Natural Treatment Site: Woodbridge

Natural Treatment Site: Woodbridge

Woodbridge NTS siteThe Woodbridge NTS site is currently the only operational in-line NTS facility.  The site is located in the San Diego Creek channel which is owned and operated by the Orange County Flood Control District. Due to heavy flows during the wet season, IRWD only operates the Woodbridge NTS site from May to September, during the dry weather flows. The NTS portion of the site is slowly taken offline during September.  IRWD’s maintenance responsibilities extend only to the channel bottom, while the slopes of the channel are maintained by the City of Irvine. 

The site has adequate removal rates for nutrients including nitrogen and phosphate; suspended solids, and total coliform removals were better. Selenium removal rates were above the standard range, however, due to the site’s location in the middle reach of the watershed, this is not unexpected. Went online in July 2008.

 Location & Size

Location: No Address; located between Jeffrey and Creek in Irvine
Size: 2.7 acres
Tributary Watershed: 17,000 acres

 Biological Values

Since the Woodbridge site is in a regularly maintained channel, where vegetation is removed constantly, there are low wildlife values. The following nesting bird species were observed on the site: Mallard, Gadwall, House Finch, Black Phoebe, Tree Swallow, Common Yellowthroat, Song Sparrow, American Crow, Red-shouldered Hawk. Additional wildlife observations are planned for next year’s report.


Routine Maintenance Activities:

  • TruGreen LandCare provides routine irrigation and landscape maintenance services at the site. Additional work such as mulch replacement, irrigation repairs, aquatic herbicide application, aquatic vegetation removal, and sediment removal were performed throughout the year.

  • System operations staff performed weekly site inspection, water quality monitoring, and landscape and irrigation maintenance review.

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