Flood Control

CHANNELS

The County of Orange maintains 380 miles of concrete, rock-lined and earthen flood control facilities. Flood control facilities are designed to handle water flow from storm drains and other runoff and "channel" the water into the bay or ocean. Operations &, Maintenance conducts regular inspections and performs cleaning as needed. We encourage the public to notify us when a channel or ditch is blocked or filled with debris to help minimize the possibility of flooding and help improve water quality. There are also numerous miles of privately owned and maintained channels and ditches within the County.

CONFINED SPACE INSPECTION

The County of Orange Confined Space Team is responsible for physically entering and inspecting all the underground county flood facilities, from 36" storm drain pipes up to 14x14' concrete boxes. Confined space also inspects all the newly constructed storm drain systems in newly developed tracts throughout the unincorporated area within the County of Orange. We also have drain cleaning crews who clean and inventory all the catch basins in County right of way once a year.

DAMS & BASIN MAINTENANCE

Seven Oaks Dam is one of the largest earth and rock-filled dams in the world. It is as high as a fifty story building and ten football fields in length from side to side. Situated between the north and south branches of the San Andreas fault, the dam has been designed to withstand an earthquake of eight-plus on the Richter scale. Seven Oaks Dam is a zoned earth and rockfill dam with a maximum height of 550 feet above the existing streambed at the dam axis and 650 feet above the lowest foundation bedrock contact. The dam crest is 40 feet wide, 2,760 feet long, and has a minimum crest elevation of 2610 feet NGVD.

PUMP STATION MAINTENANCE

Flood control is provided by a system of levees, canals, and pump stations. All stormwater runoff is conveyed by gravity through a system of drainage lines and channels into the suction bays of various pump stations then pumped to a higher elevation into larger levees or the ocean. The pump station operators are responsible for the operation and maintenance of 8 pump stations, 4 dams, 5 urban run-off diversions, containing 46 pumps throughout the Orange County watershed area. The primary goal of the group is to provide staffing for operations and maintenance of all pumping equipment and associated machinery. All pumping equipment is driven by either natural gas combustion engines with propane back-up or electric motor drives. Some pump stations are now monitored using SCADA, which stands for Supervisory Control and Data Acquisition. SCADA systems interface with District computers to alert staff of operational problems. The technology saves time money by pinpointing malfunctions and minimizing staff time to shut off general alarms for non-critical situations.

STORM DRAINS

Flood control is provided by a system of levees, canals, and pump stations. All stormwater runoff is conveyed by gravity through a system of drainage lines and canals into the suction bays of various pump stations then pumped to a higher elevation into larger levees or the ocean. The pump station operators are responsible for the operation and maintenance of 7 pump stations, 3 ultraviolet/filtration systems, and 4 urban runoff diversions containing 46 pumps throughout the Orange County watershed area. The primary goal of the group is to provide staffing for operations and maintenance of all pumping equipment and associated machinery.

VEGETATION & PEST CONTROL

The County of Orange vegetation maintenance program includes pesticide applications to manage, reduce, and control the growth of vegetation. The County uses an Integrated Pest Management Program and Best Management Practices (BMP) that consider all alternatives and methods available before proceeding with pesticide applications. When vegetation control is deemed necessary, the County will determine whether the work should be accomplished by hand crews, heavy equipment, pesticide applications, or a combination of available resources.