Year 2025 conditions.

2-1

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Water Service Area and Major Water Distribution LinesForsyth County, GA

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WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 2—SYSTEM REVIEW

TABLE 2-1 Water Source Maximum Capacity Forsyth County, GA

Estimated Maximum Production Capacity (mgd) a

Source

Current Permitted Maximum Production

Capacity (mgd) 2010 2015 2025 Forsyth County WTP 16.73 b 34 47 78.5

City of Cumming c 4.5 4.0 0 0 Fulton County 2.0 0.4 0.8 1.35 Cherokee County d No limit 0.6 0 0 Total 23.23 b 39.0 47.8 79.85 a Maximum production capacities based on the final 2025 solution presented by Optimatics in their GA Optimization Study of Forsyth County Water System Master Plan, Final Report dated November 2007 (Appendix H). b FCWSD’s existing pumping and raw water piping configuration currently limits the amount of water conveyed to the Forsyth County WTP to approximately 14.5 mgd. Therefore, additional raw water intake improvements are required to supply the FCWSD’s full 16-mgd withdrawal capacity at the WTP and to utilize the full 23.23-mgd permitted capacity. c The County’s current contract with the City of Cumming ends in 2012. d The County’s current contract with the City of Cumming ends in 2041.

The FCWSD also supplies finished water to the City of Cumming and many surrounding communities. Several small private water systems support individual subdivisions and obtain water from the County or use well water. The FCWSD expects to assume responsibility for water delivery to the small privates systems in the future due to increased regulatory requirements, fire protection, and maintenance needs. A list of the active small water systems within the County is provided in Table 2-2.

In addition to providing potable water supply, the water system provides fire protection. The FCWSD’s goal is to have fire-fighting capability at all locations and to provide sufficient delivery to over 90 percent of the service area during peak demand periods. In 2005, the FCWSD’s water system could support fire protection during peak demand periods in approximately 75 percent of the water service area.

The FCWSD is connected to the City of Cumming’s water distribution system in 20 locations. Fifteen of these locations supply water to the County and the County returns water to the City at the remaining five locations. The County is connected to Fulton County’s water distribution system in three locations. The FCWSD does not have any specific water quantity or pressure guarantees from either the City of Cumming or Fulton County at individual meter locations.

The distribution system includes one reservoir (Lake Lanier), one WTP with a high service pump station, six booster pump stations, eight water storage tanks (three elevated, five ground storage tanks including WTP clear well), and approximately 2,006 miles of pipe ranging from 2 to 48 inches in diameter (CH2M HILL, Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007). Approximately 75 percent of the pipelines have been in place for fewer than 15 years; the oldest were installed

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approximately 30 years ago. The distribution system is predominantly cement-lined ductile iron pipe (DIP) and polyvinyl chloride (PVC) pipes. The 6-inch diameter and smaller lines are mostly PVC (less than 5 percent), while the lines that are 8 inches and larger are mostly DIP. The distribution system is divided into three pressure zones: high (central), super high (northeast), and low (south). The City of Cumming’s service is located central and east of the County’s service area. Figure 2-2 schematically depicts the interconnection between the zones.

TABLE 2-2 Active Small Water Systems in Forsyth County Forsyth County, GA

Water System Name Population Serveda Beaver Ruin Subdivision 105 Brannon Mobile Home Park 150 Colonial Club Estates 247 Deerwood Water System 417 Dogwood Lane Community 36 Lanier Wood Subdivision 107 Shady Shores Subdivision 1,126 Wood Creek Subdivision 91 aAs of January 16, 2005; CH2M HILL, Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007.

2.1 High Zone The high zone is the largest pressure zone of the system, which covers approximately 90 percent of the water service area and has a target water pressure elevation of 1,421 feet above sea level. The zone currently contains the Forsyth County WTP clearwell and five storage tanks: Watson tank, a 1.0-million gallon (MG) elevated storage tank; Gilbert tank, a 1.0-MG steel, elevated storage tank; Satterfield tank, a 1.0-MG steel, elevated storage tank; Jot Em Down tank, a 0.75-MG concrete, ground storage tank physically located in the super high zone, but serves the high zone; and South tank, a 5.0-MG concrete, ground storage tank. The Old Atlanta Highway tank, a 1.0-MG ground storage tank formerly serviced the high zone, but was decommissioned in December 2005. These facilities are shown schematically on Figure 1-2.

Finished water in the high zone is supplied by the Forsyth County WTP and the City of Cumming WTP. Both WTPs receive surface water from Lake Lanier via the City of Cumming’s existing raw water intake. Raw water is transmitted from the City of Cumming’s raw water pump station (PS) to the Forsyth County WTP via two 16-inch raw water lines. At the Forsyth County WTP, five high service pumps supply finished water to the high zone pressure system.

The high service pumps at the Forsyth County WTP are operated using a variable frequency drive (VFD) on pump number 5. This VFD is set to a discharge pressure of 100 pounds per square inch (psi). The remaining pumps are manually turned on as needed in the system to

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2-5

refill tanks and maintain pressure. The discharge header connects to a 36-inch distribution main that transfers water to the south portion of the high zone and a 24-inch distribution main that serves the north portion. The valve on the 24-inch north-bound finished water main leaving the plant is always in the open position. The valve on the 36-inch south-bound finished water main leaving the plant is usually open between 0 and 5 turns during late morning and afternoon. The valve is opened more as necessary during the evening to assist filling the south tanks before early morning demand. However, as the tanks in the north portion begin draining, the valve to the south is closed to push more water to the north.

During periods of high demand, the South PS is used to supply water in the southernmost portion of the high zone. In addition, the Old Atlanta Highway, Hammond Crossing, and Castleberry Booster PSs located in the southern portion of the County service area are used to raise the water pressure from the City’s connection to the high zone. All three PSs are supplied by the City of Cumming WTP. The Castleberry PS typically runs 24-hours per day. The original purpose of the Old Atlanta PS was to service the high zone by pumping from the Old Atlanta tank; however, the Old Atlanta tank has been decommissioned.

