Comprehensive flood management and control techniques around the world

Floods have numerous consequences, including property damage and threats to human and animal lives. Fast-flowing water can lead to soil erosion and deposit sediment in other areas downstream or along coastlines. Floods can pollute or destroy fish spawning grounds and wildlife habitats. Prolonged high water levels may disrupt traffic in regions without elevated roads. Drainage and land use for activities like farming can be affected by floods. Structural damage may occur to bridges, banks, sewer lines, and other infrastructure within flood zones. Flood control and flood management means using different ways to lessen the damage caused by floods. Let us have a look at various flood management and control techniques.

Flood Management Techniques

Flood Plain Zoning
Designating flood plains or overflow areas along rivers can prevent floods from reaching cities or towns. These areas absorb water, protecting nearby communities from heavy rainfall that could lead to flooding. Floodplain zoning restricts construction near rivers to prevent buildings from flooding and preserves these areas to increase land available for water absorption, reducing surface runoff.
Flood Preparedness, Relief, and Recovery
Even with flood control measures in place, floods may still occur. Planning for flood preparedness, relief, and recovery is crucial to minimise loss of life and property. This includes flood forecasting, warnings, evacuation planning, providing community shelters, and establishing relief camps. Timely flood warnings are significant for reducing the impact of floods.

Afforestation and Reforestation
Afforestation involves planting trees in areas that were previously without forests, while reforestation restores deforested areas. Both practices help reduce flood risks by increasing water absorption and reducing river discharge. They also improve the overall environmental quality of river surroundings. However, they cannot eliminate flooding.

Rainwater Harvesting
Rainwater harvesting involves collecting, storing, and purifying rainwater from rooftops, parks, roads, and open spaces for later use. This helps reduce stormwater runoff in drainage systems, thereby lowering the risk of flooding. Implementing rainwater harvesting should be mandatory in flood-prone areas.

River Interlinking
This technique involves transferring excess water from one river to another prone to drought. It helps prevent flooding in the first river by reducing its water level and also revitalizes drought-prone rivers. This approach can mitigate flooding while addressing water scarcity issues.

Flood clean-up tasks can be risky for workers and volunteers due to various hazards. These include electrical dangers, carbon monoxide exposure, physical strain, extreme temperatures, traffic accidents, fires, drowning, and exposure to hazardous substances. Flooded areas may have sharp debris, contaminated water, live wires, and biological hazards. Managers provide safety gear like hard hats, goggles, gloves, life jackets, and waterproof boots with steel toes to protect workers.

Flood control in various parts of the world

Europe

In Europe, major cities like London and Venice rely on sophisticated flood defence systems to protect against rising water levels. London has a massive mechanical barrier on the River Thames, while Venice employs a similar mechanism, although it struggles with exceptionally high tides. However, both cities face challenges as sea levels continue to rise.

The Netherlands boasts some of the most extensive flood defences globally, known as the Delta Works. The Oosterschelde dam is a remarkable example of this system. These defences were constructed following the devastating North Sea flood of 1953. Additionally, the Dutch had previously built the Afsluitdijk, one of the world’s largest dams, in the north of the country, completed in 1932.

Americas

In Canada’s Manitoba province, extensive flood defences are in place along the Red River, which flows northward through Winnipeg into Lake Winnipeg. Due to the snowmelt pattern, southern sections of the river may experience rising levels before the northern parts fully thaw, leading to severe flooding like that seen in Winnipeg in 1950. To prevent future disasters, Manitoba constructed a vast network of diversions, dikes, and floodways, including the Red River Floodway and the Portage Diversion. These defences protected Winnipeg during the devastating 1997 flood, which impacted communities upstream.

In the United States, the New Orleans Metropolitan Area, a significant portion of which lies below sea level, relies on an extensive system of levees and floodgates for protection. However, this system suffered catastrophic failures during Hurricane Katrina, resulting in flooding of around 50% of the metro area, with inundation depths ranging from a few inches to twenty feet in coastal communities.

Asia

In China, flood diversion areas refer to rural regions intentionally flooded during emergencies to safeguard cities. Some argue that deforestation heightens flood risks, as natural forest cover can reduce flood duration. Deforestation exacerbates both the frequency and severity of floods.

Many countries with flood-prone rivers employ a variety of strategies to carefully manage these waterways. These include preventive measures like levees, embankments, reservoirs, and weirs to prevent rivers from overflowing. In situations where these measures are insufficient, emergency measures such as sandbags or portable inflatable tubes are used. Additionally, ecological approaches like planting vegetation to absorb excess water, creating terraces to slow down the flow, and building alluvial fans to redirect water away from flood-prone areas are utilized. Moreover, a range of infrastructure including dykes, dams, and storage tanks are constructed to manage excess water during floods.