Two seasons into managing our wetlands, and we have had a drought and a flood. All very Biblical but the question is, how much can we control the water levels in spite of what the weather throws at us?
Thinking about it, the solution to both extremes (drought and flood) is probably one and the same:
To let the water spread between the fields.
This statement probably needs further explanation.
The design of the project was to raise the water table by blocking drains and sluices ditches. This might work in an area that has a different topography to Potter Brompton Carr. For example, a low lying area enclosed by hills.
That is not the case with us. Potter Brompton Carr is flat as in pancakes and surrounded by more of the same. It is a couple of miles to the North Yorkshire Moors to the North and at least a mile to the Scarp of the Wolds (the Brow) to the South. Into the bargain, in the 1980s, the Drainage Board lowered the level of the river Derwent (that flows past our North boundary), which had the effect of lowering the water table on Potter Brompton Carr and the surrounding areas.
So, my reading is that we don't have much of a hope of raising the water table as topography and human endeavour conspires against the idea. By blocking drains and sluicing ditches what we achieve is to produce a gradient in the water table. We might raise the water table at the sides of the sluiced ditches, but the water obediently stay where we want it. As water is wont to do, it will find its level by spreading into neighbouring land and ultimately the river Derwent. Not quite the effect we want.
So what to do?
Our plan now is to harness the surface water that is flowing from springs and ditches to the south of Potter Brompton Carr.
Without going into too much detail, there are three ditches that carry water through the wetlands. So the idea is to use a combination of sluices with the natural gradient of the land. By digging a couple of short trenches, we will be able to divert the water from these ditches onto the land, and then let it flow out across the land. We will install steel pipes to let the water flow across existing ditches, where the land is lower on one side of the ditch than on the other. So this way, water does what water does.
In 2011, we saw that the ditches carry water from springs even in drought conditions. And if we get another year like 2012 (!), then our strategic steel pipes will let the water flow from one field to the next reducing the risk of flooding.
So the best of both worlds!
Or rather, that is the plan...
Helen is designing a graphic to illustrate our intentions and how we envisage the water flowing. I will post again on this subject when it is done.
Hopefully, next year will show that these ideas are more than just another slice of pie in the sky.