WESTERN CARY WATER STORAGE TANK Town of Cary Preliminary Engineering Report Progress Meeting June 8, 2015

Agenda Preliminary Engineering Report Recap – Hydraulic Model Evaluation – Western Cary Booster Pump Station – Western Cary Elevated Storage Tank – Water Main Improvements – Pressure Zone Boundary Connections – Opinion of Probable Cost Next Steps – Finalize Preliminary Engineering Report – Begin Design

WESTERN CARY HYDRAULIC MODEL EVALUATION

Western Pressure Zone Boundary Revisions – Reconfigure 30- and 42-inch transmission mains from Cary/Apex Water Treatment Facility to both feed CPZ – Remove Davis Drive PRV – Install new PRV on 30-inch main along Hwy 55 north of Jenks Rd – Open valves along current WPZ/CPZ boundary – Modify or abandon existing connections along new pressure zone boundary – Install 12” WL from Hwy 55 to Roberts Rd

Waterline Improvement Phasing – 2016 CPZ-1 (in design) WPZ-12 (20”) north of Western Cary Tank to existing 12” WPZ-23 (12/16”) Green Level West (developer driven) Nwy 55 north of Lewey Dr (12”) Kit Creek Road (12”) Roberts Road (12”) – 2025 WPZ-18 (12”) White Oak Church (developer driven) WPZ-22 (12”) Green Level Church/Roberts Rd (developer driven) Parallel 20” on Hortons Creek Rd – Build-Out Morrisville Parkway (12/16”) WPZ-14 (12”) McCrimmon Pkwy WPZ-19 (16”) Parallel on Green Level Church Rd WPZ-16 (16”) Carpenter Fire Station Rd gap

Emergency Scenarios 1.36” CPZ Break (east of Hwy 55) – Can keep CPZ EST from draining empty and maintain pressures through build-out 2.42” Jenks Rd Break – 2016: Can keep CPZ EST from draining empty and maintain pressures – 2025: CPZ EST empty in approximately 20 hours – Build-out: CPZ EST empty within first few hours 3.Carpenter Tank Out-of-Service – Jenks Rd & Hwy 55 PRV open during peak hour demands to avoid pressure <50 psi along Hwy ” Jenks Rd Break and Carpenter Tank Out-of-Service – Pump continuously from WPZ to CPZ via Western Cary ground storage tank – 2016 & 2025: Can keep CPZ elevated tanks from draining empty and maintain pressures (ADD) – Build-out: CPZ EST’s empty in approximately 72 hours (ADD)

WPZ Storage Requirements by Planning Period *Chatham demands included only for build-out StorageFactor Build-out Equalization20% of MDD Fire Flow3,500 gpm x 3 hours 0.6 Emergency*40% of Summer ADD Total Storage Required The Town currently has 2.0 MG of storage in the Carpenter EST In order to meet future demands, the Town decided that the Western Cary EST should be 2.0 MG in volume

Western Cary Tank Improvements New 2 MG Elevated Storage Tank – Composite and Hydropillar to be bid New Booster Pump Station – Engineer design with pre-manufactured concrete building New Waterline – Hortons Creek Road – Good Hope Church Road – Roberts Road Pressure Zone Boundary Connections – Modify 3 connections for emergency use – Remove 12 existing connections

WESTERN CARY ELEVATED STORAGE TANK

Western Cary Elevated Storage Tank Western Cary EST will store equalization, fire flow, and emergency water for WPZ and well as supplement peak demands in the CPZ Three infrastructure improvements were considered: – Elevated storage tank – Elevated and ground storage tank – Combined elevated and ground storage tank The Town decided to move forward with the design of an elevated storage tank

Western Cary Elevated Storage Tank Style StyleCost Multi-Leg$5.4M Pedesphere$7.2M Composite$3.9M to $4.5M Fluted Column$4.5M to $4.7M The Composite and Fluted Column (Hydropillar) styles will both be bid.

Western Cary Elevated Storage Tank Operation WPZ– The Western Cary EST will float on the WPZ. CPZ– The Western Cary BPS will pump out of the Western Cary EST and into the CPZ during periods of high demand. Emergency Operation – The Western Cary EST can be continually pumped into the CPZ while the WPZ High Service Pumps meet the WPZ demands.

WESTERN CARY BOOSTER PUMP STATION

Western Cary Booster Pump Station Usage Western Cary Booster Pump Station (BPS) will be utilized to facilitate turnover in the Western Cary EST and aid in meeting high demands in the CPZ As demand increases in the WPZ, the need to pump out of the Western Cary EST for water age reasons decreases During emergency operation the Western Cary BPS will provide continuous transfer of water from the WPZ into the CPZ

Booster Pump Station Operation Demand Scenario WPZ Demand (mgd) Daily Operation Western Cary Tank Average Water Age 2016 ADD2.2 None7.9 days 8 hours per day4.6 days 2016 MDD3.65 hours per day4.0 days 2025 ADD3.9None4.8 days Build-out ADD 7.4None3.7 days Pump run times are based solely on keeping water age under 5 day threshold Assumes pumping rate of 1,800 gpm

