Consider low-cost alternatives to breaching

By MICHAEL HARRINGTON
Special to the Journal

Stopping the impending extinction of this region's salmon is the greatest engineering challenge of our time. Unfortunately, current bureaucratic thinking has it that the best solution is dam removal. As an environmental engineer, I feel compelled to discuss inevitable consequences of dam destruction and propose new, more effective alternatives.

It speaks highly of our moral values that we would even consider the tremendous sacrifices associated with dam removal. But just how many dams must go? Hypothetically, let's ignore the costs and unforeseen environmental impacts of dam removal, such as releasing an avalanche of accumulated sediments. Assume a few expendable' dams are now gone, time has passed and all changes have been accurately documented. There are only three possible conclusions that can be reached:

1. Salmon runs have continued to diminish at previous rates, results are inconclusive and the removal of more dams is required to test the theory,

2. Salmon populations are now declining at an accelerated rate, costlier dam removal procedures are required in the future, or

3. Salmon numbers are increasing, the theory works and more dams must go.

Regardless of the outcome, once the destruction begins, dams will topple like dominoes.

The Pacific Northwest would stop exporting hydroelectric power and begin importing. Nationally, electric bills skyrocket. The poor could no longer afford to cool or heat their homes. Vast irrigation systems dry up. Entire counties would see productive farmland revert to sagebrush and sand. Once-protected riverside communities again experience the sudden devastation and massive floods.

Instead of raising deaf and naive food for other animals, hatcheries need to start producing fish that are frightened, paranoid and fast.

I propose a number of new, less costly and radical ideas that should be considered.

Begin by abandoning our linear, anthropocentric thinking and attempt to experience the world as a fish does. For example, all bony fish possess a sense labeled the lateral line. This sense allows fish to perceive motion from all sides and enables large schools to turn, seemingly as one. It is critical for predator evasion, especially in dark or turbid waters.

Yet our hatcheries have been constructed in such a manner as to almost completely obliterate this sense via the insensate pounding of adjacent pumps. We release smolt that have never known natural silence. How hard would it be to dampen or, better yet, completely eliminate the constant underwater vibrations? Not only have our hatchery fish had their critical evasion sense deadened by design, but the schools have also gotten a rotten education.

The fish have been fed, historically, by periodically hand broadcasting pellets on the surface. This conditions the fingerlings to wait in the most dangerous of possible places, out in the open, near the surface. Their stupidity is reinforced every time they are fed. The featureless concrete raceways provide no incentive to be anywhere else.

Rearing tanks should be lined with boulders, rocks, gravel and vegetation. Give the fish places and reasons to hide. A few sterilized, naturally occurring predators should be introduced. The loss of a few now would go a long ways toward preventing the destruction of all, later. Introduce a broad variety of naturally occurring foods randomly, with the currents.

Instead of simply raising deaf and nave food for other animals, we need to start producing fry that are frightened, paranoid and fast: stream smart.' We should stop using hatchery-raised fish for breeding stock, and instead select wild parents with more care than we give our racehorses.

States may be able to save money through privatization. The government could lease existing hatcheries to companies that would then invest by making my suggested modifications. But instead of the state paying for the number of fish released, compensate the private agencies only for the fish that actually return.

While hatchery practices are not the obvious scapegoats that dams are, they must be dramatically changed, if the destruction of rearing habitat is to be effectively offset.

Some changes in dam design

Dams remain an obvious obstacle. The question is how their design needs to change to facilitate the needs of fish. Salmon have evolved for eons with dam-like structures in rivers. It could be contended that dams have eliminated large waterfalls and actually make getting up river easier.

What's new and devastating, for the smolt going down river, is the dam's noise and turbine blades. What is needed is way to channel the fish away from turbine inlets and quiet the waters to naturally occurring levels. The Army Corps of Engineers is currently testing a $100 million, six-story, steel structure that physically guides fish away from the turbine inlets of the Lower Granite Dam on the Snake. Nothing is being done about the noise. I propose a design concept that could both quiet the dam's adjacent waters and guide fish from the turbine inlets with a single, simple and relatively cheap modification.

Creating a quiet zone

The underwater pounding of a hatchery's pumps is a gentle lullaby, when contrasted with the unnatural thunder of a dam's turbines. The vibrations are so powerful it is almost impossible to talk in a dam's deafening generator gallery. Underwater, the roar is orders of magnitude worse. Stunned by the sudden, overwhelming wall of noise, fish lucky enough to escape the blender blades, find themselves confused, disoriented and easy prey for the hungry hordes, waiting in the wash. A single Squawfish has been demonstrated to consume 10 smolt every day. Anyone who has fished below dams can attest to the localized, high concentration of these predators. Yet off-the-shelf' technology currently exists that would greatly alleviate the awesome, underwater noise pollution and associated predation.

Computers can record, analyze and almost simultaneously generate sound waves, which have the same amplitude as the offending source, but with exactly opposite phase. In effect, they can create white noise that can almost completely dampen and eliminate the offensive din. This technology has already been applied at airports and high-traffic areas. It works best when the sound is cyclic, re-occurring and predictable: precisely what is found at dams.

A system of strategically placed underwater speakers, so powered, could diminish the underwater rumbling thunder to a mild hum. This electronically created quiet zone would channel fish away from the loud, sucking turbine inlets and toward the silent, safe spillways. I believe that given a choice, small fish will opt for quiet, still waters over roaring turbulence. The emerging fry would better retain their natural lateral line sense and be more strongly equipped to escape the gauntlet of ravenous mouths. Returning adult salmon have elaborate fish ladders to help them up, past the dams. Leaving smolt need a safe, quiet zone to guide and protect them when going through the dams.

We already posses the technology to put these new ideas in place. Taking down a major dam has never even been attempted. Do we alter existing facilities to more closely mimic natural conditions or start bashing billions of dollars worth of working investments? The only certainty is that something must and will be done to save our region's salmon from extinction. You can help by copying and sharing these ideas with others.

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