Data from the First Dam Removal Efforts

While over a hundred dams are currently being considered for removal all over the United States, the Elwha dam removal and river restoration project currently taking place in Washington's Olympic National Park does not have any previous dam removal efforts to draw information from. No environmental restorative efforts of this magnitude has been previously attempted.

Elwha Dam construction (1911). The use of explosives during
dramatically altered the canyon. NPS/OLYM Archives

While anticipated benefits resulting from the elimination of the Elwha and Glines Canyon Dams has been subject to years of analysis, the most cogent and overlooked benefit of this project will be the scientific contributions made to the budding field of dam removal. A stringent project monitoring program--before, during and after the dam is removed--will surely supply a might amount of data for future dam removal practitioners to use in their endeavors. 

via Elwha Watershed Information Resource

Scientists have made a concise visual interpretation of the 6 phases the Elwha Dam will undergo to be effectively removed by 2015. Luckily National Geographic captured the historic day this 3 year long project started phase 1:

 

The Elwha watershed is 80 percent well-preserved inside
the Olympic National Park’s boundaries (see map above).

Luckily, there still exists a wealth of information for scientists, etc to draw upon while planning dam removals. I do believe Washington's forward-thinking will help promote future dam removal projects by eliminating fear of the unknown and uncertainty.

This dam removal project is the centerpiece of a multifaceted watershed restoration effort that has taken decades to prepare. The dam removal is scheduled to take three years, and once complete the Elwha River will flow unfettered after almost century of partitioning. Ecosystem function and productivity will be regenerated and the resilience of nature will shine through. A myriad of benefits correlated with a healthy ecosystem will emerge over the next 50 years.

While these two dams have had many negative impacts on the watershed, it's best to focus on a depleted economic function of the river surrounding salmon spawning. By confining migrating salmon to the lowest 4.9 miles of river instead of the full 45 miles and restricting the natural transport of sediment and debris, the once abundant salmon have disappeared from the area. The National Park service has estimated that the number of native salmon has dropped from pre-dam numbers of 380,000 to fewer than 3,000 in the 1990s.


The declining salmon population has had a ripple effect on the watershed. Salmon have been an important source of food for wildlife along much of the Elwha River. Today, wildlife above the Elwha Dam must rely on other sources of food or travel further down river to get salmon. These watershed ecosystems that used to benefit from marine-derived nutrients that can only be brought in by spawning salmon carcasses no longer have access to those nutrients.

Raceways used for intermediate rearing of steelhead
captive brood at the Lower Elwha Hatchery

The reduction in fish coming upriver was a significant loss for the Lower Elwha Klallam Tribe as well, both as a source of food and income. The tribe reserved the right to fish at traditional sites on the Elwha River under the Treaty of Point No Point. However, the dams prevent the fish from traveling to these traditional sites. Meaning this treaty is currently moot.

The dams flooded a large area of land--which was traditionally covered with native plants and home to many species of wildlife--to create the reservoirs. Currently, the dams' reservoirs cover approximately 684 acres of riparian habitat. Construction of the dams also left sacred and historical tribal sites underwater--such as the creation site of the Klallam people, which was flooded by the construction of the Elwha Dam. Spurred by the good news of the Elwha Dam removal efforts, the Klallam Indian tribe with the help of local fisheries have already made efforts to reintroduce the 10 suffering salmonidae species back into the river. Below is a picture of Larry Ward, Lower Elwha Tribal Hatchery manager, releasing one of the first coho salmon into the middle section of the Elwha River after 100 years.

photo by via Katie Campbell