The Elwha River and specifically the Glines Canyon Dam, have been the focus of much controversy over the last few years and for good reason. In the United States, more than 75,000 dams fragment our rivers,leaving less than 2% of the total length of our streams in natural conditions. This has led many groups to try and push for the removal of outdated or unnecessary dams. The first dams were gravity dams build out of stone or concrete, then earth dams were constructed which function similar to gravity dams, but are built with soil, next there are arch dams held up by it’s own strength, after arch dams came multiple arch dams, and that led to the construction of buttress dams. Glines Canyon Dam was an arch dam built of concrete in 1927 and was demolished in 2012 due to ecological concerns that the dam was impairing historical salmon runs that local Native American populations relied on for sustenance.

Not only do dams, such as the Glines Canyon Dam, harm the river ecosystem, they also pose as a hazard to human populations in many ways. Upon building the Glines Canyon Dam a critical food source was cut off from the Lower Elwha Klallam Tribe. Dams also have harmful effects on their environment due to erosion, sediment build-up, and siltation. The more dams on a river, the more sediment that is stopped from naturally travelling with the river. This eventually leads to, as shown with the Elwha River dams, the loss of a natural estuary. Five years after the removal of the Elwha and Glines Canyon Dams, it can be seen that a once rocky area has returned to it’s natural state of being a sandy estuary.

Dams actively prevent physical processes, even though the people who approved and built these dams are no longer around, they have long-standing effects.

Dams, like levees, are prone to failure if they are not properly maintained and recent events like the Oroville Dam go to show how dangerous these situations can be and how unprepared the general population is for dam failures. If a dam is not properly maintained, for example dams that are located on private property, the hazard of dam failure escalates. Dams that are placed in critical salmon habitats, such as those located in the Pacific Northwest, like the Elwha River Dam and Glines Canyon Dam. Another condition that can indicate an elevated risk is the lack of fish ladders. Dams without adequate fish ladders completely cut species off from critical breeding habitats and even dams with fish ladders can over-exhaust fish leaving them unable to reach their destination.

Once a dam is removed there are still additional conditions that put the river ecosystem at risk like freshly exposed reservoir sediment may not support rapid reestablishment of native plant species due to poor fertility or absence of arbuscular mycorrhizal fungi propagules.  The Elwha dam removal project, begun September 2011, is anticipated to change the composition, delivery rate and volume of Large Woody Debris. These things have yet to be shown good or bad, but they do elevate the risk of shoreline erosion as the reservoir returns to its natural state.
