Lewis River River Levels

Total streamflow across the Lewis River was last observed at 5,430 cfs, and is expected to yield approximately 10,770 acre-ft of water today; about 70% of normal. Average streamflow for this time of year is 7,718 cfs, with recent peaks last observed on 2025-12-09 when daily discharge volume was observed at 41,600 cfs.

Maximum discharge along the river is currently at the Lewis River At Ariel reporting a streamflow rate of 4,010 cfs. This is also the highest stage along the Lewis River, with a gauge stage of 3.44 ft at this location. This river is monitored from 2 different streamgauging stations along the Lewis River, the highest being situated at an altitude of 1,085 ft, the Lewis River Above Muddy River Near Cougar.

Historically, the river was used by the Chinook Indians as a trading and fishing route. Today, it is primarily used for hydroelectric power and is managed by the Pacific Power and Light Company. The river is dammed in several locations, including the Merwin Dam, Yale Dam, and Swift Dam, which create reservoirs for power generation and recreational activities such as fishing, boating, and swimming. The river also supports agriculture in the region, with farms located along its banks producing crops such as berries and vegetables. The Lewis River remains an important resource for the community, providing power, recreation, and sustenance.