When anyone alleges that they have a deal for me that seems to be too good to be true, it usually is (too good to be true) and sometimes the deal is not just a bad idea for me but has a broader impact.
The ode to Bill Scully in the newspaper recently is one of those too good to be true deals (”Bill Scully’s advice to Vermont: Go hydro,” July 15). Yes, Mr. Scully was an advocate for refitting long abandoned dams for hydro power. It seems like a good deal since the dam exists, water continues to flow over the dam, so why not produce power? The unsubstantiated expectation that the power will be cheap and renewable makes it seem we are already most of our way to the honey pot at the end of the rainbow.
Like all deals that are too good to be true there are costs, risks, and liabilities cloaked in the fine print. The fine print truth about all dams is that they damage rivers, and all dams have the potential to harm us. We all understand that dams block the migration of fish upstream as they search for spawning habitat. Although most people think only of anadromous fish like the Atlantic salmon when they think of migrating fish, all species of trout and several species of bass migrate from larger rivers like the Connecticut River into smaller tributaries to search out the right habitat for successful spawning. Dams that block their migration diminish the ability of nature to supply our streams with our resident fish. Along with blocking migration, all dams by their very existence allow the sun to heat up the water held in the reservoir beyond normal levels. Think about it: slow moving water with no trees shading it from the sun and as the temperature of water rises as it must from direct solar gain, the level of dissolved oxygen in the water declines. It is a simple matter of the physics of water and oxygen. Not only can low levels of dissolved oxygen stress or kill the aquatic species in the reservoir but the water that flows through or over the dam affects the river itself for miles downstream. Along with threatening the ability of aquatic organisms to breath, dams trap silt. Virtually all aquatic species at some point in their life cycle rely on the interstitial space (gaps) under and around the rocks, downed trees, and larger gravel found on natural stream bottoms. When (not if) the silt builds up behind a dam, it fills the habitat space around the rocks in the reservoir area that not only blocks water from circulating around the rocks and gravel, obviously severely restricting the ability of organisms to get food and oxygen from the water, but it is somewhat akin to someone backing up a 10-wheel dump truck load of silt to your living room window and dumping it in. The house may still be there, but you could not live in it. Unless specifically engineered to do so, dams offer no help controlling floods since the trapped silt behind the structure not only covers and destroys the open cobble habitat on the bottom of the river, but that silt is filling up any flood water storage space behind the dam. If you observe water flowing over the top of a dam during normal flow conditions there is no flood storage capacity behind the dam. Yet these dams still hold back significant amounts of water and silt slurry, and as dams deteriorate the odds increase that they will collapse under the stress of high water. If the owner does not maintain a dam, Mother Nature eventually will tear it down. Dams are expensive to build and maintain. Most of the remnant small dams we see are no longer sound and to turn them into hydro dams is a hugely expensive proposition. And NO, it is not the cost of permitting that is the major cost to put a dam back into working condition; the cost is in the construction and operation of a dam that does the least amount of damage to the aquatic environment and to assure that the dam will not jeopardize the infrastructure (roads, bridges, culverts) as well as the safety of people who live downstream from the dam should it give way. The remnant dams that litter our waterways and excited Mr. Scully were abandoned because the owners could no longer support them even in previous eras when there were no requirements to protect the environment and neighbors. It seems like a bit of Hydro-Pollyanna dreaming to think that, now that the full costs of environmental and safety impacts must be borne by the facility, and rightfully so, the dams would suddenly become capable of producing income sufficient to maintain sustainable power production and assure ongoing safety.
My counteroffer for a deal on energy is to conserve, conserve, conserve, and unless a dam has an essential economic or social function, remove it. If you do, you end up with a healthier river and you will not be worried about the dam giving way the next time we have flood waters in our rivers.