2.2 Super High Zone Located in the northeast corner of the County is the super high pressure zone system, which is the second largest zone in the service area and operates at a higher water pressure elevation at 1,591 feet above sea level. Figure 2-2 schematically shows the facilities in the super high zone. The zone contains two storage tanks, the Mollyview and Jot Em Down tanks. The Mollyview tank is a 0.25-MG concrete, ground storage tank with an overflow elevation of 1,591. As previously mentioned, the Jot Em Down tank is physically located in the super high zone, but serves the high zone.

Water is transferred from the high zone to the super high pressure zone in the system by the Jot Em Down and Hopewell booster stations transfers. Prior to the installation of the Hopewell PS, the Jot Em Down PS was used to refill the Molly View tank by pumping out of the Jot Em Down tank. However, as the demand increased in the super high pressure zone, the Jot Em Down pumping capacity could not adequately refill the Molly View tank and, therefore, the Hopewell PS was installed for this purpose. The Hopewell PS is automatically controlled by the water level in the Molly View tank. The PS turns on when the tank level drops below 12.5 feet and turns off when the tank level reaches 19 feet. Currently, the Jot Em Down PS is only run during periods of low demands in order to refresh the water in the Jot Em Down tank.

2.3 Low Zone The smallest zone, occupying less than 5 percent of the total service area, is the low zone located in the southeast portion of the FCWSD service area. The low zone is separated from the high zone by four pressure reducing valves (PRVs). During periods of high demand, a portion of the FCWSD’s service area operates at a lower water pressure of 1,191 feet above sea level. During extreme periods, pressures may range between 30 and 190 psi.

2-6

Lake Lanier

FIGURE 2-2 Pressure Zone Interconnection Forsyth County, GA

High Zone 1421 ft HGL

Forsyth County WTP

Raw Water PSCity of Cumming

WTP

Super High Zone 1591 ft HGL

Old Atlanta Hwy Booster PS

Satterfield Tank

Castleberry Booster PS

Molly ViewTank

Hopewell Booster PS

Jot Em Down Booster PSJot Em Down Tank

Two 16-in pipes

High Service PS

Gilbert Tank

Watson Tank

Low Zone 1199 ft HGL

South Tank

South Tank Booster PS

Fulton County

Hammond Crossing Connection

PRV

SECTION 3

Population and Water Demand Projections Water demands for existing conditions were developed to simulate existing operations and evaluate conditions experienced from current demands on the system. Additionally, water demands for full system Year 2025 were developed to understand the maximum possible demand on the system and the deficiencies experienced during that scenario. The County’s projection of future water demands is based on anticipated population growth in FCWSD’s service area.

3.1 Population Projections Population projections are used to develop connected population and water demand projections. In July 2005, Reilly Economics Consulting estimated the total population in Forsyth County to be 142,525. The U.S. Census Bureau placed the County population at 150,968 in 2006. In July 2005, Reilly projected a total County population of 342,577 in Year 2020 and 389,783 in Year 2025. Most recently in December 2007, Reilly updated the population projections over a 50-year study period and estimated County populations would reach 588,221 by Year 2058. The population growth between 2006 and 2058 represents a 4-fold increase. Appendix A presents the Forsyth County Population and Water Needs Update prepared by Reilly in July 2005 and the Forsyth County Population Projections prepared by Reilly in December 2007. Table 3-1 compares the two sets of population projections.

TABLE 3-1 Projected Population in Forsyth County Forsyth County, GA

County Population 2000 2005 2010 2015 2020 2025 2030 2040 2050 2058

July 2005 Forecast a 98,244 c 142,525 210,538 268,562 342,577 389,783 NC NC NC NC

December 2007 Forecast b 98,407 c NA 195,129 NC 311,522 NC 426,161 489,332 538,606 588,221

a Projections were estimated by Reilly Economics Consulting in the Forsyth County Population and Water Needs Projections Update (Table 6) dated July 18, 2005 (Appendix A). b Projections were estimated by Reilly Economics Consulting the Forsyth County Population and Population Projections (Table 2) dated December 17, 2007 (Appendix A). c US Census Bureau reported 98,407. Reilly Economics County reported 98,244 in Table 5 of the Forsyth County Population and Water Needs Projections Update dated July 18, 2005 (Appendix A).

Based on the population projections developed in July 2005, Reilly estimated the population connected to the water distribution system to be approximately 99,360 in 2005, which was derived by multiplying the total number of residential and senior citizen customers (based on the County’s 2003 and 2004 customer counts) by the average number of persons per household in the County at that time of the 2000 Census (2.85 persons). Most recently in

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WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 3—POPULATION AND WATER DEMAND PROJECTIONS

September 2007, CH2M HILL estimated the connected population to be 112,233 , which was based on the Chamber of Commerce’s median household size for Forsyth County (2.68) and the 41,878 households in Forsyth County’s service area as of July 31, 2007 (Forsyth County Engineer’s Report, Water and Sewerage Revenue Bonds Series 2007, September 2007).

The connected population in Year 2025 was estimated by Reilly to be 340,888. The projections for connected populations are listed in Table 3-2, as previously presented in the Forsyth County Population and Water Needs Projections Update dated July 18, 2005 (Appendix A). Reilly’s projections for the connected population were based on 2003 and 2004 customer counts data provided by FCWSD and the assumptions that the percentage of new residents connecting in 2005 was 90 percent and would be 95 percent in 2010 and 100 percent by 2020; 90 percent of unconnected existing residents will be connected by 2020; and a 5 percent decline in per capita consumption will occur by 2030 based on the Metropolitan North Georgia Water Planning District’s conservative Program A.

TABLE 3-2 Connected Population in Forsyth County Service Area Forsyth County, GA

Year Connected Population in

Forsyth County Service Area a 2005 99,360 2010 159,423 2015 208,591 2020 273,394 2025 340,888 2030 374,598

a Projections were estimated by Reilly Economics Consulting in Table 6 of the Forsyth County Population and Water Needs Projections Update dated July 18, 2005 (Appendix A).

3.2 Existing Demands FCWSD provided CH2M HILL with historical water billing data for all residential and industrial accounts. These data included 4 years of monthly consumption records for all customer accounts and the service address, which was geo-coded to assign spatial locations for each customer into the GIS system. Daily finished water flows were also provided for 2004. The account usage data were evaluated to identify the annual average daily demand (ADD) based on 2004 records. The average metered water usage for all 33,626 accounts in 2004 was calculated to be 8.58 mgd. The Demand Node Development Report submitted by CH2M HILL on July 27, 2005 (Appendix B) provides a summary of the analysis of the water demand data for the development of a hydraulic model of the FCWSD water distribution system.

