Masonry Dam
Dam in King County, Washington · Cedar River · forms Cedar Lake (Masonry Pool)
Height
230 ft
70 m (NID height)
Length
980 ft
299 m
Completed
1914
Cedar Lake (Masonry Pool) today
1,518.05 ft
7 days ▲ 0.29 ft
Normal storage
90,660 acre-ft
Normal for the date
Reservoir level measured Oct 23, 2026, 11:15 AM PDT. Full level page →
Facts
- Purposes
- Hydroelectric; Water Supply
- Dam type
- Arch
- Structural height
- 230 ft
- Owner
- Seattle City Light (Public Utility)
- Maximum storage
- 175,000 acre-ft
- Surface area
- 280 acres
- Hydraulic height
- 215 ft
- Drainage area
- 81 sq mi
- Army Corps district
- Seattle District
- NID ID
- WA00255
Facts from the U.S. Army Corps of Engineers National Inventory of Dams, record updated Jul 28, 2026. Search NID ID WA00255 at nid.sec.usace.army.mil. Project website.