The Agua Hedionda Lagoon ("agua hedionda" means "pestilent water" in Spanish) is a lagoon in Carlsbad, California, that is fed by the Agua Hedionda Creek. Stewardship of much of the lagoon is held by the Encina Power Station and its owner NRG Energy. In November 2000 the Agua Hedionda Lagoon was designated as a critical habitat for the tidewater goby.
The Agua Hedionda Lagoon Discovery Center is a facility for education about the natural history, ecology and cultural history of the lagoon and surrounding area. The Lagoon Discovery Center has an award-winning Environmental Stewardship School Program aimed at local 3rd graders which incorporates hands-on learning on Lagoon history, archaeology, Native American culture, migratory birds, and watersheds and wetlands. The Discovery Center also holds numerous free family festivals throughout the year, as well as free monthly lectures and birding hikes. The center opened in 2006 and features a large native plant garden and expansive lagoon views.