Maximum daily demand (MDD) is the maximum demand anticipated during a 24-hour period within any given year. The ratio of maximum daily demand to average annual demand is referred to as the “maximum daily demand factor.” This factor usually varies from about 1.2 to 3.0 and is developed by reviewing historical data to determine the maximum amount of water used in one day. A review of total daily volumes of water produced each day in the FCWSD water system from January 2004 to December 2004

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indicated a MDD factor of 1.9, which corresponds to 16.3 mgd MDD in 2004, not including unaccounted for water. In the Forsyth County Population and Water Needs Projections Update dated July 18, 2005 (Appendix A), Reilly assumed the MDD to be 1.82 times the ADD for the dry scenario demands, which is the peak factor used in the hydraulic model and the optimization for the final solution. Under the dry day demands scenario, Reilly estimated the ADD and MDD for 2005 to be 13.4 mgd and 24.4, respectively.

Unaccounted for water is calculated using the difference between the consumption and the supplied water. The supplied water for the FCWSD water system is the sum of the WTP finished water and the City of Cumming and Fulton County meters, which in 2004 were calculated to be 5.02 mgd, 4.45 mgd (metered use from three most significant City of Cumming’s meters), and 0.02 mgd, respectively. Using this methodology, FCWSD staff calculated the average unaccounted for water in 2004 to be approximately 10 percent. Based on the ADD in 2004, this equals a total amount of approximately 357 MG or 0.98 mgd.

3.3 Projected Water Demands The County’s projection of future water demands is based on anticipated population growth in FCWSD’s service area. Revised demands are based on the projections Reilly Economics Consulting prepared for the County in 2005 (Appendix A). Reilly’s review of the monthly demand data determined that fluctuating summer demands in the Forsyth County service area were based on the amounts of rainfall. Therefore, three sets of projections using varying precipitation levels were developed to capture the potential range of future annual average demands. Based on the 5-year average demand during a dry season (January 2000 through December 2004), Reilly projected an average water demand of 44.5 mgd in 2025. Using a peaking factor of 1.82, the resulting MDD for 2025 is 81 mgd. Table 3-3 presents the existing, interim, and water demands projected through 2030.

TABLE 3-3 Average and Maximum Day Demands a Forsyth County, GA

Year Average Day Demand

(mgd) Maximum Day Demand

(mgd) 2005 13.4 24.4 2010 21.4 39 2015 27.8 50.5 2020 36 65.6 2025 44.5 81 2030 48.9 89

a Projections were estimated by Reilly Economics Consulting in Table 6 of the Forsyth County Population and Water Needs Projections Update dated July 18, 2005 (Appendix A).

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.

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SECTION 4

Water Distribution System Model Development

A water distribution model is developed with several components: the infrastructure, demands, and controls. The infrastructure is developed using a geographic information system (GIS), as-built drawings, and other maps. The demands are determined through historical records and collecting additional data. The controls are developed by understanding system operations. This section describes briefly the process of using the GIS data to develop the infrastructure and refining the demands through the collection of additional data.

4.1 GIS Integration The ability of the model to predict real world conditions relies on a number of factors; one of the most critical is ensuring the pipe network reflects what is actually in the ground in terms of length, diameter, and connectivity. Knowing the status of all valves is also of critical importance during calibration. Next in importance are storage reservoir water surface elevations and then pump station flows. There are several other items required as input data, and the relative importance of all pertinent information is shown in Table 4-1.

TABLE 4-1 GIS Input Data for Hydraulic Model Development Forsyth County, GA

Level of Importance GIS Input Data

Pipe lengths and diameters and pipe connectivity 1

Valve status

Reservoir water surface elevations

Large source pump flows

2

Large booster pump flows

3 Pipe roughness factors (lining type, installation date, etc.)

Large PRV pressure settings (assuming valve elevations are known) 4

Average day nodal demand distribution

Small source pumps

Small booster pumps

5

Small PRV flow information

6 Pressure information

CH2M HILL reviewed the GIS data to ensure that the information necessary for building the hydraulic model was included in the database files. Certain aspects of the data were

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WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 4—WATER DISTRIBUTION SYSTEM MODEL DEVELOPMENT

compiled into specific formats to support building the hydraulic model. Once the GIS data were verified and compiled, and the shape files were imported into MWH Soft® H20Map Water™ using the software GIS exchange interface.

4.2 GIS Data Import to H2OMap The basis for building a hydraulic model of a water distribution system is the data collected about the system being modeled. Data can be obtained from various sources, such as hardcopy maps or GIS. Since FCWSD has a GIS containing information on the distribution system network, most of the system data were obtained through the GIS. FCWSD provided CH2M HILL with the data in the GIS in the form of a geodatabase.

Once the data were imported into H2OMap, the network connectivity had to be thoroughly reviewed and verified before finalizing the layout of the model. CH2M HILL reviewed the data imported to H2OMap and corrected many connectivity problems in the model. The disconnections were the result of such problems as missing junctions, incorrectly joined pipes, and overlapping pipes. Corrections were necessary to develop an accurate model and to ensure proper reduction of the model during skeletonization.

4.3 Skeletonization Model size affects the cost of the software license required as well as the computation time. Skeletonization is the process of reducing the number of pipes and nodes used in a hydraulic model to represent the physical system. This reduction is accomplished by removing unnecessary nodes that join pipes with similar attributes and by removing short, insignificant dead-end pipes from the model. Typically, model sizes are determined by the number of pipes in the model. As a result, the degree of skeletonization is described by the number of pipes reduced in the model. The initial model after importing the GIS data contained over 12,000 links; the final model was reduced to approximately 5,600 pipes. CH2M HILL used H2OMap Skeletonizer to skeletonize the model developed. First, any unnecessary nodes where the connected pipes had the same diameter were removed. Then, all dead-end mains shorter than a specified length (15 feet) were removed from the model.

