By ecoRI News staff
Dams and culverts exist in abundance across Massachusetts, and many of these structures, according to the state Department of Fish & Game’s Division of Ecological Restoration (DER), are in poor condition and have outlived their design life.
Although removing or upgrading these structures can require significant up-front costs, stream-restoration efforts mitigate flood risks, improve ecosystem function and relieve long-term financial burdens, according to DER.
Last year the agency commissioned a study to see how the costs of removing a dam or replacing a culvert to meet Massachusetts stream-crossing standards compared against maintenance or replacement with an in-kind structure. The study looked at costs for completed projects and used engineers’ analyses to develop estimates of what the costs would have been if the dams had been repaired or culverts had been replaced in-kind.
In short, the study found that the average cost of the six stream-barrier-removal projects was significantly less than the expense of repairing and maintaining existing structures over a 30-year period. On average, removal of the dams in the study was 60 percent less expensive and upgrades of the culverts was 38 percent less expensive, according to the study.
In addition to the cost comparison, other additional community benefits were researched, including avoided costs of flood damage and improved aesthetic conditions of the landscape.
Here are some key findings from two of the project sites:
Whittenton Dam removal (Taunton)
Removed public safety threat.
Avoided costs of emergency response due to dam-failure potential of at least $600,000 over the next 30 years.
Avoided costs to regional businesses of closures due to flooding or evacuations.
Increased habitat connectivity for native fish, including river herring and American eel.
Drift Road Culvert upgrade (Westport)
Avoided costs to the municipality of up to $150,000 for active management of flooded roads for 4-10 days a year.
Avoided travel delays for 12,000 to 30,000 travelers annually.
Improved habitat conditions for recreational and commercially valuable fish, such as American eel and brook trout.