OCBC December 2010 Storms Ignacio Ochoa, P.E. Director, OC Engineering Chief Engineer OC Public Works February 8, 2011

Overview Storms December 21-23, 2010

 Madden Julian Oscillation Events are more likely in La Niña Winters  La Niña Winters with strong Madden Julian Oscillations are characterized by long dry periods, broken by 5 to 10 day events with periods of heavy rainfall.  Can sometimes make up for the lack of rain the rest of the winter.  Could produce near normal seasonal rainfall totals.  Heavy rainfall rates bring more of a threat of flash floods and debris flows. NWS San Diego MADDEN JULIAN OSCILLATION

Greater than 100-year rainfall: Modjeska Canyon Aliso Viejo Laguna Beach Greater than 50-year rainfall: Irvine San Juan Capistrano Greater than 25-year rainfall: Irvine Lake Bee Canyon Agua Chinon El Toro RAINFALL DECEMBER 2010

Rainfall Reports Orange County Public Works January 31, 2011 LOCATION

Activation Department Operations Center and Emergency Operations Center

Orange County proclaimed a local Emergency Governor Schwarzenegger proclaimed state of emergency OC Operations and Maintenance activated Department Operations Center Orange County activated Emergency Operations Center December 21, 2010: RAINY SEASON October 15 - April 15th

OC Emergency Operations Center FOR IMMEDIATE RELEASE: December 21, 2010 Contact: Howard Sutter, office, Proclamation of Local Emergency Issued Due to Severe Winter Storms (Santa Ana, CA) — Orange County Board of Supervisors Chair Janet Nguyen has issued a Proclamation of Local Emergency for the County of Orange due to the severe winter storms currently affecting the county. The proclamation cites existing conditions related to the storms that began on December 18 as well as forecast weather cond- itions that may result in flooding, debris flows, utility outages and damage from tidal surge. “Proclaiming an emergency allows the County to request additional resources as needed to respond to changing conditions,” said Donna Boston, the County’s Emergency Manager. “The County is actively managing response to any emergency incidents reported and is coordinating its response with all cities in the county. Having the proclamation of local emergency in Place widens the County’s response capabilities during these storms.”

Department Operations Center

Emergency Operations Center

 DOC is supported by OC Inspection, OC Watershed, and OC Agriculture.  In the field, OC Parks provided hand crews and equipment in response to emergency protective measures.  O&M responded to calls for service, including Modjeska, Silverado, Santiago, and Trabuco Canyons.  Thursday, December 23, 2010 at 6 AM – OC Operations and Maintenance (O&M) continued DOC operations 24/7. COORDINATION Silverado Canyon December 22, 2010

Mud, Debris andFlooding

 Modjeska Grade Road  Modjeska Canyon Road  Live Oak Canyon Road  Rose Canyon Road  Blackstar Canyon Road  Silverado Canyon  Live Oak Canyon ROADCLOSURES

Mandatory Evacuations: Williams Canyon Silverado Canyon roads:  This a Way  That a Way  Grundy Lane  Sullman Lane  Bond  Kitterman  White Canyon  Monty Lane  Hide A Way  Anderson Way  By the Way Voluntary Evacuations:  Bell Road, Dove Canyon EVACUATIONS Silverado Canyon December 22, 2010 Silverado Canyon December 22, 2010

Silverado Canyon December 22, 2010

Silverado Canyon December 22, Freeway Anaheim Hills December 22, 2010 Williams Canyon December 2010 Dove Canyon December 22, 2010

Ladera Ranch Epona Way & Illuminita

Rancho Santa Margarita December 2010 SANDBAGGING Modjeska Canyon December 2010

Aliso Viejo December 25, 2010 San Diego Creek December 22, 2010 Laguna Canyon December 22, 2010

Laguna Beach December 22, 2010

Laguna Beach December 23, 2010

Laguna Beach December 22, 2010 Laguna Beach December 24, 2010 Laguna Beach December 24, 2010

San Juan Capistrano December 22, 2010

Trabuco Creek December 2010

 U.S. Army Corps released up to 5000 cfs from Prado Dam  OCFCD released up to 3,000cfs from Villa Park Dam  Irvine Lake (Santiago Reservoir) : Spillway Mode  Dams were manned 24 hours DECEMBER 23, 2010 Prado Dam Villa Park Dam

Damage And Repairs

 Levee washout 100 feet of channel on both sides downstream of Del Obispo Street  Total of 1,300 tons of large diameter rock have been placed at L02 washout  Evacuations were voluntary TRABUCO CREEK San Juan Capistrano

Trabuco Creek December 24, 2010

Trabuco Creek December 24, 2010

Trabuco Creek Channel San Juan Capistrano

ROADS CANYONS Irvine Lake Modjeska Canyon

December 23, 2010

Modjeska Canyon December 2010

Continuing Activities

Silverado Canyon December 2010 Silverado Canyon December 2010  Continuing inspection  Repairs  Provision of erosion control materials  Engineering Assessments for canyon residents  Seeking reimbursements for recovery costs (ex: FEMA) Modjeska Grade Road December 2010

South Orange County December 2010

Orange Park Acres Silverado Canyon Silt Removal Silverado Canyon Road Repair Box Culvert Washout Silverado Canyon Drain Cleaning

Modjeska Grade Road Via Cascadita

As of January 7, 2011, countywide estimated damages from the December 2010 Storms are as follows: Private $19,797,000 Public $18,098,550 Federal Highway & Army Corp Projects $3,058,000 ESTIMATED TOTAL COST of DAMAGE ESTIMATED TOTAL COST $40,953,550

February 16, 2004

Blue areas indicate ARkStorm flooding as projected by models used in the scenario. ARkStorm

ARkStorm hypothetical flooding in Los Angeles and Orange Counties

ARkStorm Property Loss by County COUNTY WIND FLOOD WIND FLOOD COUNTY  $50 billion flood damage in Orange County  $300 billion in State of California In $1,000s

Laguna Beach Pacific Coast Highway December 22, 2010 Questions ?