The drought has been exacerbated by the use of water for hotels and tourism purposes. Photo / Taylor Simpson

Tourists are being blamed for a shortage of freshwater in drought-stricken Bali, which has seen more than half its rivers run dry.

The holiday island is still waiting for its delayed wet season to begin as a drought that's affecting an estimated 50 million people across Indonesia continues to threaten food security, local culture and quality of life, Al-Jazeera reports.

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Some 260 of Bali's 400 rivers have run dry and the island's largest water reserve, Lake Buyan, had dropped 3.5 metres. Meanwhile, the falling water table is causing saltwater intrusion in many areas across the island, especially in the south.

"I believe Bali is in real danger," local journalist Anton Muhajir, who has been covering Bali's water crisis, told Al-Jazeera.

"Some of my friends have had to move from their ancestral homes in Denpasar because the water in their wells has turned salty. At Jatiluwih, where thousands of tourists go each day to see the most beautiful rice terraces of Bali, farmers are using plastic pipes to pump in water they have to buy in the south because the springs in the mountains are drying up.

"And now we have drought, not just in Bali but in nearly every province in Indonesia."

The blame has fallen on Bali's tourism industry, which uses about 65 per cent of the island's water, according to the Indonesian non-government organisation IDEP Foundation.

A single tourist at a resort in Bali uses between 2000 and 4000 litres of water a day, according to local estimates. Huge volumes of water are used to fill resort swimming pools and maintain gardens and golf courses enjoyed by tourists, as well as in construction of new villas and tourist facilities.

"Tourism has sped up (the extent of drought) that is happening right now, which we could have expected to happen in maybe 20 or 30 years, but it's happening now," IDEP Foundation spokeswoman Dewie Anggraini told Germany's Deutsche Welle, Coconuts Bali reported.

She said withdrawal of freshwater had been excessive.

"Many freshwater exploitation happens in areas where there are many hotels and villas, which are usually used for tourism purposes," she said.

Meanwhile, residents say they're struggling to carry out basic but essential tasks such as cooking and cleaning, while the traditional "subak" water irrigation systems used to water Bali's crucial rice crops are being threatened.

A shopkeeper in Seraya Timur, on Bali's easternmost point, told Al-Jazeera he only got water three days a week and on the other days, had to fork out about $200 — 1.5 times the average monthly wage in Bali — for a 3000L tank.

"I was born in this village and lived here all my life," he said. "It's always been dry. But never like this."

Locals said government-issued water trucks only came by sporadically.

Stroma Cole, a senior lecturer in tourism geography at the University of the West of England, has authored a scientific paper on Bali's drying rivers.

She said while saltwater intrusion had mainly been in the south, it has recently spread across the island.

"One can say the drought in the north, east and west has nothing to do with tourism because there's very little tourism there and it's always been chronically dry," she told Al-Jazeera.

"But water from the lakes can be equitably distributed across the island, or it can be massively overused for tourism, as is happening now. They're damming rivers to divert water to the south whereas they could be directing it up north.

"The villages up there aren't dry because of drought. They're dry because of politics, because of choices that are being made."

She warned the problem was likely to worsen.

"Bali's freshwater scarcity problem is only expected to get worse unless there is a paradigm shift in the mass tourism model and they embrace quality sustainable tourism," she said.

"It's ludicrous that a tropical island is running short of water."

Bali's wet season traditionally runs from October to April, however the island is yet to see rain this season.