Millhouse Beck Feasibility 2019

Foston Beck. Brewery Farm. Foston 2019

This section of Foston Beck downstream of the Environment Agency gauging station has a very low gradient culminating at a defunct steel pile weir about 700 metres below the gauging station. This weir was installed in the early 1970s by the Millhouse Beck Dry Fly Club. It is constructed with sheet piles and has a mechanism in the centre that incorporates a fish screen. Much of this structure is in poor repair and is causing heavy siltation upstream towards the Foston Mill pool.

There is very little ‘fall’ through this structure at normal flows. At high flows the weir acts as a restriction and at times blocks with floating debris following a weed cutting operation. Several meetings have been held with the fishing club and it has been decided that the weir has no practical benefit or reason for it to remain. The original reason for its installation was to prevent fish from moving out of the clubs preserves. From the above picture it can be seen that the weir is not capable of preventing fish movement in its present state. The section below this weir is very over engineered; it is slow flowing, has no marginal zones and has a deep sediment layer on the bed. This situation extends for about 160 metres to the confluence with White Dyke, a lowland agricultural drain.

An aerial shot looking upstream taken from 30 metres above the Foston Beck & White Dyke confluence.

Closer shot of the reed margin showing the potential natural meander forming.

Options:

1. Remove the weir completely and reinstate the banks and margins.

2. Remove the centre section of the weir down to bed level and retain the ‘wings’ and bridge.

Prior to altering the weir, remove as much silt above its position as possible. This can be done by leaving some silt in the margins and creating a meandering channel. The silt would be placed on the back of the left bank in one operation.

Downstream of the weir:

The original thought was to import chalk stone to create a meandering form. However following a boat survey assisted by the EA fisheries officer it was found that the project site had a very deep hard bed and over 0.78 metres of silt above it. Calculations on this method meant that several hundred tonnes of material would be needed to achieve this option. The proposal now is to use this silt to create the meanders by placing it on the reed beds that can be seen in the above aerial shot. The silt will only be removed from the centre channel and it is believed that over time a more natural channel will develop.This would go some way to negating any massive silt transport into Frodingham Beck. There is a shortage of bushes /trees on this lower section of Foston Beck. As maintenance is undertaken from the left bank it is proposed that more Hawthorne and willow bushes can be planted on the right bank that would improve cover and not affect machine access.

Access for machinery:

Between the EA gauging station the access to the Beck for machines is non-existent due to fenced paddocks and overgrown bushes. The only access is via Brewery Farm. However this does not include the 70 metre section through a former orchard. Talks are being planned with the IDB and the owner to create temporary access through the grass paddock. This will enable weed cutting and management of large poplars on the upper section.

Alan Mullinger

EYRT January 2019