Del Mar Fairgrounds Treatment Wetlands

True Environmental was part of an interdisciplinary team led by Fuscoe Engineering to tackle a unique challenge of treating surface water runoff from areas of the Del Mar Fairgrounds where animals are housed. Stormwater leaving the Fairgrounds and entering the nearby San Dieguito Lagoon did not meet regulatory thresholds for bacteria, nutrients, metals, and other constituents. The Fairgrounds, as part of their commitment to environmental stewardship, worked cooperatively with regional stakeholders to develop and permit an innovative stormwater treatment system that ensured compliance with water quality standards.

As part of this project, our team and Fuscoe designed an innovative treatment wetland that replaced existing water features within the Fairground’s racetrack. Stormwater from the site is collected into a settling pond and then passively conveyed to a treatment wetland where aquatic vegetation removes metals, nitrogen, and phosphorus from water and sediments. The final stage is a wastewater treatment facility that “polishes” bacteria from the water and gauges water quality. Stormwater can then be re-circulated through the system to maximize nutrient removal or released into nearby waterways to reduce the overall system volume once regulatory thresholds are met. The treatment wetlands are estimated to remove up to 75% of nutrients from stormwater and they function at significant cost savings to the Fairgrounds compared to non-ecologically based systems.

Aesthetic design of the treatment wetlands was a key factor to the project’s success given the Del Mar Fairgrounds’ visibility to millions of visitors who come to enjoy equestrian shows and other events. Our team continues to provide post-implementation monitoring and maintenance of the system to ensure optimal performance. This includes occasional harvesting of aquatic vegetation within the system to both maintain aesthetic appeal and “reset” the treatment wetland for continued nutrient extraction.