Representatives from the Middle Rio Grande Conservancy District (MRGCD) gave an update on replacing the Corrales siphon to a packed audience of concerned Corraleños in the Village Council chambers June 12.
During the presentation to Corrales farmers and residents, the MRGCD and staff from Wilson and Company, the architectural and engineering firm overseeing the siphon’s design, delivered updates and answered questions about the $8.5 million project aimed at replacing the aging Corrales siphon. The discussion also highlighted delays caused by federal reviews and local coordination issues.
Prompted by the discovery of a sinkhole in late 2021 along the siphon’s alignment, the project aims to replace the nearly 90-year-old, 60-inch wood stave pipe, which was found to have missing pieces of wood throughout, with a more durable 36-inch steel pipe.
Wilson and Company was tasked with conducting an alternative analysis to assess options for replacing or repairing the siphon in its current condition.
In November, the MRGCD secured $8.5 million in funding from the Water Trust Board, overseen by the New Mexico Finance Authority. The funding includes about $700,000 as a loan from the Water Trust Board, intended for repayment and about $1.5 million contributed by MRGCD to match the funding source.
“Since November of 2023, we have been working through the design process on that funding to get a trenchless siphon designed ready for construction,†said Luke Smith, a project design engineer with Wilson and Company.
Although the Water Trust Board funding is set to expire in November 2025, officials from the MRGCD are confident they will secure an extension for the funding.
“I think we have every reasonable expectation to expect that that will be extended based on just previous projects,†said Jason Casuga, chief engineer and CEO of the MRGCD.
According to Smith, Wilson and Company is on track to have everything prepared for bidding by August. Barring any unexpected setbacks, they aim to seek approval from the MRGCD board in September to start construction. Their target is to have the siphon fully operational by March 2026.Â
The trenchless design employs horizontal directional boring, a method that minimizes environmental impact by allowing the installation of the pipe without disturbing the riverbed. The process would bore under the river to the east side, while all construction activities are confined to the canal areas on each side of the riverbank.
During the presentation, a video demonstrated the process of boring a 1,200-foot-long pipe, which will be installed 40 to 50 feet below the current bottom of the siphon.
Siphon delays
According to Casuga, the Bureau of Indian Affairs (BIA) unexpectedly initiated a review of the easement maintained by MRGCD in the floodway of the Rio Grande, particularly through Pueblo of Sandia land, to determine if the easement covers the siphon. This unforeseen federal review has led to delays.
“I don’t necessarily understand why they decided to raise this question but nevertheless, they have raised this question and they’re reviewing it,†he said.
According to Pueblo of Sandia Gov. Felix Chaves in a letter to the Corrales Comment, the pueblo does not have the authority to issue easements independently since the land is held in trust by the federal government. Any easements or permissions must be granted with the approval of the BIA due to the federal trust status of the land.
Casuga said that he, MRGCD Chair Stephanie Russo Baca and Vice Chair Karen Dunning attended a tribal council meeting for Sandia Pueblo after the new year. During this meeting, the pueblo itself, not the BIA, granted them access to continue their technical work, which allowed the project to go forward.
In May, the Coalition of Six Middle Rio Grande Basin Pueblos gave an update to the MRGCD, saying they were working through the process but not including a timeline for the BIA review.
“We as MRGCD do not believe that we were in error. Quite frankly, we thought our documents were so solid. This kind of came out of the blue for us,†Casuga said. “I do not control the federal process, I have to do a lot of listening, I have to do a lot of grinding my teeth and I have to do a lot of stamping my foot. I’m talking about the impacts to communities.â€
Irrigation challenges
Initially, a temporary solution when the siphon failed, electric pumps now draw water from the river and deliver it to the Corrales irrigation system where the siphon outlet would be.
Casuga informed the Corrales farmers that the MRGCD anticipates the ongoing pumping operation will continue for at least another year. However, he noted that the pumps can only operate effectively if the river maintains a certain water elevation, ensuring sufficient suction to draw water into the pumps.
“Last year I ran them too long and broke both of them and had to pay a fee to have them fixed,†Casuga said.
He acknowledged that he did not know when the pumps would be shut off this year but expressed hope that they would operate through June and into July.
“My suggestion to you right now… if you have the opportunity to irrigate, take your opportunity and that’s the best advice I could give you right now,†said Casuga.
Another challenge for the design and construction of the siphon pipe was minimizing environmental impact. This section of the Rio Grande is home to three endangered species — the Rio Grande silvery minnow, the yellow-billed cuckoo and the southwestern willow flycatcher. The habitat along this river segment is considered critical to these species. An open-cutting approach to the river would have resulted in significant environmental penalties, dramatically increasing the project’s costs.
Staying InformedFor siphon updates, go to mrgcd.com or follow them on Facebook, Instagram, X formerly Twitter and YouTube or call 505-247-0234.