Fluid dynamics and Pakistan’s deadly floods

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DR. THEODORE KARASIK

September 02, 2022

Fluid dynamics and Pakistan’s deadly floods

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Pakistan’s historic flooding covering a third of the country is a complex humanitarian disaster illustrating how excessive water can quickly overwhelm land by brute force. Understanding the fluid dynamics of increasedflooding because of quickening climate change is essential to create preventive measures involving water runoff, water tables and tides.

The basic data is alarming. The worst flooding occurred along the Indus River in the provinces of Punjab, Khyber Pakhtunkhwa, Balochistan, and Sindh. Balochistan and Sindh have so far this year received up to six times their 30-year average rainfall. Most of that arrived in the summer monsoon.  Across the country, about 150 bridges and 3,500 kilometers of roads have been destroyed. More than 700,000 livestock and 2 million acres of crops and orchards have also been lost.

Now a water surge is flowing down the Indus river, threatening communities in southern Sindh province.  Local officials say 1.2 million people have been displaced in Dadu district in Sindh, where hundreds of villages are submerged — and there is still more water coming.  Mudslides and flood waters are traveling down from the mountains toward villages in this district. More destruction and water-borne diseases are on their way.

The UN says the situation in Pakistan is an unprecedented climate catastrophe and has appealed to the world community for massive amounts of aid. Pakistan has declared a national emergency. The disaster is causing economic problems with inflation hitting a record this month, the highest in nearly 50 years. Consumer prices have risen by 27.26 percent from a year ago. The level of damage to the Pakistani economy is an important lesson for other countries that may suffer from increasing river damage.

The immense volume of rain and meltwater inundated the dams, reservoirs, canals, and channels of the Pakistan’s large and highly developed irrigation system. The Indus River System Authority authorised some releases from dams because the water flowing in threatened to exceed the capacity of several reservoirs. This caused more damage because of compounding factors, such as the continued melting of Pakistan’s 7,000 glaciers. Pakistan holds the most glacial ice outside the polar regions. Climate warming and recent heatwaves have precipitated several glacial-outburst floods. In the rugged northern part of the country, the combined rain and meltwater has turned slopes into violent hill torrents.

The geological structure of many of Pakistan’s flooding valleys contributed to the violence of the water’s action, sweeping away every object in its path including preventive damming techniques. Importantly, river morphology is key in understanding the trajectory of historic floods such as those in Pakistan.  The massive flooding from a high-intensity monsoon system  such as the one that inundated Pakistan resulted in catastrophic climate change damage to the country and its soil and water tables. 

The terminology is important. In the fluid dynamics arena, the turbulent kinetic energy and intensity across varying terrain and vegetation zones are key to finding practical policy solutions. Not all water activity — from mountains to lowlands via river runoffs to ocean outlets, combined with tidal activity — are the same.

Planning carefully for the impact of voluminous amounts of water relies on consequence management. Cleaning up this aspect of the debris, refuse, livestock, and other matter is part of the damages. Over 1,000 people are dead and a third of Pakistan is covered in water. Water arriving downstream from northern flooding is also a factor as the Indus River swells at an alarming rate,

Fluid dynamics and flooding are an important scientific and policy nexus when it comes to climate change. The events in Pakistan illustrate the need to remodel preventive measures to “shore-up” weak areas along a river’s pathways. Videos clearly showed bridges and roads being swept away, and dams collapsing under the volume and weight of water. The infrastructure reinforcement along these rivers requires to be rethought in the light of more climate “energised” monsoon patterns; authorities need to find and implement remedies now, or abandon those areas destroyed by the floods in the mountains.

Overall, Pakistan’s epic flooding is a lesson to policymakers and practitioners to understand better how fluid dynamics are increasingly at work as part of addressing immediate climate change phenomena.

  • Dr. Theodore Karasik is a senior adviser to Gulf State Analytics in Washington. Twitter: @tkarasik

Disclaimer: Views expressed by writers in this section are their own and do not necessarily reflect Arab News’ point of view

source https://www.arabnews.com/node/2155291

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