14/01/2025

Nicholson Construction: Focus on the Clean Lake project in GeoStrata

The Clean Lake project, where Nicholson Construction has been involved in the construction of several storage tunnels, was recently highlighted in the October-November 2024 issue of GeoStrata( Geo-Institute of the American Society of Civil Engineers) magazine. A large-scale project designed to improve water quality in the Cleavland region.

Focus on the project

The metropolitan area of Cleveland, Ohio, is one of many United States cities facing the problems associated with an aging combined sewer overflows system. During heavy rains, frequent overflows impact waterways, notably Lake Erie, causing significant pollution.

To address this situation, the Clean Lake project was initiated to reduce stream pollution in the Cleveland area. This EPA-mandated, 25-year construction program aims to reduce annual overflows from 4.5 billion to less than 0.5 billion liters.

This $3 billion project includes :

Construction of large-diameter storage /conveyance tunnels.
Large pipes.
Strategic wells for wastewater collection.
Underground pumping stations.

The aim of this project was to increase the storage capacity of wastewater treatment plants in order to restore watercourses and reduce their pollution levels.

Nicholson Construction’s contributions

Nicholson Construction has played a key role in the construction of three of the seven Clean Lake tunnels installed to date.

Dugway storage tunnel
- Nicholson Construction installed secant piles to temporarily support the excavation. This work made it possible to build a baffle drop structure (to direct water by reducing its velocity.), as well as two rectangular gate structures, each connected to existing sewer systems on two separate sites.
Westerly storage tunnel
Our teams have :
- Installed an unreinforced diaphragm shaft 1.07 m thick and 46.33 m deep to support the excavation of a drop shaft.
- Built a 0.61 m thick, 21.64 m deep, steel-reinforced diaphragm wall to stabilize the connecting gate structure.
- Created an unreinforced diaphragm wall 0.91 m thick and 53.34 m deep to support an aeration shaft connected to a 6.1 m diameter drop structure.
Shoreline Tunnel

The teams have :
- Built three diaphragm -wall access shafts along the tunnel alignment, enabling the TBM to be deployed and retrieved.
- Casting three cement bentonite pavers with mass to break in/break out the TBM.
- Installed two soldiers pile to support the excavation of near-surface structures.