In October Israel revealed that they had known in early 2014 of Hamas plans to use tunnels into Israel to launch a major terror attack on Israel. It was later discovered that this attack was planned for the Jewish New Year (Rosh Hashanah), which took place on September 26th in 2014. When the fifty day war with Hamas began in July Israel still not have a lot of details about the Hamas “tunnel offensive”, but they knew that they could now go into Gaza and find out some details.
Before this ground invasion Israel had some knowledge of these Hamas tunnels, mainly because they had already found four of them in the last two years. In March Israeli troops found one that was 1,800 meters long and extended 300 meters into Israel. Hamas dismissed this find as a tunnel that had been abandoned because of a partial collapse. But the Israelis said the tunnel had been worked on recently and equipment, like generators, was found in it. The tunnel was lined with reinforcing concrete and was 9-20 meters (30-63 feet) underground. Three of these tunnels were near the town of Khan Younis and apparently part of a plan to kidnap Israelis for use in trades (for prisoner or whatever) with Israel. Israeli intelligence knew Hamas leaders were discussing a much larger tunnel program, involving dozens of tunnels. This plan included building the tunnels but not completing them (by tunneling upwards to create the exit in Israel). As long as the tunnel construction stayed deep the available monitoring equipment was slow and often ineffective if there was no one actively working on the tunnel below or if there was no exit (yet) on the Israeli side. Hamas had been building and “stockpiling” these tunnels for at least two years and most of the completed ones could only be detected inside Gaza, where their entrances were. These were also hidden, at least from aerial observation. Israeli intelligence had discovered some of these entrances by detecting the Hamas activity around the entrances (entering and leaving, removing dirt). Hamas tried to hide this activity and Israel knew this meant they probably succeeded in some cases. Thus before the Israeli troops went into Gaza on July 17th, commanders had lots of information on where to look. Israeli combat engineers had been trained to destroy the tunnels, which was not easy because Hamas had booby-trapped some of them. Israel at first suspected there are over fifty of these tunnels and soon decided it was essential to stay inside Gaza until they were sure they had found all of them, and collected information on how they were built and how they could be detected from the ground or air. If Israel knows where a tunnel is, before they destroy it they can run some tests with their sensors and that knowledge will make it more difficult for Hamas to build new tunnels.
Before July Hamas had boasted about how it had lots of these tunnels and planned to use them to get terrorists into Israel to capture or kill Israelis. By early August Israel has found and destroyed most of the tunnels that extended into Israel and several more that were just used inside Gaza. Israeli intelligence, because of data collected during the several weeks Israeli troops were inside Gaza, now had a better idea of where additional tunnels were. One side effect of this was Israel realizing it had to hustle and come up with more effective detection methods. Currently the best method was using a large mobile drill (normally used for digging wells) to go deep dozens of times in an area where a tunnel was suspected until it was found. That method had long been used on the Israeli side of the border but it was slow work. The most obvious opportunity here is for better sensors. One idea was a series of wireless sensors buried a few meters down all along the Gaza border that would broadcast the inevitable (and hard to conceal) sounds the Hamas men would make as they dug towards the surface to “open” a tunnel on the Israeli side. For obvious reasons the Israelis are not giving out any details on this sort of thing but at the moment it’s one of the best potential solution for the tunnel threat. Meanwhile Israel is trying to make the UN and other major Hamas donors (like Arab oil states) understand that a large chunk (over $10 million in the last few years) of their aid money has gone to this enormous tunnel project and that better management of aid to Gaza could reduce the amount being spent on tunnels and terrorism in general. The UN took this seriously but the Arab donors were less inclined to pay any attention to the tunnel problem.
By the time the 50 day war was over in late August Israel knew a lot more about the tunnel program. All fourteen of the tunnels for the attack on Israel were not completed when Israel and Hamas went to war in July over other issues and this enabled Israel to enter Gaza and deal with the entrances as well as the exits for the tunnels. Israel also captured a lot of the planning documents and some of the people involved. Over 200 Palestinians had been trained to use the tunnels to get into Israel, killing as many Israelis (from villages along the border) as possible and get back to Gaza with some Israeli (preferably soldiers) captives.
The tunnels are not a new problem. The Palestinians in Gaza have been building tunnels (mainly into Egypt for smuggling) since the 1980s. The Egyptians long tolerated this because the Egyptian police and soldiers got bribed and that kept everyone happy. But tunnels into Israel were another matter, because these were not for smuggling but for killing or kidnapping Israelis. No bribes involved here, just murder and abduction (for ransom). But during 2014 Egypt found itself with more Islamic terrorism in the vicinity of Gaza and more and more of the terrorists were found to be based in Gaza and using tunnels to get into Egypt and then back into Gaza. In October Egypt had had enough and decided to finally do something about their tunnel problem.
In late October 28 Egypt ordered people living within 300 meters of the Gaza border to leave their homes immediately, taking their possessions with them. At least 10,000 Egyptians were displaced by the order. The army is setting up a 13.8 long security zone along the Gaza border that will eventually be 500 meters wide. This is in order to detect and destroy smuggling tunnels. To make it even more difficult for tunnel builders the security zone will feature a 40 meter (128 foot) wide and 20 meter deep ditch from the Mediterranean inland. This ditch will be filled with salt water from the sea and make it even more difficult to build tunnels because the water will seep down deeper and make it more expensive to tunnel beneath it. This and the new detection methods will also force the tunnels to be dug deeper and all this will make it more expensive to build and use the tunnels. Most Egyptians in northern Sinai are anti-tunnel because the tunnels are basically run by gangsters and Islamic terrorists, two groups that are seen causing more trouble for the locals.
All these anti-Gaza measures are a response to a recent terror attack against Egyptian soldiers that left 31 soldiers dead and Egyptians in general very angry. In addition to the security zone, the Egyptians declared a three month long state of emergency and curfew in northern Sinai. Egypt blames Hamas for much of this violence because Hamas tolerates the presence of these anti-Egypt Islamic terror groups in Gaza and lets them use the smuggling tunnels to move between Egypt (where they stage attacks) and Gaza (where they are safe from Egyptian retaliation). Even before the security zone decision Egypt had detected hundreds more tunnels using satellite based sensors and new ground based search procedures. The 500 meter security zone will make most of the current tunnels useless and force the tunnel operators to dig deeper into Egypt.