Sediment Management


The flood control system that protects the residents of Los Angeles County is the largest municipally-owned flood control system in the world, providing the backbone of flood control for the entire Los Angeles basin1, and the San Fernando, San Gabriel and Santa Clarita Valleys. As such, the maintenance and operation of that system are no small feat. It takes hundreds of employees working fulltime to maintain and operate the system, contract with vendors to provide services, and comply with numerous.

The disastrous flood of 1914, which caused over $10 million in property damage, prompted the California Legislature to authorize the creation of the Los Angeles County Flood Control District in 1915. The District was formed to control and conserve flood, storms, and other wastewaters. In 1985, District personnel were merged with other County engineering departments to form the Los Angeles County Department of Public Works. The duties of the district are now administered by Public Works, maintains and operates 14 dams, 529 miles of open channels, 2,811 miles storm drains, 398 debris retaining facilities, and 35 sediment placement sites. Much of the flood control system is over 50 years old, so there is a great need to maintain and repair the aging system. New developments continue to connect to existing infrastructure, which expands the system and increases the need for more maintenance operations.

In order to strategically locate personnel throughout the County to address concerns related to the flood control system, three distinct areas were created. Termed the south, east, and west, these areas are served by a primary field office which houses the engineering staff and management for each area. Depending on the infrastructure needs, additional satellite offices are also strategically located through the areas. The map below depicts the three areas. In addition to the field offices, a Public Works' headquarters office is located at 900 South Fremont Avenue, Alhambra, CA.

diagram of injection wellFigure 1 - Map of the 3 flood maintenance areas; South Area (blue), East Area (red) and West Area (green).

Each yard is staffed with various laborers, maintenance workers, crew leaders, foremen, superintendents and support staff. The daily maintenance operations are coordinated through the Department of Public Works Maintenance Management System (MMS), which generates work orders for crews to complete based on the needs of each facility.

In the course of routine maintenance, crews become aware of deteriorating conditions, such as spalling concrete on a channel wall or erosion within the District's right of way, which is then reported to office staff who in turn generate the necessary work orders. This cycle continues everyday with tens of thousands of work orders being generated every year. In some instances, the repair is of such a magnitude that due to time constraints and lack of experience, the work will be contracted out.

As the Los Angeles Basin continues to develop, it is vital that the flood control infrastructure remains well maintained and operated to peak performance. The men and women of the LA County Department of Public Works strive to provide effective and caring service.

1 Quote taken from LA County Department of Public Works Director, Donald Wolfe, in a June 2006 Metro Investment Report Interview