Reminder for Seattle Area Boaters: Lakes are Being Refilled

I was at the boat yesterday and noticed that. It really is amazing how quickly they bring up the level of such a huge body of water!

 

I've lived in WA for ~50 years and never knew they raised the lake at a certain point.

Two questions:
1 Why do they raised it and how long did it take? (OK, that was a 2 part question, sorry)
2. Where does that increased water come from?

 

Found this article from the Army Corps of Engineers: https://www.nws.usace.army.mil/Medi...lake-washington-levels-to-drop-below-20-feet/ (this was last year, there wasn't the normal snow pack last year, so the lake never reached the summer level).

All of the extra lockings in the summer slowly reduce the water level to winter levels where they maintain it until February. From Feb-June the level is raised through water released from the Chester Morse Dam and makes its' way into Lake Washington from the Cedar River.