This post has been updated. See the end of the post.

Oregon Public Broadcasting recently reported that portions of a levee defining the west side of Agency Lake have been removed, creating significant new aquatic habitat. I used Google Earth to create the image on the left, the entire area inside the yellow lines will eventually be under water.

I have failed in my attempts to talk to someone directly involved with this project, so the rest of this post is based on the OPB article and my understanding of this area where I have spent a lot of time over the years. There are clear benefits for waterfowl and sucker fish. Any benefits for trout are less obvious.

As you can see in the image, the area inside the yellow lines is subdivided into “units”. Water has been released into two of them with plans to further breach levees and flood the entire area. The water depth should be around three feet in good water years.

This project appears to primarily be a collaboration between Ducks Unlimited, the Klamath Tribes, and the US Fish & Wildlife Service. I understand the interest from Ducks Unlimited as the flooding should create excellent waterfowl habitat. The Klamath Tribes are interested in additional habitat for endangered and culturally important sucker fish. The potential impact on trout is unclear.

Most of the yellow line on the top of the border is the Sevenmile Canal. This used to be Sevenmile Creek and was important habitat for trout. The upper portion of Sevenmile Creek, which feeds the canal, has not been channelized and continues to be spawning habitat. There are plans to return the creek to its historic channel, which could be beneficial to trout. On the other hand, the depth of the water in this new wetted area will be shallow so it may mostly provide habitat for chub and perch, populations that are exploding in Klamath Lake, Agency Lake, and well up the Williamson River. Time will tell.

UPDATE: A day after posting this I received a return call (after a week) from someone who is knowledgeable about the project and is optimistic about the benefits for trout. Phase 3 of the project, beginning about two years from now, will see all water from Fourmile Creek diverted into a restored Sevenmile Creek. The largest irrigation diversion out of Sevenmile Creek will also be closed. The net result is around 40 cfs of cold, high quality water will flow through the creek during irrigation season and around 70 cfs outside of irrigation season, assuming a good water year and stable groundwater levels. This represents a significant addition of high quality water to Agency Lake along with improved access to trout spawning habitat.

It was an hour long conversation about fish in the Klamath Basin and I’ll continue to post on the subject. One tidbit for now is the impact of good water years on the lake. It’s both good news and bad. The biggest problem with Klamath Lake is excess “nutrient load”. This is a nice way of saying water pollution from agriculture, primarily cattle ranching. More water washes more of their effluent into rivers and streams and then into the lake. This promotes algae growth which robs the lake of oxygen. Of course, more water should be a benefit and initially can be before the algae blooms, but there is a delayed adverse impact. Hopefully the new wetlands on the edge of Agency Lake will help filter some of these nutrients, but there are many rivers and streams that deliver nutrient load in high water years that will not flow through these restored wetlands.