Exploring Regional Water System Interconnections in the Triangle 95 TH Annual Conference | November 2015 | Raleigh Convention Center, Raleigh, NC Jeff Cruickshank, Hazen and Sawyer Steve Brown, Town of Cary

Presentation Outline Project Background Technical Aspects Modeling Examples Conclusions 2

Interlocal effort begun in 2009 to coordinate planning and further development of the regional water supply to meet future needs Local government led initiative – demonstrate that local leadership can solve regional water planning challenges What is the Jordan Lake Partnership? 3

Long term sustainable and secure regional water supply for the Research Triangle area. Purpose of the Partnership 4

Apex Cary Chatham County Durham Hillsborough Holly Springs Morrisville Orange County OWASA Pittsboro Raleigh Sanford Wake County Who are the Partners? 5

Water Service Areas 6

Water System Connections 7

A secure, sustainable water supply for the region Promote water conservation and efficiency Model cooperation and communication Provide a forum to address mutual interests and work through challenges Ensure regional/basin-wide ability to meet long term water supply needs The Partnership does not… Make ANY policy decisions What are the Goals? 8

Partnership Next Steps Plan future infrastructure investments Western Intake, treatment and transmission facilities Regional interconnections Broaden focus of regional collaboration Emergency response planning Water efficiency education Water shortage indicators 9

JLP Interconnection Project: Phase 1 Mapped all 42 interconnections for the first time Used GIS for pressure-zone level of detail Tabulated key information about each system: production capacity demand tank overflows and volume Described each system’s: facilities vulnerabilities limitations 10

Phase 1 Map 11

Phase 2: Interconnection Modeling Scope and Approach Began by compiling laundry list of modeling requests Consolidated requests into 13 modeling projects Specified two-way transfers for all projects Considered sustainable flows for long durations Outlined an incremental approach for building combined model to provide info as project progressed 12

Phase 2 Approach: Identify Limitations Pressure Zone Pumps or PRVs Pipe Capacity Supplying System Interconnect Receiving System Control Valve or Pumps Production Capacity Interconnect 13

Modeling Approach: Extended Period Simulations Steady state not good enough for sustainability and full impacts Extended period simulations check pumps & tanks over time Multiple connections analyzed simultaneously – interactions Steady StateEPS 14

Model Demands Agreed Upon by JLP 5-month summer average for supplying systems Maximum week in receiving systems Diurnal patterns applied to demands in each system 15

10 Modeling Projects in Phase 2 Scope Each provides information requested by Partners All determine limitations on sustainable flows with current infrastructure Most include testing improvements to increase transfer capacity to achieve specified targets Nearly all involve two-way transfers Projects ordered to build combined model incrementally 16

Hydraulic Model Status for Phase 2 PartnerModel ? Demands Updated Infrastructure Updated Last Calibration Software Used ApexYes2005 WaterCAD CaryYes2008 InfoWorks Chatham CountyYes WaterGems DurhamYes WaterGems HillsboroughYes WaterMax Holly SpringsYes2012 InfoWater MorrisvilleIncluded in Cary Orange CountyNoN/A OWASAYes2011 WaterCAD PittsboroYes WaterCAD RaleighYes2014 InfoWater SanfordYes2007 InfoWorks 17

Technical Challenges Maintaining unique IDs for model elements Designating active pipes to model 2016 conditions Debugging vestiges of model conversions - units Adding interconnection details 18

Project 1: Convert and Combine Models of Cary and Durham Converted InfoWorks and WaterGEMS models to EPANET and imported into new InfoWater model 39,000 pipes 5 modeling tasks Durham Cary Main Zone (568) SE High Zone (615) Western Pressure Zone (540) Central Pressure Zone (641) Southern Pressure Zone (595) High Zone (700) 19

57,000 pipes 8 modeling tasks OWASA Durham Cary Main Zone (568) SE High Zone (615) 640 Zone Central Pressure Zone (641) Southern Pressure Zone (595) High Zone (700) 740 Zone Western Pressure Zone (540) Project 2: Add OWASA 20

Project 3: Add Hillsborough 58,500 pipes 3 modeling tasks OWASA Durham Cary Main Zone (568) SE High Zone (615) Central Zone (737) High Zone (700) North Zone (814) South Zone (832) Hillsborough Closed valves between Hillsborough and OWASA 21

Project 4: Add Apex and Holly Springs 63,000 pipes 3 modeling tasks Hillsborough Durham OWASA Cary Apex Holly Springs

Chatham North Chatham Ashbury Chatham Southwest Hillsborough OWASA Durham Cary Apex Holly Springs Chatham County US 64 Project 5: Add Chatham County 65,000 pipes 2 modeling tasks 23

Project 6: Add Raleigh 137,000 pipes 120 mgd demand 8 WTPs 24

Example Project: Move Water Between Cary and OWASA Through Durham From Cary to OWASAFrom OWASA to Cary 25

Identifying Pipes Limiting Transfers Head Loss in 2-foot increments 26

5.9 mgd Sustainable Flow from OWASA through Durham to Cary & Apex 5.74 mgd By gravity 4.2 mgd by gravity at I-40 meter 616 Zone Apex 5.74 mgd Max Week 641 Zone Cary 26.2 mgd Max Week 540 Zone 3.1 mgd Davis BPS 2.8 mgd Intermittent NC 55 BPS 1.7 mgd by gravity at NC 54 meter Durham 28.9 mgd Max 5-mo 568 Zone Jones Ferry WTP 13.7 mgd 28.9 mgd Durham WTPs OWASA 6.83 mgd Max 5-mo 640 Zone 26.0 mgd Cary/Apex WTP 27

Pressures Changes with Flow from OWASA through Durham to Cary & Apex In OWASA 27 psi max drop near Durham In Durham 10 psi max rise near OWASA 22 psi max drop near Cary In Cary 16 psi max rise near Durham Pressure Change 28

Predicted Tank Performance Shows Transferred Flows are Sustainable Red: OWASA Green: Cary Blue: Durham 29

Interconnection Modeling Summary Bridged the gap between thinking about interconnection transfers to seeing how they work Explored and quantified sustainable flows Tested interconnections without affecting costumers Developed operating procedures – no surprises 30

Potential Benefit: Reduce Water Supply Costs By Sharing Surplus Capacity 31

AWWA Supports Regional Approaches 32

Acknowledgements Jordan Lake Partnership: Steve Brown, Co-author Sydney Miller, Project Manager Hazen Modeling Team: Jinggy Espinosa Todd Davis Kevin Widderich Wayne Zhang 33