Author: Afra Anjum Samiha – Bangladesh – PROMPT! Cohort #1

I grew up in a land where rivers are the veins of life, where the scent of wet earth after the first monsoon rain feels like home. But natural beauty here walks hand in hand with danger. The same water that nourishes our fields can rise overnight, swallowing homes, roads, and memories. In Bangladesh, we learn young that the rhythm of life is tied to the tides, the rains, and the storms. Growing up in Bangladesh means living with water as both a friend and a foe. Here, monsoon is not just a season, it is a reminder that the nature decides the rules. 

The sufferings of people know no bounds during such calamities. Every year, millions of people in Bangladesh face the harsh reality of natural disasters like floods, cyclones, and landslides that turn their lives upside down. One of the worst disasters is flooding, which causes people especially those living in rural areas to face difficulties every year. 

According to IPCC Sixth Assessment Report Working Group II (2022), Chapter 10: Asia — which covers Bangladesh as part of South Asia:

“South Asia, including Bangladesh, faces increased flooding risks due to climate change, affecting millions through river flooding, flash floods, and storm surges.” (IPCC, 2022, Chapter 10)

The report furthermore identifies that —

“In 2019, Bangladesh, China, India and the Philippines each recorded more than 4 million disaster displacements.” (IPCC, 2022, Chapter 10)

Every year, after the floods leave behind a trail of destruction—taking lives, washing away homes, and stealing people’s hard-earned belongings, it feels like the nature has reduced them to the most helpless beings on the planet. Yet, even in the face of such heartbreak, they gather every last bit of strength and begin the slow, determined journey of rebuilding their lives. But the cruel truth is, their hard work rarely pays off, because by the time they piece together the fragments of their world, the floods return this time with even more force and determination to tear everything apart once again. Unfortunately, this vicious cycle has been continuing for as long as anyone can remember. It breaks my heart to see their hope and hard work getting washed away time after time, year after year.

This cycle got stuck in my mind, and I couldn’t find peace thinking about the pain people go through every year. I felt restless and wanted to understand if there was any way to help. So, I started searching and learning about floods and how they might be controlled. That’s when I came across hydraulic engineering. It is a field that focuses on managing water flow and designing systems like dams and drainage to reduce flooding. While it doesn’t solve the problem in a snap, it’s a step toward helping communities protect themselves better. It made me realize that even small changes and efforts can matter in facing such a huge challenge.

Now, before we dive in, what on earth is hydraulic engineering anyway?

Hydraulic engineering is a sub-division of civil engineering concerned with the flow and conveyance of fluids, primarily water. In easier words, it means applying fluid mechanics principles to the storage, control, transport, regulation, measurement, and use of water. It’s intimately linked to designing structures like dams, bridges, canals and sanitary systems. 

The Lowdown on Hydraulic Basics

The fundamental principles of hydraulic engineering include fluid mechanics, fluid flow, behavior of real fluids, hydrology, pipelines, open channel hydraulics, mechanics of sediment transport, physical modeling, hydraulic machines, and drainage hydraulics.

According to the book Fundamentals of Hydraulic Engineering written by Alan L. Prasuhn:

“Understanding the behavior of real fluids, including their flow characteristics and resistance, is essential to solving practical hydraulic engineering problems.”

From the above reference, we can understand that knowing the properties of fluids is essential for hydraulic engineering because it helps us predict how water and other liquids behave in different situations. Another important aspect is sediment transport, which involves how particles like sand and soil move with water. This affects riverbeds, reservoirs, and erosion control. As explained in Level Engineering article:

“Sediment transport mechanics is vital to prevent damage to hydraulic structures and maintain navigable waterways.” (Level Engineering, 2024)

The Minds Behind Hydraulic Engineering

Hydraulic engineers are the problem-solvers behind the systems that manage our most precious resource: water. They are responsible for the design of water supply networks, drainage systems, and irrigation systems. Hydraulic engineers also work on flood management, river and coastal engineering and hydraulic modeling. Hydraulic engineers develop strategies for managing surface and groundwater resources. This includes the design of reservoirs, aqueducts and water supply systems that ensure access to clean water for drinking, irrigation and industrial uses. Flooding can devastate communities and ecosystems. Hydraulic engineers design flood control systems such as levees, floodwalls and storm water management systems to mitigate the risks associated with heavy rainfall and rising water levels. The management of water bodies is critical for maintaining biodiversity and ecological health. Hydraulic engineers work on projects that restore wetlands, riverbanks, and other ecosystems that have been degraded by human activities. Agriculture heavily relies on 

efficient water usage. Hydraulic engineers design irrigation systems that optimize water use for crops, ensuring food security while conserving water resources.  

Engineering Against the Tide: Dams and Reservoirs for Flood Mitigation

Think of a dam like a giant water-saving sponge. When heavy rain pours down, it soaks up the extra water instead of letting it rush downstream all at once. This slows the flow and keeps rivers from suddenly overflowing. The reservoir behind the dam has special gates and spillways that let water out slowly and safely, so there’s no sudden flood surge hitting communities.

 Statistically Proven Reductions in Flood Magnitude- 

•Ebro River Basin (Spain): flood peaks dropped to 69% for 2 year floods and 58% for 25 year floods. (ScienceDirect)

•U.S. large dams: average flood peak reductions of 67%. (ScienceDirect)

•California river basins: reductions between 53% and 81%. (ResearchGate)

Notable Case Studies

•The Three Gorges Dam on the Yangtze River (China) has a flood storage capacity of around 22 km³. Since its completion, it has reduced the frequency of major floods from once every 10 years to once every 100 years, noticeably moderating even super flood events. For instance, during the 2010 floods, inflow peaked at ~70,000 m³/s but outflow was controlled to ~40,000 m³/s, preventing severe downstream flooding. (wikipedia)

•The Terminus Dam in the U.S. functions primarily as a flood-control structure. Since 1962, it has prevented over $373 million in flood-related damages and protected communities and farmland downstream. (wikipedia) 

Why Bangladesh needs this?

In Bangladesh, floods are not just water spilling over land, they destroy homes, wash away crops, and force families to start over. Hydraulic engineering, especially through dams and reservoirs, can change that story. By holding back excess water and releasing it slowly, these structures reduce flood peaks, with studies showing reductions of 33% to 81%, saving lives, property, and livelihoods. To make a real difference, dams and reservoirs should be strategically built upstream of major rivers as well as on tributaries. Placing them in flood-prone districts and low-lying areas will ensure that water is controlled before it reaches communities. If thoughtfully planned, this network could protect homes and farmland, ease the sorrows of flood-hit families, stabilize the economy to a great extent, and turn the monsoon from a season of fear into one of safety and hope.