Israel's military has reportedly put in place controversial and high risk plans to flood Gaza's vast network of underground tunnels used by Hamas with sea water. High powered pumps have already been set up at key locations in the Gaza Strip.

The plan is to force Hamas militants above ground or else drown them, utilizing a series of pumps to pull water from the Mediterranean Sea, which are expected to provide enough water to fully flood the tunnels within weeks. According to details in The Wall Street Journal, US defense officials have been briefed on the 'option' - and with pumps now in place - but it's not believed that the Israelis have pulled the trigger on it yet. 

"The Israel Defense Forces finished assembling large seawater pumps roughly one mile north of the Al-Shati refugee camp around the middle of last month," the report indicates. "Each of at least five pumps can draw water from the Mediterranean Sea and move thousands of cubic meters of water per hour into the tunnels, flooding them within weeks."

Some US officials were cited as expressing "concern" about the plan, also given the potential to kill more civilians and further destroy the Strip's infrastructure. A prime issue is that some 137 Israeli and foreign hostages remain in Hamas captivity after the end of last week's ceasefire and prisoner swap deal. 

Very likely all or many of them are being kept somewhere within the tunnel system and its cavernous rooms. Hamas even has subterranean offices and command centers within. Israel has thus far identified at least 800 tunnels, but believes the network is still much bigger than what's known.

"We are not sure how successful pumping will be since nobody knows the details of the tunnels and the ground around them," one unnamed security source told the WSJ. "It’s impossible to know if that will be effective because we don’t know how seawater will drain in tunnels no one has been in before."

There's also the question of the seawater destroying altogether what's left of the Strip's already damaged water system, which draws on Gaza’s increasingly saltier aquifer. The whole flooding initiative could also bring down more buildings or entire blocks, making the place uninhabitable for years to come. 

"Wim Zwijnenburg, who has studied the impact of war on the environment in the Middle East, said that assuming that about one-third of the tunnel network is already damaged, Israel would have to pump roughly 1 million cubic meters of seawater to disable the rest," the WSJ report notes.

Last week, Secretary of State Antony Blinken was in Israel where he pressed for a "clear plan in place that puts a premium on protecting civilians." But if Israel 'gets creative' with these daring plans to flood the tunnels, this will bring even more pressure to bear on the White House internationally to condemn or reign in the IDF.

While President Biden has been personally relatively quiet on the issue, his security officials as well as Vice President Harris have been increasingly vocal on the need to protect civilians.

A month ago there were wild reports and speculations that Israel could pump Sarin gas or other chemical weapons into the tunnels. However, this is unlikely to have ever been a real option given the unpredictable nature and potential spread of nerve agents to confines not intended to be targeted (such as civilian homes, hospitals and buildings above the tunnels).