Project Spotlight - City of Rockaway Beach, McMillan Creek Reservoir

HBH designed a 2.0 million gallon bolted glass-fused-to-steel reservoir for the City of Rockaway Beach. The City had declared an emergency due to the loss of capacity in its existing reservoir coupled with a surge in growth. In February 2008, the City requested that HBH design a new reservoir and have it operational by July 3rd, 2008.

The Geotechnical Report revealed 35’ of unsuitable soils beneath the proposed reservoir site. After consultation with the geotechnical engineer and the owner, HBH decided to excavate the first 10’ and install stone columns for the remaining 25’ beneath the tank. These columns were installed at 10’ on center and saved the owner over $200,000 in over-excavation costs.

There are two primary companies that supply glass-fused-to-steel tanks. HBH met with both companies and discussed schedule, costs, and details of the project. There were some differences in each company’s design that had to be overcome in the contract specifications. HBH provided preliminary cost estimates for construction. After drilling the site and the determining to use stone columns, we worked with the City, Contractors, and maintenance to bring the project cost into control. The final construction bid for the combination of the tank and the stone columns fell within the initial preliminary estimate without the columns. HBH’s success with this bid was due to close contacts with both tank manufacturers and potential contractors.

Access to the site consisted of a single lane road. This created problems with delivery of material and construction timing, as the reservoir fill line was proposed in this roadway. HBH worked closely with the contractor to overcome this obstacle. HBH wrote an easement for the City to cover the access road and piping from a local resident and another for the reservoir site from Green Diamond Timber Company.

The design was completed in six to seven weeks and the reservoir reached substantial completion on July 3rd as scheduled.