Sea water pouring into Mississippi River, posing a threat to water supply in the US
Xinhua News Agency, Houston, September 29 – The Mississippi River, a major source of fresh water in southeastern Louisiana, is facing a crisis as seawater pours into the river from the Gulf of Mexico, threatening water supply systems in many areas.
Due to an ongoing drought and hot weather, the water level of the Mississippi River is near its lowest in history. The intrusion of seawater into the river has been occurring for several months and is now approaching New Orleans and surrounding areas. This poses a risk to the water supply systems in these regions.
Monitoring agencies, along with the state government and US media reports, indicate that as of press time, seawater from the Gulf of Mexico has flowed northward for approximately 70 miles along the Mississippi River. It is expected to reach multiple water intakes in New Orleans by mid-to-late October. This could potentially make the city’s water supply unsafe for drinking within the next three months and also threaten farmland irrigation and infrastructure along the river. It is estimated that the affected population may exceed 800,000 by the end of October.
New Orleans Mayor LaToya Cantrell reassured the public that the drinking water supply in the city is currently safe and that relevant departments are closely monitoring the hydrology. However, there have been reports of bottled water shortages in supermarkets in New Orleans over the past few days.
In addition to the immediate threat to the water supply, there is concern about the city’s aging lead pipeline system. Approximately 48% of the water supply system in New Orleans consists of old lead pipes. The intrusion of seawater into these pipes could lead to corrosion and the release of heavy metal substances that can be harmful to human health, affecting the brain, heart, kidneys, and other organs. The extent of lead contamination will depend on factors such as salt concentration in the water supply system and the duration of the saltwater intrusion. Corroded pipes may continue to release lead for months or even years.
The New Orleans Sewerage and Water Supply Commission stated that it is currently too early to determine the severity of lead contamination. Government agencies at all levels, along with environmental protection departments, are discussing response plans.
Both the state of Louisiana and the city of New Orleans have declared emergencies to mobilize resources in preparation for a possible water supply crisis. US President Biden has approved federal agencies to provide emergency assistance to Louisiana to address the situation.
Proposed response measures include the construction of fresh water pipelines in affected areas north of New Orleans and the installation of large-scale water purification reverse osmosis devices capable of removing salt and transporting up to 36 million gallons (nearly 140 million liters) of fresh water per day. Priority will be given to ensuring clean water in schools and hospitals.
In July of this year, the US Army Corps of Engineers built an underwater levee on a section of the Mississippi River affected by seawater intrusion. However, the levee was recently overturned by the seawater. The Corps is currently planning to expand and raise the height of the embankment.
The backflow of seawater into the Mississippi River is a naturally occurring cyclical phenomenon. In some lower reaches of the river, the river bed is below sea level. When the river flow drops below a certain level, denser seawater flows upstream along the river bottom, beneath the less dense freshwater.
Data from the US Weather Service indicates that this year has been one of the hottest years on record in Louisiana, located along the lower Mississippi River. Abnormal drought conditions have also affected other states where the river flows, causing water levels to be close to record lows. The governor’s office stated that downstream freshwater flows have been very low this year due to the ongoing drought in Louisiana and the Mississippi River Valley. This significant decrease in water levels has allowed water from the Gulf of Mexico to slowly flow northward along the bottom of the Mississippi River for several months.
Preventing further intrusion of seawater into the river requires a substantial increase in rainfall in the area north of New Orleans to replenish the Mississippi River with fresh water. However, the weather forecast for the region does not appear optimistic in terms of rainfall in the coming weeks.
[Editor in charge: Wu Liang]