Floods are one of the world’s most common natural disasters. There is a 26% chance of experiencing a flood and only a 4% chance of having a house fire (source: www.fema.gov). Floods can be caused by Mother Nature—hurricanes, tropical storms or other heavy rains, storms or thaws—or human nature—clogged drainage systems or changes in development of the area. If you have a well providing the drinking water for your property you should be wary of floods and prepare your wells. There are precautions that you can take to protect the well, but do not rely on them. Test water in the well before and after.
After a flood the water can become contaminated due to floodwater entering the well or the aquifer that feeds it. The contaminants in the flood water come from livestock waste, herbicides or pesticides, sewage and more. As well, the water in the well may become contaminated by surface water runoff even if the surrounding areas have not been flooded. Wells that do not have watertight caps or seals are at the greatest risk as well as wells that do not have a grout seal between the walls of the well and the drilled hole. If the well itself was submerged with flood water, it is at greatest risk. Test water after any of these conditions.
Before a flood, you can protect your well to minimize the impacts of the flood.
Ensure the land around the well slopes away so that the water will flow away from it. The well casing should be at least 30 cm above ground or above anticipated flood water level. Also, as mentioned above, be sure that the seals and casings of the well are in good condition. You can give extra protection to the well by covering it with plywood and tarps and securing it with sandbags. Prepare the area that will flood beforehand. Clear away all livestock waste, fertilizers and pesticides and empty septic tanks prior to the flood. Remember that these are precautions only and you still must test water afterwards.
Don’t forget about any unused wells in the area. Floodwaters entering an abandoned well can still contaminate your active well or its aquifer. Be sure that unused wells are permanently sealed.
Following these precautions is no guarantee that the well water will not become contaminated. After a flood, it is very important to decontaminate the well with chlorine to kill the bacteria. Once chlorinated, the well should sit for 6-8 hours before being flushed. This procedure may need to be repeated more than once. After the chlorination process, test water for drinkability. The chlorination process will clean away the fecal coliform bacteria but not the nitrates, pesticides or heavy metals. Further water tests will need to be performed.
Be sure that you consult professional well drillers for help in securing your well before the flood and test water experts after the flood to give you peace of mind. AquaKnow has a large range of test water kits and the expertise to advise you on which ones you need. Professional test laboratories can also analyze the water test to see if there are any contaminants in it. Contact AquaKnow at 877-734-7661 to consult with one of their representatives. firstname.lastname@example.org
February 24, 2012 at 8:43 am Comments (0)