After skeletonization, the revised model was overlaid with the original model to verify that the model was reduced properly and that no important features of the model were lost in the process. Figure 4-1 displays the model after skeletonization, which removed short, dead-end pipe segments and joined pipes with similar attributes but broken by an intermediate node. The figure demonstrates the effectiveness of skeletonization in reducing the size of a model while maintaining an accurate representation of the distribution system.

4.4 City of Cumming Model In order to represent the water being supplied from the City of Cumming, the City’s model was imported into the Forsyth County model. The City of Cumming provided a copy of its model in WaterCAD format. CH2M HILL converted and imported the model into H2OMap, and identified the City pipes with specific identifiers in the model. The City pipes and nodes were excluded from any analysis. The City model was able to represent the source of water

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from the City WTP and represent the hydraulics and water age as it reaches the Forsyth County water system through the interconnection meters through the City system.

FIGURE 4-1 Skeletonized Water Distribution System Hydraulic Model Forsyth County, GA

Source: Skeletonized model generated by CH2M HILL with H20Map software.

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4.5 Demand Diurnal Curves A diurnal demand pattern reflects the variations in water usage for a specific region over a 24-hour period. The diurnal demand patterns developed for the FCWSD water system were broken into four categories: residential and commercial (system), the top users, and unaccounted for water.

The residential and commercial curves were based on the overall system demand diurnal pattern that was generated for the FCWSD water customers within the service area. The mass balance of the water entering and being stored in the system allows for the calculation of the system demand throughout the course of the day. This mass balance was accomplished with the use of the Meter Master flow recorders connected to the three most significant City of Cumming meters (98 percent of total flow from the City of Cumming) as well as the SCADA data from the FCWSD). The system diurnal pattern was established for 3 days during the week of May 1, 2005. An average system diurnal pattern was also created for this same 3-day period.

Meter Master flow recorders were also used to develop individual demand diurnal patterns for the top 12 customers in the FCWSD service area (not including private water systems), as listed in Table 4-2. The unaccounted for water demand was assumed to occur uniformly throughout the day. As a result, these demands were applied evenly, without any peaking in a 24-hour period. The diurnal demand patterns for each of the four categories (residential, commercial, top users, and unaccounted for water) are illustrated in the Demand Node Development Report, which is presented in Appendix B.

4.6 Point Demands After ADD, MDD, and diurnal patterns were developed to represent existing conditions in the distribution system, the demands were added to the model by allocating them to the appropriate model nodes using the Demand Allocator extension within H2OMap Water. The data to be allocated included over 32,000 customer locations with demands and category geospatially located throughout the FCWSD service area. Thiessen polygons were created around the model demand nodes, and the customer meters located within the polygons were allocated to the associated model node. The customer categories were preserved throughout this process, which allowed for the use of the diurnal patterns based on the type of use.

Some demands, referred to as “point demands,” were also assigned to individual nodes, rather than being grouped together with additional demands on a single node. The purpose of this step was to more accurately place larger demands geographically within the model to best represent the top 12 users (based on customer billing and not including private systems).

4-4


TABLE 4-2 Top Twelve Water Users Forsyth County, GA

Customer Name Average Daily Usage (gpd) a Etowah Water and Sewer Authority 24,267 Siemens Energy 18,157 Tucker Concrete 16,553 Allied Ready Mix 16,455 Thomas Concrete 15,874 Scientific Games 11,824 Blue Circle Materials 11,423 Hoover Precision Products 10,152 Solvay Advanced Polymers 9,800 Advantis Technologies 9,707 Continental Plastics 7,881 UPS 6,667 a Based on 2004 meter readings presented in the Demand Development Report submitted by CH2M HILL on July 27, 2005 (Appendix B).

4-5



4-6

SECTION 5

Optimized Solution for 2025 By 2025, the County’s ADD is expected to increase from 13.4 mgd in 2005 to 44.5 mgd and MDD is expected to increase from 24.4 mgd to 81 mgd (Reilly Economics Consulting, July 2005). The optimal solution and all of its associated infrastructure improvements were developed in the genetic algorithm (GA) optimization phase of the project to meet the County’s future water demands.

5.1 Optimization Scope During optimization, solutions were developed using a range of upgrade options and performance criteria related to pressure, velocity, flow and tank performance while minimizing the total present value of the improvements. The allowable upgrades considered during optimization included:

• Adding new pipe alignments and duplicate mains

• Abandoning existing pipelines (or closing them to isolate high-pressure pipelines)

• Adding new system interconnections between zones

• Adding new or expanding current water storage volumes in the system and in WTP’s clearwell

• Adding new or alternative pump station sites

• Expanding or upgrading existing pump stations

• Selecting pumping hours and flows for individual pumps or pump stations

• Identifying locations and setting of new valves

• Changing existing valve settings, if necessary

• Selecting capacities of existing and future water source options

The methodology and results of this iteratively refined optimization process are detailed in four individual reports—Design Data Summary, Interim Solution Report, Final Solutions Report, and Final Report (Appendices E through H). The following list summarizes the most significant performance criteria met by the final optimized solution:

• Water supply from the Forsyth WTP (78.5 mgd) and Fulton County (1.35 mgd)

• No water supply from the City of Cumming, Gwinnett County or Cherokee County

• Water maximum allowable pressures - 150 psi throughout the service area except in the super high pressure zone where pressures up to 180 psi were allowable

• Minimum allowable pressures - 35 psi, with some exceptions at locations near water storages

5-1

WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 5—OPTIMIZED SOLUTION FOR 2025

• Maximum allowable flow velocities - 5 feet per second (fps) for large diameter transmission pipelines and 8 fps for smaller distribution pipelines (as long as head losses were minimal)

• Minimum and maximum tank and standpipe levels – Start the day at 80 percent full, and range between 60 percent full and overflow levels over a 24-hour period

• Minimum tank drawdown (and refilling) – In a 24-hour period, storage levels return to starting level at least once and achieve at least 30 percent turnover

• Allowable volume range of Forsyth WTP clearwell, 20 to 30 MG or greater, if deemed necessary due to the removal of the Baldridge Road storage

• Total storage volume in system equivalent to one ADD (Optimatics used 43 mgd in the GA optimization model compared to the 44.5 mgd projected by Reilly Economics Consulting in July 2005.)

