RAWALPINDI: Muhammad Zafar awoke to the sound of torrential rain pounding his two-story home in Rawalpindi. By the time he got downstairs, four to five feet of water had accumulated on the ground floor.

The Sept. 1 flooding destroyed furniture and electronics in Zafar’s home in Khayaban-e-Sir Syed, one of several low-lying neighborhoods inundated after heavy rains pushed the nearby Nullah Lai stream to dangerous levels.

The episode is part of a much wider challenge for Pakistan, where the annual monsoon routinely brings deadly flooding and increasingly intense rainfall is testing drainage and disaster-management systems. The country is still rebuilding from catastrophic floods in 2022 that affected 33 million people, killed around 1,700 and submerged vast areas of the country.

The vulnerability was again evident during the 2025 monsoon, when floods affected 6.9 million people nationwide, according to the UN. In parts of northwestern Pakistan, exceptionally intense cloudbursts and flash floods overwhelmed communities with little warning.

For communities along Nullah Lai, however, the threat predates those national disasters. The waterway is central to Rawalpindi’s drainage but has flooded repeatedly for decades, with residents and officials now debating how much of the problem stems from extreme rainfall and how much from encroachments, waste and inadequate urban infrastructure.

“We have suffered a massive loss,” Zafar told Arab News. “In the same way, the lane in front of our home suffered more damage. The loss suffered just by our area of Khayaban is, I think, in tens of millions.”

Nullah Lai originates in the Margalla Hills, passes through Islamabad and runs into adjoining Rawalpindi, a densely populated city neighboring the Pakistani capital. Rainwater from upstream areas therefore flows toward lower-lying Rawalpindi, making the stream an important outlet for the city’s stormwater.

On Sept. 1, heavy rainfall flooded streets across the twin cities, with videos on social media showing water entering homes and vehicles being swept away. Authorities declared a holiday at educational institutions in Rawalpindi as the water level in Nullah Lai rose to 28 feet at Kattarian and 24 feet at Gawalmandi, according to official data.

The stream’s most devastating flood in recent history came in July 2001, when 620 millimeters of rain fell in about 10 hours. Nullah Lai and its tributaries overflowed, killing at least 74 people and affecting around 400,000, according to a Japan International Cooperation Agency report.

ENCROACHMENTS AND EXTREME RAIN

The latest flooding has revived a longstanding debate over Rawalpindi’s rapid urban growth and whether construction and encroachments have reduced the capacity of natural waterways to absorb increasingly intense downpours.

Naveed Kanwal, a member of the Rawalpindi Chamber of Commerce who works on traders’ welfare issues, said Nullah Lai was considerably wider three to four decades ago but had been narrowed by encroachments.

“When it rains a lot, the water doesn’t get a proper way to flow out because of the encroachment,” Kanwal told Arab News. “So, it accumulates on the sides and causes destruction in our residences and bazaars.”

Hammad Fazal, director of sewerage and drainage at the Water and Sanitation Agency Rawalpindi, attributed the latest flooding primarily to the intensity of the rainfall.

He said rainfall in the past was often spread over longer periods, giving accumulated water more time to flow through Nullah Lai. The Sept. 1 downpour, however, brought a large volume of water over a shorter period, the type of intense rainfall that has increasingly tested communities across Pakistan during recent monsoons.

“Because of this in the settlements upstream, there was blockage and the water also overflowed,” Fazal said. “We received these complaints.”

WASA received reports of flooding from low-lying areas including Javed Colony, Arya Mohalla, Sadiqabad and Fauji Colony and is still assessing the full impact, according to Fazal.

The problems facing Rawalpindi reflect a broader challenge for Pakistan: adapting rapidly growing cities and aging infrastructure to more destructive weather. During the 2025 monsoon, the UN described severe flooding in Pakistan as having been exacerbated by climate change, while humanitarian agencies repeatedly called for greater investment in resilience and disaster preparedness.

In Rawalpindi, the geography adds another complication. Fazal said a previous JICA study proposed diverting some of the water flowing downstream from Islamabad, which sits at a higher elevation.

“Rawalpindi, comparatively, is a low-lying area,” he said. “So, some of that water should be diverted.”

LONG-PENDING SOLUTIONS

Successive governments have proposed major infrastructure projects to reduce the danger posed by Nullah Lai, but some of the most ambitious plans remain unfinished.

Among them is the long-delayed Lai Expressway, a road and flood-management project associated with former federal minister Sheikh Rashid Ahmed. Initially estimated to cost Rs8 billion ($29 million), its projected cost has since risen to around Rs100 billion ($361 million). The project, which includes constructing permanent concrete walls along both sides of the waterway, remains incomplete.

Fazal rejected criticism that inadequate removal of silt and debris had contributed to the Sept. 1 flooding, saying annual desilting was completed by May 30, with additional work carried out on tributaries after Eid Al-Adha.

Illegal dumping of solid waste, however, continues to narrow the channel, according to officials, adding another man-made pressure to a drainage system dealing with intense bursts of monsoon rainfall.

The Rawalpindi Development Authority is reinforcing sections of Nullah Lai and working to improve stormwater capacity, while the National Engineering Services Pakistan is studying vulnerable points along the waterway and its tributaries.

The challenge extends far beyond Rawalpindi. Climate-related disasters have caused Pakistan more than $18 billion in damage over the past two decades, a figure that rises above $60 billion when major flood disasters in 2010, 2011 and 2022 are included, according to UN figures released this year.

For families living beside Nullah Lai, however, the consequences of that vulnerability are measured less in national damage estimates than in what remains inside their homes after the water recedes.

Zafar estimates the damage to his household at around Rs1.5 million ($5,400).

“Every room is filled with ruined belongings,” he said. “We’re just sitting here helpless, ruined.”