Staff from the Upper Columbia Salmon Recovery Board recently took two flights with Lane Gormley, a volunteer pilot with LightHawk. The first flight was dedicated to taking aerial photography of the low water in the Wenatchee River. Flow that morning at Monitor was 380cfs, one third the average flow for this date and the lowest on record for the entire 52 years of monitoring. The second flight brought a member of Senator Patty Murry’s staff on the same flight path to witness firsthand the low water conditions and see the effects of the recent Sleepy Hollow fire.
A warm winter with near record-low snowpack followed by extreme warm weather and low precipitation this spring and summer has put our salmon in an uncomfortable position. The warm winter didn’t allow for snowpack accumulation which means very little water to replenish our streams and rivers throughout the summer with cooler water. The early season hot weather (June average temperatures were 10.9º F above normal in Wenatchee) caused what little snowpack we had to melt at least a month earlier than usual. The mainstem Columbia has been running about 50% lower than average in the months of June and July (Columbia River DART). According to the Department of Ecology, 43% of rivers statewide are running at record-low levels. Streams across the Upper Columbia are running at record lows and many in the Okanogan have already dried up for the year.
Not only are water levels low, but the rivers are warming. Stream temperatures have exceeded lethal temperatures (70º F or 20o C) in many areas and fish are relying on cold tributaries and refugia to survive. According to Jeremy Cram, a research scientist with WDFW, PIT-tagged fish are being found in colder tributaries they don’t normally enter. Every year there are a certain number of spring Chinook and steelhead that stray from their normal routes, but this year they are entering these cold streams in higher than normal numbers. What’s even more out of the ordinary is that sockeye, which don’t normally stray, have been identified in colder tributaries. Additionally, there is a higher than normal number of spring and summer Chinook and steelhead that should have been heading to Yakima but instead are overshooting and have arrived upstream of Tumwater dam and entered Upper Wentachee tributaries. Not only are fish migrating to cooler areas, but they are also arriving earlier. Usually the peak sockeye run above Priest Rapids dam is July 4th but this year the peak hit about two weeks earlier. Even with the earlier run, fish were unable to avoid the hot weather this year.
The combination of low water levels and high temperatures is stressing fish and makes them more susceptible to disease and predation. Mortality has been documented in the lower Columbia and Snake Rivers and recently a major fish kill occurred in the Okanogan. Weekly fish surveys across the Columbia Basin are finding hundreds of dead salmon, sturgeon, and, steelhead. The most likely cause of death has been determined to be Columnaris, a bacteria that fish are more susceptible to during warmer water conditions (July 10, 2015). Sockeye fishing on the Columbia from Rocky Reach to Chief Joseph Dam was closed for the season July 26th due to estimates that roughly half of the salmon will die before reaching their spawning grounds. Only about half of the expected Okanogan-bound salmon have made it past Wells Dam (based on counts at Bonneville and Wells). In a typical year survival past Wells is around 70%, it’s too early to say what the survival will be this year and how conditions will impact this number.
Spring Chinook have already entered rivers but holding in these conditions is likely leading to high pre-spawn mortality. Steelhead have started to migrate up the Columbia and will likely encounter even more dire conditions when the bulk of the population hits the Upper Columbia August through October. However, Upper Columbia steelhead have been shown to enter lower Columbia River streams to seek thermal refuge, which may mitigate the effects of the warmer temperatures to some degree. These thermal barriers are normal in the Okanogan, but this is the first time Casey Baldwin, Senior Research Scientist with the Confederated Tribes of the Colville, has seen this occur in the Wenatchee. Upstream migrating in these hot water temperatures is akin to a human running a marathon in temperatures over 100°F. Large losses of this run year are expected for both listed species.
One theory on the cause of this strange weather is what has been dubbed “The Blob” – a warm section of the Pacific Ocean hundreds of miles long. This Blob averages 2-7ºF warmer than the surrounding ocean, has appeared along the Pacific Northwest coast the past two years, and may be causing the warm weather patterns to move landward.
On a positive note, organizations in the region are focusing on keeping more water in the rivers, thereby mitigating the negative impacts of these low-water years. Trout Unlimited’s Pioneer Pump Exchange Project, completed in 2013, relocated the point of diversion on the Wenatchee River for the Pioneer Water Users Association’s irrigation canal from near Monitor to the confluence of the Wenatchee and Columbia Rivers. The project also changed the diversion from a continual flow gravity-fed system, to a closed system on-demand pump station. According to Dan Jaspers of Trout Unlimited, the upgrades from this single project along the Wenatchee have allowed stream flow savings of approximately 35 cfs in the river. Combined with similar water conservation projects being completed by TU and other local organizations, these savings are especially significant in these low-flow years when every drop counts.
It’s too early to make predictions on the long-term effects of this situation on salmon but it certainly is a daunting story and likely to get worse in the coming months as more fish move upstream and more areas dry up and heat up.