However, many of the areas requiring new conveyances are either heavily urbanized or established residential neighborhoods. Due to the environmental impacts associated with open-cut construction, and the long-term operational concerns associated with pump stations, more municipalities are identifying tunneling methods as their preferred means of installing gravity-based conveyance systems.
Mott MacDonald’s expertise in CSO and wastewater conveyances ranges from small-diameter pipelines constructed using microtunneling and horizontal directional drilling methods, to large machine-bored openings in excess of 40 feet in diameter.
Striking the right balance
The design of wastewater conveyance systems is dictated by the need to provide storage and/or conveyance of dry weather and/or wet weather flows. Depending on each project's design and operational criteria, we bring the right balance of tunnel alignment control, construction engineering, and suitability of final linings to meet the project's requirements.
A key element of our tunneling business is the engineering of CSO facilities. By combining our tunnel, shaft, and hydraulics engineering expertise, we are advancing the state of knowledge in the engineering of drop structures required to convey shallow flows to deep storage and conveyance tunnels. In combination with numerical and/or physical modeling, we can tailor innovative drop structure designs to meet unique project requirements.
Our wastewater-related capabilities include these:
- Facilities plan development
- Consent decree mitigation strategies
- Tunnel and shaft engineering
- Hydraulic engineering
- Corrosion control methods
- Odor control methods
- Drop shaft modeling
- Alternative final lining evaluations
- Construction schedules and estimates