Ten Years After - A Realistic Progress Check on the San Diego Creek Natural Treatment System (NTS)
TEN YEARS AFTER – A REALISTIC PROGRESS CHECK ON
THE SAN DIEGO CREEK NATURAL TREATMENT SYSTEM
In 2005, Irvine Ranch Water District (IRWD), in Orange County California, adopted a master plan for a system of 45 wetlands distributed throughout the San Diego Creek watershed. The Natural Treatment System (NTS) was the first regional wetland system of its kind; a network of constructed wetlands designed to reduce the impacts of urban runoff.
The idea of NTS first emerged about 2000 as regulators and the regulated both wrestled with implementing the US Environmental Protection Agency’s (USEPA’s) new Phase II Stormwater Rules. A relatively new regulatory term, “maximum extent practicable,” allowed for the use of flexible, innovative approaches to clean up urban stormwater and dry weather flows. IRWD’s San Diego Creek watershed NTS is just such an approach.
Why is a water agency involved in stormwater issues? That was a common question when IRWD volunteered to treat urban runoff. There were two reasons. First, public officials were suggesting that dry weather flows be diverted to the sewer system and treated by expensive sewer treatment plants owned by agencies like IRWD. With the prior success of its San Joaquin Marsh in treating San Diego Creek low flows, IRWD knew there was a less expensive way to clean up urban runoff.
Second, as a water agency, IRWD had extensive expertise in water treatment and analysis; experience that was limited at flood control agencies at the time. Recognizing stormwater was simply part of the community’s local water cycle, IRWD saw it had a role in the community’s response to the new regulations. It also recognized that a significant portion of dry weather urban runoff was water wasted by some of its customers.
The presentation will provide background and a progress report on the implementation of San Diego Creek NTS, comparing the stated goals of the master plan with actual conditions on the ground ten years after its adoption. Such a presentation fits perfectly with the CASQA conference theme: Stormwater – Are We Making a Difference? The presentation is a vital element of the overall progress report on implementation of USEPA’s Phase II Rules in Central Orange County. It demonstrates how regional systems like NTS are definitely making a difference.
A set of monitoring and reporting protocols, called WetTraq, was developed and published by IRWD to guide the ongoing tracking of NTS progress. This publicly-accessible plan will be available to the audience to apply to their own wetlands.
Maintenance of treatment wetlands has always been a hot topic for agencies considering their use. The presenters will discuss what has worked well and what has not, along with estimated maintenance costs and revenue sources. There will also be some tips for the audience on what physical assets to include in wetland construction to control maintenance costs and optimize effectiveness.
Beyond data, the presentation will include the soft issues of integration of NTS wetlands into the human and natural communities. There will be discussion of how audience members can engage the greater community in the long term success of NTS type facilities.
The report will be jointly presented by Norris Brandt, PE, who led development of the NTS Master Plan, and Ian Swift, who is responsible for stewarding the NTS Master Plan. There will be lively discussion, and potentially a little debate, between the master plan developer and the current real-life steward, that will keep the audience’s attention.
The speakers are skillful at audience engagement. Techniques will include questions, show-of-hands polls on similar efforts by the audience and a wetland species (plant and animal) identification quiz. Everyone can identify at least one species correctly but nobody can identify all correctly. Answers to the quiz will be provided at the end of the presentation.