Nine Mile Reservoir drawdown complete, spillgate work begins   

Tags: Avista Utilities, Electricity, Hydro power, Infrastructure upgrades, Spokane River, Washington, Safety

Lake Spokane above Nine Mile Dam

The installation of new operable spillgates at Nine Mile Dam began this week as Avista finished drawing down Nine Mile Reservoir Thursday to allow a work barge and crew to begin. The upgraded system will allow Avista to pre-program desired heights and give operators the ability to raise and lower the height of the spillway at any time, incrementally if needed, in order to maintain the reservoir pool at a more constant level throughout the entire year.

The reservoir level must be lowered during construction to allow the contractor to erect the new spillgates. During construction, the pool level will be 2 to 4 feet below the spillway crest (about 12-14 feet below full pool), which may be lower than what it has been in the past when the flashboards were erected each year in mid-summer.

Construction should be complete and the reservoir level back to full pool by November of 2010. Our blog post, “Nine Mile Dam Spillway Improvement Project starts this summer” has more detailed information about the project.

As a side note, to announce this news, this week we used a new e-mail tool for communicating directly with customers, river users, property owners and stakeholders interested in operational and environmental activities related to our Spokane River Project. This is one more way we’ll try to get  information about river and reservoir levels, stewardship work and other river operations to folks quickly and directly. If you’re interested in being part of Avista’s mailing list for Spokane River News, send an e-mail to
Posted by  System Account  on  7/16/2010
0  Comments  | 0  Links to this post | Bookmark this post with:          


Add a Comment

We encourage comments on this blog, but this is a family friendly conversation, so please check out our discussion guidelines so we’re all on the same page. By submitting a comment, you agree to these terms and our Privacy Policy.  

Customers must have a My Account and be logged in to comment.
Login to My Account | Create My Account


We're hopeful that this space will encourage thought provoking and informative community discussions about issues related to our products and services. Currently you must be an Avista customer to participate in the conversation, but stay tuned. In the coming weeks we'll also provide an opportunity for non-customers to participate in this forum.