The pallid sturgeon’s survival in the Yellowstone River system is being entrusted to the rebuilding of Intake Diversion Dam, according to the U.S. Army Corps of Engineers’ final management plan and environmental impact statement.
The lengthy document was released recently with the comment period open through Oct. 9. The final EIS can be found online at http://www.nwo.usace.army.mil/mrrp/mgmt-plan/.
Pallid sturgeon have been listed as an endangered species since 1990. It is estimated that only about 125 wild pallid sturgeon exist in the Yellowstone River, although hatchery-raised fish have been planted.
The final EIS identifies Alternative 3 as the preferred action, but allows for adaption if new science arises.
“It’s a beast,” said Zach Shattuck, native species coordinator for Montana Fish, Wildlife & Parks, of the lengthy EIS.
Shattuck had just sent the document out to his staff so they could offer comments, but noted, “We’re looking to see what’s best for our fish and wildlife.” He added that the Corps seems to be “Intake focused” for the time being. Intake Dam is located 71 miles upstream from the Yellowstone River’s confluence with the Missouri River.
Within the many pages referencing scientific analysis, studies, charts and maps is this statement: “Improvements to fish passage are expected to be a substantial step forward in assisting the long-term survival and recovery of the pallid sturgeon in the upper basin by providing access to up to 165 miles in upstream reaches of the Yellowstone River.”
The “improvements to fish passage” is the $40 to $50 million reconstruction of Intake Dam, a Bureau of Reclamation project that will raise the height of the dam while also constructing a separate two-mile-long bypass channel that engineers predict will allow pallid sturgeon to swim around the dam, extending their riverine habitat. No similar project has ever been undertaken on such a large scale and with regard to the wild flows of an undammed river like the Yellowstone.
In April, environmental groups lost their court challenge to halt the dam. They were pushing for pumps to be installed to supply irrigators instead of building a new dam.
Extending upstream habitat for pallid sturgeon is necessary, studies have shown, to allow the offspring of the fish to drift after they hatch. Right now, studies have shown the larval fish are being smothered in sediment at the head of Lake Sakakawea in North Dakota.
Meanwhile, management of flows from Fort Peck Reservoir on the Missouri River is taking a back seat in the Corps’ final EIS. Montana Fish, Wildlife & Parks officials have long lobbied for warmer flows and heavier releases from Fort Peck Dam in the spring to more closely mimic actual river behavior to benefit all native species, not just pallid sturgeon. The agency’s staff has also noted that fish use both rivers — which join just across the North Dakota border — and therefore a comprehensive approach would be beneficial.
But the Corps’ EIS stated, “Meaningful levels of recruitment (of pallid sturgeon) in this reach are improbable given the current constraints.”
“I don’t know that the Corps has shut the door at Fort Peck,” Shattuck said, but it will be “subsequent with what we learn at Intake.”
A phone message to the Army Corps’ Omaha office was not returned by press time.
The pallid sturgeon is not the only endangered species on the Corps’ radar regarding management of the Missouri River. Increasing habitat for the Northern Great Plains piping plovers and interior least terns is also addressed. Both species use sandbar habitat to nest. Those features are less likely to build below dammed rivers, which blocks much of the necessary sediment to build the islands.
Despite the creation of manmade islands, reducing vegetation on those islands, killing predators that may eat the birds’ eggs and signage to keep humans away, the Corps’ document stated that piping plovers could see “a risk of local extirpation on the Missouri River within 50 years under the existing management approach.”
In analyzing the three species and citing the need for planning, a Corps’ analysis found that “considerable uncertainty remains regarding the type and extent of management actions ultimately needed to lead to population growth for each of the three species.”
Under the proposed alternative, the Corps would oversee the continued construction of sandbars “at an average rate of 332 acres per year in the Garrison, Fort Randall, and Gavins Point river reaches in years where construction is needed.”