Aztec and Bloomfield city leaders gather to discuss a preliminary engineering report on replacing the Aztec-Bloomfield water line. (David Edward Albright/Tri-City Record)
Aztec and Bloomfield city leaders gather to discuss a preliminary engineering report on replacing the Aztec-Bloomfield water line. (David Edward Albright/Tri-City Record)

With drought conditions looming, Aztec and Bloomfield officials say a long‑planned overhaul of their shared water line may become urgent sooner than expected.

The two cities met June 9 to review engineering findings that show the 12‑inch transmission line connecting their systems is deteriorating under severe soil corrosion.

The joint workshop, held ahead of Aztec’s regular commission meeting, brought together leaders from both municipalities to discuss a preliminary engineering report outlining needed upgrades to the 2002 emergency line.

Built to allow the two cities to share water when either the Animas or the San Juan river supply is compromised, the line is now experiencing frequent failures, according to a study by Souder, Miller & Associates. Officials said both communities are committed to developing a memorandum of understanding to move the project forward, which includes pump replacements, new metering infrastructure and additional pipe to meet commercial fire-flow requirements.

The Aztec-Bloomfield water line, built as an emergency project for drought alleviation in 2002, was constructed as a joint agreement between the two San Juan County cities.

“The workshop was to present the findings of the PER (preliminary engineering report) and loop in the city of Bloomfield to our intentions and desire to work together on this project,” Jaramillo said.

Bloomfield Mayor John Mohler and councilor Scott Eckstein

joined Aztec city commissioners, City Manager Jay Ruybalid, Jaramillo city commissioners and a few interested residents.

Jaramillo
Jaramillo

Findings of the preliminary engineering report, recommendations from the engineer, and next steps for moving the project forward were discussed, said Jaramillo, who added there were no discernable points of controversy or contention.

“The two cities are eager to work together to develop and complete this mutually beneficial project,” Jaramillo said.

No official resolutions or agreements were made at the workshop; rather, the cities will work toward developing a memorandum of understanding, he said.

Aztec waterline project limits. (Courtesy Jeric Jaramillo)
Aztec waterline project limits. (Courtesy Jeric Jaramillo)

According to the preliminary engineering report, the core engineering challenge is the 12-inch ductile iron transmission line connecting Aztec and Bloomfield, which is “experiencing frequent failures due to severe soil corrosivity.

“This line is critical to regional water security, as it is the primary emergency conduit allowing Aztec (supplied by the Animas River) and Bloomfield (supplied by the San Juan River) to share water when either source is compromised,” the preliminary engineering report states.

Primary design requirement for the replacement line is the ability to deliver Aztec’s Stage 4 drought demand of 664 gallons per minute over a 24-hour period.Both proposed alternatives utilize high-density polyethylene pipe, which has thick walls, minimal joints and is highly resistant to the corrosion plaguing the current system.

Detailed breakdown of alternatives, with two primary construction methodsAlternative T-1: parallel replacement (Open-Cut) – involves digging a new trench parallel to the existing transmission line from U.S. 550-mile marker 159 to the Bloomfield Booster Station, by installing a new 10-inch HDPE pipe alongside the old one. Operational Impact: Water service can be maintained through the existing line for the majority of the construction phase, minimizing service interruptions. Construction challenges: Approximately 12,200 linear feet of the route involves bedrock at a depth of 15 inches or less, requiring extensive and costly rock excavation. Additionally, there is a high density of existing utilities within the NMDOT right-of-way along U.S. 550, which introduces significant conflict risks. Estimated capital cost: $19,155,747.

Alternative T-2: Trenchless replacement (Slip Lining) – utilizes a trenchless installation method in which pull pits are excavated and a new 10-inch HDPE pipe is pulled directly through the inside of the existing 12-inch ductile iron pipe. Calculations show a radial clearance of roughly 10.25%, which falls well within optimal engineering guidelines for slip lining. Construction advantages: By using the existing pipe casing, this method greatly reduces the need for expensive rock excavation and avoids major utility conflicts along the highway. Operational Impact: Because the existing host pipe will be occupied during construction, water supply to both cities must be maintained using a temporary 1-mile above-ground bypass pipe. The bypass creates logistical hurdles, requiring access ramps for highway businesses and posing a risk of overnight vandalism. Construction risks: slip lining is complex; there is a lack of ability to visually verify the condition of the host pipe prior to installation, which carries a higher risk for change orders if the pipe gets stuck. Estimated Capital Cost: $16,386,727.

Regardless of whether T-1 or T-2 is selected, several critical appurtenances and upgrades must be included in the project scope to ensure the transmission line functions appropriately.

Regarding booster station overhauls, the pumps at both Aztec and Bloomfield stations are nearing the end of their design lives, requiring replacement with new duplex pump systems.

Also, the variable frequency drives will be installed to efficiently control flow rates without the need for manual throttling. And, the corroded buried piping at both booster stations will require replacement.

Boundary metering, with a two-way totalizing water meter housed inside a vault will be installed at the municipal boundary to accurately measure mutual water transfers.

Finally, targeted fire flow additions state that neither 10-inch transmission line alternative alone can provide the 1,866 gallons per minute (at 63 psi residual pressure) required for the Pepsi Building. Therefore, 1,040 linear feet of 16-inch pipe and 2,157 linear feet of 12-inch pipe will be installed specifically to meet the commercial fire flow requirement.

dalbright@tricityrecordnm.com