Raising Dam 1-1/2 Feet Wouldn’t Hurt River, Researchers Predict

Raising Upriver Dam may anger fishers and silence rapids, but researchers predict it would do little damage to plants along the Spokane River.

City engineers want to add 1-1/2 feet to the height of the dam, located near Felts Field airport, to generate an additional $170,000 worth of electricity each year. The extension would add another half mile of slack water to the pool that extends four miles behind the city-owned dam.

Researchers Michael Folsom and Robert Quinn counted 142 trees and numerous shrub thickets they believe would be drowned by the rising water.

Most of the lost shrubs and trees - serviceberries, ponderosa pines, elm, black locust and others - would take years to die, wrote the Eastern Washington University geographers. They would be replaced as the rising water creates a new, still-narrow riparian zone.

“The net result, in the absence of chain saws and bulldozers, should be a virtually complete replacement of the present riparian and wetland communities along the shoreline,” it states.

Biologists say riparian zones - moist, sometimes flooded areas along rivers where a variety of plants grow in dense communities - are among the most important homes for wildlife. Such areas also are among the most threatened wild areas nationwide, as streams are diked and shorelines developed.

According to the report, the riparian zone along the Upriver pool already has taken a beating. It is thinner than on portions of the river with no dams, where fluctuating water levels provide irrigation for a wide band of plant life.

About two miles of the pool is west of Argonne Road, where lawns and concrete walls have replaced wild plants.

Many walls were built without permits between 1986 and 1991 with money provided by Spokane taxpayers. The city spent $225,000 during those years buying strips of shoreline from 91 owners in anticipation of the dam-raising.

City engineers encouraged landowners to spend the money building bulkheads so their property wouldn’t wash away when the dam was raised.

Upstream from Argonne, there is less development. Still, the riverbank is too steep and the water level too well-regulated for water-loving plants to grow more than a few feet from the river, the report says.

Opponents of the project say the extension would hurt wild trout populations and flood a series of rapids just upstream from the Centennial Trail bridge near Plantes Ferry Park.

A study last year concluded that trout spawning beds near the bridge are not productive.

The $8,000 city-funded plant study is part of an environmental impact statement required by the Federal Energy Regulatory Commission.

There’s no telling when the environmental study will be completed, said an FERC spokeswoman.

Once it is done, people will have a chance to comment, then FERC will decide whether the city can raise the dam.

City engineer Mallur Nandagopal said the project would cost about $900,000.

Much of that money - including the $225,000 for buying land that would be flooded - already has been spent.

, DataTimes ILLUSTRATION: Graphic: Proposed Upriver Dam water level increase