A river should function as a kind of central cooling system for the surrounding urban areas, regulating the temperature, carrying the dirty air out to sea, and providing flood control, irrigation, and aquatic resource benefits.
一條河，對於它周圍密密麻麻的「都市森林」，就好比大樓裡的中央冷氣系統，除了能調節溫度，河面冷空氣的對流，會把大都市每天製造的髒空氣送到外海；河口、沿岸的沼澤，則是富有最佳教育題材的自然生態區；它還有防洪、灌溉、供養水產等功能。