flooded allotment

[kazzie1958]

My flooded allotment

What do i do when all this water has gone???. I have only had the allotment 6 months and have not expeienced anything like this. The water will be contaminated as it is from a beck that has burst its banks. Any advice would be greatly appreciated.

[snohare]

Well, I'm no soil scientist, not any scientist at all actually, just a science buff, so don't take what I say as gospel...
It seems to me there are two issues to concern you here, Kazzie. One is what happens longer term - will all your plants die, will your soil be unfit for growing in in the future - and the other is simply, will any surviving produce be edible ?
As you no doubt have heard, flooding causes sewers to back up and the sewage to enter into the flood waters. So bacterial contamination, and to a lesser degree because sewage contains medicines and heavy metals, contamination by trace elements, is definitely a problem.
Plants while living take up contaminants from the soil, water and air around them, into tissues that are growing at that time. So if a cabbage has four leaves, and then grows two more leaves while the ground is contaminated by for example, copper, then only the later two leaves will contain copper. In terms of bacterial contamination, unless it is particularly heavy you should find that normal precautions such as washing veg before cooking and use, or if you are really worried giving them a second rinse, should be enough. Obviously, plants are prone to bacterial infections same as humans, and you should discard any produce that looks unhealthy or diseased.
For the likes of brassicas, I'd be inclined to soak them in cold salty water for maybe twenty minutes, then discard the water before cooking as normal. (The salty water method is also one way of reducing heavy metal contamination, if I remember correctly from research done on radioactivity in food in the Chernobyl area. There however they may have cooked in the salty water, and discarded it after it had absorbed elements released as the cell walls broke down during cooking.)
Longer term, it tends to be heavy metals and chemicals building up in the soil that are the problem. I believe that in China large areas of arable land were out of use for four years recently due to contamination by floods: however, the amount of pollutants lying around in China is massive compared to most parts of the UK, so I would expect that is an extreme case. (Also, that ground was used for organic growing, so probably needed to be re-certified to a relatively high standard.)
If it is only very transient pollution by sewage, then the problem will sort itself out relatively rapidly; the quicker the water drains the better, and of course soil that is soaked for too long will become full of anaerobic bacteria ("sour") which kills plants. But there are so many different types of micro-organisms in the soil that they will normally soon kill/eat/outcompete any bacteria left by the sewage, to a level where you are no more at risk than when eating commercially grown organic crops.
If there is chemical pollution by local industry - garages, factories, industrial units, medical premises - then your problem may be a lot more severe. Again, the time frame decides a lot, as does source proximity. In this case you need to approach officialdom. I would suggest that you might want to talk to your local university, see if you can find any soil scientists, toxicologists or chemists who might be able to give you some advice or point you in the direction of further sources of information. Failing that, you might try MLURI (Macaulay Land Use Research Institute) in Aberdeen, who are world-class soil scientists, and see if you can send them some soil samples for analysis. I know they used to offer such a service, you might be lucky and find that it is very affordable, especially if they can get a research paper out of it.
Hope that helps. It may not all be doom and gloom !

[kazzie1958]

Thank You so much Snohare, this advice has helped me a great deal.