Mexican Officials Confirm Amount Of Sewage From Transboundary Spill In Mexicali

The Mexican Section of the International Boundary and Water Commission has provided additional details regarding a sewage spill that was originally reported in Mexicali in February. According to a report summarizing the spill, a total amount of 424,240 cubic meters or approximately 112 million gallons spilled into the New River in Mexicali between February 10 and February 22. The New River flows north into the United States at Calexico, California.

Mexican officials initially reported the spill on February 10 to U.S. officials from the International Boundary and Water Commission, California Regional Water Quality Control Board, and U.S. Environmental Protection Agency, and continued to provide periodic updates until the flow stopped.

According to information provided by Mexican officials, the release of wastewater to the river occurred following a problem on February 10 related to a 50-year old 36-inch diameter sewer pipe. To inspect and repair the pipe, officials from the Mexicali utility (CESPM) shut down Pumping Plant 1, which conveys wastewater to the Zaragoza Wastewater Treatment Plant in Mexicali. A backup pumping system was constructed but was subsequently shut down because there was not sufficient capacity in the available sewer pipes to handle the volume of flow. As a resulted, utility officials diverted the wastewater to the New River at a site approximately two miles from the international border.

According to Mexican officials, the sewage releases occurred as follows:

• February 10 at 9:00 a.m. through February 17 at 5:00 p.m., wastewater flow at the rate of 600 liters per second (13.7 million gallons per day).
• February 17 at 5:00 p.m. through February 22 at 11:00 a.m., wastewater flow at the rate of 200 liters per second (4.6 million gallons per day).
• Total volume discharged was 424,240 cubic meters (112 million gallons).

The International Boundary and Water Commission has reiterated the importance of providing timely information on transboundary sewage spills and taking action to minimize the amount and duration of discharges.

U.S. Commissioner Edward Drusina said, “While receiving timely information about these spills is important, more should be done to contain the sewage before it crosses the border.”