South Sound Science: Human Influences on the Deschutes River, Capitol Lake & Budd Inlet

Mindy Roberts at the state Department of Ecology, presents on:

Human Influences on the Deschutes River, Capitol Lake & Budd Inlet. Human activities have unintentionally unraveled a variety of ecological processes manifested in high water temperatures, bacteria concentrations, and fine sediment levels, as well as low dissolved oxygen concentrations.

Notes from her talk:

Budd Inlet, Capitol Lake, and Deschutes River are microcosms of the problems of Puget Sound.

Why impound the Deschutes estuary? There is a tendency to romanticize the past. Not only was there industrial waste, there was a lot of human waste

When the tide went out on Little Hollywood (a poor community on the tideflats), the tide literally stank. Capitol Lake was created a more beautiful place.

They did this without knowing the water quality problems it would create.

Also, filling in tidelands was common, nearly destroying the tidal prism. The water has nowhere to go. This probably impacted the circulation in southern Puget Sound.

Circulation stagnates in Budd Inlet and Capitol lake because of damming and fill, making the area more sensitive to inputs. So, if any pollution comes down, it will stay there for awhile.

With a push of the button, they took out the Lake, and saw what happened. Fewer portions would reflect the impact of nutrients, simply because circulation came back.

In the freshwater Deschutes system, it gets cooler as you move down the watershed because of freshwater inputs. If you model a mature forest, the temperature pattern stays the same, but with a overall drop in temperature, making the entire watershed good for fish.

Adding trees also improves dissolved oxygen situation on the river.

Questions and Answers

Effects of die-off of freshwater biota in the saltwater?

They did.

Does only considering only point sources change the restoration strategy?

They’re still working on the project, so will include non-point sources. They’re considering the impacts of everything.

Did you include a sediment transportation study associated with Capitol Lake?

They did include the information from that study, did use their output when putting together the model.