Coastal pollution prevention

September 2013 » Features » PROJECT CASE STUDY

The University of California, San Diego implements structural and non-structural BMPs to treat stormwater and dry-weather runoff.

Half-moon shaped media filters are located along the beach bluff adjacent to Scripps Institution of Oceanography.

The University of California, San Diego's (UCSD) section of La Jolla Beach, adjacent to Scripps Institution of Oceanography, is enjoying some tender loving care and advanced environmental systems that put it in great shape as the community and wildlife plunged into summer. Designated by California's State Water Resource Control Board as an "area of special biological significance," this particular coastline demands gentle hands and a higher level of consideration. Any discharge is completely prohibited, and the areas are actively monitored for any signs of negligence or hazards.

Project
Coastal stormwater treatment, La Jolla, Calif.

Participants
Nasland Civil Engineering
KTU+A Planning and Landscape Architects
MACTEC Engineering
Sheene Consulting
Western Rim Constructors, Inc.

Product application
A Modular Wetland System biofilter works with other BMPs to treat and control runoff along a protected beach.

UCSD has met these challenges head on with proactive, innovative, and organized systems of proven pollution prevention. Beach and ocean contaminants that would otherwise originate from its property as stormwater and dry-weather runoff are being addressed and reduced by their Environmental Affairs Department. Each runoff category is known to contain high concentrations of oils and grease, trash, sediment, and bacteria, but these contaminants can be managed with a variety of media filters that are changing the way society combats river, lake, and ocean pollution.

The largest media filters – half-moon shaped and located right along the beach bluff – are working and hiding in plain sight. Each poses as the final line of defense against any remaining pollutants before entering the ocean. These large media filters may be the most well understood and recognizable tool UCSD is employing, but there is a cast of systems in the university's inventory successfully combining to give UCSD award winning and exemplary status. In a UCSD press release, Chiara Clemente, senior environmental scientist with the San Diego Regional Water Quality Control Board, said, "I'm most impressed with the comprehensive approach on all fronts to eliminate dry-weather water runoff and the pollution from stormwater runoff."

As of 2011, the UCSD Stormwater Management Plan has addressed the reduction of discharged pollutants through effectively controlled and treated stormwater and dry-weather runoff. There are a number of categories and settings for different Best Management Practices (BMPs) – construction and post-construction sites and structural and non-structural – but regardless of the location and design, all efforts exist to eliminate flow and contamination issues that overwhelm most water bodies and coastlines.

In the structural stormwater treatment category, which can significantly reduce pollutants such as oils and grease, trash, pesticides, nutrients, bacteria, metals, and total suspended solids, UCSD has employed more than a dozen systems. These systems include BMPs that target the listed pollutants as well as many others. A Modular Wetland System (MWS) is contributing measurable levels of treatment and control of stormwater runoff at the newly completed Rady School of Management. The MWS is a biofilter that incorporates screening, hydrodynamic separation, sorptive media filtration, and bioretention into a single system. It is the only biofilter to utilize horizontal flow.

"Picture a one-dimensional biofilter system treating water as it flows downward," explained Zack Kent, stormwater engineer with Modular Wetland Systems. "Its treatment rate is limited by the flow direction as speed and filter surface are fixed. Now picture a biofilter cube with four times the surface area. Within a treatment chamber it can occupy the same amount of working space but treat four times the amount of water and at a more controlled and efficient flow rate."

This principle helped the MWS achieve Washington State Department of Ecology approval, a distinction widely regarded by other states and often adopted as their own benchmark for acceptable stormwater treatment technologies.

"In 2009, the university completed its $4.9 million water pollution control project and the San Diego and Imperial Counties Chapter of the American Public Works Association and the San Diego-area chapter of the American Society of Civil Engineers recognized the university's project with the 2011 Project of the Year and Outstanding Award." said Gary C. Matthews, vice chancellor of Resource Management and Planning in a UCSD press release. "The award-winning design developed for the Scripps area can also be applied to future campus projects to both reduce dry-weather runoff and more effectively and efficiently treat any stormwater that leaves the campus."

This article was contributed by Modular Wetland Systems, Inc. (www.modularwetlands.com).

Additional information about this project is available at http://ucsdnews.ucsd.edu/newsrel/general/06-08-11beachProtect.asp and www.nasland.com/sio-stormwater-water-pollution-control-plan

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