Dam may grow to meet increased water needs

Proposal would double storage capacity of dam

Mateusz Perkowski
Capital Press Staff Writer

January 5, 2007

Demand for water in rapidly growing areas such as Oregon's Willamette Valley has the potential to turn farmers, suburbanites and environmentalists into fierce rivals, if not outright foes.

Growers need to irrigate their fields regardless of the dishes that need washing or toilets that need flushing in new housing subdivisions, and conservation groups continue to push for watershed restoration, which by definition requires cool, freely flowing water.

In anticipation of the looming conflict, Clean Water Services - the agency responsible for managing storm and wastewater systems in the Tualatin River Basin - plans to nearly double the region's water storage capacity in Henry Hagg Lake near Forest Grove, Ore.

"We don't want to become the next Klamath Basin," said Tom VanderPlaat, the agency's water supply project manager. "There are quite a few competing uses for the water, so we want to be sure to balance those uses.

Clean Water Services' upcoming proposal to raise the Scoggins Dam at the southeast corner of the lake by up to 40 feet may seem reasonable and farsighted, but the plan has a long list of obstacles to overcome before it can become a reality.

Not only will the $300 million project need to pass muster on various governmental levels to win funding and bureaucratic approval, but it must also deal with logistical issues - the immense increase in water level will affect surrounding private property, displace popular recreational areas, and force rebuilding or relocation of half the existing roads that encircle Hagg Lake.

The agency is now working on completing an environmental impact statement that will meticulously outline the effects raising the dam will have on both wildlife and human habitat in the Tualatin Basin.

The idea first came about when Clean Water Services launched its water supply feasibility study in 2000. With that analysis well under way, VanderPlaat hopes to open his findings to public review in 2007, finalize the plan by 2008 and, if all goes well, begin construction between 2012 and 2015.

"There's a lot of steps as far as the process goes," VanderPlaat said.

Currently, the water stored in Hagg Lake serves about 500,000 people. If the dam is elevated, its maximum active capacity will expand from about 53,000 acre feet to more than 105,000 acre feet, allowing the facility to serve twice as many people by 2050.

When this happens, the amount of water reserved for the estimated 400 farmers who irrigate about 17,000 acres of grass seed, wheat, corn, nursery stock and other crops in the Tualatin Valley Irrigation District will remain the same. Roughly 70 percent of the newly stored water will be allocated for municipal and industrial uses, while the remainder will be devoted to water quality improvements.

"There are opportunities for a continued, shared partnership with agriculture," said VanderPlaat, adding that if not for the urging of Henry Hagg and other local farmers in the mid-20th century, the water supply procured by Scoggins Dam would not exist at all. "Agriculture is the reason it got established."

Despite the eventuality of decreased winter water flows in Scoggins Creek - which connects the dam with the Tualatin River - the net ecological effect in the basin is expected to be positive because more water will be available in-stream during the hot summer months, said Jeanna Cernazanu, the agency's public involvement coordinator.

For more information on the proposal to raise the Scoggins Dam, visit www.cleanwaterservices.org or call 503-681-3600.