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June 13, 2024 6:52PM
June 13, 2024 18:52PM

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Natural Treatment System

Natural Process. Clean Water.

The Natural Treatment System is a cost-effective, environmentally sound method for treating dry-weather runoff. It is modeled after the successful system of natural treatment ponds that remove nitrogen, phosphorus and bacteria from water entering the IRWD San Joaquin Marsh Wildlife Sanctuary from San Diego Creek. Watch our video about this Natural Treatment System, or view our Natural Treatment System Fact Sheet

The Natural Treatment System works much like the San Joaquin Marsh, only using smaller man-made wetlands placed strategically throughout the San Diego Creek Watershed. Low-flow natural and urban runoff, as well as smaller storm flows, are diverted into man-made wetlands. There, contaminates are removed and prevented from reaching the Upper Newport Bay.

Click here to watch IRWD Wetland Scientist Mo Wise explain the NTS process and its many benefits in a 2020 video podcast with Orange County Coastkeeper.

landscape open house

Treating urban runoff is one of IRWD's core responsibilities. Section 35539.12 of the California Water Code grants IRWD the authority to build, maintain and operate urban runoff treatment facilities in our service area. The Natural Treatment System also provides riparian habitat and water-quality benefits to wildlife throughout the watershed.


 Current Natural Treatment Sites


NTS Frequently Asked Questions

What is NTS?+
What is Urban Runoff? +
Why is the NTS necessary? +
NTS Guidelines +
Who are partners involved with NTS? +
Who maintains the NTS? +
Are NTS sites accessible to the public? +