The San Bernardino City Unified School District started this school year with the grand opening of Cesar Chavez Middle School. To satisfy permit requirements and continue construction of the new school, the project had to comply with state water quality requirements and obtain Section 401 certification from the Santa Ana Regional Water Quality Control Board. Obtaining certification required installation of an acceptable stormwater best management practice (BMP) device.
Stormwater runoff from parking areas and streets at Cesar Chavez Middle School contained debris, oil, sediment and other pollutants. The District was required to mitigate the first flush of 0.80 cfs of runoff, and needed a stormwater treatment system that would both meet the removal requirements and conserve land for development.
The District, working with designers at David Evans and Associates, Inc., evaluated several options and decided to install the Stormwater Management StormFilter and StormScreeen. The StormFilter is a passive, siphon-actuated, media-filled filter system that traps and adsorbs particulates and pollutants. The StormScreen removes trash and debris larger than 2400 microns and some solids from stormwater runoff through direct screening. Runoff from the 10.4-acre school site is directed to the StormScreen by the StormGate high flow bypass integrated in the six by twelve foot vault. With five StormScreen cartridges the system can treat up to 2.5 cfs.
Runoff from 4.13 acres of paved roadway in front of the school is directed via a StormGate to an 8-ft. by 16-ft. StormFilter with 24 filter cartridges. The filter cartridges are filled with a mixture of perlite and zeolite filter media. Perlite filter media, a naturally occurring puffed volcanic ash, removes TSS and oil. Zeolite filter media, a naturally occurring mineral, removes soluble metals and some organics.
In the end, the StormFilter and StormScreen systems allowed the School District to meet permit requirements for pollutant removal while maximizing land use. Selecting the StormFilter, StormScreen, and StormGate made more land available for development and protected the water quality of the adjacent waterways that ultimately feed into the Santa Ana River.