Tuesday, 6 December 2011

Flooding

Our allotment site is rather prone to flooding - it's on very low ground, in a dip, so whenever the water table gets very high (especially at the end of winter) we're the first to know - and it's on the old course of the local river, the Ver, which occasionally bursts its banks and tries to revert to its old ways. This winter, however, it isn't the water table or the river that's causing a problem. It's a 15" water main three metres below the site, which has burst. Oh dear.


This is just two plots away from ours, but luckily for us our plot is much higher, and not affected.

I have to say I've been most impressed by the rest of the committee and how quickly and effectively they investigated the situation and had the problem traced. Ten heads are certainly better than one - I first thought there would be nothing we could do but warn plot-holders to take precautions against flood damage. It took someone else to point out that the water table can't possibly be this high, another to report that the watercress beds nearby had been positively droughted until a few days ago but the water level had suddenly shot up, another to spot a letter in the local paper wondering why the level of the river had also risen suddenly, another to call in the council, and another to be available to meet with Environment Agency and water board officals... A real team effort! How long it will now take for the water company to fix it (and how much damage is done in the process) remains to be seen...


Meanwhile, there's not a lot else we can do but feel sorry for those affected. But, as newsletter editor, and since this certainly won't be the last time we're affected by flooding, I've been trying to put together a list of pointers to help plot-holders and gardeners deal with flooding, minimise flood damage, and recover from it, in future. Here goes:

All year round:
  • Build up your soil's organic-matter content to promote aeration and drainage.
  • Promote healthy microbiological activity in your soil with plenty of good compost, and consider using a seaweed extract to strengthen your plants and your soil. A healthy soil will stand up better to any problems.
  • Keep your site tidy, keep chemicals sealed and to a minimum, and always remove diseased plant matter.
  • Make the sure the bottoms of sheds, in particular, are waterproofed and protected against rot.
  • Plant trees and shrubs on raised ground where possible.

When flooding threatens:
  • Remove tools and equipment from sheds and greenhouses - or at the very least, raise them off the floor. 
  • It may be possible to protect your shed or greenhouse with sandbags.
  • Ensure all chemicals and treatments are out of reach of floodwaters, to prevent contamination of the water.
  • Remove rubbish and loose items from the site, or secure them so they can't float away.
  • Raise pots and tubs up on bricks, or remove them from the site.
  • Harvest everything you can and store it at home.
  • If you know you're going to lose certain crops but it's not too late to resow, do it right away, so you'll be ready to plant out again as soon as your plot has recovered.
  • Remember that floodwater can sometimes carry dangerous contaminants. Avoid contact with it where possible - wear waterproof gloves and footwear if needed, and shower and wash your clothes after contact. Protect cuts and grazes. If you fall ill after coming into contact with floodwater, see a doctor.

When the water goes down:
  • Carefully check sheds, greenhouses and other structures for any structural damage before using.
  • Try to avoid walking on waterlogged soil until it has dried out. If you need to get across it, lay planks down to spread your weight on the ground.
  • Don't sow/plant in waterlogged soil - wait for it to dry out.
  • Speed drying by aerating the soil with a fork or similar.
  • Remove debris and dead or decayed plant matter as soon as possible. Empty any containers that have collected floodwater.
  • Most plants will recover if they have been flooded for less than a week, but consider taking cuttings of valued perennials, so that you have back-ups in case they don't.
  • Check for any exposed roots, and cover them with soil. Check for plants that may need staking for extra support while they recover.
  • Clean any silt or mud off recovering pants, and feed them. Seaweed extract may help to build disease resistance and promote new root growth.
  • Prune struggling plants right back, to give them an easier time while they recover.
  • Waterlogging can affect the pH of your soil and drain it of nutrients - consider checking the pH and dressing with manure or fertiliser before replanting.
  • Consider growing a green manure before you plant crops, to help to rebuild soil structure and add nutrients. This may also help by indicating if you have any more serious soil problems such as contamination or an unhealthy pH.
  • Once it's dry, check your soil for signs of life, forking through it gently. Worms are very sensitive to contaminants and are a great indicator of the health of your soil.
  • Whether or not it's safe to eat vegetables which have been in floodwater is a controversial matter; health guidelines say don't do it, but if the source of the water is known and localised, if it looks and smells clean, if there is no industrial activity near your site and no chance of the water having come into contact with sewage, and if plotholders have taken steps to avoid local contamination of the water, you may prefer to make up your own mind. Wash all vegetables carefully and cook before eating. But if in doubt, throw it out.
  • Don't be discouraged! Get growing again as soon as you can, even if it means growing in pots or growbags temporarily. Sow some fast-maturing crops such as salads for quick results. Ask for help if you need it.

And if you're unaffected, consider how you might be able to help your fellow gardeners:
  • Keep your plot tidy and free of debris and contaminants too.
  • Lend tools where they are needed - perhaps you even have surplus you could give away.
  • Propogate plants for others to help them get going again.
  • Share surplus crops and compost from your plot.

3 comments:

Robert Brenchley said...

I'd add that you need to be aware of where the water's likely to come from. You can't plan for a burst main, but you can build up flood banks along a watercourse, as long as everyone along the bank works together.

Sue@G.L. Allotments said...

That really is a shame - I wonder what would happen in a rainy year?

Nome said...

Robert, great point, thanks.

Sue, it's been much worse than this I'm afraid - it's just one of those things we have to deal with, being on such low ground. At least it usually happens in the dead of winter, not the summer when everything's in full growth (though this burst water main was, of course, unexpected!).

Related Posts Plugin for WordPress, Blogger...