Exploring the Potential of Scaling Up Israel's Flooding Strategy on Hamas Tunnels
Israel's experimentation with flooding Hamas tunnels poses challenges and controversy Aside from the risk of damaging surface infrastructure, there are concerns about contaminating freshwater sources Additionally, the presence of hostages within the tunnels further complicates this method of warfare
After seven weeks of Israel's ground operation in Gaza, a major obstacle for the Israeli military is the complex network of Hamas tunnels that reportedly crosses the entire Strip.
In an attempt to dismantle the underground system, Israel has started to flood certain tunnels in Gaza with seawater, as per a statement from a US official to CNN on Tuesday. It was also noted that the Israelis are taking a cautious approach and are testing this method on a limited scale.
If successful, flooding could be ramped up to degrade the tunnel network on a larger scale.
Brig. Gen. Yehuda Fox, leader of the army's Gaza division, tours tunnels destroyed near the Israeli kibbutz of Kissufim, Feb. 2, 2018. Israel is spending almost $1 billion on an underground-barrier project to seal its border and prevent attacks from tunnels dug by Gaza militants. (Uriel Sinai/The New York Times)--PART OF A COLLECTION OF STAND-ALONE PHOTOS FOR USE AS DESIRED IN YEAREND STORIES AND RECAPS OF 2018 -- Uriel Sinai/The New York Times/Redux
The Gaza metro is a secretive underground tunnel network utilized by Hamas. However, the method used is both challenging and contentious. Even with ample water and high pressure, its success may be limited. Additionally, there is a risk of polluting freshwater sources and causing damage to the remaining surface infrastructure.
The Israeli government also faces the risk of harming hostages still held by Hamas in Gaza, with many believed to be underground. According to an American official, the Israelis are uncertain about the effectiveness of the method but have assured the US that they are taking care to only test it in tunnels where they do not believe hostages are present.
CNN has reached out to the Israeli military for comment.
A spokesperson for Hamas on Thursday said the group had built its tunnels to withstand possible attempts to pump water into them.
Hamas spokesperson Osama Hamdan announced at a news conference in Beirut, Lebanon that the well-trained and educated engineers who built the tunnels anticipated potential attacks from the occupation, including water pumping. Despite this, the tunnels have served as a crucial economic link for the residents of Gaza, allowing for the transportation of people, goods, and even American fast food in the midst of a 17-year blockade by Israel and Egypt.
An Israeli soldier stands in an underground tunnel in Gaza City on November 22.
Victor R. Caivano/AP
A tool of warfare
Throughout history, tunnels have served as a strategic component of warfare. From their use by the French in the interwar period, to al Qaeda in the mountains of Afghanistan and the Viet Cong in the jungles of Southeast Asia. However, the tunnels built by Hamas are distinctive in their depth, sophistication, mining, and trapping techniques, according to Danny Orbach, a military historian at the Hebrew University of Jerusalem.
US National Security Adviser Jake Sullivan speaks during the daily briefing in the Brady Briefing Room of the White House in Washington, DC, on November 13, 2023.
Saul Loeb/AFP/Getty Images
Bidens national security adviser says Israel will move to new phase of war focusing on precisely targeting Hamas leadership
Beneath much of the densely populated territory of the Gaza Strip, it is believed that a vast underground structure has been constructed, with some reports claiming it extends hundreds of feet below the surface. Hamas tunnels are said to be spacious enough to accommodate adult fighters, weapons, and even vehicles, with some featuring reinforced cement walls and metal doors. Not all of these tunnels are interconnected, according to experts.
It is uncertain how much water and pressure the Israeli military is using to flood the tunnels, as well as which specific tunnels are being targeted. In order for the operation to be successful, the water pressure must be strong enough to not only break through the cement walls, but also the thick, metal doors separating some of the tunnels.
There will likely be complications
The flooding operation, according to Orbach, could potentially compel Hamas militants to relocate within the tunnels. This could greatly assist Israeli intelligence in locating militants and potentially hostages.
Israel and Gaza are familiar with the method of flooding tunnels to shut them down. In 2018, the Israeli Defense Forces used this method to allegedly shut down tunnels built by Hezbollah on the Israel-Lebanon border. However, the flooding resulted in cement spilling out onto the surface in a southern Lebanese village above the structure.
In 2013, Egypt took action to stop the smuggling of weapons by Islamist insurgents from Gaza into its Sinai Peninsula by flooding tunnels underneath the shared border using seawater, sewage, and cement. This caused significant damage to crops, polluted fresh water supplies, and posed a risk of disease spread, according to Palestinian factions in Gaza.
