Incident@Lambrok is how the Environment Agency titled its report on the week-long torrent of heavily sedimented, chlorinated water that Wessex Water let flood from a broken water main, through the Lambrok down to the Biss, taking in Southwick Country Park and its precious freshwater biota on its way.
It is difficult to say when the incident began. Last Saturday the water in the Lambrok was cloudy. On Sunday it was obvious that something serious was going on upstream and FoSCP explorers found a digger parked by a mound of earth, a pool of muddy water and a notice, in the corner of a field. A passing dog-walker said that the digger had been there for some weeks.
We rang a Wessex Water hotline and they sent a man, who rang us later to say it wasn’t sewerage, which we already knew; he said it was groundwater. This seemed so unlikely that we rang the Environment Agency with a map reference.
The Environment Agency contacted Wessex Water, who said it was, after all, a broken water main but we were not to worry because there were no chemical contaminants in the water and it wasn’t chlorinated. They were waiting, they said, on something that could not be delivered until Tuesday when the break would be fixed. The Environment Agency asked them to turn the water pressure down to reduce the flow and the sediment and they said they would.
By Monday morning the water in the Lambrok was looking like cafe au lait, flowing very rapidly and easily 25cm deeper than usual. At the site of the leak, the water escaping from the main was making a noise that could be heard fifty metres away. We rang the Environment Agency; the Environment Agency rang Wessex Water who said the work would start the next day and, by the way, the water was chlorinated; all mains water is chlorinated.
drinking chocolate the site of the leak
By Thursday, it was apparent that Wessex Water had done nothing to reduce the flood of silt and chlorinated water that had been smothering the bed of our stream and all its occupants for a week. Yesterday morning (Friday) they told us that the equipment to mend the leak was being assembled and they would start work next Monday. We rang the Environment agency. We don’t know what the Environment Agency said to Wessex Water but several people rang us to say that work would begin immediately.
silt laden vegetation beautiful demoiselle
This morning, at the site of the leak, there is a much bigger pile of dirt, a temporary settlement tank built out of metal plates and full of clear water, and a pipe feeding the clear water into the stream. In the park, the stream is still running fast, but the water is at least clear.
We don’t know yet how much damage has been done, The bed of the stream, its vegetation and presumably the invertebrates that live there are covered with silt and there are no fish to be seen. There was a pair of beautiful demoiselles among the iris stems this morning; let’s hope the water was clear enough and the chlorine diluted enough for the female to find somewhere to lay her eggs.

From my own past experience with water voles in the Lambrok at Wynsome Street, Wessex Water do not always seem to take environmental issues as seriously as they should.
They were very polite but seriously uninformed. The Environment Agency at least understood that it was an emergency.
On second thoughts, it was the Environment Agency not Wessex Water that two years ago showed a complete lack of understanding of how to treat water voles when clearing the banks of the river Lambrok at Wynsome Street. Perhaps they are now more aware of these environmental issues.
Hopefully, Wessex Water will now have a better understanding in the future.
Two years ago the EA was probably working to the old water vole mitigation rules which said that if you cleared the vegetation, the voles will move without suffering harm. New research has shown that is not so and the mitigation requirements are being rewritten.
Yes, that’s just what I was told, The water voles will just move out of the way and come back later when they had finished clearing the river banks. Local residents reported a big reduction in water voles seen in this part of the Lambrok after the river was cleared.
This was received wisdom until last year. New research has shown that the water voles actually stay put and get dug up with their holes.