Wetlands perform certain functions, including water filtration and the provision of wildlife habitats, from which humans benefit in the form of drinkable water and biodiversity. Trees produce oxygen, capture air and water pollutants, and provide shade, which help humans breathe, manage storm waters, and find a comfortable place to relax on a hot day. These are services that are provided by functioning ecosystems and are measured through the ecological economics of ecosystem services. The study of ecosystem services has provided an important insight: for the most part, those very services are ignored or undervalued. Although humans derive enormous benefits from ecosystem services, these services are neither bought or sold in the marketplace, and, therefore, have no market value.

This Article applies the idea of ecosystem services to the management of watersheds and, in particular, the manner in which decisions in floodplains often undermine ecosystem functionality in floodplains. For instance, road and home construction along water courses and riverbed dredging can disrupt (or trade-off) the ecosystem’s ability to provide flood control and habitat services. The dangers in making such trade-off decisions are illustrated by the flood damage suffered during Tropical Storm Irene and contextualized within the framework of ecosystems services.