Flood Management Methods I


One of the ecological crises facing our local communities is flooding or erosion. Every year, the Nigerian Metrological Agency (NIMET) releases flood forecasts warning communities of impending erosion and flooding. This is similar in many other countries. Worse still, each year, the warnings appear more urgent. In our effort to conserve the environment, we have worked on different projects to help communities dealing with flood and erosion. Some of these projects IFEHS has undertaken include the Nigeria Erosion and Watershed Management Project (NEWMAP). Through our involvement, we have found these methods efficient for erosion management:

Flood crisis
flood control measures

Tree Planting

Tree planting is effective in flood control. This is due to many reasons. Trees have the ability to absorb water into the ground – as deep as 200 feats. Trees also help to reduce flooding by reducing the intensity with which rain water falls to the ground, after they must have first dropped on leaves and other tree parts. In addition, lots of raindrops that fall on leaves are evaporated straight into the air, this reduces the amount of water that reaches the ground and flows as flood.

Reclaimed land staff at a reclaimed landscape in Kano State. The land was reclaimed through afforestation and tree planting programme of NEWMAP

Tree roots also help to hold the soil together, as a result, making the soil stronger and less porous to flooding. Tree planting, especially near streams and rivers are effective in checking flood as they help reduce the amount of water that goes into these water bodies, stopping them from overflowing their banks and destroying farms, aquatic habitats, houses and other things. Planting grasses, shrubs and vegetations, especially legume crops or allowing them to grow also helps to improve the cohesion of the soil, reduce the intensity of water flow on the soil, reduce the washing away of soil by rain, amongst other things.  According to Environmental Agency of America, ‘’planting trees around rivers could reduce the height of flooding in towns by up to 20%’’ if it is properly done.

Proper waste disposal

Throwing away wastes indiscriminately causes flood. This is because, when it rains, these wastes are carried into drainage systems, sewages and on the streets blocking the flow of water; thus, leading to flooding. Some waste materials that are not properly disposed end up in streams and rivers, thus obstructing their flow and causing them to flow over bank.  These wastes also contaminate these waters leading to water borne diseases such as diarrhea, dysentery, typhoid fever and cholera.

We need to always clear our surroundings and water channels of debris and wastes. Especially surroundings that have leafy/ leave-shedding trees.

Avoiding indiscriminate excavation of sand

Indiscriminate excavation of sand is not good for the soil; it weakens the soil, making it porous. A porous soil is more likely to give in to flooding. However, individuals and communities are advised to clear sand from gutters and drainage systems, just as they clear debris and other solid waste materials. This is to avoid clogging and the occupation of the drainage system’s space with materials that takes the space water is supposed to pass through. During rains, drainage systems filled with sand and debris are more likely to overfill its bounds and release flood into the road or into the community.

Avoiding indiscriminate cutting of trees and vegetations

Just as we are encouraged to plant trees, shrubs and grasses, we are also expected to stop cutting trees and vegetations, carelessly. While we may need these trees for purposes such as construction, wood and paper making, we should bear in mind that it could expose the soil to erosion. To avoid this, trees and vegetations in flood prone areas should be protected, just as tree planting and replanting of cut trees should be encouraged.

Construction and maintenance of standard drainage systems

In our erosion-intervention efforts, we noticed that communities with no proper drainage systems are more likely to experience flood. This is because there are no properly mapped out channels for water to pass, hence, it finds it way into homes, farms, roads and other places. The importance of standard drainage systems in erosion control cannot be overemphasized. Most roads constructed without drainages soon wear out, due to flooding, while those with poor standard drainages cannot manage the water flows. They do not withstand the impact of rain for long and they give in to damage. Sometimes, the damage of these drainages eithers marks the beginning of, or the worsening of the damage of the roads around them. In construction of roads therefore, attention should be paid to their quality, as well as to the availability and standard of drainage systems.

These drainages should also be maintained, both by local communities and agencies. They should avoid dumping of wastes on water channels, clear sands, clogs and debris from these channels regularly and maintain the roads and drainage systems through timely repairs and other activities. The Federal Road Maintenance Agency (FERMA), State and local road maintenance agencies should give the maintenance of drainage systems due attention as well.

Fetching of rain water

Fetching rainwater, otherwise known as Rain Water Harvesting (RWH) has been an ancient way of erosion control. Rain Water Harvesting (RWH) reduces the amount or water that runs off to the ground. By fetching rainwater, most communities reduce flooding, though some do this without knowing it. However, in some countries such as United Kingdom, France, China, Italy and Brazil, this method is used deliberately to reduce erosion.

We encourage communities to collect rain water, this is a cheap, tested, old and highly efficient way of not just controlling erosion, but conserving water.

These are some of the methods we teach communities to adopt in flood management, towards the protection of lives and properties and for the ultimate preservation of the planet earth – our common home which is endangered by flood and other environmental crises. We hope you find these useful and join us as we play our parts in ensuring environmental sustainability.

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