"Blood and water cannot flow at the same time," Modi was quoted as saying by government spokesman Gopal Baglay after an uptick in violence in contested Kashmir.

What is the Indus Water Treaty?

The treaty, which was brokered by the World Bank, stipulates that Pakistan receives water from the Indus and two of its tributaries -- the Jhelum River and the Chenab River.

India has full control over the three eastern rivers -- Beas, Ravi and Sutlej -- and limited access to the Jhelum and Chenab.

The agreement is hailed by experts as one of the most successful water-sharing pacts in the world. It has survived the Indo-Pakistani wars of 1965 and 1971 and numerous other standoffs between the two nations.

However, recently, tensions between the nuclear neighbors have ratcheted up and the treaty's strength has once again been put to the test.

In November, Modi reiterated India's rights over the eastern rivers, as determined by the treaty.

"This water belongs to India's farmers. That water is not coming to your farm, but is rather flowing to Pakistan and eventually to the ocean," Modi said.

"I am determined to bring every drop of that water back to the farmers of Punjab, Jammu and Kashmir... for India's farmers."

Lifeblood for farming

The point of the treaty, says analyst Rebecca Keller from Stratfor, a geopolitical intelligence firm, is that it provides a level of consistency -- in writing -- for a natural resource that is much needed by both nations, but shared over disputed borders.

The Indus river basin supports an enormous 75% of Pakistan's irrigated land, says Keller, making it "the largest contiguous irrigation network in the world."

"Roughly a quarter of the country's GDP comes from the agriculture sector and it is the largest source of foreign exchange earnings," she said.

While India has other basins that support its agricultural sector, the Indus still remains essential for regional farming.

Dam dispute

India also wants to use the rivers to provide hydropower -- something Islamabad first objected to a decade ago.

In 2010, Pakistan filed a formal complaint with the Permanent Court of Arbitration at The Hague about plans to build the Kishanganga dam.

It feared that India would have the power to control the water flow into Pakistan's agricultural heartland.

Islamabad has since renewed its opposition to the dam. It insists the amount of water the project could draw from the Indus River Basin will exceed India's allotted share of the rivers under Pakistan's control.

India, however, argues it utilizes only a fraction of the 20% of waters it's allowed to use under the terms of the treaty for hydropower and agricultural projects.

"Some estimates put its use of the waters under Pakistan's control at just 4% of its total allocation," Stratfor said in a recent report.

Although the two countries are at loggerheads over the water treaty, experts say it's highly unlikely either nation will be looking to jettison it when they meet this week.

However, talks are likely to be tense, with both nations determined to protect their own interests during the negotiations -- especially with general elections on the horizon.

"Both countries can use the dispute as a tool to advance their political aims in the coming year," says Keller.

"This is not the first dispute that has happened under the Indus Water Treaty, nor will it be the last."