Sweasey Reservoir extended 18,000 ft upstream in 1937 when the dam was completed. 9,200 ft was lost due to siltation between 1937 and 1955, and now only 4,800 ft remain. The 1955 flood carried a lot sediment into the reservoir. It is estimated the reservoir contains 200 AF of water. The wooden transmission pipe from the dam down to Arcata is worn out.