Disputing Mara Leveritt's contention about Capitol Lake

Re:  Reasons to jump into our rivers, published Monday, October 23, 2023 in The JOLT. 

For years, I thought as Ms Leveritt seems to regarding Capitol Lake's effect on our Chinook salmon run. However, after reviewing the literature, I find the following to be reliable and of paramount importance.

The information below has been gathered mostly from two publicly funded studies: 1) Robert Engstrom Hegg 1955, Environmental relationships of young Chinook Salmon in Capitol Lake and the Deschutes River System and 2) M. Koehler et al Diet and bioenergetics of Lake-rearing Juvenile Chinook Salmon in Lake Washington, 2006 Transactions of the American Fisheries Society.

The abrupt change from salt water to freshwater is a non-issue. With the dam out, the same salinity gradient change will exist below Tumwater Falls and Percival Creek outlet.

Predation on these salmon by harbor seals and otters will increase fourfold with the dam removal. (The railroad bridge, Percival Creek mouth, I-5 bridge and Tumwater Falls pinch points (bottlenecks) will now increase the effectiveness of these predators). This most likely will reduce the number of Chinook available to our endangered Southern resident orcas.

The flow of aqueous toxins from urban run-off into Budd inlet (The cause of Urban Runoff Mortality Syndrome) will no longer be prevented from entering the "very clean" Capitol Lake Basin by the dam. We must all remember that stormwater is the #1 cause of pollution in Puget Sound and urban pavement is the #1 contributor to that source. The dam currently prevents toxic exposure to these sensitive juveniles during the months of April-July as they develop in the "very clean" Capitol Lake.

Temperature and DO [dissolved oxygen] issues are not a problem in Capitol Lake, especially if the Lake is allowed to be properly dredged.

(Estuary advocates have opposed Lake dredging for decades for no supportable reasons. According to Thurston County Health Department data, bottom water in Capitol Lake is well oxygenated throughout the year, this includes April - July, the Chinook rearing period, and when the adults return mostly in September. "The deep portions of the Lake are kept well aerated by the inflow of river water which, being colder and heavier than lake water, follows the bottom of the old channel during the summer months."

Two important conclusions from the Engstrom-Hegg study are : 1) "The data..... show growth of Chinook salmon in Capitol Lake to be extremely rapid, greatly exceeding that attained by fish of the same stock held in hatcheries." And 2) "The data do not indicate that the conversion of Capitol Lake to freshwater had any great effect on survival, either for better or worse."

Dietary advantages to our Chinook juveniles in Capitol Lake deserve mentioning. With the dam in place, the major diet of our juvenile Chinook fry and smolt are naturally occuring Chironomid and Daphne spp. which occur in Capitol Lake's "very clean" freshwater. Removing the dam will require the use of a man-made diet, probably in pellet form.

Those in charge of the system of choosing between retaining Capitol Lake and an estuary-mudflat gave little or no attention to the above critically important research findings. For reasons which are incomprehensible to most of us who have had the time to become informed, their goal has been to ignore valid research that unequivocally supports retaining Capitol Lake while saving the public many hundreds of millions of dollars which could be used to address other truly important problems such as housing, mental health and ocean pollution.

Many thanks to Ms Leveritt for exposing just a few of the major community misunderstandings on such an important issue.

           ~ Jack Havens, Olympia 

The opinions expressed above are those of the writer and not necessarily those of  The JOLT's staff or board of directors.  Got something to say about a topic of interest to Thurston County residents? Send it to us and we’ll most likely publish it. See the Contribute your news button at the top of every page.