• Redundancy or reliability constraints

5.2 Optimization Results The final optimized solution for the pipelines for the FCWSD system is shown on Figure 5-1. Figures 5-2, 5-3, and 5-4 show the sizes of new, duplicate, and replacement pipelines for the staged solutions in 2010, 2015, and 2025, respectively. The locations of the pressure zone options and City/County connections are shown on Figure 5-5. The final solution pump station layout is presented on Figure 5-6. The new pump station proposed at Post Road has been relocated to the county-owned property at the Fowler Water Reclamation Facility (WRF). Figure 5-7 shows the locations of the new tanks that are required to satisfy the 2025 water demands.

Table 5-1 summarizes the cost of the final solution presented in this report. The total cost of the FCWSD final solution through the Year 2025 is $107 million. This includes the capital cost of pipes, tanks, and pumps (excluding the high service pumps at the Forsyth County WTP) implemented in the solution as well as an approximation of the net present value (NPV) operating cost over the 50-year planning horizon and discount rate of 6 percent. The total pipe capital costs are made up of duplicate mains, interconnections, and extra costs incurred where a main crosses a main road or stream. The storage capital costs are from the expansion of Watson and Gilbert (each expanding from 1 MG to 2 MG), and the new storages at Smith Road (2 MG), Mollyview (1 MG), and the county-owned property for the Fowler WRF (5 MG). The total cost of the final solution does not include the capital or operating costs for the improvements at the Forsyth County WTP. The Forsyth County WTP clearwell and high service pump improvements will be presented in a separate TM. The unit cost rates used for the capital infrastructure and operating costs are detailed in the Design Data Summary presented in Appendix E. The complete details of the final solution are described in the Final Solutions Report prepared in January 2007 (Appendix G) and the Final Report prepared in November 2007 (Appendix H).

5-2

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WATER DISTRIBUTION SYSTEM MASTER PLAN SECTION 5—OPTMIIZED SOLUTION FOR 2025

FIGURE 5-5 Pressure Zone Options and City/County Connections Forsyth County, GA

Source: Optimatics, GA Optimization Study of Forsyth County Water System Master Plan, Final Report, November 2007 (Appendix H, Figure 1-1).

Cherokee County Connections

Fulton County Connections

Gwinnett County Connection

City/County Connections currently used

City/County Connections not currently used High Zone

Low Zone

City of Cumming

Super High Zone

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5-7


FIGURE 5-6 Final Solution Pump Station Layout Forsyth County, GA

Source: Optimatics, GA Optimization Study of Forsyth County Water System Master Plan, Final Report, November 2007 (Appendix H, Figure 3.13). Labels updated by CH2M HILL to denote that proposed tank at Post Road has been moved to the County-owned property at the Forsyth County WRF.

Forsyth WTP

Post Road (moved to Forsyth WRF)

South

Old Atlanta (relocated) New PS

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Existing PS

Not in use

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Bramblett

Martin Road

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5-8


FIGURE 5-7 Final Solution Storage Layout Forsyth County, GA

New Storage

Expanded Storage

Existing Storage

Smith Road

Forsyth WTP Clearwell storage

South

Gilbert

Satterfield

Post Road (relocated to Forsyth WRF)

Watson

Mollyview

Source: Optimatics, GA Optimization Study of Forsyth County Water System Master Plan, Final Report, November 2007 (Appendix H). Labels updated by CH2M HILL to denote that proposed tank at Post Road has been moved to the County-owned property at the Forsyth County WRF.

5-9


TABLE 5-1 Final Solution Cost Breakdown Forsyth County, GA

Estimated Cost (in millions $) a Breakdown

2010 2015 2025 Total Capital b Pipes Pipe Costs (Total 483,292 LF)

New (47,718 LF) $ 0.827 M $ 0.636 M $ 2.82 M $ 4.28 M Replace (435,574 LF) $ 20.5 M $ 18.8 M $ 21.5 M $ 60.8 M

Major Road Crossing (285 LF) $ 0.057 M $ 0.075 M $ 0.048 M $ 0.18 M

Stream Crossing (360 LF) $ 0.03 M $ 0.072 M $ 0.048 M $ 0.15 M Subtotal: $ 21.4 M $ 19.6 M $ 24.4 M $ 65.4 M Pumps New

PS at County-owned Forsyth County WRF Property $ 0.5 M $ 0.5 M

Martin Road PS (1 mgd) $ 0.255 M $ 0.255 M Expansion

Jot Em Down (1.5 mgd) $ 0.116 M $ 0.116 M Subtotal: $ 0.616 M $ 0.255 M $ 0 M $ 0.871 M Tanks New

Tank at County-owned Forsyth County WRF Property (5 MG) $ 2 M $ 2 M

Smith Road Tank (2 MG) $ 0.53 M $ 0.53 M Mollyview Tank (1 MG) $ 0.424 M $ 0.424 M

Expansion

Gilbert Tank (Expand to 2 MG) $ 1.2 M $ 1.2 M

WatsonTank (Expand to 2 MG) $ 1.2 M $ 1.2 M Subtotal: $ 2.53 M $ 2.4 M $ 0.424 M $ 5.354 M Total Capital Costs $ 24.5 M $ 22.3 M $ 24.8 M $ 71.6 M Operating Costs d Annual Operating Costs $ 0.094 M $ 0.092 M $ 0.119 M $ 0.305 M

NPV Annual Operating Costs $ 1.48 M $ 1.45 M $ 1.87 M $ 4.8 M

Annual Water Supply Costs $ 9.2 M $ 7.9 M $ 13.5 M $ 30.6 M Total Solution Cost c $ 35.2 M $ 31.7 M $ 40.2 M $ 107 M a All costs in 2007 dollars and include all construction/engineering/administration costs. b Forsyth County WTP Clearwell and High Service Pump Improvements will be presented in a separate TM. c The original size of the Smith Road tank was 1 MG, which is the tank size modeled by Optimatics. d Includes Net Present Value (NPV) of annual operating costs, except for: 1) Forsyth WTP High Service Pump Station, 2) difference in operating cost between the Post Road Tank and the tank at the Forsyth County WRF property which replaced it, 3) difference in operating cost between 1MG tank and 2MG tank at Smith Road

5-10


5.3 Fire-flow Demand Verification Fire-flow simulations will be conducted in the model with the final solutions in place for 2025 MDD. The results of the fire-flow analysis are presented in a separate TM. Generally, the optimized solution provided good performance during the worst-case scenario evaluations during peak hours on a MDD. Therefore, the deficiencies identified during the fire-flow model runs will result in only minor adjustments needed to serve the projected worst-case scenarios. The minimum allowable pressure during fire flow analysis is 20 psi.

