While most casual visitors of the Copper Country are aware of Seneca Lake, they most likely do not know of its little sister who resides just outside of the small mining location of Seneca. Like its big brother to the west Seneca Pond is man made, formed by impounding a small unnamed creek that flowed nearby. The dam was built to supply water for the adjacent Seneca No.1 shaft, which contrary to its numbering was actually the last shaft sunk on the property – around about 1918. As to why this particular dam was even needed considering the existence of the adjacent Seneca Lake, its a mystery to me. Sanborn maps seem to indicate that the water was used for fire protection, and I suppose the establishment of a closer water source for such a purpose might make sense.

Seneca Dam sits right alongside the road to Seneca Location, which sits atop an earthen embankment that forms the backside of the dam’s structure. At the reservoir facing side the dam consists of a concrete wall of unknown size that is visible running atop the water line.

Running atop that concrete wall is this iron railing, which is built out of long pieces of angle iron. It seems like an odd feature for a mine to invest in, considering safety never seemed like a major concern. Perhaps the pond’s location right alongside a public road might have prompted its installation. Or I suppose that it’s possible that the railing is a more modern addition, put up in a more safety conscious era. But I want to think that its original to the dam itself.

The dam’s spillway sits halfway along the dam’s length, protected by a series of bars spread across its opening.

Making our way across the road we climbed down behind the dam to take a look at the spillway’s backside – which unfortunately was hidden deep within a culvert.

Outside that culvert things got a bit more interesting, as the area was littered with several pipes, valve stems, and wood cribbing. The water from the spillway itself made its out of the culvert and into a short section of creek, before disappearing again into yet another culvert. From there the water seems to have disappeared entirely, as our subsequent exploration of the adjacent mine revealed no trace of any stream or creek.

Lining both sides of the creek bed were large iron pipes, each one fitted with a valve assembly. At first I thought these might have been supply lines for the mine, but it turns out that the dam’s actual feed line was from a small pump house sitting just east of the pond. These pipes were of the discharge variety, used to control the flow of water leaving the reservoir. When the water entering the reservoir were in volumes too large for these valves to properly discharge, the spillway would have handled the excess.

The valves (and pipes) were supported by a collection of wood cribbing placed within the stream bed – some of which you can view here in this badly shot photo (it was the best shot I had).

In another great photo you can see the destination of those discharge pipes: right into the same small culvert that the creek disappears into. This arrangement wouldn’t make much sense for supply lines, but does make perfect sense for the discharge variety.

With the dam behind us and any evidence of its discharge stream now hidden underground, we decided to continue forth and see what else we could find in the adjacent woods. I suspect we might find ourselves a mine…