Subject: Emergency Dredging of San Diego Creek
Dear Chair Wilson and Board of Supervisors:
I am writing to ask that oppose the "emergency" dredging of San Diego Creek at your Board meeting next Tuesday, December 16.
This action should not be an emergency and should go through proper channels including an environmental assessment, review and approval by agencies such as the State Department of Fish and Game, US Fish and Wildlife Service, Army Corps of Engineers, Regional Water Quality Control Board, Coastal Commission, etc, and mitigation requirements.
None of this will happen with an emergency declaration, with work to begin within two days of your decision.
The San Diego Creek contains riparian habitat including willow trees and mulefat, which is habitat for the endangered species Least Bell's Vireo, and could contain other threatened or endangered species of amphibians, turtles, birds and other animals and plants. The emergency dredging plan calls for removing most, if not all, of 20 acres of vegetation in a 2.5 mile stretch of the creek. The silt released from the dredging will increase the siltation of the Upper Newport Bay, along with toxics within the silt.
The riparian habitat has been present for many years with no adverse impacts from flooding. The coming winter rain is projected to be 80% to 100% of normal. There seems to be no more reason to call this an emergency than last year, or the year before, etc. The only difference has been an engineering calculation made last summer that has created this emergency situation.
I request that you require more study and confirmation from the various agencies before you make this important decision that may set a precedent to do emergency work with little to no environmental review, public notice and agency review, or mitigation.
In the meantime, I would suggest you recommend IRWD to increase sewage diversion capability at the Michelson Reclamation Plant in case of flooding, so that raw sewage cannot be released into Upper Newport Bay in any type of flood. This should have happened long ago and should be in place at the current time. There is no excuse for IRWD not having sewage diversion capabilities to prevent sewage from flowing into the bay under any storm and flooding scenario.
Here is the Project Summary from OC Flood Control, presented December 10:
Title: Restoring Flood Capacity to San Diego Creek
The Orange County Board of Supervisors on Tuesday, Dec. 16, will consider declaring an administrative emergency to immediately begin restoring flood capacity along a 2.5-mile segment of San Diego Creek that has become overgrown with vegetation and, as a result, poses a potential flooding threat during a significant rainstorm event.
The 2.5-mile segment runs from Michelson Drive to MacArthur Blvd. (along Harvard and University) in Irvine. Irvine Ranch Water District's Michelson Water Reclamation Plant is located along the west bank and could be covered by as much as 10 feet of floodwater during a significant rainstorm if full Creek capacity is not restored. Severe flooding at the plant would shut down wastewater-treatment operations and cause raw sewage to flow into San Diego Creek and into Upper Newport Bay.
Other areas could also sustain flooding, including portions of UC Irvine, the Irvine Worship Center, the Mariposa Villas disabled persons housing facility and Rancho San Joaquin Golf Course.
The Creek is now at 54% of original flood capacity design. To add immediate capacity, the County will remove vegetation that is restricting flow in the 2.5-mile segment of the Creek. It is anticipated that vegetation removal in critical areas, which is the highest priority, will take three months. Flood capacity will improve incrementally with each day of work. A 40-foot buffer of cattails, grasses, trees and other vegetation will remain along the east bank; trees and vegetation will also be selectively thinned. Sediment removal will take an additional one to two months. The cost of remediation is approximately $2 million, which will be paid by the Orange County Flood Control District. County crews will begin work immediately following the Board of Supervisors' action.
The County identified the problem in late August during engineering studies for an environmental enhancement project in the Creek. Since then the County has examined several alternatives to restore flood capacity, including those that would not impact vegetation. Building a floodwall along the banks and constructing a vertical concrete wall in the Creek along the west side were considered. These alternatives would, however, change the characteristics of the channel and, in some cases, increase flooding to residential and commercial properties upstream of the 1-405 and on the east side of the Creek.
San Diego Creek was channelized as a flood control facility in 1969 with the sole purpose of carrying large amounts of water away from homes, businesses and streets to prevent flooding. It is a main tributary within the 112.2-square-mile San Diego Creek Watershed and runs from the foothills north of Irvine through Irvine and Newport Beach to Upper Newport Bay. Previous attempts to control fast-growing vegetation in the Creek have been restricted due to regulatory controls.
Today, the Creek is a multi-use facility, providing flood-control protection as well as sediment capture and habitat for birds and animals. The County, Irvine Ranch Water District and others have worked collaboratively over the years to maintain the critical balance of protecting public health and safety with the need to safeguard Upper Newport Bay and the enhancement of over 500 acres of habitat along the Creek and in the adjacent San Joaquin Marsh.
End of Project Summary
Thank you. Reply back or call for questions. I can send you Bitmap attachments of the cross sections of creek and vegetation. This project should clearly not be an emergency. The only reason for calling it an emergency is to bypass normal environmental review, public notice and input, and mitigation requirements.
Jan Vandersloot (949) 548-6326
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