Water Conveyance
Population center growth is increasing the demand for additional sources of domestic, industrial, and agricultural water supplies. Compounded by issues associated with aging infrastructure, there is an increasing demand for linear conveyances requiring connections to new and existing water sources. Tunnels are increasingly viewed as the most cost effective or least environmentally disruptive means to achieve the required connections.
Whether for raw/potable water transmission or the generation of power, the engineering of water conveyance tunnels requires an appreciation of a range of construction and operational considerations, including:
- subsurface tunneling conditions
- groundwater hydrology
- insitu ground stresses as related to conveyance leakage
- hydraulics of confined and unconfined flow
- transient pressures
- lining requirements for long-term serviceability and maintainability
- head losses related to tunnel surface roughness
Hatch Mott MacDonald has engineered some of the longest and most challenging water conveyance tunnel projects in the world, and appreciates the significance of these complex issues. The breadth of our world-wide experience is brought to bear on every water conveyance tunnel project, no matter how small or large the assignment.
From the hardest rock to the softest clay conditions, beneath cities, rivers, oceans, or mountains, our extensive experience allows us to effectively identify the most appropriate tunneling technology. Depending on the ground conditions and internal and external hydraulic pressures, our tunneling team will evaluate the need for a tunnel lining, and if so, what type. We have engineered linings consisting of cast in place concrete, pre-cast concrete, troweled shotcrete, embedded or pre-stressed concrete cylinder pipe, steel pipe, or no lining at all.
Often, tunnel boring machines (TBMs) are the most efficient means of excavation. HMM has extensive experience in the evaluation of the right type of TBM for the project, whether contractor-selected or owner-specified.
Our water conveyance-related capabilities include:
- rock mass characterization
- TBM performance assessments
- lining /ground load transfer
- groundwater modeling
- hydraulic jacking testing
- assessment of Insitu stress
- water leakage assessments
- lining roughness / headloss evaluations
- dynamic modeling of transient pressures
- cavitation evaluations
- construction schedules and estimates
