Multiple Choice, Multiple Answers

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Urban wetlands, often bulldozed for development, quietly perform functions that engineered infrastructure struggles to replicate cheaply. A marsh at a city's edge can absorb stormwater during heavy rain, reducing flash-flood risk in surrounding neighborhoods far more economically than expanding underground drainage tunnels. The same wetland filters pollutants, as reeds and sediment trap heavy metals before they reach a river. Wetlands also support biodiversity, offering nesting grounds for migratory birds within otherwise built-up areas. Some city planners have begun restoring paved-over wetlands rather than building new stormwater tanks, citing lower long-term maintenance costs. However, restoration is slow: a functioning wetland ecosystem can take a decade or more to mature, and restored sites remain vulnerable to encroaching construction unless protected by zoning law.