Calstock flood defence improvement scheme
The existing flood embankment provides an important role in reducing flood risk in Calstock, but surveys have shown it is in a poor condition. The Environment Agency is working hard to try to develop an affordable scheme to continue the standard of flood protection to properties within Calstock (https://www.gov.uk/government/publications/calstock-flood-defence-improvement-scheme/calstock-flood-defence-improvement-scheme).
Visit to the site.
Mrs Copson-Ball and Miss Evans met with site foreman Adam Duncan to find out how the flood defence works are progressing. Here you will find lots of pictures that Adam shared with us.
Adam showed us the plan which they are working to. The kidney shaped bits are being dug out to create the bund which will retain the water when the riverbank is eventually breached in about a year. The sections between the kidneys are veins connecting all the ponds so that they drain when the tide goes out. The bunds that are being created are at least 2 metres tall.
The topsoil is skimmed off first because it’s too soft; it’s put into heaps so that it can be put back on top of the new bunds. Stronger soil is used to build up the bunds, dug from the kidneys and the better parts of the fields, whilst the less good stuff goes back in the holes where we don’t want kidneys. It means we move a lot of earth around to get what we want!
The new bunds would trap any water running from the land so we are also digging new ditches and laying pipes so that this water can be held safely when the river is high and drains away as the tide goes out.
The weather is kinder to us now, it was so wet in the autumn that the ground turned to mud when we tried to work with it so we stopped. Now there is less rain we can work most of the time and the bunds are coming up fast, the ditches and drains are nearly done and we’re thinking about topsoil and seed for the banks. We’ve found an old pipe which takes water off Eric Road and Harewood Road; it runs underneath where we are extending a short bank into higher ground so we are working out how best to build that in a way which doesn’t damage the pipe or make a mess of the garden. There’s another pipe under the existing bund near the sewage works which we need to fix so that water can run out but not back in; we’re going to push a small camera through it to see what state it’s in then decide what we can do.
The main work on site should finish in September, then there’ll be time for the bunds to harden and the grass to establish, and time for the Community Trust to construct the bridge which will carry the riverside path once the breach is made. That will happen in the autumn next year so that it has the least impact on the special fish which live in the Tamar.
What is happening?
Adam showed us the plan which they are working to. The kidney shaped bits are being dug out to create the bund which will retain the water when the riverbank is eventually breeched in about a year. The sections between the kidneys are veins connecting all the ponds. The bunds that are being created are at least 2 metres tall.