5.4 Water Quality Verification The water quality model verification are submitted in a separate TM. The water quality model can be used to analyze water age and chlorine residual throughout the existing system for both winter and summer demand scenarios. This tool can be used to evaluate how changes to the distribution system infrastructure and operations impact water age and chlorine residual.

5-11

SECTION 6

Capital Improvement Plan

Once the 2025 MDD model run investigation established that the scenario with no connections with the City of Cumming was the County’s preferred choice, staging model runs were carried out for two intermediate periods, 2010 and 2015 MDD. In order to be feasibly implemented, each of the infrastructure improvements identified in the 2025 interim solution and by the County were evaluated in the staging runs based on budgetary and growth-related constraints. The staging runs also identified the optimal sequence of improvements required at the intermediate years in order to facilitate the development of a CIP. The final results of the staging runs are detailed in the optimization study’s Final Report (Appendix H).

6.1 Recommended Pipeline Improvements Due to the significant growth in the County’s service area, duplicate and new pipelines (along existing roads and across the City of Cumming system) were identified by the County for prioritization. Using the pipes identified by the County and the interim 2025 optimization solutions, the optimization during the staging runs selected the most effective pipeline upgrades and pipe diameter sizes based on the capital costs of the pipeline and any costs incurred where a main crosses a main road or stream. Table 6-1 summarizes the pipelines by year, pipe diameter size, and road type.

The final solution of the optimization prioritized the duplicate mains for the larger diameter pipe sections transferring water from the Forsyth WTP to the zones within the service area. These larger diameter duplicate pipelines parallel existing pipelines that extend north from the Forsyth WTP through the City of Cumming service area toward the super high zone and that extend south toward the low zone passing through the high zone. A large diameter main was also selected in the final solution to transfer water west of the City of Cumming service area to the western portion of the County’s high zone. The majority of the distribution mains that were identified in the final optimization run are located throughout the high zone.

The recommended water pipeline improvements for the intermediate staging year 2010 are listed in Table 6-2. The recommended pipeline improvements for 2010 are estimated to cost $21.3 million and include approximately 9,250 linear feet (LF) of new pipeline and 144,550 LF of duplicate pipelines. Appendix I shows the 2010 pipeline improvement project locations in more detail.

6-1

WASTER DISTRIBUTION SYSTEM MASTER PLAN SECTION 6—CAPITAL IMPROVEMENT PLAN

6-2

TABLE 6-1 Summary of CIP Pipelines for 2010, 2015, and 2025 Forsyth County Water System Master Plan

Pipe Diameter Local Road State Road

Size (inches)

Duplicate (LF)

New (LF)

Subtotal (LF)

Duplicate (LF)

New (LF)

Subtotal (LF)

Total (LF) Additional Notes

2010 8 17,350 1,662 19,013 0 0 0 19,013

10 12,706 2,143 14,849 0 0 0 14,849

12 26,152 0 26,152 0 0 0 26,152 120 ft of stream crossing

16 25,329 4,872 30,201 1,913 0 1,913 32,114 24 11,312 0 11,312 7 0 7 11,319

30 4,770 0 4,770 6,431 574 7,006 11,776 95 ft of major road crossing

36 0 0 0 38,578 0 38,578 38,578 2010 Total 97,620 8,677 106,297 46,929 574 47,503 153,800

2015

8 14,865 1,148 16,013 0 0 0 16,013 10 21,865 0 21,865 0 0 0 21,865 12 20,819 1,961 22,780 163 4,365 4,528 27,308

16 13,370 0 13,370 4,837 0 4,837 18,207 240 ft of stream crossing

24 11,242 0 11,242 6,286 0 6,286 17,528 36 37 0 37 9,068 0 9,068 9,106 48 0 0 0 16,034 0 16,034 16,034

2015 Total 82,199 3,109 85,308 36,387 4,365 40,752 126,060

2025

8 69,766 2,946 72,711 473 0 473 73,184 240 ft of stream crossing

10 39,744 0 39,744 0 6,459 6,459 46,203 12 7,890 2,142 10,032 0 0 0 10,032 16 2,457 8,985 11,442 2,353 10,460 12,813 24,254 24 4,747 0 4,747 8,369 0 8,369 13,116 30 1,699 0 1,699 14,029 0 14,029 15,729 36 4,602 0 4,602 0 0 0 4,602 42 0 0 0 4,039 0 4,039 4,039 48 0 0 0 12,273 0 12,273 12,273

2025 Total 130,904 14,073 144,977 41,536 16,919 58,455 203,432 Grand Total 310,723 25,859 336,582 124,852 21,859 146,710 483,292


TABLE 6-2 Cost Estimates for Recommended Water Pipeline Improvements in Year 2010 Forsyth County, GA

Name 2010 CIP Pipeline Description Length (ft) Installation Cost a

Line 01

Duplicate 36-inch diameter pipeline from Forsyth WTP and along Health Dr., Antioch Rd., Pilgrim Rd., Dahlonega Hwy, Tribble Gap Rd., Sawnee Dr., and Canton to intersection of Bethelview Rd. and Canton Hwy

38,161 $ 9,540,000

Line 02 Duplicate12-inch diameter pipeline from intersection of Buford Hwy and Bonnie Brae Rd. and south along Buford Hwy to Chamonix Dr

2,657 $ 226,000

Line 03 Duplicate 8-inch diameter pipeline from the intersection of Buford Hwy and Chamonix Dr. to River Club Dr 3,267 $ 157,000

Line 04

New 8-inch diameter pipeline from intersection of St Gallen Ct. and Chamonix Dr. (toward the southwest) to intersection of Windermere Xing and Gladstone Pl. crossing Windermere Xing and Gants Hill Pl

1,662 $ 80,000

Line 05 Duplicate 10-inch diameter pipeline parallel to Old Alpharetta Rd. from Pine Grove Rd. to Peachtree Pkway.

