Alternative Hydro Schemes

The argument here is simple. For small renewable energy schemes to be effective against climate change there need to be a significant number of them - 50 schemes the size of the Torrs hydro project would counter 5% of the carbon emissions in New Mills.

So we need to look for a variety of renewable energy sources - water, wind, solar, etc. Some of these schemes, like the Torrs hydro, will have a downside, which means they may best be avoided.

Here we look at some alternative possible means of generating electricity from water power in the New Mills area. Each site has National Grid cables close by.

Rock Mill

Midway between Torr Mill at the upper weir and Torr Vale Mill at the lower weir, there was once a complex of buildings called Rock Mill. At a rapid section of a bend in the river there was a weir and waterwheel. Part of this weir still exists. However, the proposal here is not based directly on this now dilapidated weir, rather on the power available in the rapid section of water at a narrow point of the river.

At this point, directly down below Rock Tavern and Rock Garage, the river is compressed between the cliff face and a walled projection of land. As with the scheme for the upper Torrs weir, a box would be constructed to house a 3m by 8m Archimedes screw. However, instead of being placed alongside the river, this box would be built in the river bed next to the embankment. This construction will not be a problem, as during low flow this part of the river dries out, since most of the flow passes up against the rock face.

The remaining 8m gap between the box and the rock face would then be dammed by lowering concrete beams into the river. Fortuitously the rock face has an outcrop, so that these beams would wedge, against the flow of the river, between the outcrop and a niche in the box. To consolidate and reduce the pressure on the dam, and to allow fish to pass, it would be filled either side with coarse rocks, and capped with anchored stones to make it attractive. The concrete box would also be faced with stone.

The screw box would be in a rapid section of river and so would gain a fall over its 10m length. The dam would be at the upstream end of the box and the river would pool at this point to a height of 3m above the outlet from the box. If necessary the outlet could have a tailrace channel, extended over the downstream rapid section of river, to increase the overall fall from one end of the screw to the other.

The great advantage of this location is that it does not damage an existing amenity, since this area is an out-of-the-way part of the Torrs park.

Mousley Bottom

Below Torr Vale Mill, along the track towards Station Road and Mousley Bottom, there is a shallow weir across a broad expanse of river. On the far bank there is a leat that took water across to a mill and may have been used in times past to run a turbine. This system could be reinvestigated as a means to generate electricity using the latest technology.

An alternative is that an Archimedean screw could be installed on the track side of the river. Between the shallow weir and a pipe crossing the river, there is enough room to construct a 3m by 10m box for the screw. This would need to be up to 4m deep and only 1m of this would be accounted for by the drop in the river from one end of the box to the other.

The remaining 3m drop would be gained in two ways. Firstly by placing anchored stone blocks across the top edge of the weir. These would also be necessary to redirect the flow from the far bank towards the screw box. The remainder of the fall required by the screw would be gained by a tailrace over the rapid section of river below the weir. This simply involves creating a channel in the river to allow the water to escape from the bottom of the box. The channel has to be long enough to eventually come level with the river as it falls over the rapid section. The channel would need to be 2.5m deep at the outlet of the screw, but this depth would quickly fall off as the river descends the rapid.

This location has the advantage of being away from the scenic areas of the Torrs Park, but easily accessible by people who want to see the screw in action.

Peak Forest Canal

At Whaley Bridge the Peak Forest Canal is pretty much level with the river Goyt. By the time the two waterways are in New Mills they have a very significant difference in height. This means that quite a small flow of water can achieve the same power generation as a large flow from a weir. For instance if the water drops 30m from canal to river, only one tenth the flow is needed compared to a 3m drop at a dam in the river.

The small flow of water required, means that it can be contained in a steel pipe of relatively small diameter. This pipe can be buried to deliver the water to a turbine down at the river. The great power in the large drop means that only a quite small turbine is needed, and this too can be underground.

There are several places at which the river closely approaches the Peak Forest Canal. One convenient place would be at Goytside Meadows, as this is owned by the Town Council. This land extends from the canal to the river over a considerable drop in height. The whole scheme could be hidden below ground.

Map showing five points where the Peak Forest Canal and river Goyt approach close enough to allow a hydroelectric scheme