The Rundown
- Army Corps, for fourth consecutive year, authorizes an underwater dam to keep salt water from moving up the Mississippi River in Louisiana.
- A cold-water flow experiment at Glen Canyon Dam to disrupt non-native fish downstream will end within a week.
- Senate passes a defense spending authorization bill with water-related provisions.
And lastly, EPA sits on a “forever chemical” toxicity assessment, ProPublica finds.
“Do not make American families pay the price for Trump’s war on affordable American energy.” – Sen. Martin Heinrich (D-NM) speaking on the Senate floor to rally votes to end President Trump’s national energy emergency. Heinrich and his Democratic colleagues faulted the White House for increasing electricity prices by cancelling wind and solar projects and fully supporting data center developments, which consume large quantities of electricity. Yet, the Democrats’ effort to repeal the emergency declaration failed.
In context: Data Center Energy Demand Is Putting Pressure on U.S. Water Supplies
By the Numbers
River Mile 53.1: Approximate location of the front of the saltwater “wedge” that is pushing up the Mississippi River, in southern Louisiana, according to the Army Corps of Engineers. If the wedge moves far enough upriver it will endanger drinking water supplies for communities that draw from the river. Chloride concentrations are higher in the trailing sections of the wedge. The Corps estimates that the point at which they exceed EPA drinking water standards is 15 to 25 miles behind the wedge front.
News Briefs
Saltwater Barrier
The Army Corps of Engineers, for the fourth consecutive year, has authorized the construction of an underwater dam across the bottom Mississippi River as a way of keeping salt water from the Gulf of Mexico from moving upriver and spoiling municipal water supplies.
A contractor is building the dam at river mile 64. As of October 10, the front of the saltwater wedge was estimated at river mile 53.1.
Salt water intrudes when river flows are too feeble to push it out. These low-flow conditions have happened in the late summer or early fall every year since 2022.
Because salt water is heavier than fresh, the intrusion happens along the bottom of the river, which is why the temporary earthen dam is placed across the river bed.
If salt water moves too far upstream, it will contaminate the water supply for communities whose intake pipes extend into the river. In 2023, the Army Corps barged 153 million gallons of fresh water to communities in southern Louisiana that were affected by the saltwater intrusion.
Senate Passes Defense Spending Bill
The Senate passed a bill that authorizes defense spending for fiscal year 2026. The bill also has a number of water-related provisions.
It requires the Defense Department to conduct a pilot wastewater surveillance study at four or more military installations. The goal is to test wastewater for substances that would identify drug use among service members or the presence of infectious disease. (Wastewater surveillance grew in prominence as a testing tool during the Covid pandemic.)
It establishes a working group on “advanced nuclear” technologies that could power desalination facilities.
It requires a report on energy and water use for any data center built or expanded on military property.
It repeals a moratorium on the burning of PFAS substances, including firefighting foam.
The bill includes an amendment from Sen. Tim Kaine (D-VA) that requires NASA to pay for new drinking water wells for the Eastern Shore town of Chincoteague. The town’s existing wells were contaminated with PFAS when the land was owned by the Navy. That land has since been transferred to NASA.
Studies and Reports
EPA Sits on ‘Forever Chemical’ Report
An EPA report on the toxicity of PFNA – one of the thousands of PFAS in circulation – was ready to be published in mid-April, ProPublica reports. But the agency has not yet released it.
PFNA is one of six PFAS that the Biden administration decided to regulate in drinking water. The Trump administration announced in May that it would attempt to reverse that decision for four of the chemicals – including PFNA.
On the Radar
Glen Canyon Dam Flow Experiment
The Bureau of Reclamation began releasing cool water from the depths of Lake Powell in mid-August.
The cold water is meant to disrupt smallmouth bass spawning downstream of Glen Canyon Dam. Smallmouth bass are a non-native species that federal agencies and their partners are attempting to rein in to protect threatened native species like the humpback chub.
The cold-water flow experiment is set to end by October 20.
Because the cold-water flows bypass Glen Canyon Dam’s turbines, the dam has been producing less power. That means more power purchased on the market. According to the Western Area Power Administration, which markets federal hydropower, purchased power expenses are “significant.” WAPA opposed the cold-water release plan, arguing the end date should be October 1, which would reduce purchased power costs.
Sales of hydropower fund the operation and maintenance of Glen Canyon Dam.
Federal Water Tap is a weekly digest spotting trends in U.S. government water policy. To get more water news, follow Circle of Blue on Twitter and sign up for our newsletter.
