INNOVATIONS ON THE HIMATANGI BEACH COMMUNITY SEWERAGE SCHEME Mike - PowerPoint PPT Presentation

INNOVATIONS ON THE HIMATANGI BEACH COMMUNITY SEWERAGE SCHEME Mike Fletcher – MDC Project Manager

• Present the key innovations that were able to deliver an affordable scheme for the Himatangi Beach Community • Innovations delivered 15% in capital savings

Overview • The Himatangi Beach Community Sewerage Scheme • Design Innovations • Design Approach

The Himatangi Beach Community Sewerage Scheme • The Himatangi Beach Community • Key Drivers • Procurement Methodology

The Himatangi Beach Community • Approx. 400 dwellings + Holiday Park + Community Facilities • 440 Permanent residents but Increases to 2500 during peaks • Deprivation Index 10 • Limited community support so connection is voluntary • 294 dwellings signed up plus Holiday Park & Community Facilities

Key Drivers • Growth • Environmental • Regulatory • Availability of funding

Procurement Methodology • Expressions of Interest • Tender • Contract award

Design Innovations • Sharing of pump stations • Electrical connections

Type %age of Peak No. Days/year %age of year flow Christmas Holidays 31%-100% 30 8% Other Long 50% 13 4% Weekends Other Typical 34% 86 24% Weekend School Holiday 33% 30 8% Weekdays Normal Weekday 23% 206 56% TOTAL 365 100% Summary of Peak Flow Estimates and Duration for Design

Parameter Value Pressure limit 60m Duty Flow 1 l/s Tank Capacity 900 litres Pump start level 170 litres Pump stop level 50 litres High level alarm 330 litres Emergency capacity 570 litres Alarm Level - 160 Litres Run Level - 120 Litres Empty Level - 50 Litres Selected Pump Station Unit Characteristics

Key On-lot pumping station Private gravity drainage Private rising main Public rising main Public Road Public Road

Electrical Connections

Design Approach • Scope and design development • Dynamic modelling

Scope and Interfaces Project Phase On-lot Works Interface Reticulation Interface WWTP Interface Irrigation Client - gravity drainage, PSU and pressure laterals Contractor Contractor Client (MDC) locations Design (Irrigation (Designer - (Process and Contractor Services Beca) Treatment (Mono - Pump Ltd) Upstream of boundary kits Pond) Supplier) - Hydraulic, civil, Upstream of screen structural Contractor Wet Well (Civils - HIL) Contractor M&E (ADG) Contractor Contractor (Irrigation Construction Services FTM (HIL) (HIL) Ltd) (Waterclean Technologies) Contractor Contractor M&E (ADG) Commissioning Contractor (HIL) (Irrigation (HIL) Services Ltd)

Dynamic Modelling • Considers pumps performance • Increased system optimisation • Modelling of system spatially • Allows system operation to be assessed Source: Beca Infrastructure Ltd (20 12) “ Himatangi Beach Community Sewerage Scheme: Design Report ”

Reticulation Layout

Relative Increase in Pipe Installed Cost vs Pipe Diameter 140% Relative increase in installed cost (%) 180 120% 100% 80% 125 110 60% 90 40% 75 20% 63 50 0% 0 50 100 150 200 PE Pipe Diameter (mmOD )

System Assessment • Identify sections in network reticulation over 6 bar • Identify which PSUs may not empty due to sustained system pressures • Pipe velocities • Retention times

Scheme Costs • Project value $9.25m (based on 500 HUEs) • Unsubsidised cost per connection $18,500 c.f. Typical costs for other NZ schemes range between $25,000 to $35,000 • Subsidised cost per connection $8,500

Summaries 1. Several key drivers ensured that the project received support from the community 2. The key design innovations produced significant capital cost savings 3. With defined scope and interfaces, the project team was able to optimise and test the system under future scenarios

Conclusion By using a collaborative approach with a focus innovation, the project was able to deliver an affordable sewerage scheme for the Himatangi Beach community

The Future post SWSS??? • SWSS ended June 2013 • MoH have no plans to replace scheme • TLA’s need to lobby MoH for new central government funding to make these schemes affordable for property owners and TLAs