The recent attention paid by Dave Fellows, Graham Evans and Andy Dnnis, amonst others, to the long lost steam powered pumping station at Chasewater has caused some curiosity and no small amount of debate, particularly between myself and top local history ferret [Howmuch?], who last night expended no small quantity of hot air and beer over the subject. What prompted that discussion in particular was an expedition I took out yesterday afternoon to look at the site of the former pump house and investigate the spillway arrangements, which I must confess have me quite intrigued. I thought I’d supply some maps and images and see what you readers make of them.
First up, there’s an aerial image of the basin and former ‘Nine-Foot’ pool taken in May, 2010. The Nine-Foot was named after the measuring post that used to stand in the centre of the pond.
Even today, the spillway is still extant and stretches in a line from the dam bridge eastwards to the top of the brick sluice into the canal, opposite the overflow. It can be seen that the overflow empties across the heath northwards to the Crane Brook, culverted under the new road. Yesterday, I investigated the brick-lined sluice. It’s an interesting bit of civil engineering.
This seems to me like a system designed to contain water, as well as provide an overflow path. The question is, why would water need to be contained here, at the same level as Chasewater, quite a few metres over the level of the canal? When the spillway was full – having wiered from the rear of the Nine Foot, water would have pooled in the channel to the top of the sluice – referred to as ‘Basin’ in the maps posted by Graham Evans. Form here, it would have overflowed into the canal below by means of the twin overflow culverts. What was the purpose of this body of water?
There’s several possibilities, I think. The steam engine would have needed a read supply of clean water. The canal water would have been an evil brew at the time – mixing raw sewage with spoil heap runoff and other industrial sediments. To use this water it would have to be settled. The spillway provides a shallow, easily cleaned settling pond. The gates could be opened in very bad overflow conditions. Water from a pump could also be fed here to settle before entering the lake.
This isn’t as daft as it may seem – the Environment Agency created a system like this at Lea Marston for purifying the Tame, with a huge degree of success.
Mapping from the earlier decades of the last century is very interesting.
To put it bluntly, I have little idea what’s going on with the arrangement here, and even less the pump. It’s clearly there to refill Chasewater, and the canal would have been using huge qualities of water when at full traffic, so conserving it where possible and feeding it back into storage would have made sense. If a canal ran out of water, it would not only be hugely embarrassing for the operators, but would have crippled local commerce.
All comments, contributions and speculation welcome.