Where Rivers Are Born

All of humanity and the entire global economy depend on a daily supply of clean water. Most of that water originates in small streams and wetlands—the headwaters—which are often unnamed and unmapped. Yet these anonymous headwaters are essential for maintaining downstream water quality, preventing flooding, providing wildlife habitat, and improving people’s quality of life. This document summarizes the scientific basis for the value and benefits of small streams and wetlands, which are often unnoticed, unappreciated, and unprotected, and yet are a critical part of the natural infrastructure that sustains humanity. This second edition is an update to the original version, first published in 2003, and draws on hundreds of relevant scientific papers that have been published in the past two decades. 

In the United States, the Clean Water Act has proven remarkably successful at protecting and improving water quality, to the substantial benefit of the American people. Part of this success is because the Act was historically interpreted as protecting most small streams and wetlands. However, shifting definitions of the “ Waters of the United States”— the legal term for the Clean Water Act’s jurisdiction— have resulted in different degrees of protection under different federal administrations. At the time of this writing, new rules are again under consideration that could substantially reduce protection for many headwater streams and most freshwater wetlands. The authors of this document were motivated by the belief that people should have access to good scientific information so they can express informed opinions about the policies that affect their lives. Thus, we have endeavored to distill the sc ience of headwater streams and wetlands into straightforward and understandable language.