The City of Evanston needed to build a new 5-million-gallon reservoir tank at the clearwell drinking water facility to support an expanding population. High attention to detail was required to construct the 265’ x 145’ tank, 25’ below grade, positioned directly between Lake Michigan and a large student dorm. The project featured a complex 5 phase earth retention system. The project was completed ahead of schedule with both stakeholders pleased with the execution and results while navigating 9 project stoppages for university events because the project was located on Northwestern University property. Northwestern even brought their construction and engineering students to tour the jobsite multiple times.

Improving views, enhancing community aesthetics, and adding new public space. The project site, originally an aging parking lot that detracted from the aesthetics of the area has been upgraded to green space for the residents of the adjacent Northwestern University (NU) dormitories and the community. Converting a parking lot into green space has not only improved aesthetics, but has also added a new public space, and provided a safe area for bikers and walkers, allowing them to enjoy the view of Lake Michigan and giving them better access to the beach. Furthermore, adding green space is aligned with one of the key strategies in the city of Evanston’s climate action and resilience plan.

Meaningfully engaging stakeholders. The project team established sound and meaningful programs for stakeholder identification, early and sustained stakeholder engagement, and involved stakeholders—including regulatory organizations, nearby communities such as NU, and Evanston’s wholesale water customers—in project decision-making. As part of the temporary construction easement that was required to perform the work, a partnership between Evanston and NU was formed. Working together, the two partners effectively achieved solutions with respect to any issues with project plans and specifications.

Implementing an innovative design. The project utilized an innovative underdrain collection system that provides many benefits, including protection against damage to the Clearwell from underground uplift forces; protection of the potable water supply from groundwater contamination; and significantly lowered capital costs, lowered energy use, and lower operations and maintenance costs over the life of the project compared to constructing a new pump station that would be required for an above-ground Clearwell. To implement this innovative design, the project team needed to overcome barriers—barriers in the form of current regulations that no longer allow for clearwells to be constructed below grade. The team successfully obtained a permit to implement this design from the Illinois Environmental Protection Agency after demonstrating the benefits and safety of the design.

Protecting the natural world. This project is protecting the natural world in many ways, including:

• Protecting nearby wetlands. Construction of this project would have been easier had the location been moved to the east side, away from existing NU dormitories; however, identified wetlands would have been impacted so this action was not taken.
• Preserving undeveloped land. Siting alternatives included moving the project to a greenfield, but ultimately the team and NU decided to site the project below an aging parking lot used by the University, and they converted the parking lot above the Clearwell to a much-needed green space.
• Protecting soil health. Most of the construction work was located within paved and developed areas; thereby, limiting the area disturbed by construction activities. Two small areas of green space, located to the north and south of the construction work area, were used as storage and staging for the contractor. All vegetated areas disturbed by development activities were fully restored with appropriate soil type, structure, and function to support healthy plant and tree growth. Furthermore, existing trees within the storage and staging areas were fully protected.