Woldgate Weir Removal 2018

Gypsey Race Improvement Project - Woldgate Weir Removal 2018

Woldgate Gauging Station

Gypsey Race is ephemeral in its upper reaches (well upstream of Woldgate Weir); the remainder of the watercourse flows all year (except in extreme drought events).

Gypsey Race has a run of sea trout which run up it to spawn in the headwaters. However just upstream of the A165 road is Woldgate Weir; this is a defunct and dilapidated gauging weir. The weir is a barrier to fish passage and to the sea trout spawning grounds. Woldgate Weir is owned by East Riding of Yorkshire Council; they have given permission for this weir to be removed as they have no operational need for the structure. The project seeks to restore Gypsey Race by narrowing the channel and making more varied flow patterns. It will also remove Woldgate Weir and then restore the affected section of channel to a more natural condition. The project will benefit a range of wildlife.

Woldgate Weir has ponded part of the watercourse upstream of the weir and this area is a mass of burr reed which requires still or very slow flowing water. However in a natural flow regime, Gypsey Race should contain plants characteristic of a chalk stream such as water crowfoot. The combination of river restoration and the removal of the weir will allow a more natural flow regime throughout the catchment and mean that plants associated with chalk streams can colonise (or be reintroduced). Removal of Woldgate Weir will also aid the migration of lampreys and eels. Finally restoration of Gypsey Race and the removal of Woldgate Weir will ensure that there are more natural sediment processes in the watercourse.

The Gypsey Race Project compliments, but is separate to the wider Bridlington Renaissance Project which East Riding of Yorkshire Council is managing. The Bridlington Renaissance Project seeks to improve Gypsey Race through the town and make it more natural and a place that people value and want to visit. The upstream of the A165 the Environment Agency has agreed to deliver the section of the project that will include removal of the defunct weir.

The Gypsey Race Project will ensure that this watercourse is improved upstream of the area covered by the Bridlington Renaissance Project.

The contract to remove the weir was awarded to a local contractor experienced in demolition works.

Demolition of the meter building and associated stilling well.

As with all similar gauging weirs the structure is built using re-enforced concrete.

The method chosen to demolish this type of structure is with the use of a hydraulic breaker. The re-enforcing wire is toughened steel and has a high resistance to any breaking force.

Hydraulic breaker demolishing the weir retaining walls.

The “V” shaped gauging section can be seen on the river bed. This section of concrete was over a metre deep with many strands of re-enforcing wire.

With the concrete removed the bank was reformed. The angle on this left bank needed to be left steeper than ideal. This was due to the position of the fence on the bank top. Care was needed to prevent undermining the posts.

All concrete and bricks were removed from site by the contractor. This material is crushed and sorted at their site where the steel wire is recovered for re-cycling. The crushed concrete is used for roads etc...

Once the weir site had been completed the landscaping part of the project began. The channel was blocked with reeds (Sparganium) this indigenous plant species can slow river flows and cause rapid siltation, all problematic during flood flow conditions.

Sediment was removed from the watercourse using a method that will allow the river to meander within its restricted course. The variations made in both depth and width will assist in promoting natural geomorphological actions to develop, especially during high winter flow patterns.

 

Alan Mullinger

East Yorkshire Rivers Trust - December 2018