Hurricane Helene recently ravaged the Gulf Coast with destruction and flooding not seen in years. More than 190 people have died in six states, making Helene the second-deadliest hurricane to hit the U.S. mainland since Hurricane Katrina in 2005.
As water wells are susceptible to contamination in floods, Michael Schnieders, PG, PH-GW, president and principal hydrogeologist at Water Systems Engineering Inc., updated an article for Water Well Journal that he first wrote in 2014 titled, “Responding to Flooded Wells.” The article is freely available on WWJ's website.
Schnieders, the 2017 McEllhiney Distinguished Lecturer, notes in the article wells that could face potential contamination include:
- Older wells completed in areas now designated as floodplains
- Wells in which the casing is not finished above the high-water level
- Wells not adequately capped or sealed, or older wells with shallow grout or insufficient surface seal
- Wells in areas structurally unstable, or where previous erosion or subsidence has compromised the structure and landform
- Wells with an abnormal affinity for bad luck.
Any well that has been flooded or is suspected of having been influenced by floodwaters should be viewed as unsafe for potable use until such time the well has been evaluated and tested to make sure it is safe for use as drinking water.
The updated article also contains information on new chlorinated isocyanurates that are gaining popularity for disinfection.
NGWA also encourages water well contractors to review its best suggested practice, Residential Water Well Disinfection Following a Flood Event: Procedures for Water Well System Professionals.
The document, which is free to NGWA members, contains helpful information to use on-site including the inspection of the flooded well for the presence of organic matter; well flushing and cleaning; the proper mix, contact time, and distribution of well disinfection agents; and water testing intervals. Click here to access it.