The Miskin Project
Clearance of multi-tree log-jam on the River Ely at Miskin. Grid Ref. ST 04337 81108
To allow migratory fish access to an additional 12 km upstream of Miskin to use the spawning gravels in the headwaters and tributaries of the River Ely.
This multi-tree log-jam was identified by Environment Agency Wales as a barrier to fish migration during one of their river walk over surveys and was viewed by South East Wales Rivers Trust representatives during 2009.
The log-jam consisted of approx. 16 very large trees and root plates which blocked approx. three quarters of the river width and extended downstream for approx. 20 metres. It had been compacted with silt over time adding to the difficulties for removal and the blockage had created excessive erosion of the left hand bank and excessive silt deposition on the right hand bank due to deflected high winter river flows. The following pictures show the extent of the work
Contractors were approached to carry out this clearance work and quotations received and eventually accepted. However, confusion over the method of funding grants from the Welsh Assembly Government caused long delays to the start of this project.
Establishing land ownerships for permission to access the site of this log-jam proved very difficult, but eventually, with EAW assistance, we managed to identify and contact the various land owners and obtained the necessary permissions.
Clearance work eventually began on Monday 23rd September 2010 with five days stoppages due to high flood water levels and unsafe working conditions. Work was eventually completed to our satisfaction on Monday 11th October. However, because there was no effective machine access to the site, the contractors had to use portable equipment (winches,tirfors and chainsaws). They had great difficulty in removing some of the very large root plates. We then made a conscious decision to leave one large root plate in the river close to the left hand bank. This created a feature which helped to improve the river habitat (large woody debris) ensuring that all the protruding limbs had been removed preventing the trapping of further debris in the future. The following pictures show the work in progress
The woody materials were removed from the river and stored on the left hand bank in the vegetation. Some of the largest tree trunks were laid into the river bank as revetments to help regenerate the eroded areas of river bank. Below are some pictures of the site after completion of the work.
The effectiveness of removing this log-jam will be monitored during the winter to visually check that access for migratory fish is being maintained. Hopefully, analysis of future EAW electro-fishing surveys will confirm the presence of migratory fish (fry/parr) upstream of this site, indicating that migratory fish had naturally spawned upstream of this location.
