Flooding the Tunnels of Gaza
Possibilities and implications of a much-mentioned method
Since the start, on 7 October 2023, of the ongoing war in Gaza, many of the headlines contending for my attention have argued that Israel will, ought to, or has already begun to pump seawater into the tunnels used by Hamas. Alas, most of the articles and videos in question has failed to fulfill the promises made by their titles and tag-lines. Worse, the one story that makes the unequivocal claim that such flooding operations have already begun, comes from a YouTube channel bearing the painfully presumptuous title of Divine Justice.
Rather than wasting my time mining this slag-heap of clickbait and bald-faced partisanship for tiny nuggets of fact, I decided to start, as the cinematic incarnation of Maria von Trapp once said, at the very beginning. Thus, I took a look at the geology of Gaza, and, in particular, the movement of water beneath below, and besides, its many tunnels.
The cities and farms of Gaza sit atop, and its tunnels run through, a layer of sand, gravel, and sandstone. In the west, near the sea, this stratum reaches down to a depth of five meters or so. In the east, under the high ground along the long border with Israel, it grows (so to speak) to a depth of seventy meters.
The relatively soft composition of this underground belt facilitates both the digging of tunnels and the sinking of wells. It also makes it easy for water to seep from higher elevations into the underground lake that lies beneath it. This aquifer has long provided most of the water used by the people who live in Gaza. Indeed, so much water has been withdrawn by means of the aforementioned wells that the underground lake has, over the course of the past half-century or so, shrunk considerably.
The result is an extraordinarily thirsty environment that, if I am not too badly mistaken, will absorb much, if not most, of the water pumped into the tunnels. In the short term, this means that the task of flooding the tunnels will involve a much greater volume of water than would be needed to fill an equivalent volume of leakproof pipe. In the long term, it means that a whole lot of seawater will soak into the soil, and, what is even worse for the prospects of the civilian population, the underground lake.
Thanks to its scale, the pumping of so much seawater will present lots of targets to Hamas fighters. These will include the pumping matériel (which may include fire trucks, irrigation equipment, and repurposed desalinization gear); the places where the hoses enter tunnels; and the work force. I suspect, moreover, that there will be lots of “use it or lose it” moments when Hamas will attempt collapse those sections of their tunnel network of greatest value to the pumping operation.
Taken together, these considerations suggest that any wholesale flooding of tunnels will take place towards the end of the Israeli campaign in Gaza. That is, it will have less to do with the near-term attempt to destroy Hamas as a fighting force than a long-term effort to inhibit its revival by, among other things, sowing with salt the fields of the people it rules.