Proposed Pump Characteristics EquipmentDescription Pump TypeCanned Vertical Turbine Number of Pumps3 Flow per Pump Design Point900 Total Head Design Point125 Efficiency Design Point84 Motor Horsepower50 Pump ManufacturerFairbanks Morse

Pumping Summary Pumping Scenario Flow Rate (gpm) EQ Volume High Water Level EQ Volume Low Water Level Tank Low Water Level 1 Pump Operation 1,0501, Pump Operation 2,0001,8501,350 3 Pump Operation 2,8002,6001,900 All pumps will run off of variable frequency drives and the third pump will be designed to turn on in emergency scenario Summary of flow rates at 100% operating speed for different pumping scenarios is provided in table below

WESTERN CARY WATER MAIN IMPROVEMENTS

Water Main Improvements Three separate water main improvement recommendations were identified during hydraulic model efforts: – CPZ Connection – WPZ Connection – Roberts Road Improvements

CPZ Connection – Good Hope Church Road Approximately 3,200 feet of 16-inch waterline along Good Hope Church Road from the Western Cary EST and BPS site into the CPZ Includes trenchless crossings of the CSX railroad, Saunders Grove Lane, and Morrisville Carpenter Road

WPZ Connection – Hortons Creek Road Extension Approximately 4,200 feet of 20- inch waterline along a portion of NC-55 ROW and then cross country along a proposed Unnamed Collector Road and future Hortons Creek Road extension Includes trenchless crossings of NC-55 and open-cut underneath an existing NC-540 bridge

Roberts Road Improvements Approximately 1,800 feet of 12-inch waterline from the NC-55 and Jenks Road intersection to Roberts Road This waterline will eliminate the 30- inch diameter dead-end on NC-55 that would otherwise be created with the pressure zone boundary modification

WESTERN CARY PRESSURE ZONE BOUNDARY CONNECTIONS

Pressure Zone Boundary Connections Connections were divided into two categories: – Non-Emergency – Connections that will be abandoned and create a permanent separation between the WPZ and CPZ – Emergency – Connections will act as a semi-permanent barrier and will utilize a PRV so that in emergency scenarios, the Town could open the connection and allow water to flow from the CPZ into the WPZ Remove existing WPZ and CPZ pressure zone boundary PRVs

Waterline Modifications 3 Emergency Connections – 3 PRVs – 4 Hydrants/Blowoffs – 1 Isolation Valve – Waterline 12 Non-Emergency Connections – 10 Isolation Valves – 3 Tees/Elbows – 3 Hydrants – Waterline

WESTERN CARY CONCEPTUAL OPINION OF PROBABLE CONSTRUCTION COST

Opinion of Probable Construction Cost – Hydropillar Style Tank

Opinion of Probable Construction Cost – Composite Style Tank

WESTERN CARY QUESTIONS?

Emergency Scenario 1 36-inch CPZ feed east of Hwy 55 out of service Assume 36-inch for CPZ-1 Assume max day demand Can keep CPZ elevated tanks from draining empty and maintain pressures through build-out

Emergency Scenario 2 42-inch Jenks Rd Pipe out of service Assume max day demand Pump continuously from WPZ to CPZ via Western Cary ground storage tank – One ground storage pump on in 2016 – Two ground storage pumps on in 2025, build-out 2016: Can keep CPZ elevated tanks from draining empty and maintain pressures 2025: CPZ elevated tanks empty in approximately 20 hours Build-out: CPZ elevated tanks empty within first few hours

Emergency Scenario 3 Carpenter Tank out of service Assume average day demand Jenks Rd & Hwy 55 PRV open during peak hour demands to avoid pressure < 50 psi along Hwy 55

Emergency Scenario 4 42-inch Jenks Rd Pipe & Carpenter Tank out of service Assume average day demand Pump continuously from WPZ to CPZ via Western Cary ground storage tank 2016 & 2025: Can keep CPZ elevated tanks from draining empty and maintain pressures (ADD) Build-out: CPZ elevated tanks empty in approximately 72 hours (ADD) Results similar to Emergency Scenarios 2 and 3

Western Cary Booster Pump Station Design Three pump station design options were considered for the Western Cary BPS – EST Column Design – Placing pump station inside of EST column with separate building for electrical equipment. Option was eliminated by the Town and therefore costs were not developed – Pre-packaged Design – Use of a pre-packaged pump station designed and built off-site – Engineer Designed – Design of pump station would be by CDM Smith specifically to meet the project needs Pump Station DesignConstruction Cost ($) Pre-packaged$790,000 Engineer$815,000 The Town decided the Western Cary BPS should be designed by CDM Smith

Western Cary Booster Pump Station Building Three building options were considered for Western Cary BPS – Pre-Packaged Building – Building supplied by manufacturer of pre- packaged pump station – Pre-Manufactured Building – Steel or concrete panels designed off-site and erected around pump station – Built On-site Building – Design of building would be by CDM Smith specifically to meet the project needs Building DesignCapital Cost ($) Pre-Packaged$530,000 Pre-Manufactured Steel$425,000 Concrete$605,000 Built On-site$543,000 The Town decided the Western Cary BPS should be housed inside of a Pre- manufactured concrete building