Rushup: Trial by Water (30th April)

Derbyshire County Council commenced work on Rushup Edge byway in 2014. (Also known as Chapelgate or Chapel-en-le-Frith Byway Open to All Traffic 144.) You can see all our articles on the subject, here.

Following the rain over the weekend, which was heavy at times, but nothing unusual. There has been a noticeable affect on DCC’s trial surfacing on Rushup.

Our observations from a committee member’s visit to the site on Monday evening (29th):

  1. The failure was catastrophic and at the first real test of the section.
  2. Most of the fines and smaller particles were washed downslope and out onto the top of the Roych and also out onto the road – some of the material on the Roych may have been the previous infill having been washed into the trench on the path between the top of the Roych and the bottom of Chapel Gate.
  3. The water draining had penetrated down to the bedrock and burst upwards. This is evident from one of the starts of a gully in the centre of the path. I would make a calculated guess that the tanking predicted had happened and the water backed up lifting the compressed surface and causing it to break up and be washed downslope.
  4. The materials have shown their unsuitability as has the technique – it has left a lot of loose aggregate with particle sizes ranging from 3 – 5cm dia up to 10cm depending upon the section of the track.
  5. There is ample evidence of rapid gully formation which clearly shows the nature and direction of drainage on the track – i.e. all water drains into the track and then washes downhill with no other outlet than the gate at the end of the track.
  6. The drainage concept on the left hand side as you move east, comprising of aggregate failed.
  7. There are now three large sections of gritstone slabs cemented in place that look incongruous to the remaining bedrock.
  8. There is now more unstable and loose material on the track than before this work took place.
  9. In one section they appear to be digging a very large hole 1.5 – 2m diameter and 0.5m deep where they have removed some some very large stones. From the images posted yesterday and those I took tonight this appears to have happened today.
  10. It appears as though they are proceeding with cementing slabs in place despite the claim to there being just test areas.

30 April 2019