In 2021, Hamas announced the construction of 500 kilometers (311 miles) of tunnels under Gaza, although CNN is unable to confirm this claim. The Israeli military reported destroying over 500 tunnel shafts in Gaza and locating more than 800 in the Palestinian enclave, with many of them found in civilian areas and structures.
Flooding tunnels underneath populated areas could have a catastrophic impact on the region, depending on the method used. This poses a risk of damaging the remaining infrastructure and contaminating the freshwater source, according to experts.
Israeli soldiers stand near the opening to a tunnel in Gaza City on November 22.
According to Orbach, using seawater for flooding poses a problem, especially in Gaza where the sandy topography can lead to leakage and destruction of the aquifers, the source of drinking water.
The Coastal Aquifer, the territory's sole freshwater source, is facing growing depletion due to excessive extraction and contamination from sewage and seawater intrusion, as reported by Amnesty International.
The ongoing war has severely limited access to clean drinking water, leading humanitarian organizations to sound the alarm about Palestinians being compelled to consume contaminated or saline water in order to satisfy their thirst, heightening the risk of waterborne illnesses.
On 15th November 2023, in Khan Yunis in the Palestinian Territories, Palestinians sought refuge at a school operated by the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA). They had fled the northern Gaza Strip due to the fear of Israeli bombardment. The photo was taken by Mohammed Talatene/picture-alliance/dpa/AP Images.
Mohammed Talatene/picture-alliance/dpa/AP
We have the right to live. Starvation, disease, and winter chill threaten the survival of displaced civilians in Gaza
Orbach warned that if the tunnels are fully submerged, it could lead to the collapse of the buildings above them, resulting in significant damage to civilian infrastructure. However, experts suggest that the intention behind the flooding may not be to completely demolish the tunnels at this point.
Matthew Levitt, director of the Reinhard program on counterterrorism and intelligence at The Washington Institute for Near East Policy, emphasized the need to neutralize the extensive network of tunnels without completely destroying them. He also suggested the possibility of working with a post-war governing body in Gaza to completely dismantle the tunnel network. Levitt also noted the importance of considering the safety of hostages believed to still be underground in Gaza when determining the amount of seawater necessary to make the tunnels unusable.
Hostages may be in the tunnels
"I believe there is a misconception about flooding the tunnels, as if it involves pumping in so much water that the entire tunnel is devoid of oxygen and completely filled with water," he stated, "but I don't think that's the reality."
Many Israelis are deeply worried about the fate of the dozens of hostages still in Gaza, with reports indicating that many may be held underground. The Israeli government is facing strong public demand to secure the safe return of the hostages.
The leaked audio recordings of a recent meeting between Prime Minister Benjamin Netanyahu and the freed hostages revealed frustration and anger over the plan to flood the tunnels. One freed female abductee, whose husband is still in captivity, expressed disbelief at the idea of washing the tunnels with sea water, especially as heavy bombardment was ongoing in the same area.
On November 9, 2023, a crowd gathered outside the ICRC offices in Tel Aviv, holding signs and calling for the release of hostages abducted by Palestinian militants on October 7 and currently held in the Gaza Strip. This demonstration took place amid the ongoing conflict between Israel and the Palestinian group Hamas. (Photo by AHMAD GHARABLI / AFP) (Photo by AHMAD GHARABLI/AFP via Getty Images)
Ahmad Gharabli/AFP/Getty Images
Leaked audio of heated meeting reveals hostages fury at Netanyahu
"The woman accused of prioritizing politics over the safe return of the kidnapped individuals," said the woman. According to the prime minister's office, there are believed to be 132 hostages in Gaza, with 112 thought to be alive and 20 presumed dead. Those freed by Hamas in October described the tunnel system as a complex spiderweb structure.
Adina Moshe was forcibly taken from her safe room in Israel to Gaza on October 7th, where she was reportedly brought into tunnels located five stories underground, as stated by her nephew Eyal Nouri.
Regarding this situation, Levitt mentioned that Hamas has invested considerable time and resources in building this infrastructure, which does not benefit the people in the Gaza Strip. Levitt also emphasized that from Israel's standpoint, it remains a critical military target. "Therefore, Israelis will undoubtedly be seeking ways to neutralize the Hamas tunnel system."
CNNs Hamdi Alkhshali, Joshua Berlinger, Natasha Bertrand and Donald Judd contributed to this report.
