Israel floods Gaza tunnel network: scientists assess risks

The Israeli military has begun injecting “high flow rates” of seawater into tunnels built by Hamas beneath the Gaza Strip as part of an attempt to “neutralize terrorist infrastructure.”

On January 30, the Israel Defense Forces (IDF) confirmed that plans to flood underground tunnels in the Gaza Strip, which had been rumored since December, were in progress at a number of undisclosed locations. The IDF statement said the relocation was a “significant engineering and technological advance” and added that the location was chosen “to ensure that local groundwater is not compromised.”

But some water researchers warn that flooding the tunnels with seawater could have a devastating effect on Gaza’s already scarce freshwater supplies and destabilize the buildings. . There are also concerns that flooding in the tunnels could put many of the remaining 130 or so Israeli hostages abducted in the October 7, 2023 Hamas attack at risk. The hostages’ whereabouts remain unknown. However, one researcher said, Nature He said he believed the impact of the floods would be limited because Gaza’s aquifers were already contaminated with seawater.

Former hostage Jocheved Lifshitz told the media after his release last October that the tunnel was a “spider’s web” of damp passages dug into the sand. Each tunnel is 50 meters deep, some with multiple entrances, reinforced with concrete and equipped with power cables and pipes, according to Israel’s Ministry of Foreign Affairs. The tunnels were probably used to store weapons and hostage prisoners. They span nearly every corner of the crowded and desolate 363 square kilometer Gaza Strip.

biggest concern

One of the biggest concerns is that the seawater used to flood the tunnels will contaminate the vital coastal aquifer that lies between Gaza, Egypt and Israel, and supplies almost 80% of Gaza’s water.

Marc Zeitoun, executive director of Switzerland’s Geneva Water Hub and a water engineer, says Gaza’s main source of drinking water is contaminated. “When you put salt water into a freshwater source, it contaminates, contaminates, and poisons,” he says.

Zeitoun added that seawater injected into the tunnel could leak out. “If you just tried to fill the tunnel with water, I don’t think it would be sealed well enough to hold the water. The water would run off and flow into the aquifer,” he says.

Ahmed Rafat Gaudier, a geographer based at An-Najja National University in Nablus in the West Bank, agrees that the aquifer is likely to become irreversibly contaminated with salt water.

“If these tunnels were to flood, seawater would be forced through the geological formations and into the aquifer,” Gaudier said. “Such an action would have a serious impact on all aspects of life in Gaza, including agriculture, soil and infrastructure.” Gaudier said seawater could create sinkholes and destabilize building foundations. He added that it is sexual.

But hydrologist Noam Weisbrod, director of the Jacob Blaustein Desert Research Institute at Ben-Gurion University of the Negev in Israel, said people are concerned that entire coastal aquifers could become irreparably contaminated. says they are probably overestimating the impact of flooding. “We don’t know if the environmental risks are as extreme as people believe,” he says. The impact of flooding will vary depending on the location of the affected tunnels, he added.

Water levels in Gaza’s coastal aquifers range from about 60 meters below the surface in the east to just a few meters deep near the coastline, according to a 2020 study published in the same journal. water¹. More water is being withdrawn from aquifers than can be naturally replaced with fresh water, and as a result, aquifers are already being infiltrated with seawater.

Weisbrod’s reasoning takes into account the fact that in areas close to the coast, aquifer water is already saline. Additionally, “much of the water in the aquifer is already contaminated by things like unregulated sewage systems and fertilizers,” he says.

Weisbrod also said the impact of Israel’s plan could be limited. The tunnel network is “not one big subway project like in New York or London,” he explains. “There’s not one big thing that’s all connected. So you end up spending a lot of effort and end up overflowing with something that’s pretty limited. So maybe it’s not worth it. unknown.”

Gaza water crisis

The debate over the tunnel highlights problems that existed before the flooding began. Regardless of the extent to which aquifers are contaminated by seawater pumping, clean water is in short supply in Gaza. In 2020, the United Nations agency estimated that 10% of the population had access to safe drinking water.

Some water is piped in by Israel and Egypt. A EUR 10 million (US$10.9 million) European Union-funded desalination plant opened in Gaza in 2017, but will likely not function without electricity. Before the war, about half of Gaza’s electricity came from Israel, but the Israeli government cut off the supply in October.

The war has displaced around 1.9 million people, many of them living in tents or on the streets in Rafah, a city in southern Gaza. After January’s heavy rains, Gaudier said many people were storing drinking water in plates and buckets. David Lehrer, director of the Center for Applied Environmental Diplomacy at the Arava Environmental Institute in Israel’s Arava Valley, said some people buy water from tanker trucks, meaning low-quality water from aquifers desalinated by private companies. , he says.

Once the war ends, Lehrer says, Israel and Gaza need to start planning for a better water future. In 2023, Arava Institute, through a partnership with the Israeli company Watergen, the Palestinian non-governmental organization Damour for Community Development, and the Israeli Civil Affairs Authority, will install five solar-powered atmospheric water generators at municipal medical centers in the Gaza Strip. installed. According to the Arava Institute, they can produce around 900 liters of clean drinking water per day by capturing, condensing and filtering moisture.

Lehrer said this effort and other interim measures, such as off-grid sewage treatment, “offer a glimmer of hope that things will eventually improve.”