Flooding can range from inconvenient to deadly, and often results from human activities. Clearing of vegetation (especially forest), paving ground so that it cannot absorb water, and discarding litter (especially plastic bags) into waterways, all exacerbate flooding.
Reducing flooding
Flood levels can be reduced locally in several ways:
- Swales, rain gardens, permeable pavements and other forms of groundwater recharge, especially when implemented at higher levels, reducing the amount of water reaching the flood zones. Keyline farming can help in farming areas.
- Improving the water storage capacity of the soil, through building a healthy soil with high humus content.
Large scale flooding
Note that when the flooding is a result of larger scale hydrology, these may have little impact. They are still good things to do for their own sakes, but will have a relatively small impact when there massive quantities of water from outside the area.
In some cases, such as in Jakarta, there is a combination of poorly designed development which increases stormwater runoff, litter which clogs drains, and a lack of adequate drainage (e.g. through lack of finances, or diversion of finances for other purposes. Suitable local measures such as absorption wells and banning single use non-compostable plastic bags, applied over a large enough area, could conceivably remove the need for the large scale, top-down stormwater solutions.
Mitigating damage
- Setting housing back from flood zones.
- Raising all sensitive/valuable things in the home, through shelves set high, or keeping valuable items on higher levels. Electrical outlets are also set high. This is often effective but:
- only protects against moderate floods,
- may be inadequate in flash floods if some items need to be moved from the main living space to a higher level
- Setting houses on stilts, such as the traditional Queenslander.
- Keeping an inflatable boat available in the highest part of the house, so it is possible to escape from an upper window as a last resort.