In a decision that restores critical Clean Water Act protections for small headwater streams and wetlands across the country, a federal judge has vacated the 2020 “Navigable Waters Protection Rule” developed by the previous administration. That rule had stripped Clean Water Act protection from ephemeral streams, which are critical tributaries to larger streams.

Responding to a case brought by the Pascua Yaqui Tribe, Tohono O'odham Nation, Quinault Indian Nation, Menominee Indian Tribe of Wisconsin, Fond du Lac Band of Lake Superior Chippewa, and the Bad River Band of Lake Superior Chippewa. U.S. District Judge Rosemary Márquez found that the 2020 rule illegally and unscientifically put these waters at risk of destruction.

“This is a big win for common sense, science, and clean water,” said Chris Wood, president and CEO of Trout Unlimited. “It is especially fitting that six Tribal nations, the representatives of peoples who have relied on clean water for millennia in North America, were the plaintiffs who won this landmark victory.”

Over the past two years, Trout Unlimited scientists have documented how drafters of the rule failed to assess its potentially devastating impacts on “ephemeral” streams, which are critical tributaries to larger streams.

Streams that do not flow year-round, but instead flow seasonally as “intermittent” streams, or in direct response to precipitation events as “ephemeral” streams, are the backbone of every watershed and had largely been protected for decades under the Clean Water Act. The 2020 rule categorically removed Clean Water Act protections for all ephemeral streams, which in Colorado represent greater than 25% of the state’s more than 350,000 miles of streams as mapped by the US Geological Survey.  Those figures are conservative; TU scientists determined that nationally ephemeral streams account for almost 50 percent of stream miles in the lower 48 states when accounting for other ephemeral stream channels not included in USGS maps.

“It seems like basic common sense, but for the Clean Water Act to protect our rivers it needs to prevent pollution and protect watershed health at the source – the many small headwater streams that feed our larger rivers,” said Colorado Trout Unlimited Executive Director David Nickum.

The court’s ruling is good news for river conservation, which was already suffering from weakened Clean Water Act protection on the ground. By examining the Environmental Protection Agency’s Clean Water Act Approved Jurisdictional Determinations (JDs) database, TU determined how many streams and wetlands were no longer receiving Clean Water Act protection.  Of the 14,224 waterbodies evaluated under the 2020 rule between June 22, 2020, and June 9, 2021, TU found that 6,266 wetlands were determined to be no longer covered by the Clean Water Act, along with 3,096 ephemeral stream reaches. Many of these were in watersheds that support trout and salmon.

With large-scale damage to the nation’s waterways now averted by this week’s federal ruling, the EPA and the U.S. Army Corps of Engineers can turn to the critical job of developing a new “Waters of the United States” rule that is scientifically sound and durable.  Both Nickum and Montana TU Executive Director David Brooks recently provided comments on that rulemaking effort at EPA/Corps Town Halls, highlighting the importance of protecting headwaters and ephemeral streams.