Final answer:
Towns in flood-prone areas often use levees to protect against rising water. Sandbags and wetlands also play roles in flood defense, with sandbags serving as temporary measures and wetlands offering natural protection against surge and flooding.
Step-by-step explanation:
Many towns in flood-prone areas are surrounded by levees that are built to hold back rising water. These structures are crucial in preventing flooding and the potential devastation it can cause to cities and towns, particularly those located in low-lying coastal areas. In cases where levees are compromised, measures like using sandbags can help manage the situation. For example, when a levee starts leaking due to a high river level, sandbags can be placed around the leak to form a column that holds water. The water inside this sandbag column rises until it reaches the same level as the river, balancing the pressure and preventing further water from flowing under the levee. This is an effective temporary solution to a potentially dangerous situation. Moreover, the conservation of wetlands can serve as a natural barrier against storm surges and flooding, which also contribute significantly to protecting populated cities situated in vulnerable coastal regions from rising sea levels.