Water valves on Boredale Hause

 

The mains water signage on Boredale Hause is always strange to see. There seems to be a lot of speculation about the precise nature of the path - some say aqueduct from Hayeswater but I can't find a map showing its course and the photographs showing aqueduct near Hayeswater are much lower down the hill. However, it seems that the pipes continue down into Boredale. It'ds also quite hard to find information about the signage. It seems AV means air valve, so that gas that has built up in the system can be bled. This would normally be at the high point in a system because air is less dense and floats up. SV is sluice valve and allows the water flow to be stopped. The top number is apparently pipe diameter in mm and the lower number would be distance to the valve - but 100 metres would be a long way. These might not even be metric.