In Hastings, Minnesota, a pioneering water main rehabilitation project keeps the streets clear for both a bi-weekly classic car show and an annual summer festival. More than that, it's helping the City usher in a downtown riverfront renaissance.
Like many historic riverfront communities, the City of Hastings, Minnesota, is in need of various downtown infrastructure improvements. However, it was not feasible for the City to construct these improvements – which include plans to renew Levee Park and downtown streets – without first rehabilitating the 100-year-old water main pipe beneath them. The water main rehabilitation would have to be completed with minimal impact to downtown businesses and popular summer weekend activities.
For this project, the City wanted to take particular care in minimizing disruptions to two highly popular local events. The first was the Saturday Night Cruise-In, a bi-weekly classic car show that draws hundreds of cars, car enthusiasts, and tourists to the streets of downtown Hastings. The second was the annual Rivertown Days celebration in mid-July.
The traditional dig-and-replace method was not optimal for the City because it would be too disruptive to not only these downtown activities but also daily downtown business activity. Also, the dig-and-replace method was considerably more costly than the City’s budget would allow. Directional drilling and pipe bursting were not chosen because of difficulties using these tools in Hastings’ shallow bedrock. The City chose structural cured-in-place-pipe (CIPP) lining as the method that best suited its needs.
The construction process began by digging small pits at intersections along the center of the street. By decreasing the size of the excavations, the project team was able to control the cost of rock excavation and reduce traffic disruption when compared to the dig-and-replace method.
After installing CIPP liner from these pits, the contractor used a robotic drill to reinstate building services from inside the rehabilitated pipe. Such an approach avoided the need to dig an additional pit in front of each building to reinstate service. In the end, there were only a few disturbances in front of buildings served by the pipe.
Often in CIPP projects, a temporary water main network is laid at the surface and atop the sidewalks. However, to avoid conflict with storefront access, the City and SEH developed a plan to take advantage of the many back alleys in the area and use them as the corridor to serve buildings from the rear.
Ultimately, this million-dollar project, which had small carbon and physical footprints, will facilitate the City’s future downtown revitalization efforts – known within the community as the “Riverfront Renaissance.”
SEH estimates that the City saved 40 percent of what it would have cost to rehabilitate its downtown water main pipe using dig-and-replace method. The social impact of the project, which sidestepped numerous potential pitfalls with local businesses and area stakeholders, is incalculable.
Paul J. Pasko III, PE, is a civil engineer, project manager and pipe health specialist. Contact Paul