Seawater Intrusion Threatens Water Supplies in United States as Mississippi River Reaches Historic Low Levels
By Xu Jianmei, Xinhua News Agency Correspondent in Houston
A severe drought and hot weather in the United States have pushed the water level of the Mississippi River to a historic low, leading to the intrusion of seawater from the Gulf of Mexico. This intrusion is now approaching New Orleans and surrounding areas, posing a significant threat to the water supply systems in these regions.
The Mississippi River serves as the main source of fresh water for southeastern Louisiana, flowing from north to south into the Gulf of Mexico. According to state government, monitoring agencies, and US media reports, the Gulf of Mexico seawater has already advanced up to approximately 70 miles (about 113 kilometers) of the river. By mid- to late October, it is expected to reach New Orleans, potentially rendering the city’s water supply unsafe to drink within three months. This crisis not only endangers farmland irrigation but also poses risks to critical infrastructure along the river, with the affected population predicted to exceed 800,000 by the end of October.
Addressing concerns, New Orleans Mayor LaToya Cantrell assured the public that the city’s drinking water supply remains safe and that hydrology is being closely monitored. However, local media reports indicate that in recent days, there has been a surge in demand for bottled water, leading to shortages in many supermarkets.
Furthermore, approximately 48% of New Orleans’ water supply system consists of aging lead pipes. Seawater entering the system can corrode this infrastructure, resulting in the release of harmful heavy metals that can cause damage and diseases affecting the brain, heart, kidneys, and other organs. The extent of lead contamination will depend on factors such as salt concentration and the duration of saltwater flow. Corroded pipes can continue to release lead for several months or even years.
Efforts to Respond and Counteract the Crisis
In response to the imminent water supply emergency, the New Orleans Sewerage and Water Supply Commission stated that it is premature to predict the severity of lead contamination. Government agencies at all levels, along with environmental protection departments, are currently formulating response plans.
The state of Louisiana and the city of New Orleans have already declared emergencies, mobilizing various resources to address the crisis. Additionally, President Biden has approved federal agencies to provide emergency assistance to Louisiana in tackling the water supply challenges.
The proposed response measures include the construction of fresh water pipelines in areas north of New Orleans and the installation of large-scale reverse osmosis water purification systems capable of removing salt. These systems can provide up to 36 million gallons (nearly 140 million liters) of fresh water per day, prioritizing clean water supply to schools and hospitals.
Efforts by the US Army Corps of Engineers to address the seawater intrusion involve the construction of an underwater breakwater along a vulnerable section of the Mississippi River. However, recent reports indicate that the breakwater was overturned by seawater last week. Currently, the Corps plans to widen and raise the height of the embankment to enhance its effectiveness.
Understanding the Cause
According to the US Army Corps of Engineers website, the backflow of seawater from the Gulf of Mexico into the Mississippi River occurs cyclically due to natural factors. In some lower reaches of the river, the riverbed lies below sea level. If the river flow drops below a certain level, denser seawater can flow upstream alongside the less dense freshwater, creating a massive “wedge” beneath it.
This year has witnessed one of the hottest periods in Louisiana’s history, an area located downstream along the Mississippi River. Drought conditions in various states through which the river passes have contributed to abnormally low water levels. As the drought persists in Louisiana and the Mississippi River Valley, freshwater inflows into the river have significantly decreased. Consequently, seawater from the Gulf of Mexico has slowly infiltrated northward along the river bottom for months.
The hydrological monitoring agency highlights the urgent need for substantial rainfall in the areas north of New Orleans to increase the volume of fresh water in the Mississippi River and prevent further seawater intrusion. However, current weather forecasts do not offer an optimistic outlook for rainfall in the region.
[Editor: Wu Liang]
Xinhua News Agency, Houston, September 29 Summary: Seawater is pouring into the Mississippi River, threatening water supplies in many places in the United States
Xinhua News Agency Correspondent Xu Jianmei
Affected by the ongoing drought and hot weather, the water level of the Mississippi River in the United States is close to the lowest level in history, resulting in seawater intrusion into the Gulf of Mexico for several months. It is now approaching New Orleans, the largest city in Louisiana, and the surrounding areas, threatening the water supply systems in these areas.
emergency
The Mississippi River, which flows from north to south into the Gulf of Mexico, is the main source of fresh water in southeastern Louisiana. Based on information from state government, monitoring agencies, and US media reports, as of press time, seawater from the Gulf of Mexico has flowed north to about 70 miles of the Mississippi River (about 113 kilometers), and multiple water intakes are expected to reach New Orleans between mid- to late October It may make the city’s water supply unsafe to drink within the next three months, threatening farmland irrigation and some infrastructure along the river. By the end of October, the affected population is expected to exceed 800,000.
New Orleans Mayor LaToya Cantrell issued a statement saying, on the afternoon of the 29th local time, that the drinking water supply in New Orleans is still safe and that relevant departments are closely monitoring hydrology. He also called on the public not to panic. However, according to media reports, bottled water has been broken up in many supermarkets in New Orleans over the past few days.
In addition, according to local media reports, about 48% of the water supply system in New Orleans is an old lead pipe system. When seawater enters the water supply system, it will corrode the supply infrastructure water. The heavy metal substances released by this corrosion can have harmful effects on the human brain and heart, kidneys and other organs causing damage and causing disease. The degree of lead contamination depends on factors such as the concentration of salt in the water supply system and how long the salt water continues to flow Corroded pipes can continue to release lead for months or years.
respond
The New Orleans Sewerage and Water Supply Commission issued a statement saying that it is too early to predict the severity of lead contamination at this time, and government agencies at all levels and environmental protection departments are discussing response plans.
Currently, the state of Louisiana and the city of New Orleans have issued emergency declarations for potential water supply emergencies to deploy multiple resources to respond. Recently, US President Biden approved federal agencies to provide emergency assistance to Louisiana to deal with the water supply crisis.
According to reports, the proposed response measures include the construction of fresh water pipelines in the relevant areas north of New Orleans and the construction of large-scale reverse osmosis water purification devices capable of removing salt and transporting it to to 36 million gallons (almost 140 million). litre) of fresh water per day. , giving priority to ensuring clean water in schools and hospitals.
The US Army Corps of Engineers built an underwater breakwater in July of this year on a section of the Mississippi River where seawater intrusion occurred, but it was overturned by seawater last week. Currently, the Corps plans to widen and raise the height of the embankment.
Cause
The US Army Corps of Engineers website states that backflow of seawater from the Gulf of Mexico into the Mississippi River was originally a naturally occurring cyclic situation, primarily because the river bed in some lower reaches of the Mississippi River was lower than sea level. If the river flow falls below a certain level, denser seawater will flow upstream along the river bed as a huge “wedge” under the less dense fresh water.
According to data from the United States Weather Service, this year has been one of the hottest years in history in Louisiana, located on the lower side of the Mississippi River. Many other states where the Mississippi River flows have also experienced drought. abnormal, causing the river water levels to be near record lows. The governor’s office said freshwater flows down the river have been “very low” this year as drought continues in Louisiana and the Mississippi River Valley. The excessive drop in water levels has caused water in the Gulf of Mexico to slowly flow northward along the bottom of the Mississippi River for months.
The hydrological monitoring agency said that preventing the continued intrusion of sea water requires a large amount of rain in the area north of New Orleans to increase the amount of fresh water in the Mississippi River. However, given the weather forecast for the period next time, the amount of rainfall in this area is not optimistic.
[Golygydd â gofal: Wu Liang]
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