The new year brought a new round of beach closures to Coronado as storms pushed sewage from Tijuana into coastal waters, but it also brought a new federal budget with $300 million slated to fix it.
The money, combined with $144 million from Mexico, will help fund a plan that promises to reduce cross border pollution by 76% through a combination of projects, including expansions to wastewater treatment plants and recycling wastewater.
The projects are slated for completion by 2027, with some of its largest – including increasing the capacity of the South Bay International Wastewater Treatment – expected to enter the design phase this year. Longer-term projects are also planned, though funding has not yet been secured for them.
The issue arises when the Tijuana River experiences transboundary flow: water from Mexico is pushed from Tijuana across the border and into coastal waters. Most days, this movement is nonexistent, but with rain comes river flow. Major storm events, like those experienced in early January, exacerbate it.
Transboundary flows happen, on average, 153 days out of the year, though it doesn’t always prompt beach closures.
Lawmakers secured funding to address cross-border pollution in 2019 under the Trump administration, but President Biden opted to review the project before including it in the 2023 federal budget.
“Bureaucratic red tape has prolonged the decades-long crisis in the Tijuana River Valley, preventing much-needed funding from getting to our communities,” said Congresswoman Sara Jacobs, who worked with Representatives Juan Vargas and Scott Peters to secure the funding.
A final draft of the proposed projects was released in November by the Environmental Protection Agency (EPA) and the International Boundary and Water Commission (IBWC), which considers several alternatives but recommends a list of core and supplemental projects. The period for public comment closed in December, and a final record of decision is expected within the month, said Sally Spener, U.S. Secretary for the IBWC.
The U.S. and Mexico in 2022 agreed on a cost-sharing agreement for sanitation at the border under Treaty Minute 328, an implementing agreement to the United States-Mexico-Canada Agreement (USMCA). The U.S. agreed to fund $330 million for mitigation, and the remaining money will come from Border Water Infrastructure Program (BWIP) funds from the EPA and “not-yet-identified” state and federal sources.
The proposed projects include expanding the South Bay International Wastewater treatment plant’s capacity from 25 million gallons per day (MGD) of river flows to 60 as well as constructing a new treatment plant in San Diego to treat an additional 60 MGD of river flows. It will also build a treatment plant in Mexico to address polluted water that flows to U.S. beaches under certain ocean current conditions.
The agencies will also install at least one trash boom in the Tijuana River to capture solid waste, and install infrastructure to divert flows from the polluted Tijuana River.
Finally, the plan will build infrastructure for the reuse of treated wastewater in Mexico. Currently, effluent wastewater from two treatment plants are pumped into the Tijuana River, where it is recontaminated with sewage, chemicals, and trash. During transboundary flow, it then needs to be retreated before reaching the ocean, Spener said. It’s inefficient, of course, to treat water twice, and it also strains the treatment plant by increasing the volume of water it needs to process.
Diversion also may help address another concern: On one side of the border, beaches close, but on the other, taps run dry. Tijuana’s low water supply causes water outages around the city, which are unpredictable and can last for days.
“The cutoffs are really abrupt,” said Jatziry Mariche, a former resident of Tijuana. “You become really frugal with water and are almost counting the drops you’re using to wash a single dish – it’s survival mode.”
Like San Diego, Tijuana’s water supply depends on the Colorado River, but its pipeline is smaller, as is its supply. The river’s shrinking water levels are of concern on both sides of the border, and in 2021, San Diego introduced Pure Water San Diego, whose goal is to provide at least half of the city’s drinking water from water reuse by 2035.
Conserving water in Mexico through these projects could have a secondary, socioeconomic impact by decreasing water shortages and reducing the overall dependency on the Colorado River as a whole. Although the aim of the project isn’t to address water scarcity in Tijuana, it could be a positive side effect.
“We do know that the Colorado River is in drought,” Spener said, “To the extent that you can reuse this water, it could eventually help support the reservoirs, and that could help reduce Tijuana’s reliance on the Colorado River.”