Flooding is a significant issue worldwide, causing damage and loss of life. It is a complex problem due to the varied scales and types of flooding. Riverine flooding is particularly challenging because it is not linear, with flooding often occurring when a river overflows its banks into the surrounding floodplain.
To mitigate flooding, several strategies and structures have been developed. These include:
1. Levees: earthen or concrete walls that confine rivers and protect developed areas.
2. Diversion canals: human-made channels that divert floodwaters around developed areas and back into the natural waterway downstream.
3. Dams: structures that impound or store large volumes of water, creating reservoirs that can help manage flood risk.
However, these structures are not foolproof and can have unintended consequences, such as exacerbating flooding in other areas. Additionally, the concept of "flood control" is being reevaluated in favor of "flood risk management," which acknowledges that it is not possible to completely control nature.
Instead, strategies focus on reducing the consequences of flooding, such as reserving or converting floodplains for natural wetlands, parks, and trails. Flood buyouts, where high-risk properties are purchased and converted to green space, can be an effective way to reduce flood damages in the long term.
As climate change increases the frequency and severity of extreme rainfall events, it is essential to develop and implement effective flood risk management strategies to protect lives and property.
Here are the key facts extracted from the text:
1. Every year, floods affect populated areas, resulting in loss of life and millions of dollars in damages.
2. Nearly every major city in the world is susceptible to extreme rainfall and has areas vulnerable to flood risk.
3. Strategies and structures have been developed to reduce vulnerability and mitigate flood risk.
4. Large watersheds can flood in response to widespread and sustained wet weather, while smaller watersheds flood during single intense storm events.
5. Riverine flooding is a challenge due to its non-linear nature.
6. A watershed is the entire area of land where precipitation collects and drains into a common outlet.
7. Levees are a common structural solution to flooding, protecting developed areas by confining rivers within artificial banks.
8. Diversion canals are another flood control technique, diverting floodwaters to undeveloped areas where they won't be as damaging.
9. Dams can serve multiple purposes, including flood control, hydropower, and water supply.
10. Dams meant for flood control are kept partially or completely empty to store large volumes of water during major flood events.
11. The term "flood control" is falling out of favor, replaced by "flood risk management."
12. Flood risk management considers climate, weather, and the maximum amount of flow that can be released without damaging property downstream.
13. Overbanking flows can be beneficial, improving habitat, ecology, soils, and groundwater recharge.
14. Strategic development, such as reserving or converting floodplains for natural wetlands and parks, can reduce the consequences of flooding.
15. Flood buyouts, where high-risk property is purchased and converted to green space, can be the most cost-effective way to reduce flood damages in the long term.