134 year old earthen dam with concrete spillway. Overgrown with trees and vegetation. Portions crumbling off both sides.
To breech or not to breech? Remove or repair/replace?
These are the questions being debated in towns across the nation as they try to figure out what to do with aging dams that need repair. On average, dams in the U.S. are 56 years old, and there are almost 91,000 of ’em. Close to 20% of these are so-called “high hazard” potential dams, which are ones that would, if failed, put human life at the greatest risk. Many of these were not in this highest hazard classification when they were built, but as more people moved into the areas down stream more and more human lives were put at risk and they became high hazard.
The picture shows a high hazard installation in PA. This one impounds a reservoir that was initially built in the 1800s for ice harvesting (believe it or not) and recreation. The debate revolving around this dam illustrates many of the common concerns. Ownership is a particular theme in this case.
- The U.S. Army Corp of Engineers concluded the dam was in poor structural condition 37 years ago, and 31 years ago the road running over it was closed for safety reasons.
- The PA Department of Environmental Protection (DEP) considers it an “orphan dam” since no private or municipal organization has claimed ownership or responsibility, and as a result no repairs or maintenance occurred.
- A private entity owns the land upstream, the county owns the park downstream, and the borough historically maintained the road over the dam, but none claimed responsibility of the dam.
- Five years ago, the dam was in such bad shape, “entire pieces of the wall crumbled on the upstream and downstream side.”
- The DEP came in and lowered the lake behind the dam to the lowest level possible. An action they had to repeat two years later because no one took responsibly to maintain the lake level.
- The cost to replace it is estimated at $3.5-4 million. Removing it is less expensive than replacing it.
- Replacing it raises environmental concerns about the 1.1 acres of parkland that would be subsumed.
- Removing it raises environmental concerns about the harm to the habitat and animal life depending on the impounded pool.
- The decision was to breech it to lower the water and remove sediment to safe levels
- It is being paid for by state and municipal grants.
It is not surprising that no one has stepped up to claim ownership of the dam with all of its obligations. Removing or repairing/replacing is expensive and substantially borne by the taxpayers.
The LPS powered dam modules offer another alternative for discussion. These modules could be used to replace sections or all of a deficient dam to return it to health. With the recently enacted FERC fasttrack regulations for small hydro and conduit power, and most states’ favorable economics for renewable power, in addition to obviating transmission costs altogether, adding hydropower capability to a dam turns it into a moneymaker to more than offset the tax dollars expended on the dam repair or replacement.