5,000 $ 375,000

Line 06 New 16-inch diameter pipeline from intersection of Bridle Ridge Dr. and Sidesaddle Ct. to intersection of Brookwood Way and Deauville Way

862 $ 82,000

Line 07 Duplicate 24-inch diameter pipeline connects to existing 12-inch pipeline parallel to Old Atlanta Rd to proposed 30-inch outlet pipeline (Line 8) of South Pump Station

477 $ 79,000

Line 08 Duplicate 30-inch diameter pipeline connects to proposed 24-inch pipeline (Line 7) in the east of Old Atlanta Rd and continue to South Tank

333 $ 67,000

Line 09

Duplicate 8-inch diameter pipeline connects to dead-end 8-inch pipeline parallel to Windy Hill Dr to existing 8-in and 10-inch pipelines at intersection of Brandon Trl. and Grassland Pkwy

853 $ 41,000

Line 10 Duplicate16-inch diameter pipeline parallel Atlanta Hwy from Fowler Rd. to Castleberry Rd. 1,741 $ 183,000

Line 11

New pipeline (2,143 LF) will connect to existing 6-inch pipeline parallel to Drew Campground Rd. and continue south to Campground Rd; duplicate pipeline (1790 LF) will parallel Campground Rd. to Bentley Rd.

3,933 $ 295,000

Line 12

Duplicate 8-in diameter pipeline connects to proposed 10-inch pipeline (Line 11) at intersection of Campground Rd. and Bentley Rd., and parallels Bentley Rd. to North Fox Dr.

4,976 $ 239,000

Line 13

Duplicate 12-inch diameter pipeline connects to proposed 8-inch pipeline (Line 12) at intersection of Bentley Rd. and North Fox Dr., and parallels Bentley Rd. to Post Rd.

6,449 $ 548,000

6-3




Line 14 Duplicate 12-inch diameter pipeline parallel Post Rd. from Wesley Hughes Rd. (or Polo Dr.) to Pittman Rd. 606 $ 50,000

Line 15 Duplicate 8-inch diameter pipeline parallel to Post Rd. from Pittman Rd. to Bentley Rd. 2,419 $ 116,000

Line 16 Duplicate 16-inch diameter pipeline parallel Post Rd. from Bentley Rd. to Kelly Mill Rd. 5,525 $ 525,000

Line 17 Duplicate 8-in diameter pipeline parallel Post Rd. from Kelly Mill Rd. to Wellington Pl. 5,836 $ 280,000

Line 18

New 16-inch diameter pipeline (4,010 LF) will start from intersection of Post Rd. and Wellington Pl., continue east to Aaron Sosebee Rd., and duplicate pipeline (7,078 LF) will continue north along Aaron Sosebee Rd. to Ineal Dr.

11,088 $ 1,053,000

Line 19 Duplicate 30-inch diameter pipeline parallel Canton Hwy from Aaron Sosebee Rd. to Bethelview Rd. 5,976 $ 1,285,000

Line 20 Duplicate16-inch diameter pipeline parallel Pilgrim Mill Rd. from Impala Dr. to Magnolia Ave. 621 $ 59,000

Line 21 Duplicate 12-inch diameter pipeline from intersection of Pilgrim Mill Rd. and Magnolia Ave., and south along Pilgrim Mill Rd. to Mill Station Ln.

2,038 $ 173,000

Line 22 Duplicate 30-inch diameter pipeline from intersection of GA Hwy 400 and Browns Bridge Rd., and southeast along Browns Bridge Rd. to Keith Bridge Rd

4,892 $ 985,000

Line 23 Duplicate 24-inch diameter pipeline from the intersection of Browns Bridge Rd. and Keith Bridge Rd., and northeast along Keith Bridge Rd. to Leland Dr

10,836 $ 1,788,000

Line 24 Duplicate 16-inch diameter pipeline from the intersection of Keith Bridge Rd. and Leland Dr., and northeast along Keith Bridge Rd. to Little Mill Rd

12,106 $ 1,150,000

Line 25 Duplicate 12-inch diameter pipeline from intersection of Keith Bridge Rd. and Little Mill Rd., and northeast along Keith Bridge Rd. to Waldrip Rd.

10,491 $ 892,000

Line 26

Duplicate 10-inch diameter pipeline from intersection of Keith Bridge Rd. and Waldrip., and northeast along Keith Bridge Rd. to existing 8-inch pipeline parallel to Dawsonville Hwy.

2,981 $ 224,000

Line 27 Duplicate12-inch diameter pipeline from intersection of Hopewell Rd. and Hubbard Town Rd., and east along Hubbard Town Rd. to Millstone Dr.

1,264 $ 107,000

Line 28 Duplicate12-inch diameter pipeline from intersection of Hubbard Town Rd. and Millstone Dr., and east along Hubbard Town Rd. to GA Hwy 400.

2,936 $ 220,000

6-4




Line 29 New 30-inch diameter pipeline from intersection of Hubbard Town Rd. and GA Hwy 400, and east along Cross Roads Rd. to Settingdown Rd.

574 $ 124,000

Line 30 Duplicate 12-inch diameter pipeline from intersection of Cross Roads Rd. and Settingdown Rd., and south along Settingdown Rd. to Glen Haven Dr.

2,646 $ 225,000

Line 31 Duplicate 36-inch diameter pipeline from intersection of Peachtree Pkwy. and Sharon Rd., and southeast along Sharon Rd. to a proposed 24-inch pipeline (Line 32)

394 $ 98,000

Line 32 Duplicate 24-inch diameter pipeline connect to proposed 36-in pipeline and existing 36-inch pipeline, which parallel to Sharon Rd.

7 $ 1,000

Line 33 Duplicate 16-inch diameter pipeline connect to WTP clearwell near Health Dr. 172 $ 18,000

Line 34 Duplicate 36-inch diameter pipeline connect to existing 12-inch pipeline parallel to Bethelview Rd. and existing 24-inch pipeline parallel Peachtree Pkwy.

