NOTE: The following emails are reproduced in chronological order, with the original inquiries about the Dam appearing first, followed by Orange County Chief Engineer Herb Nakasone’s response.

-----Original Message----- From: Jim Obermayer Sent: Sunday, February 13, 2005 11:13 AM To: [email protected] Subject: Fw: Dam Failure Potential?

Mr. Campbell:

As you can see the citizens of East Orange and Villa Park are concerned about the Santiago and Villa Park Dams.

Is it true that the county does not have an emergency preparation plan? We understand that the dams upstream are full and more rain is expected. Does the county take a leadership role in helping the cities recognize the danger and threats of the waterways which run through the city of Orange? Does the county in any way oversee the preparation of the cities for catastrophic failure of these earthen dams?

James Obermayer Chairperson Mabury Ranch Environmental Committee Mabury Ranch - Bordering on 385 Homes in East Orange

------Original Message ------Sent: Saturday, February 12, 2005 1:24 AM Subject: Dam Failure Potential?

To all concerned:

The Earthen Santiago Dam is full to the bottom of the baffle plates with 25,000 acre feet behind it. Water has been going over the spillway for several weeks now. With the baffles in place the lake will hold another 3,000 acre feet. That's a column of water on an acre that presently goes up 25,000 feet high. What would happen if we had a sudden dam failure tonight? A lot of people could die needlessly downstream due to the absence of real time 24 hour monitoring of dam conditions, the lack of an effective notification/warning system and the lack of a specific evacuation plan.

Constructed in 1933, Santiago Dam is 136 feet above the creek bed. Baffle plates cover the square openings to the spillway to create a total capacity of 28,000 acre feet. This is usually done to save water after the rainy season ends, as was done in 1983 and 1998.

Freemont Dam, which is upstream of , is also full. Even if Fremont Dam failed first, the water would overtop Santiago Dam and quickly erode it's earthen base away. Next is Villa Park Earthen Dam that was built just for flood control, not to contain the inundation from the Santiago Dam failure. It would most likely go in a short time just like a domino. A 50 to 100 foot high wave could result downstream according to previous inundation studies. Newly discovered local earthquake faults are an additional possible cause of sudden dam failure, especially when they are full.

See: http://www.abag.ca.gov/bayarea/eqmaps/damfailure/dfguide.html

A near emergency condition already existed even before this weeks rains arrived. Water will soon have to be released at damaging rates if the rainy pattern continues. The forecast was changed tonight for rain two more times in the next week. I measured two more inches today for a season total of 23.25 inches. In the higher elevations of the Santiago Creek Drainage Basin the rain totals are typically 2 to 3 times higher.

See the list of Dam Failures here: http://cee.engr.ucdavis.edu/faculty/lund/dams/Dam_History_Page/Failures.htm

Every Dam Failure is unexpected and people were always assured before hand that they were in good condition.

Here is a PDF file from the California Division of Safety of Dams: STATUTES AND REGULATIONS PERTAINING TO SUPERVISION OF DAMS AND RESERVOIRS 2004

Check out this web site about Dam Failure Results: http://simscience.org/cracks/intermediate/death.html

I hope the County of Orange, the City of Orange, the City of Villa Park, the Serrano Water District and the Irvine Ranch Water District can get together as soon as possible to develop a truly effective monitoring, warning and evacuation plan in the "unlikely event" of catastrophic dam failure(s).

Bob McGowan

PS: To those who were blind copied, feel free to pass this along.

-----Original Message----- From: Herb Nakasone Sent: Monday, February 14, 2005 7:38 PM Subject: Villa Park Dam

I am Herb Nakasone, Director of Public Works/Chief Engineer for the County of Orange. Mark Denny of Supervisor Campbell’s office requested I respond to your concerns regarding dam safety and emergency operations at Villa Park Dam.

Please be assured County staff is operating and maintaining the Villa Park Dam to provide maximum flood protection to downstream residents and businesses and is prepared to respond to emergencies if necessary. A County staff person lives on the Villa Park Dam site and monitors and operates storm discharges from the dam to maximize storage behind the dam thereby providing maximum flood protection. A 24 hour seven day week operational plan with trained personnel who understand the operations of the dam is ready to be implemented in the event a storm is anticipated to fill the storage behind the dam and control discharges are necessary 24 hours a day.

Damage or failure to the dam is a highly unlikely scenario. Villa Park Dam performed exceptionally well during the major storm events of 1969 providing even more assurance of its structural stability. Nonetheless, the County’s Emergency Operations Center (EOC), managed by the Sheriff’s Department, is prepared to respond to such an emergency event. The EOC has an Operational Plan for such an emergency and is staffed with representatives from Public Works of the Resources Development Management Department, Sheriff’s Department, Orange County Fire Authority, Red Cross, Orange County Department of Education and other County Departments as necessary.

The Sheriff’s Communications Center is at the EOC and is able to communicate directly with all City police departments in Orange County to inform cities directly and quickly of emergency conditions. The EOC has flood inundation maps which identifies evacuation limits should the unlikely event of a dam break occur and evacuation is necessary. The Executive Committee of the Orange County Emergency Operations which includes representatives from cities and special districts meets regularly to discuss and coordinate emergency operational requirements. The Committee is currently Chaired by Supervisor Wilson with Supervisor Campbell as Vice Chairman.

For your information, Villa Park Dam, along with all dams owned by the Orange County Flood Control District, is inspected yearly by County staff and also by the State Division of Dam Safety on a regular basis. We are currently monitoring the storage behind Santiago Dam and are aware it is currently full and expect flows from Santiago Dam with the next large storm. I can assure you Villa Park Dam is a safe dam and is able and ready to safely accommodate a storm such as we recently experienced even though Santiago dam is full. Please call me at 834-2308 or our Operations and Maintenance staff at 834-6300 should you have any questions on Villa Park Dam.