Dams were regularly used by the mills along the Mendocino Coast to create mill ponds. Dams were used by the Mendocino mill on Big River to bring the cut logs to the mill.
The Mendocino Lumber Company was "famous" for damming Big River. With rare exceptions, dams along Big River were used only during the winter season. The picture right shows the Hellsgate dam on Big River being built.
Logs were stored in the stream beds (see picture below).
Note the size of the ox team on the right compared to the size of the logs.
Winter rains furnished the freshet (body of water) for floating the logs down river, but in most cases, did not. Dams were then used to build up a reservoir of water. When the dams were tripped (blown up), a flood was created along with a "head." A head is similar to the shore side of an ocean wave. Near the dam, a head might begin as high as 10 feet dropping to three-foot height 15 miles down river. A higher head, which would result in being able to float more logs a greater distance, would be obtained by tripping/blowing up more than one dam in succession. This, for sure, was in the days before environmentalists were invented.
In his book, Big River Was Dammed, W. Francis Jackson documents at least 27 dams on Big River. In his book – Jackson recalls how he walked the river banks and reminisced about his many relatives who had worked on Big River and filled a young boy's head with stories of logging camps, bull teams, and log rafts. The largest of the dams that Jackson documents used over 1 million feet of timber in its construction. The dams, which were major threats to aquatic wildlife, are gone. The last log drive and operation of the dams was in 1937; the result was a log jam – see picture below of a massive log lam. The dams fell into ruin over time, although there is still lingering evidence of their presence. The California Department of Fish and Game called for the destruction of others in order to allow for the migration of fish.
Details of the dams on Big River can be found on the Mendocino Redwood Company’s site here.
The picture of the map of the location of these dams (right) is in the Guest House museum in Fort Bragg. Below the map picture is a picture of Main River Dam(No 11), one of the dams which can also be found in the Guest House Museum.
The one other dam that our research has located was the one at Elk/Greenwood shown in the photo below left. This dam was the one that controlled the height of the water in the mill pond.