LINKEDINCOMMENTMORE

BLOOMFIELD — The U.S. Bureau of Reclamation, which oversees the operations of Navajo Dam, will release 5,000 cubic feet of water per second for five days this year.

“The dam has a lot of purposes,” said Susan Behery, a hydraulic engineer for the Bureau of Reclamation, during a meeting on Tuesday in Bloomfield. “Lots of reasons for releases, lots of reasons for storage.”

This year's release will be a bit different than releases the Bureau of Reclamation has done in the past.

The release will not last as long as in past years. In 2017, the Bureau of Reclamation released had a month-long release of 5,000 cubic feet per second. In 2016, the release began in May and ramped down in July.

There was not a spring peak release in 2018, but the bureau did release water over the summer to balance the low flows from the Animas River and maintain at least 500 cubic feet per second in the San Juan River between Farmington and Lake Powell.

Flooding is possible during the release

Behery said property owners along the San Juan River could notice some flooding. She said valuable items should be removed from the river banks.

Behery said this flooding is possible during releases from Navajo Dam or when tributaries like Largo Wash are running.

Shawn Williams, district manager for the Office of the State Engineer, said property owners should not try to stabilize the banks on their own. Instead, he said the U.S. Army Corps of Engineers can assist property owners.

The water release is intended to clear out sediment, debris

The Bureau of Reclamation has been releasing large amounts of water for several weeks on a yearly basis since 2006. In 2006, a record of decision was issued for the Navajo Unit that detailed requirements to mitigate the impacts of the dam on endangered species. When there is enough water, the bureau makes large releases in the spring or early summer to mimic the natural spring runoff from snowmelt in the Colorado mountains.

Behery said the San Juan River ran at 20,000 cubic feet per second at Blanco prior to the dam being built in the early 1960s. By 1970 the channel capacity had reduced to 16,000 cubic feet per second at Blanco and 15 years later it had shrunk to 5,000 cubic feet per second.

She said the Bureau of Reclamation wants to keep the channel capacity at 5,000 cubic feet per second.

“To have capacity for 5,000, we have to have 5,000 in the river,” she said.

The release will likely happen in late May or early June 

Behery said the release will be timed based on when the Animas River peaks. She anticipates that will be in late May or early June. Notice will be posted online 10 days before the release on the project's page on usbr.gov.

The full 5,000 cubic feet per second will not immediately be released. Behery said the Bureau of Reclamation will gradually increase the amount of water it is releasing over five to seven days until it reaches 5,000 cubic feet per second.

After five days of releasing 5,000 cubic feet per second, Behery said the bureau will decrease the flow over three days.

She said the San Juan River will likely be flowing at 10,000 cubic feet per second below the confluence with the Animas River during the channel maintenance release.

Bureau of Reclamation is trying to rebuild reserves

In a normal year, the Bureau of Reclamation would release 300,000 acre feet of water during the spring peak release. However, this year’s release will only be 70,000 acre feet.

The smaller release is intended to clear out the channel without losing too much water from the lake. Behery said the release will likely reduce lake levels by five to six feet.

While the Bureau of Reclamation is trying to rebuild reservoir’s water storage following the 2018 drought, Behery said the bureau did not want to put off doing a release altogether.

The Bureau of Reclamation did not do spring peak releases from Navajo Dam in 2013, 2014 or 2015 due to drought conditions. Sediment and vegetation began to encroach on the river banks. This caused problems in 2016 during the spring peak release. A trailer nearly washed into the river, and the Bureau of Reclamation was only able to release up to 4,500 cubic feet of water per second rather than the full 5,000 cubic feet per second.

Turbid waters should improve

“The turbid water is still an issue right now,” Behery said.

She said it has cleared up enough that the City of Farmington is able to operate the hydroplant at Navajo Dam, but it is still impacting water quality below the dam

Behery said the cloudy, or turbid, water was likely caused by the low water levels in the lake when runoff began entering the reservoir from two rivers.

“It’s just natural runoff from the Pine and Piedra that normally would have settled out,” Behery said.

She said the low levels in the reservoir likely caused the turbid water to back up behind the dam.

“We don’t really know when it’s going to clear up,” Behery said.

Hannah Grover covers government for The Daily Times. She can be reached at 505-564-4652 or via email at hgrover@daily-times.com.

 

 

LINKEDINCOMMENTMORE
Read or Share this story: https://www.daily-times.com/story/news/2019/05/01/navajo-dam-san-juan-river-channel-maintenance-increased-flows/3641464002/