Water Storage Levels

Surface Water Storage

Water is withdrawn from surface and ground water sources throughout the Region.  The levels of our significant surface water reservoirs are tracked in relation to targets established by the physical limitations of the weirs and the dams and the Province’s guidance for storage levels, referred to as rule curves.

Data will be updated every 4 to 8 weeks from October to March and every 1 to 2 weeks from April to September.

Cowichan Lake

Graph

cowichan_weir2

Current Storage: 100%

Target Storage: 13%
Last updated: October 23, 2017
Cowichan Lake Details

The available water storage calculation is based on 100% storage corresponding to the crest of the weir and 0% corresponding to the lake level that can sustain the minimum flow of 7 m3/s. The lake can store water above the crest of the weir, however water stored above the weir is not released into the river at a controlled rate and so it is not considered “available storage”. Prior to July 1st, the target water storage is the crest of the weir. After July 1st, the target for water storage is a regulated rule curve. For Cowichan Lake, the rule curve is the regulated limit set by the Province for the maximum amount of water that can be stored during the Summer and early Fall.  The Cowichan Lake level graph shows the change in lake level throughout the year.

Holland Lake

Graph

Holland Lake

Current Storage: 51%

Target Storage: N/A
Last updated: November 2, 2017
Holland Lake Details

The available water storage calculation is based on 100% storage corresponding to the level of the spillway and 0% storage corresponding to the level of the water intake (the point of withdrawal).  The Holland and Stocking Lakes can actually store up to 0.6 meters above the spillways.  However, water stored above the spillways is not released into the rivers at controlled rates and so it is not considered “available storage”.  The Holland Lake Storage Graph shows the change in available storage over time.

Stocking Lake

Graph

Stocking Lake

Current Storage: 70%

Target Storage: N/A
Last updated: November 2, 2017
Stocking Lake Details

The available water storage calculation is based on 100% storage corresponding to the level of the spillway and 0% storage corresponding to the level of the water intake (the point of withdrawal).  Stocking Lake can actually store up to 0.6 meters above the spillways.  However, water stored above the spillways is not released into the rivers at controlled rates and so it is not considered “available storage”.  The Stocking Lake water storage graph tracks the available water storage through the year.

Shawnigan Lake

Graph

Shawnigan

Current Storage: 56%

Target Storage: 54%
Last updated: September 29, 2017
Shawnigan Lake Details

The available water storage calculation is based on 100% storage corresponding to the crest of the weir and 0% corresponding to the level of the gate when it is fully lowered.  The lake is physically capable of storing water beyond 100% available water storage, however water stored above the crest of the weir is not released into the river at a controlled rate and so this volume is not considered “available storage”. For Shawnigan Lake, the target for water storage is to keep the lake level above the rule curve, a regulated minimum set by the Province for the amount of water that can be stored from March 15th to October 31st.   The Shawnigan Lake level graph shows the change in lake level throughout 2015.

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The New Normal is an initiative of the Cowichan Valley Regional District.

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More info

Kate Miller, Manager
Environmental Services
Engineering Services
Cowichan Valley Regional District
250.746.2509 / 1.800.665.3955
Email

Living the New Normal

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