Washington is home to some of the world’s most important and famous dams, including Grand Coulee and Bonneville. But it’s the smaller dams, the ones almost no one knows about, that are the most dangerous.
An analysis released this week by the Associated Press finds that the Evergreen State has 50 “high-hazard” dams known to be in “poor” condition and in need of repair. Two of the structures are in Clark County. Problems at both dams have already been addressed.
The list was compiled by the state Department of Ecology, which inspects and tracks the structures, but isn’t in charge of repairing them. Most of the dams are privately owned.
It’s important to note that none of the 50 dams on Ecology’s list is believed to be in imminent danger of failing. But all of the dams need attention.
A dam makes the “high hazard” list because, if it were to fail, it is probable that at least one person will be killed. A dam is designated as being “poor” if, in the state’s opinion, it has safety deficiencies that may realistically occur, meaning repairs are necessary.
The largest of the two problematic dams in Clark County is northeast of La Center. Known as the Tsugawa Brothers Reservoir or the Tri-Mountain Estates dam, it impounds 55 acres of water in the vicinity of 35001 N.E. 91st Ave. A 2015 inspection showed problems with vegetation, damage from burrowing animals and a nonfunctional low-level outlet. A 2020 reinspection found that the owner had addressed the issues, so the state gave the dam a conditional assessment of satisfactory. Work continues to control vegetation, remove old tree stumps and repair erosion.
The second dam on Ecology’s list is Haight Reservoir, which lies within the city limits of Camas near 2521 N.W. 12th Circle. It is much smaller than the Tsugawa Reservoir, impounding water on about 3.7 acres in a neighborhood of newer homes on smaller lots.
A 2019 inspection of the Haight Reservoir found a lack of stability analysis and dense vegetation that hindered proper inspection, which led to the poor condition rating. The city of Camas has budgeted for that work in 2022. Other work, such as vegetation control on Haight Reservoir’s main embankment and overflow spillway, has been done, as were repairs due to wave erosion.
Not every dam has received similar attention. In fact, the national trend has been the other way. A recent analysis found more than 2,200 high-hazard dams in poor or unsatisfactory condition. That is substantially more than a similar analysis AP conducted three years ago. And, the actual number is likely greater, because some states won’t make inspection records available to the public.
According to AP, there are a variety of reasons for the dramatic increase in problematic dams. Some states have put more emphasis on inspection in the wake of well-publicized problems such as the Oroville, Calif., dam spillway that was heavily damaged by rain in 2017. Some dams have deteriorated due to deferred maintenance. And some dams were added to the “high hazard” category simply because of more development around them, thus increasing the potential for damage.
With climate change creating ever-wilder weather patterns, it’s time to concentrate more resources on dam repair. Owners should be first in line to bear the cost of repairs. But it’s likely some government intervention and regulation will be required.
As any homeowner knows, ignoring needed repairs costs you more in the long run. When it comes to dam safety, those costs could be intolerably expensive.