Is it okay to dump seawater to extinguish wildfires

Faced with limited supply of freshwater, firefighter are scooping gallons of seawater and dumping it on the wildfires in Los Angeles area as a last resort. However, seawater has its drawbacks

Hyderabad: Battling the deadly wildfire in Los Angeles area, the firefighters, who are facing limited supply of freshwater, are now scooping gallons of seawater and dumping it on the fires. Using seawater to fight wildfire sounds a simple and quick solution in the emergencies like what Southern California is facing, and the Pacific Ocean has endless supply of water.

However, seawater also has drawbacks. Saltwater corrodes firefighting equipment and may harm ecosystems, especially those like the shrub lands around Los Angeles. Excessive salts can stress and kill plants. Sea-level rise has risen by an average of 8 inches globally over the past century, and storms push seawater ever farther onto the land, including forests and farms, eventually killing trees and creating ghost forests, a result of climate change that is widespread globally.

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During an experiment, where researcher exposed a certain area in a coastal forest to salt water. It was found that though that coastal forest showed little effect initially, with the longer exposure, the trees started drawing water from the soil more slowly, which could be an early warning signal. Later, the leaves of the coastal trees turned brown and started falling several weeks earlier than normal.

The research group is still trying to understand all the factors that limit the forest’s tolerance to salty water. Tree leaves turning from green to brown well before fall was a surprise, but there were other surprises hidden in the soil below.

Rainwater percolating through the soil is normally clear, but the soil water turned brown and stayed that way for two years. The brown colour comes from carbon-based compounds leached from dead plant material. It’s a process similar to making tea.

The lab experiments suggest that salt was causing clay and other particles to disperse and move about in the soil. Such changes in soil chemistry and structure can persist for many years.

While ocean water can help fight fires, there are reasons fire officials prefer freshwater sources – provided freshwater is available.

US coastlines, meanwhile, are facing more extensive and frequent saltwater exposure as rising global temperatures accelerate sea-level rise that drowns forests, fields and farms, with unknown risks for coastal landscapes.