Anderson Dam meeting

On Monday, Morgan Hill residents were invited by the Santa Clara Valley Water District to ask questions and voice concerns about environmental issues and impacts related to the proposed Anderson Dam Seismic Retrofit Project.
It’s been two years since the SCVWD presented results of an independent seismic study which determined that a 7.25 magnitude earthquake along the nearby Calaveras Fault could cause liquefaction of material at Anderson dam’s base and slumping of its crest, posing the risk of an uncontrolled release of reservoir water that could flood Morgan Hill within minutes.
The SCVWD has been working with various stakeholders on plans and studies for a roughly $180 to $185 million seismic retrofit of the dam, which was built in the 1950s. The goal is to improve and stabilize the dam so it can withstand large earthquakes and perform through periods of heavy rain storms, without posing a threat to public safety.
According to water district officials, there is no plan to increase the storage capacity of Anderson Reservoir, which has 89,073 acre-feet of capacity and is larger in area than all of the SCVWD’s other nine reservoirs combined. Proposed dam improvements are expected to extend its operation for 50 years.
Project Update
At this week’s meeting, residents received an update on the project, which is moving from initial planning stages into an estimated two-year reporting, review and design phase. The meeting also opened the public commenting period, which closes on September 25, 2013. Construction is slated to run from 2016 through 2018. The project’s total cost is estimated at $180 to $185 million.   
“This is a very expensive project,” noted Erica Pham of Holiday Lake Estates, a hillside community of 512 homes overlooking the southern shore of Lake Anderson in Morgan Hill. “With projects of this size there’s always an add-on. I hope we can do more to make the improved dam work longer than 50 years.”
The SCVWD developed six variations on a core plan designed to meet project objectives involving cost, environmental impact and community-stakeholder relations. One of those plans was reviewed and approved by the SCVWD board this summer.
The SCVWD has also prepared and circulated planning documents required by various local, state and federal agencies responsible for project permitting and approvals. These agencies have 30 days to review and provide feedback.
That feedback will also be used to define the scope and content of an Environmental Impact Report to satisfy California Environmental Quality Act requirements. The project’s permitting process will likely take a year, according to SCVWD Deputy Operating Officer Katherine Oven. 
Construction will require drawing down Anderson Reservoir in 2016, based on the current schedule. At that time, the reservoir will be closed to boating, fishing and other recreational activities.
Audience attendees had a chance to voice their concerns during the meeting, asking questions related to potential environmental impacts and noise abatement.
Nathan John of Holiday Lake Estates pointed out that “Anderson Dam is an integral part of the area ecosystem. Interrupting it for three years comes at a significant cost. [The reservoir] is a safety net for water. Several years of drought could be very dangerous. How long will the reservoir be shut down? It seems like the math doesn’t add up in terms of the schedule.”
Morgan Hill resident Bill McPherson asked if anything could be done for noise abatement during construction.
“The reservoir is a natural amphitheater and dealing with 120 decibels daily would impact people and wildlife,” he cautioned.
SCVWD officials have compiled these concerns, along with many others submitted by community members related to the seismic retrofit project and will address them following the close of the public comment period at 5 p.m. Wednesday, Sept. 25. The SCVWD will include a scoping summary report as an appendix to the draft EIR, expected to be ready by early summer of 2014.
The following seismic retrofit project elements were outlined by SCVWD Deputy Operating Officers Frank Maitski and Katherine Oven:
-Interim action has been taken to reduce water to two-thirds capacity, bringing the level to 45 feet below the dam crest, reducing pressure on the dam and ensuring the crest will remain above water even if the dam were to slump during an earthquake. Emergency preparedness plans have also been developed and shared with local governments and agencies.
?Construction of a coffer dam will handle any water flowing into the reservoir from limited summer runoff.
?Raising the dam crest by seven feet will prevent over-topping of the dam in the event of a probable maximum flood as required by the Federal Energy Regulatory Commission and the California Division of Safety of Dams.
-Adding new low-level and high-level outlets will support fast draw-down of the reservoir to meet Division of Safety of Dams requirements.
-Raising the spillway walls by approximately seven feet will support runoff in periods of heavy rain storms.
-A portion of Cochrane Road will be realigned.
-Is there a contingency plan to get water in case of emergency?
-When will we regain full use of Anderson Reservoir?
-What impact will the retrofit have on area flood maps, in downstream areas and along Coyote Creek?
-What impact will faster draw-down have on properties at the upper end of Holiday Lake Estates?
-Will the water district offer any performance bonuses or penalties to contractors for an incentive to finish construction on time?
-Will the project require moving homes or landmarks?
-How will the project impact local wells?
-How long will Cochrane Road be closed?
-Who is responsible if the foundations of residential homes along the lake are impacted during construction?
-What impact will the project have on deer, eagles, elk and fish in the area?
-If we encounter a few years of drought during this project, how will it impact people and wildlife in the area?
-Why not dredge the reservoir?
-What about noise abatement during construction?
-What about air quality issues caused by construction?
-Will you take soil samples prior to blasting to identify potential materials such as asbestos in the dam foundation?
-Can we ensure the dam will operate for more than another 50 years?

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