Greenville-Banning Channel (Facility No. D03) is a flood control facility owned and maintained by the Orange County Flood Control District (OCFCD). Historically, the watershed drained westerly into the Santa Ana River. Stabilization efforts and sediment laden flows on the Santa Ana River caused the invert elevation to equalize above the adjacent land.
The Talbert Drainage District constructed the “Talbert Drainage Ditch” to help alleviate the drainage problems in the area, but the ditch was too small to effectively eliminate flooding issues. Greenville-Banning Channel was constructed in 1958-59 to replace the Talbert Drainage Ditch. The bottom width of the earthen-trapezoidal channel varied from 6-25 feet and extended from the ocean outlet to Edinger Avenue.
The City of Costa Mesa nominated an improvement project for D03 to the City Engineers Flood Control Advisory Committee (CEFCAC) from California Street to the I-405 freeway primarily to address concerns over erosion in the earthen channel. The project reach has been extended to 1050-feet downstream of California Street to downstream of the I-405, a distance of approximately 3,500 feet. Flood Control Design is currently evaluating alternatives to control the erosion problems and increase the channel capacity to reduce flooding risk associated with the channel.