Emergency Solutions, Dam Replacement
When Tropical Storm Irene unleashed its fury in the summer of 2011, the Greenfield Dam – an important water supply dam on the Green River – was in its path. The earth embankment section on the eastern side of the dam overtopped and breached, during a major flooding event estimated to exceed a 500-year storm. The event caused loss of the water supply impoundment, as well as washed out water supply pipes and the abutment of a covered bridge downstream of the dam.
Analyzing Solutions, Designing Dam Replacement
Our team first provided site evaluation, design, permitting, bidding assistance, and construction administration services to establish emergency coffer dams at the site. Then we moved ahead with preparing a dam replacement design. This include a hydrologic and hydraulic analysis, and then determining dam repair recommendations based on those results.
We provided final design, construction drawings and technical specifications that included an evaluation and repair of the concrete intake structure, a new concrete core wall, and replacement of the earth embankment. This included designing the placement of articulated concrete blocks over the embankment to protect against possible future overtopping events.
All of this involved working closely with the Town of Greenfield and regulatory agencies for this fast track project.
Tighe & Bond’s scope of services included site evaluation, design, permitting, bidding assistance, and construction administration services. We also provided permitting that included an emergency certificate from MADEP to perform work in and near the river, and a Chapter 253 Dam Safety Permit. In addition, we were on-site on a full time basis to observe the work for compliance with our design.