Dredging has changed direction

It was hoped that had dredging been able to continue at the same pace, the basin end would have been completed around the middle of the week 9/7/14.  However at the planning stage a risk was identified in that when dredging into a dead end with no water flow the normal temporary deterioration in water quality which accompanies such massive disturbance of the bed becomes more significant.  Monitoring of the water for ammonia and oxygen content was intensified, and concerns raised when the dredger was approaching the basin.  The problem was compounded with a motor problem meaning that the aerator barge could not operate at full capacity.

On the Wednesday morning the decision was taken to suspend dredging, as had been the contingency plan for such a water quality concern, and move the dredging operation to the east of Highline while the water recovered.  The dredger would then come back and finish the basin.  This is a little bit tiresome for the people concerned as the dredging digger has to come off its barge to get under a couple of low bridges, but these were already known about from the outward journey.

Before leaving the basin the dredger and tugs completed the demolition of the pier, which did not have significant bearing on the water problem, then moved to the eastern end of the moorings.

By Thursday morning the dredger was working close to Mansion Lane bridge.

Close to the bridge the water was filled not so much with silt, but with discarded large items of rubbish, thought to have been thrown off the bridge. Sadly a problem to some extent everywhere, but a particular problem here.

The intention now is to finish the work at this bridge and then spot dredge some other sites while travelling east, before returning to the basin