MARTINEZ — It looks like any other parking lot — asphalt, numbered spaces and a pay station.

But beneath the surface, the parking lot at Ward and Las Juntas streets is doing its part to clean up the environment. The lot was redesigned to funnel storm-water runoff into planters where plants and layers of sand, topsoil and mulch filter out pollutants before the water eventually flows into nearby Alhambra Creek. The innovative layout even managed to squeeze out a couple more parking spaces.

The two-year project involved advanced mathematical calculations and rigorous adherence to a set of complicated construction guidelines.

But city leaders didn’t hire high-priced engineers to design the parking lot. They turned instead to a group of high school students from the Environmental Studies Academy at Briones Independent Study School. Students in the program work in teams on community-based projects in addition to completing regular course work.

The parking lot is a demonstration project for construction regulations the San Francisco Bay Regional Water Quality Control Board hopes will help clean up storm water and reduce creek bank erosion, said City Engineer Tim Tucker, who worked closely with the students. The city paid about $40,000 to rebuild the parking lot.