Hi Alan,
I was hoping you would see this discussion and have a input, i wish the NWT would meet with you or at least get in touch with you about East Chevington as its obvious through your profession and experience of East Chevington you know how it works.
Steve,
please get in touch with Alan Gilbertson about East Chevington, we could have a superb reserve once again that caters for every species of bird.
Hi Dave. Thanks for the comments. I've added a couple of edits to my post above with added information.
Other than that I've very little to add other than drawing attention to the following facts.
The outfall stream from the north pool is governed by three fixed points, all on original ground and on the original course of the Ladyburn, none subject to any imagined subsidence.
The first (and highest) of these is the hard invert of the bed of the sluice at the south end of the pool, which has never been put to its intended use (as designed in the 90s by NWT) as I explained on page 218.
The second is the invert level of the pipe that carries the stream across the old coal road track to the dunes. This was put in as far as I recall at the time of the construction of the coal road for Coldrife site (now the country park) in 1966. My late father-in-law was a ganger on the building of the road, and it was from this road that I had my first view of Chibburn Mouth from the back of a Land Rover on my way to Coldrife Site when I began work as a surveyor in 1969. This pipe is below the level of the sluice, so water will flow from the lake to the crossing, if it is allowed.
The third is the inlet pipe to the concrete culvert at Chibburn Mouth, at the south end of the burn in the dunes. It in turn is lower than the pipe under the old road, so no 'uphill' sections. If the channel is clear, water will run.
So in simple terms, all that is required to get the north pool outlet stream to flow as it did happily for hundreds of years until the mid 2000s is to ensure that the channels between these three points are kept as they used to be, without any high spots to prevent flow. These high spots are presently created by vegetation growing and blocking the channel. It used to be called routine maintenance when I was contract managing that sort of thing as an engineer later in my career, but according to the response I had to my comments in 2010 this isn't routine any more.
To me, it's simple. It's not rocket science.
There are three points, each one lower than the one to its north. All it needs is that they are kept so that water can move from one to the other.
It's a fact that the gradient is slack. It always was slack, even before mining and it always will be. It's the Northumberland coastal plain and that plain is flat. Look at the land south of Druridge for an example.
The fact of the slackness of the gradient is an indication that it needs more, not less management and there should be constant effort to ensure its flow. It's no good relying on a figure plucked out of thin air such as 'clean every five years' in situations like this. If restricted flow means that it needs cleaned after three, or even two years, then clean it. If there is growth developing that is likely to cause a problem, shift it before it does. Don't say something like 'It's not in this year's schedule, we'll be doing it the year after next'. A stitch in time saves nine.
The problem now is that it's April. We're once more into another breeding season, so even if an outbreak of rationality were to happen, nothing can be done to fix the pool until the autumn, and another year is lost.
I really have nothing to say other than this to the NWT.
I wrote to them years ago pointing out these same problems in 2008 and received a brush-off. I'm still awaiting a reply to my response to it. I have no intention to getting into bed with them now so that they can say I was 'consulted' when they carry on doing what they would have done anyway.
It's not rocket science. They have a slope. All they have to do is make water run down it.
