Rachel, our state-of-the-art tunnel boring machine (TBM), continues to quietly build an 18-foot internal diameter tunnel from our Joint Water Pollution Control Plant (JWPCP) in Carson to Royal Palms Beach in San Pedro. Over 2,000 feet of tunnel has been constructed thus far. Rachel is now about 70 feet deep below ground and less than ½ mile from Harbor Regional Park. Earlier this year, Rachel stopped temporarily to allow a specialized crew to inspect the cutting discs at the front of the TBM. These metal discs allow Rachel to cut through rock and soil. Much like deep sea divers, the TBM crew entered a pressurized chamber behind the cutting head to examine the cutting discs. Once the inspection was completed, they entered a decompression chamber to let their bodies readjust to normal atmospheric pressure. Most cutting discs were found to be in good condition. Some discs were replaced. Once the maintenance work was completed, Rachel resumed tunneling.

2021 was the driest year in over 1,200 years. As the megadrought persists and reservoirs throughout the west dry up, water recycling is increasingly important for ensuring the sustainability of our region.

Most of the cleaned water from 10 of the Sanitation Districts’ 11 wastewater treatment plants is beneficially reused—mainly for groundwater replenishment. Since 1962, we have recycled over 1 trillion gallons of water, which has reduced the amount of water Southern California has needed to import. Our last untapped source of recycled water is the cleaned water produced by the JWPCP. That water is too salty to reuse without advanced treatment.

We have partnered with the Metropolitan Water District of Southern California on the Regional Recycled Water Program. This program is in its environmental planning phase and would purify and reuse water from the JWPCP. Our partnership has resulted in a 500,000 gallon per day demonstration facility that has been operating for two years. At full scale, the program may produce 150 million gallons per day of purified water—enough for 1.5 million people—and become one of the largest water recycling programs in the world.

For more information on the Regional Recycled Water Program, including requesting a tour or presentation, please visit https://www.mwdh2o.com/rrwp, email rrwp@mwdh2o.com, or call 213-217-7262.

We continue to offer educational presentations about environmental stewardship as well as virtual tours of our wastewater (sewage) treatment plants to schools in our service area. Our hope is to resume in-person tours and presentations soon.

We recently added a presentation on how Rachel builds the tunnel as it digs. Our goal is to inspire careers in science, technology, engineering, and math (STEM). To request a tour or presentation, please click on the request a presentation button below.

Answer to question: A snail goes farther than a TBM. A snail travels about 79 feet in a day, whereas a TBM goes about 40 to 50 feet per day.