At Audubon, we know the value that wetlands, rivers, lakes, and streams provide to birds. These waterways are critical habitat for the lifecycle of millions of birds, not to mention the millions of people who rely on clean water to drink, bathe, wash, and grow our food.
Riverside forests and wetlands—fed by both continuous and intermittent water sources—are essential for birds, particularly in the arid Southwest.
However, under the 2019 Proposed Revised Definition for Waters of the United States (WOTUS) many waterways that flow for only portions of the year would be excluded from Clean Water Act protections. This means ephemeral waterways like the Rio Puerco in New Mexico, Centennial Wash in Arizona, Milpitas Wash in Southern California’s Imperial County and Chemehuevi Wash in San Bernardino County would no longer be protected. Without WOTUS protections, developers can build in these areas without federal permits, and the waterways and their surrounding environments would be unprotected from potentially harmful discharges. In the past, industrial operators used these dry washes as disposal sites for pollutants, only to end up contaminating the groundwater below.
Along many of the dry washes in the desert Southwest, trees like mesquite, palo verde, and ironwood thrive. When water occasionally flows through these normally dry washes, these thrifty trees take advantage. Along these washes, trees grow tall and into dense desert forests. They support abundant avian life, especially Lucy’s Warblers, Bell’s Vireos, Black-tailed Gnatcatchers, Phainopeplas, and Ladder-backed Woodpeckers. These woodlands comprise only five percent of the acreage in the desert regions of the Southwest but support 90 percent of the bird life, according to A Natural History of the Sonoran Desert. For these habitats to be stripped of their protections under the Clean Water Act means a serious risk of habitat loss in areas of outsized importance for birds.
On the human side of the equation, excluding dry washes and ephemeral streams and rivers risks damage to property through flooding. In Arizona, for example, drainages coming off local mountain ranges flow infrequently. However, when they do flow due to rain or snow events, floodwaters can overwhelm the normally dry channels. Clean Water Act protections can require that developers mitigate impacts to these washes, or mandate that development keep the washes intact in order to act as drainages for storm events. As part of the urban fabric, these washes serve as flood protection for communities during storm events and as corridors for wildlife when dry.
Losing protections on thousands of stream and river miles because they only flow seasonally or after rain events or snowmelt will negatively impact the birds and people who rely on these important water resources throughout the Southwest. Audubon will submit formal comments on the proposed WOTUS definition to the Environmental Protection Agency and the Army Corps of Engineers by the April 15, 2019 deadline, and we invite you to do the same.