Wednesday, April 30, 2014

Downton Reservoir to be kept at a reduced elevation level for 10-15 years

Downton Reservoir to be kept at a reduced elevation level for 10-15 years

I have received this letter this morning and will be following up in order to determine the various implications for our community.

Dear Ms. Demare, Mr. Verner and Ms. Tegart,

This message is to advise you of potential operational changes for the Downton Reservoir in the Bridge-Seton system, which could result in a lowering of the reservoir level for a 10-15 year period.  No decisions have yet been made to proceed, pending further discussions with St’at’imc (as per the St’at’imc Hydro Agreement), the Comptroller of Water Rights and provincial and federal agencies.

The purpose of the potential changes is to address a dam safety risk at the La Joie Dam related to seepage, which causes concerns in relation to seismic events.  BC Hydro Dam Safety has recommended a modified reservoir operation of Downton Reservoir, to reduce the reservoir elevation level from 749.81 m to  734 m, as an interim measure to mitigate the seismic risks identified at La Joie Dam until capital upgrades can be initiated and completed in approximately 10 to 15 years’ time.  This modified reservoir operation results in ~50% reduction in active storage volume in Downton.  The proposed changes will not impact the existing Water Use Plan order. 

Public safety is the number one priority for BC Hydro, and BC Hydro’s rigorous Dam Safety Program ensures that the dam will remain safe.  The Dam Safety Program involves regular inspection of the dams to ensure safety in the event of earthquake or flood.  The program compares the condition of BC Hydro dams against current national and international best practices and continuously upgrades the dams on this basis.

The La Joie Dam remains safe under normal operating loads. As noted above, there are concerns for the safety of the dam when subjected to large seismic loads when the reservoir is high. Keeping the reservoir low will enable the dam to withstand a large seismic event.  Regular maintenance and monitoring by Dam Safety will continue at La Joie.

If you have any questions please contact me.

Sincerely,

Judy Dobrowolski

 Judy Dobrowolski
Senior Stakeholder Engagement Advisor
Capital Projects Communications  
 
BC Hydro
333 Dunsmuir Street, 15th Floor
Vancouver, B.C.  V6B 5R3

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