Harpers Hill Reservoir and Lochinvar Trunk Main Upgrade
About the project
Pensar delivered the Harpers Hill Reservoir and Lochinvar Trunk Main Upgrade for Hunter Water Corporation, a major potable water infrastructure project supporting the Maitland and North Rothbury water supply network. The project increased potable water storage capacity and improved water security for the growing Lochinvar, Branxton, Greta, North Rothbury and Huntlee areas.
The works replaced the existing 0.9ML Harpers Hill Reservoir with a new 7ML reservoir and delivered a new 2.4km DN375 trunk main from Lochinvar 2 WPS to the reservoir site. The upgrade also included associated civil, mechanical, electrical, instrumentation and control works, access upgrades, testing, commissioning and operational handover. The works were delivered across two separable portions.
Location
Harpers Hill, New South Wales
Client & Duration
Hunter Water
Jan 2024 - Mar 2026
Project Scope
Harpers Hill Reservoir
- Design and construction of a new 7ML potable water reservoir
- Demolition and disposal of the existing 0.9ML steel reservoir
- Bulk earthworks, civil works, reservoir base slab, walls, roof, vents and associated structures
- Reservoir pipework, valving, flow metering, chemical dosing allowances, control upgrades and associated ancillaries
- Electrical, instrumentation and control works
- Extension and upgrade of Harpers Hill Lane to provide all-weather access to the reservoir site
- Testing, commissioning, restoration and handover documentation
Lochinvar Trunk Main
- Construction of a new 2.4km DN375 trunk main from Lochinvar 2 WPS to Harpers Hill Reservoir
- Trenching, pipe installation and road reserve works
- Trenchless crossings, including under-road bores
- Service location and management of existing utilities
- Tie-in works between the trunk main and reservoir infrastructure
- Testing, commissioning, restoration and handover documentation.
Challenges
- The works were delivered across two separable portions with different delivery models: design and construction for the reservoir, and construct-only delivery for the trunk main
- The trunk main alignment crossed roads, residential areas, creek crossings, private property and multiple utility interfaces
- Existing services in the road reserve required live utility management, service proving and realignment of trunk main sections to reduce conflicts
- A medium pressure DN250 gas main required utility coordination, clearance management and construction controls
- Aboriginal heritage constraints and significant artefacts encountered during works required heritage management and stakeholder coordination
- Major reservoir concrete pours required detailed planning, including an 8m high in-situ wall section delivered in one lift.
Achievements
- Delivered a major potable water storage and trunk main upgrade, improving network capacity and water security
- Targeted planning, procurement and stakeholder engagement supported accelerated delivery
- Reservoir design elements were optimised with Hunter Water, including inlet and outlet locations, roof grades and metalwork materials
- Approved departures from Hunter Water standards improved constructability and design efficiency
- Trunk main sections were realigned away from live services, reducing construction risk
- The project recorded no work-related injuries.