New River sewage treatment “no longer just a Calexico problem” says County

Jose Angel, Executive Officer of the California Regional Water Quality Control Board, addresses the Imperial County Board of Supervisors Tuesday, March 21, 2017.

EL CENTRO — With the recent massive sewage spills into the New River originating from Mexicali, Regional Water Board Executive Officer Jose Angel called upon the Imperial County Board of Supervisors Tuesday morning to help reassess how the New River water could be adequately treated.

Angel noted that before the year 2000, there was virtually no treatment of the contaminants, trash, and raw sewage entering the New River from Mexicali.

“Quite frankly, we couldn’t get our heads around the degree of pollution,” Angel recounted.

To address the sewage issues in Mexicali, a binational effort between Mexico and the United States was undertaken, and included emergency repairs of pumping plants, rehabilitation of twenty miles of sewer lines, and a brand new treatment plant that would eventually process 20 million gallons a day (mgd), which was enough to virtually eliminate the entire 20 mgd of sewage being discharged into the river. The sources of that sewage included Mexicali slaughterhouses, industrial run-off, and agricultural discharge.

The new facility, known as the Las Arenitas Wastewater Treatment Facility, was completed in 2007. The facility and other projects would end up costing over $80 million, split roughly 55/45 between the U.S. and Mexico, respectively, according to Angel.

These projects, as well as other costs since 2007, add up to roughly $70 million that the United States has invested into water treatment in Mexicali.

According to Angel, such treatment plants typically have an operational life of at least 25 or 30 years. The various pumping stations and plants in Mexicali, however, began to suffer failures and sewage bypasses in 2013, though the oldest pumps had been operating for only twelve years. Angel attributed the shorter lifespan to Mexicali’s sewer infrastructure design.

“When it rains, the storm water run-off washes the city but it also washes the sand in the streets, and that sand is a grit,” Angel explained. “That grit is a killer for pumping equipment.”

More sewage bypasses occurred in 2015 and 2016. A federally funded study was completed and concluded that a myriad of needs faced the Mexicali sewage infrastructure, as well as the operations and management of the system. Angel noted that the local cooperation between the Mexican and American governments was unprecedented, and not a cause of the maintenance failures.

“The problem isn’t lack of cooperation, but a lack of resources,” stress Angel.

Ultimately, international pollution is a responsibility belonging to the State of California. yet, the prospect of holding the state accountable for the quality of the New River was deemed problematic.

“We can always draw a parallel to the Salton Sea to hold the state accountable,” observed Supervisor John Renison, referring to the years spent before actionable steps were taken by the state. “Look how long it’s been.”

According to Angel, the New River water at the border comprises 17-20% of the water that reaches the Salton Sea.

The projected cost to address the problems ranges from $75-$80 million. Yet, the Board was skeptical that sending more money to Mexicali was the only solution. Angel noted that meetings with the Binational Technical Committee, which oversees the treatment projects, would take place in April and May of this year and would allow them to get a more accurate perspective on Mexico’s priorities. Still, Angel agreed that processing the wastewater north of the border might be a viable long-term resolution.

“We really have to re-evaluate our strategy,” said Angel.

One solution could involve sending the polluted water back into Mexico.

“Why don’t we enable Mexico just to keep all the dirty water?” suggested Angel. “I’d rather have that area dry than have no control whatsoever.”

The New River’s contamination has also affected the Calexico Phase of the New River Improvement Project, which includes a trash screen where the river crosses into the United States, a disinfection facility to further treat the water, and a river parkway (a pedestrian and bicycle pathway designed for public recreation).

The creation of the river parkway was built on the assumption that the New River would continue to meet minimum quality standards, which the disinfection facility was intended to provide in conjunction with the Mexicali treatment plants. However, the disinfection facility is now of “questionable” use, given the New River’s accelerated decline from Mexicali sewage. Caltrans is overseeing the construction of the parkway, which is still on schedule.

“They got ahead of us. The deal was to address the water problems first, then build the parkway,” said Angel.

In short, Calexico is on course to have a new public park built on the most contaminated section of America’s most polluted river. The park is already funded and much of the paperwork has been completed, allowing construction bids to be accepted soon.

The proposed location for the river parkway in Calexico. The park will feature trails for hiking and bikes. Photo by Javier Guerrero.

Angel also indicated that the national border wall project might include paying for the trash screen, allowing the remaining funding to go to the other components of the project.

Those other components include a separate channel from the river’s entrance into Calexico that leads to nearby wetlands. After the water is treated there, a pump-back system to send treated water back into the New River near where it crosses the border into Calexico, thereby the river to meet acceptable levels as it makes its way through the city. Yet, the entire system design was dependent on the sewage from Mexicali to be treated before entering the river.

“It’s no longer a Calexico problem, this a County problem,” said Renison.