GAZA STRIP (AFP) — When huge sinkholes and deep cracks began appearing across the ploughed fields and asphalt roads of the southern Gaza Strip, residents and farmers knew better than to blame natural causes.

Although no one has ever seen it, locals around Rafah city — on Gaza’s border with Egypt — claim the culprit of this landscape destruction is a one-meter wide underground pipeline set up by Cairo to pump seawater deep into the frontier earth.

Cairo has never confirmed the pipe’s existence, but Palestinians are adamant it is being used to deliberately flood smuggling tunnels between Gaza and Egypt.

Egypt and Israel have imposed an air, sea and partial land blockade on Gaza since 2006, designed to prevent the Islamist Hamas movement that controls the territory from rearming.

Egypt says the cross-border tunnel network has allowed militant groups to smuggle personnel and weapons between the enclave and the vast Sinai desert, where security forces are battling a jihadist insurgency.

A picture taken on March 1, 2016, shows sinkholes and deep cracks across ploughed fields next to the border between Egypt and Gaza, in the city of Rafah, in the southern Gaza Strip. (AFP PHOTO / SAID KHATIB)

But the sea water is also allegedly devastating the quality of the earth and causing crops to fail.

Plumes of smoke rise on the horizon in the southern border area caused by the Egyptian army bombing jihadists who carry out near-daily attacks on security forces in the Sinai.

A few meters from the border, under a plastic shelter between deep craters, a group of Palestinians are struggling to scoop puddles of water out of a tunnel which plunges into the sand.

Coated to the knees in mud, they scrabble to solidify the cracking walls.

“There is mud, mud everywhere,” laments one of the men who, like others, refused to disclose his identity.

“One hundred people used to work here every day. It’s all over now.”

The men say the tunnel was built to carry goods into the area, which is impossible to visit without the approval of Hamas.

Palestinian and Egyptian traders used to smuggle all kinds of goods in and out of Gaza but since 2013, Egypt’s army has destroyed hundreds of tunnels, which Israel says are used by Sinai-based jihadists to access hospital treatment in Gaza.

Cairo makes no distinction between tunnels for commercial or military purposes.

‘This is a disaster’

Egyptian President Mohammed Morsi meets Hamas Prime Minister Ismail Haniyeh in Cairo, July 26 (photo credit: MOHAMMED AL-OSTAZ/Flash 90)

Then Egyptian president Mohammed Morsi meets Hamas Prime Minister Ismail Haniyeh in Cairo, July 26, 2012 (Mohammed al-Ostaz/Flash 90)

Hamas was a close ally to Egypt’s former Islamist president Mohammed Morsi, who was toppled in 2013 and replaced by former army chief Abdel-Fattah el-Sissi.

Since then, Cairo has regularly accused Hamas of supporting jihadist attacks inside Egypt.

Palestinians believe the flooding of the area has played a major role in a spate of separate tunnel collapses so far this year, in which at least 15 Palestinians — including 11 Hamas fighters — have died.

The Egyptian authorities declined to comment on the army’s activities along the border, but stressed they were not intended to harm Gaza residents.

Palestinian officials warn the sea water is having a devastating impact on agriculture, with large areas of land becoming effectively unusable.

“This is just the beginning and it is already a disaster,” said Abu Osama Nogira, an engineer in charge of Health and Environment in the Rafah municipality.

Nogira shows pictures, impossible to authenticate, allegedly showing the pipe. One meter in diameter, it supposedly runs along the 12 kilometer (7.5 miles) border 20-25 meters (22-27 yards) below the surface and is pierced at intervals to allow sea water to seep into the ground, he said.

Impossible to live

A third of Rafah’s water, its agricultural reserves and parts of its infrastructure network, are located in the immediate vicinity of the border, Nogira said, warning that continued flooding could lead the electricity grid, roads and water treatment facilities to break down.

Even before talk of the pipeline, Palestinian authorities estimated that 97 percent of groundwater in the area was polluted and dangerous for consumption, and it is feared that meager drinking water supplies are now also likely to become salinated.

Palestinian farmer Farouq Breika, 37, gestures towards sinkholes and deep cracks across a ploughed field next to the border between Egypt and Gaza, in the city of Rafah, in the southern Gaza Strip, on March 1, 2016. (AFP PHOTO / SAID KHATIB)

“The governorate of Rafah, with 230,000 inhabitants, will become impossible to live in,” Nogira says, echoing UN predictions that the entire Gaza Strip may be uninhabitable by 2020.

On the Egyptian side of the border, human rights groups say that more than 3,000 families were forcibly evicted and thousands of homes destroyed when the army established a buffer zone designed to secure the border.

Egypt’s alleged actions leave Farouq Breika, literally, with a bitter taste in his mouth.

“We used to drink water from the well and cook with it,” the 73-year old farmer reflects. “Now it is not even good for agriculture.

“The earth has been soaked with salt water for months,” he says.

Faced with closed borders from both Israel and Egypt, he adds, “we have nowhere else to go.”