22 $ 6,000

Total Capital Cost for 2010 CIP Pipelines 153,800 $ 21,291,000 a Costs based on 2007 unit costs from FCWSD. Installation costs developed by Optimatics and summarized in GA Optimization Study of Forsyth County Water System Master Plan Final Report dated November 2007 (Appendix H).

6.2 Recommended Storage Improvements The storage solutions selected by the optimization were based on the capital costs. The final solution recommended new storages at Smith Road and Post Road. Subsequent to the optimization study, the Smith Road tank size was increased from 1 MG to 2 MG and the recommended Post Road storage was relocated to the County-owned property at the Fowler WRF. At the time of the 2007 Engineer’s Report, the new tank at the Fowler WRF property was sized for 5 MG.

The final solution also recommended the expansion of storage at several existing tanks, including Watson, Gilbert, Mollyview, and the Forsyth WTP clearwell. The Watson and Gilbert tanks were both increased from 1 MG to 2 MG. By 2025, the total volume of the clearwell would comprise 26 MG, including 5 MG of the existing capacity. The Old Atlanta and Jot Em Down Tanks have been decommissioned. Table 6-3 summarizes the cost estimates and scheduling for recommended storage with the exception of the Forsyth County WTP clearwell tank. The costs associated with the expansion of the clearwell will be provided in a separate TM.

6-5


TABLE 6-3 Cost Estimates and Scheduling for Recommended Storage Tank Improvements Forsyth County, GA

Recommended Improvements a CIP Year Estimated Cost b ($) Comments

New Fowler Storage Tank 2010 $2,000,000 Post Road Tank recommended improvement relocated to the Fowler WRF property.

New Smith Road Storage Tank 2010 $530,000 Volumes needed in final solution are too large to satisfy 30% tank level turnover criteria.

Expanded Gilbert Storage Tank 2015 $1,200,000 Expanded from 1MG to 2MG Expanded Watson Storage Tank 2015 $1,200,000 Expanded from 1MG to 2MG

New Mollyview Storage Tank 2025 $424,000 Volumes needed in final solution are too large to satisfy 30% tank level turnover criteria

Total Storage Tank Improvements $5,354,000 a Forsyth County WTP clearwell and high service pump improvements presented in a separate TM. b All costs in 2007 dollars and include all construction/engineering/administration costs.

6.3 Recommended Pump Station Improvements Recommendations for new pump stations and the expansion of existing pump stations were determined by both the capital and operating costs. The final optimized solution recommended the expansion of the Forsyth County WTP high service pumps and new PSs at Post Road and Martin Road. The PS recommended for Post Road has been relocated to the County-owned property at the Fowler WRF. No improvements are recommended for the Castleberry, Old Atlanta, and Bramblett PSs since water is no longer supplied to the County from the City at these locations.

Table 6-4 summarizes the cost estimates and scheduling for recommended PS improvements for the new PSs at Martin Road and the Fowler WRF property and the expansion of the Jot Em DownPS. The pumping costs associated with the expansion of the clearwell will be provided in a separate TM. The cost of the Martin Road PS includes the capital cost for one duty and one standby pump sized for maximum flows under 2025 MDD. Currently, the Hopewell PSsupplies water to the super high zone. The duty pump at the new Martin Road PS would only operate in conjunction with the duty pump in the event that the Hopewell PS fails or goes off line.

6-6


TABLE 6-4 Cost Estimates and Scheduling for Recommended Pump Station Improvements Forsyth County, GA

Recommended Improvements a CIP Year Estimated Cost b

($) Comments New Fowler Pump Station 2010 $500,000

Upgraded Jot Em Down Pump Station 2010 $120,00

Jot Em Down was decommissioned; extra duplicate mains are recommended along existing transmission mains from Forsyth WTP to the super high zone to eliminate low pressures during peak demand.

New Martin Road Pump Station 2015 $260,000

Controlled by trigger levels based on Smith Road Tank; sized to provide redundancy to the Hopewell Pump Station, in case it is taken off line

Total Pumping Station Improvements $760,000 a Forsyth County WTP clearwell and high service pump improvements presented in a separate TM. b All costs in 2007 dollars and include all construction/engineering/administration costs

Optimization was also used to develop pump controls for new pump stations or existing pump stations with time-based controls.

6.4 Recommended Pressure Zone In order to address both high pressures and to improve water supply to some developments within the service area, the optimization also considered adjustments to the pressure zone boundaries by selecting pipes to be closed, adding new pressure reducing valves (PRVs), or adjusting the settings of existing PRVs. In the optimized solution, the existing low and super high zone boundaries were modified to increase the total areas with the County’s service area. The new zones were shown previously in Figure 5-5. No capital costs have been included for the new PRVs in the final solution.

6.5 Annual Implementation Cost The total planning and implementation horizon utilized for this plan is 50 years, with implementation beginning in 2007 and projected to end in 2025. The total projected capital cost for the plan, excluding operating costs, water supply costs, and the expansion of the Forsyth County WTP and high service PS, is $71.6 million. This results in an average annual capital cost of almost $4 million. These projected costs do not include improvements associated with development, with the assumption that all development categorized costs will be funded by outside entities.

6-7



6-8

SECTION 7

Conclusions

The Water Distribution System Optimization Study performed by utilized a systematic and defensible process to develop this CIP. The study began by CH2M HILL building and calibrating a hydraulic model. This calibrated model was used as the tool to identify deficiencies under current conditions and under projected future year 2025 conditions. Once these deficiencies were identified, possible solutions were developed. These possible solutions were then utilized by Optimatics to formulate the GA optimization to identify the optimal, comprehensive solution to meet future demands under specified performance criteria. These optimized solutions have been prioritized and phased in this CIP for implementation by FCWSD.

In conclusion, this study has employed a clear and well-documented engineering process to develop this plan. This process will give FCWSD confidence that the best solution has been developed to meet customers’ demands in the most cost-efficient manner, providing quality service at a reasonable price. The plan serves as a roadmap for guiding FCWSD through the terrain of growth and expansion over the next 50 years of service to its customers.

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Final Report Water Distribution System Master Plan...System Master Plan project to create a...

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