Flooding, Flood Structures and How These Structures Work

Today's topic is flooding, and how humans manage to control and manipulate water. This control mechanism is for preventing damage and making use of the excess water to be used in droughts. Environmental impacts of all types of structural and non-structural measures are to be assessed jointly in the long term in order to maintain sustainable development of land and water resources.

For rivers, the river streams join or separate because of the geological processes. A Watershed is the area of land that collects precipitation, there are areas where mostly drainage occurs too. These have a controllable ratio, but there are instances where this ratio may not be sustained. 

Source: https://bewaterfriendly.com/our-water/watersheds/

The wetland and overland areas that are seen in the figure may change with geological or hydrological alterations. This affects the settlements near the flow. Reasons may include; slopes on the side of the flow may not be steep. When the cannel over banks, this instance may lead to disasters. Solutions for this problem includes; Building Levees or earthen embankments on the sides of the river. 

Source: A Case Study of a Fluvial Deltaic Reservoir. (2018). ResearchGate.

Another solution is diversion canals; diverting water for purposes like irrigation, hydropower generation, and safety. To create a completely different path for the canal is not environmentally and economically achievable. So the canal is merged back into the original flow after taking a different path. So when the water levels rise, this canal transports the excess water to needed areas instead of it damaging the surrounding. 

Souce: Water Transport Structures(2021) FAO

Another solution; Dams. These infrastructures provide storage for excess water.  Each dam has a specific purpose, some may be full for most of the time to provide hydropower, irrigation... But Some dams are usually empty, when a big flood happens the storage fills up. If the reservoir is full then floodgates must be opened in order to let water through. 

The correct way for flood risk management is to determine the climate, geology, and other factors and designing the appropriate flood structure. These structures have negative effects as well so the design must be well thought. Since climate change is creating extreme situations(for example unnatural precipitation and drought.) and we need water resource management more than anything. 

Here are some related video's:

Sources:

• (Water Resources Engineering, Yanmaz A. Melih, 2018)
• (PDF) A Method to Integrate Geological Knowledge in Variogram Modeling of Facies: A Case Study of a Fluvial Deltaic Reservoir. (2018). ResearchGate. https://doi.org/10.4236\/ijg.2018.96021

• 8. Water Transport Structures(2021)   http://www.fao.org/fishery/static/FAO_Training/FAO_Training/General/x6708e/x6708e08.htm

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