The Spill Effect: Life in the Salish Sea
During the winter, Southern Resident orcas make their way along the Pacific coast, feeding on large Chinook salmon runs gathering at the mouths of some of the west’s largest rivers. One of their favorite feeding spots is at the mouth of the Columbia River. The Columbia Basin was once the most productive salmon basin on the planet, supporting some of the largest Chinook salmon runs and some of the fattiest fish the world has ever seen. Southern Residents would feast on the bountiful salmon that were returning to make their way back up-river to lay their eggs and spawn. For the orcas, this was a smorgasbord.
Sadly, years of industrial development on the rivers of this basin caused the precipitous decline of salmon. As go the salmon, so go the orcas. The large dams and warm, slackwater reservoirs on the Columbia and Snake Rivers have made the salmon’s journey much more difficult, and in some cases, impossible. Juvenile salmon rely on natural, cold, free flowing rivers to carry them safely to the ocean. As dams slowed the rivers, salmon populations in the Basin crashed, leaving this population of orcas without one of their most critical sources of food. While much work needs to take place to protect and restore healthy salmon populations in the Basin, a recent court order is helping move us in the right direction. On January 9, the U.S. District Court in Portland required the federal dam agencies in the Northwest to spill as much water as legally allowed over the eight dams on the lower Columbia and lower Snake rivers.
As the Columbia and Snake rivers flow from the inland northwest to the Pacific Ocean, they carry with them small, newborn salmon that ride the rivers to reach their new marine homes. ‘Spill’ is a technical term used to describe water that is poured over the dams (through spillways) instead of sending it through turbines to produce energy. Spill more closely mimics the natural flow of big rivers, like the Columbia and Snake, and delivers juvenile out-bound salmon and steelhead trout more quickly and safely to the ocean. The more fish that are ‘spilled’, the more fish that return to the river as adults to spawn. Without spill, juvenile salmon are sent through dam turbines or elaborate bypass systems. These dams and reservoirs kill as much as 70% of the out-migrating juvenile salmon and more than 15% of the returning adults. Some juveniles die further downstream as a result of cumulative stress and injury. Scientific research collected annually since the mid-1990s demonstrates conclusively that additional spill significantly increases juvenile salmon survival and subsequent adult returns. By allowing more water to go over dams instead of through their turbines, more young salmon can safely circumvent this barrier, allowing them to reach the ocean and grow into big fatty fish that reproduce and feed orcas.
Despite several decades of collaborative, peer-reviewed science confirming that increasing spill increases both juvenile salmon survival and numbers of returning adults, efforts are underway to roll back recent progress to help critically endangered salmon. In a disappointing move, Congresswoman Cathy McMorris-Rodgers (R-Spokane) introduced a bill (HR 3144) which would make it illegal to evaluate the costs, benefits and tradeoffs associated with increasing spill at the federal dams in the Basin or removing four of these dams on the lower Snake River in southeast Washington. This bill would circumvent multiple court decisions and undermine major federal environmental laws. HR 3144 would move the Northwest and the nation backwards. Hydropower management in the Columbia Basin is in desperate need of reform to recover salmon, and the benefits of reform would extend to orcas, Tribes and fishing communities that depend on the survival of the fish and the ecosystem.
Fortunately, orcas and salmon have some powerful advocates in the Northwest. Washington’s and Oregon’s Governors, Jay Inslee and Kate Brown, have both publicly expressed their opposition to this bill, citing concerns that it would derail years of collaborative work to create a legal and science-based plan for the Columbia Basin. Both Governors have also recognized the need to increase spill at the eight federal dams in the region to aid salmon recovery. This bi-state collaboration is what we, and the orcas, need moving forward.
The court’s recent decision to increase spill is expected to go into effect this spring, but there’s even more that Governors Inslee and Brown can do to restore salmon in the Columbia Basin. Spill levels at these eight dams are legally limited by state water quality standards, also called Total Dissolved Gas (TDG) standards. As water spills over the dams, the cascading water mixes in gas bubbles from the surrounding air, which increases the TDG levels. Research has shown that juvenile salmon can be harmed if TDG levels are too high, but we’ve also learned that salmon can handle more gas than scientists initially thought. The current TDG levels in Oregon and Washington can be raised by 5% to 10% without significantly harming juvenile salmon. In fact, by avoiding dam turbines and arriving at the ocean more quickly, salmon survival increases and more adults return to the river in the years that follow. By increasing their states’ allowable TDG levels in the Columbia and Snake Rivers, Oregon and Washington can allow even more spill as early as 2019.
Recovering Southern Resident orcas will require us to restore the salmon they depend on throughout their range, including their winter range along the west coast. These amazing, and endangered, whales can be seen from Vancouver, BC to Monterey Bay, CA. Like many predators, their annual migrations are dictated by where their prey is. Sadly, salmon runs across the west coast have plummeted. It will take years of dedicated, collaborative work to restore salmon runs to healthy, stable levels. With only 76 individual Southern Resident orcas left, there is no time to waste.
We applaud Governors Inslee and Brown for opposing HR 3144 and encourage them to continue fighting for orcas and salmon by allowing more spill at the major federal dams in the Columbia Basin. This is a particularly effective — and immediate — step our region can take to increase the prey that the Southern Residents need to survive and recover. There’s much more work to do, but this would be a significant step in the right direction to recovering the Columbia Basin and orcas.
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