Boaters and property owners with docks on Mayfield Lake are running out of time as Tacoma Power is about to lower the lake about 10 feet to allow for an upgrade to the boat launch at the Mayfield Lake State Park, just off U.S. Highway 12.
Dock owners will see their docks pulled up and many broken apart if they do not disconnect. Boaters will not be able to launch until Sept. 30 when the waters will return to normal levels.
“We originally intended to lower the reservoir to 410 feet, but we’ve discovered through the planning process that going to 415 feet will be sufficient. The elevation will fluctuate between 415-416 feet for the majority of the project. We typically operate between 421 and 425 feet of elevation,” Tacoma Power stated in a press release.
Tacoma Power recommended removing docks from boat launches by yesterday. On Sunday they will close the boat launch in the morning and start lowering the lake. Tacoma Power will work on the boat launch from Sept. 18 through Sept. 27. They will then increase the flow from Riffe Lake through the Mossyrock Dam from Sept. 27 through Sept. 30.
During the drawdown, Tacoma Power spokespeople state all boat launches will be inoperable and shorelines will be closed.
“If you have a boat or other watercraft on Mayfield Lake, please remove it before Sept. 15. Failure to do so could result in your boat or watercraft becoming stranded and/or damaged,” Tacoma Power stated in a press release.
The lowering of the lake will expose lakebed at levels unseen since the Mayfield Dam was constructed in 1963. This will create hazards such as deep mud, shallow bottoms and exposed tree stumps.
“Boating, swimming, water skiing, diving, and other similar activities will be hazardous in shallow waters or areas where these dangerous obstacles are near the water surface.For your safety, please do not access the lake or walk along the exposed lakeshore during the drawdown, and take special care to keep children and pets away from the shoreline,” Tacoma Power stated.
The main reason for the drawdown is to improve the Mayfield Lake Park boat launch ramps. They are cast-in-place concrete that over the past years have deteriorated and failing.
“Over time we have attempted to repair the launches, but the repairs just haven’t worked out,” said Cowlitz River Project Manager Chad Chalmers. “It became apparent a few years ago that in order to continue to provide boaters with year-round access to Mayfield Lake we needed to repair the existing ramps and reduce the lakebed scouring that’s occurring at the end of them. The scouring is a result of people loading their boats while under power and the prop-wash is eroding the rock away from the end of the concrete sections and developing a shallow spot in the lake about 5 feet past the end of the launch.”
Chalmers said parts of the concrete launch have failed due to large holes at the end of the launch from eroding rock, causing problems for boaters when launching and loading their boats.
“We have had to close the boat launch ramps at times in order to try and mitigate the damage caused by the scouring to avoid safety and property damage concerns for the public,” he said.
The repaired launches will be built with pre-cast concrete panels, that will allow a surface that will speed up launching and also extend far enough into the lake to stop loading boats under power from causing degradation at the end of the launch. It will minimize maintenance and increase the times the launch will be open.
The cost of the project will be about $175,000.
The last time Mayfield Lake was lowered was in 2004 when Tacoma Power dropped the lake to 416.5 feet for Washington State Parks to make repairs on the Ike Kinswa boat launch.
One major concern for Tacoma Power is people looking for treasures that have fallen off boats in the past decades — wallets, sunglasses, jewels and the like.
“The shoreline will be closed,” said Chalmers. “Our top priority is public safety, so we are asking people to not access the lake or walk on the exposed shoreline, and to take special care to keep children and pets away from the shoreline. There will be hazards exposed that are not visible due to years of sediment migrating down the river system and being deposited in different areas of the lake, covering stumps, springs, or other items that may be soft walking surfaces.”
Tacoma Power benefits from power generation from its hydroelectric dams on Riffe and Mossyrock dams. They produce enough electricity to power 140,000 homes each year. Mayfield Dam was built in 1963 and creates the 13-mile-long Mayfield Lake. Mossyrock Dam, built in 1968, is the tallest dam in Washington state at 606 feet above bedrock, and forms Riffe Lake, which is 23.5 miles long.