Israeli plan to flood Hamas tunnels comes with extreme environmental risks

A sanctuary

Since assuming control of Gaza in 2006, Hamas recognised the tunnel network's potential to provide sanctuary and tactical advantages against Israel's superior military capabilities. This understanding prompted the group to intensify the development of these tunnels.

The naturally soft sandstone beneath Gaza has enabled Hamas to dig deeper — now exceeding 20m (65ft) compared to the original tunnels at around 10m (32ft) — increasing the difficulty of targeting and destroying these passages. Additionally, the tunnels have been reinforced with concrete, enhancing their resilience.

By 2021, the network extended over 500 kilometres, providing a secure refuge beyond the reach of Israel's formidable military capabilities.

Since the commencement of the ground offensive in Gaza, the Israeli army claimed to have discovered over 800 access shafts into the tunnel network and have destroyed or sealed more than 500. However, the tunnel network itself remains too perilous for Israel to clear, rendering it an underworld under the control of Hamas.

Flood plan

To neutralise the tunnels, Israel completed the assembly of large seawater pumps approximately one mile north of the Al-Shati refugee camp around the middle of last month. Each of these pumps can draw water from the Mediterranean Sea, moving thousands of cubic meters of water per hour into the tunnels, potentially flooding them within weeks.

Last week, various sources confirmed that the tunnel flooding had begun, albeit in a limited trial capacity. While the pilot was deemed a success by Israeli military officials, Hamas officials asserted that the tunnels were engineered to withstand flooding, among other threats.

Furthermore, experts have highlighted that the tunnels are not all at the same level, suggesting that while some sections might flood due to seawater, it might not affect the entire network uniformly.

Regardless of the effectiveness of this method, environmental experts have warned of potential pollution to Gaza's already devastated water supply and damage to its crops. Seawater will likely seep into the soil from the tunnels, particularly in areas where tunnels have been previously damaged.

Extended risks

The risk extends beyond the seepage of highly salty water into the ground. Along Gaza's coast, seawater is contaminated with untreated wastewater continually discharged into the sea from the enclave's dysfunctional sewage system.

The seawater would also wash out all toxic materials in the tunnels, whether introduced by Israel or stored by Hamas, into the soil and groundwater. This would exacerbate pollution and contamination of the groundwater, already degraded by besiegement and wars.

Similarly, the seawater flooding would cause long-term damage to Gaza's agriculture and significantly limit crop choices. The flooding also poses risks to the already degraded infrastructure of essential services and residential buildings.

Despite these risks, Israel is likely to argue that flooding the tunnels is 'proportionate' as a military objective under international law, citing their use by Palestinian fighters. However, this method, which could potentially cause lasting environmental damage, is unlawful.

Prolonged and extensive flooding of the tunnel network would violate customary international humanitarian law norms that prohibit methods of warfare expected to cause widespread, severe, and long-term damage to the natural environment.

Israel's consistent disregard for civilian lives in Gaza suggests that the implications of its unconventional military strategy on both the environment and infrastructure might be of even lesser concern.

Therefore, the international community should intensify efforts to prevent Tel Aviv from adding another violation of international humanitarian law to its already extensive record.