On Sunday, October 20, 1991, the City of Oakland, CA experienced a major fire which, during the span of four days, consumed over 1800 acres of public and private property, destroyed 2699 private residences, 507 apartments, claimed 25 lives, injured 150, and left 5,000 homeless. The fire burned residential neighborhoods, wooded hillsides, and grassland hillsides. Acres of vegetation were totally destroyed, leaving the slopes unprotected from the erosional effects of wind and precipitation. The slopes in the area are typically very steep, as much as 60 degrees from vertical.
The fire was declared under control Wednesday morning, October 23, 1991. City Public Works (CPW) crews were first allowed into the area on Wednesday to begin assessing damage and clearing debris. Initial work consisted of clearing streets and sidewalks, clearing debris from 2000 storm drain inlets, and clearing debris from drainage structures such as culverts, streambeds, etc. With the assistance of two contractors, the emergency clearing work was completed prior to the Friday night rainfall. As part of this work, storm drain inlets were protected with straw bales to prevent clogging with mud or debris.
On Thursday, October 24, 1991 the City of Oakland, (City) asked Woodward-Clyde Consultants (WCC) to assist them with the development and implementation of an emergency short-term action plan for control of erosion and drainage from the approximate 2000-acre burn area in northeast Oakland. In response to the City's request, WCC designated Mr. Scott Huntsman (Project Manager), Carol Forrest, Mike Harding, and Tom MacDonald, experts in geotechnical engineering, erosion and reclamation, erosion and sediment control, and hydrology/hydraulics, respectively, to review current activities and site conditions, and to formulate an emergency action plan for control of erosion and drainage. The emergency action plan was divided into three phases:
Phase One
– Protect undamaged homes
– Protect receiving water bodies
– Protect storm drain system
– Protect public safety (roads, utilities, etc)
Phase Two
– Reduce erosion from burn area into storm drain system
– Reduce windblown ash and dust
– Evaluate potential landslides
– Evaluate and reduce debris and mud flow potential
– Evaluate damaged retaining structures
– Evaluate and remediate storm drain system damage
– Provide public information
Phase Three
– Operate & monitor installed systems during & after storms
– Implement landslide warning system
– Continue public information program
The Action Plan was delivered to the City within 48 hours and implemented immediately with Woodward-Clyde's Mike Harding acting as Field Operations Supervisor. California Conservation Corps (CCC) crews were the primary workforce installing the ash and sediment containment practices and erosion control blankets. Hydraulic seeding contractors from California implemented the more extensive surface erosion control and re-vegetation treatments. The work was completed within 45 days with no injuries and no significant erosion problems or mudflows developing during the winter rainy season.
Woodward Clyde's guidance to the City of Oakland contributed to their being awarded the Environmental Excellence Award in 1992 by the International Erosion Control Association and the Engineering Excellence Merit Award in 1992 by the Civil Engineers and Land Surveyors of California (CELSOC).
