The Natural Treatment System

a cost effective and environmentally sound alternative for handling both dry weather  and stormwater runoff

The County, Cities and Irvine Ranch Water District are taking IRWD’s successful wetlands restoration program at the San Joaquin Marsh and extending it throughout the watershed. The County and Cities acknowledge that IRWD has the experience and is recognized as a leader in outstanding programs and water quality. The Association of California Water Agencies recognized IRWD’s work by awarding the District the prestigious “2000 Theodore Roosevelt Environmental Award,” for its San Joaquin Marsh project. It is IRWD’s experience and leadership that will guide the planning and implementation process for the Natural Treatment System.

Click on links below to view documents:


NTS Master Plan - June 2005

Revised Draft EIR - Jan. 2004

NTS Design Guidelines - November 2005

NTS WetTraq - April 2007