FJ15,

Mud Mountain Dam (MMD) is an Army Corps of Engineers flood control dam that reduces flood damage to Auburn, Puyallup, Sumner, and Tacoma. It is not related to Lake Tapps. Lake Tapps is, or was, a storage reservoir for Puget Sound Energy’s White River hydropower project. However, as hydro projects go, it was not an economical project, and complying with Federal Energy Regulatory Commission license requirements and ESA chinook protection requirements made the project even less economic, so PSE shut it down.

Lake Tapps remains as a significant social, economic, and political issue however. There are a lot of expensive (high property tax revenue) waterfront and water view homes in the area, including my cousin’s and aunt and uncle’s. In addition, Lake Tapps is Pierce County’s most heavily used County park. Legally, PSE could drain Lake Tapps as a part of retiring the hydro project. PSE owns the lake and lake bottom, and conceivably could develop additional real estate there. Every deed on Lake Tapps includes the provision that PSE might some day retire the hydro project and drain the lake, and that purchasing property there does not include any entitlement to perpetual lakefront property. Ah, but the politics conflict with that legality, and so PSE and many other parties are working cooperatively to try to save the lake even as the hydro project is retired.

This is going to get really interesting. Who’s responsibility is it to keep adding water to Lake Tapps? (The lake leaks into a small creek and some springs and would eventually drain.) The Corps owns and operates MMD. The Corps’ fish ladder and trap is located at PSE’s diversion dam, which is 5 miles downstream of MMD. The Corps is looking to build a new barrier dam (not diversion dam, as water diversion is not an authorized purpose of MMD) at the diversion dam site to better facilitate their fish passage responsibility. It will be interesting to see if Pierce County politics are powerful enough to get water diversion to Lake Tapps added to the Corps’ MMD operations responsibility. And if so, who is going to buy PSE’s lake bed and water diversion canal from them? Presumably, all of PSE’s property associated with the hydro project will be for sale. Will the Lake Tapps property owners and Pierce County step in and pay for the benefits they receive, or will there be a federal taxpayer bailout? Are you starting to “get it?”

As it turns out, the White River probably has enough water to share to keep Lake Tapps from draining. That will require only a very small percent of the available flow compared to the hydro project, which took most of the river’s water supply, to the detriment of the fish runs. I think the Lake Tapps problem is solvable, the issue is who will pay for it.

MMD isn’t going away, because the White River flood threat is real, and it isn’t going away. And upstream and downstream fish passage at MMD seems to be effective, and should improve when the Corps constructs a new barrier dam and makes fish ladder improvements. The White River supports spring, summer, and fall chinook, coho, pink, and chum salmon, steelhead trout, bull trout, but I haven’t heard of any significant sockeye run in the White that is blocked by MMD. Oh, and last April’s fish kill occurred when the Corps controlled flow to the White River at PSE’s request so PSE could re-install flashboards on their diversion dam.

Sincerely,

Salmo g.