The following was written by Matt Buckler, an expert in upland restoration, and the Green Party candidate for Derbyshire Dales at the 2019 general election. We need to implement these sensible strategies before we experience more disastrous floods.
"We need to work with the natural world and make space for water. The climate is changing, and we know we will suffer more frequent extreme weather for the foreseeable future whatever actions we take to decarbonise our economy.
Rainfall is not distributed evenly. You get much more rainfall in the uplands, for us that’s on the hills of the Peak District. All of this water flows downhill into our rivers.
Flood defences may protect a community, but stop water leaving a river, making flooding worse downstream.
This is where managing water within the landscape comes in, and the best for wildlife is to use Natural Flood Management. Every decision taken within the landscape changes the chances of flooding downstream, particularly when multiplied by millions of people. We need to:
● Make space for water (give it somewhere to sit and reduce peak flow)
● Slow the flow
In the lowlands you can construct dams and allow floodplains to reconnect with rivers, flooding farmland and allowing water back into rivers when the danger has passed.
The Derwent at Cromford, during the height of the 2019 flood in Matlock. Allowing the fields on the right to flood, rather than holding water off of them with a berm, would have reduced the height of floodwaters in Whatstandwell and Ambergate.
But it’s not all about big places to hold water. Possibly the most important space for water is virtually invisible, in soil. In the uplands, peat should be about 97% water.
Apologies, but let’s talk numbers.
Normal soils can hold about 25% of their volume as water. So, a cubic metre of soil can hold about 250 litres of water.
A soil in good condition, with pores of different sizes and plenty of organic matter (lots of earthworms!) holds water in the top 30cm.
A typical soil, compacted by heavy farm machinery and livestock, holds water in the top 10cm, so you need 3 times the area to hold as much water as a good soil.
A hard surface, such as a roof, road or car park holds no water at all, except for the water that sits on it, which is normally referred to as surface water flooding.
Water simply flows off hard surfaces, into drains and ultimately rivers.
Bare soils wash off into rivers. This reduces the amount of good quality soil to hold water and reduces the capacity of rivers to hold water. Dredging, often spoken about as a cure for flooding, is another symptom of the problem of managing soil and land.
Trees intercept rain and increase the time it takes to reach the ground. Their trunks will divert water flowing down a hillside. Hedgerows and drystone walls slow the flow. Short grass is better than tarmac, long grass is better than short grass, scrub, bracken, brambles are all great at slowing the flow of water. And the best plant of all is a tiny plant that lives at the top of the Derwent catchment, in blanket bogs, sphagnum moss. This is over 97% water and has a huge amount of space between its stems, storing lots and lots of water. You can tell where it has grown in the past, as it forms peat because of the water-logged conditions. It is already being reintroduced in upland catchments and I want to support and massively increase this type of work across the Derbyshire Dales."
Promoted by JOHN HILL, 103 MAYFIELD ROAD, ASHBOURNE, DE6 1AS on behalf of the GREEN PARTY, The Biscuit Factory A Block (201), 100 Clements Road, London, SE16 4DG