Researchers are working on new ways to detect contamination of muddy flood plumes. 

After a flood, muddy contaminated plumes are discharged into the sea from rivers, posing a hazard for swimmers and sealife.

A New Zealand research team has tested a new way of sampling from a fast boat to map a flood plume in Wellington Harbour, while at the same time sampling source water from the Hutt River. 

They found that faecal contamination - indicated by E. coli bacteria - correlated closely with various measures that can help to monitor plumes, including salinity, sediment and coloured dissolved organic matter.

The team says these easily-detected tracers could indicate worst-case (invisible) faecal contamination in satellite imagery. 

Rapid plume surveys, combined with long-term river observations, could usefully add to routine coastal water monitoring, they say.

More details are accessible here.