Another day on the River

Thursday 21^st August

A late change of plan enabled all nine volunteers to spend another day working on the River Isbourne bridge (21A).

Polly, Nigel and Martin focused on improving the ‘homemade’ steps that lead down from the up side vacant trackbed to the bridge parapet. This involved some chain saw use to remove as much as possible of two tree stumps. They also added two new steps; dug out the bank and added some spent ballast to make the steps level.

Polly, Nigel and Martin working on the up side steps.

The results of the improvement.

Dave and Ian concentrated on the down side low mileage toe ditch. This runs from the B4632 road bridge past the back of the industrial estate. It was very overgrown; but still damp in places which shows that water does flow down to the river The twinwall pipe under the right bank gabions was checked for obstructions. In the river bed some of the silt build up was removed to ensure a channel for the discharge from this pipe to flow away. They cut an access to the ditch; and then began clearing the ditch. This was slow work – by the end of the we think only a quarter of the distance to the road was cleared.

Ian inspecting the twinwall pipe under the gabion. [Photo by Dave]

The toe ditch looking towards the B4632. [Photo by Dave]

Dave surveys the plants growing on the single bank in the river bed. Note the channel for the flow right by the gabions. 

The rest of the group (Jonathan, John, Peter and Andrew) worked on the downstream, up side of the bridge. More use of restraining harnesses attached to the parapet safety rails enabled the headwall to be cleared of moss and other items of vegetation. By working on just below the gabions (the water level is still very low) they removed lots of Himalayan balsam and other vegetation by the wing walls. Peter and Andrew removed yet more Himalayan balsam and some willow trees from the down stream banks. Jonathan dug out some of the silt that had built up where the vegetation has taken hold. John was on stamping duty, treading on the flowers and seed heads of the cut balsam. Hopefully this will reduce the spread of this plant.

Up side (down stream) portal of the bridge. Jonathan hiding behind the grass whilst dredging the silt.

Close up of the up side high mileage wing wall. As this is the north side of the bridge the vegetation stays damper; so the mortar joints are not as good as those on the down side which gets more sunshine.

Wildlife report: Early on we spotted a kingfisher on the down (upstream) side of the Isbourne; obviously there is good fishing here. Lots of ripening blackberries and sloes on the embankment side. And of course plenty of Himalayan balsam. That does seem to attract lots of bees. On the oak tree (down side, low mileage of the river) we noted lots of galls, each containing a larva of the common spangle gall wasp.

Galls on oak tree. [Photo by Dave]