Cascade Water Alliance will fill Lake Tapps to the upper range of the full pool in early August and leave it full all summer as a result of its assessment of the White River Project and changes to its fish screen facilities.

Cascade will fill the lake to about 543 feet, about four inches of water. It will then slowly lower the lake over the following 10 weeks, staying within the agreed-upon full recreational pool level, above 541.5 feet, as outlined in its agreement with the Lake Tapps homeowners.

In addition to its ongoing assessment of the condition of the White River Project, CWA will modify its fish screen facility to comply with regulatory criteria while operating lower flows than previously done. This task has not been done in about seven years.

To accomplish the outage and still assure the lake remains at full pool throughout the summer, Cascade will clear all the water out of the entire flow line from the headworks to the twin pipe inlet structure east of Printz Basin late this summer and into the early fall. This process, called dewatering, will allow staff to examine the structures and facilities and determine what must be fixed.

The project will last for about eight to 10 weeks, beginning Aug. 23 and running into October, allowing Cascade to address issues it finds in its assessment of the flow line.

Cascade Water Alliance, which bought Lake Tapps in December 2009, is a non-profit corporation, made up of the cities of Bellevue, Redmond, Kirkland, Issaquah, Tukwila, the Covington Water District and the Sammamish Plateau and Skyway Water and Sewer Districts. Its purpose is to provide safe, clean and reliable water to its 370,000 residents and 22,000 businesses.