Lake level looks decent enough to maintain summer river flows

At this point, it appears as though the Cowichan River’s summer flow won’t dip to below seven cubic meters/second.

  • Jul. 4, 2011 11:00 a.m.

At this point, it appears as though the Cowichan River’s summer flow won’t dip to below seven cubic meters/second.

This, Catalyst Paper Crofton Division environmental manager Brian Houle said, is thanks to there being more snow pack this year than last.

Catalyst operates the Cowichan Lake weir, which controls how much water flow goes into the Cowichan River, in order to maintain at least seven cubic meters/second flow throughout the dry summer.

Those looking at the Cowichan River in recent weeks may have noticed a few tell-tale signs, such as visible rocks, that river flows have been decreasing.

“As of this moment, we’re below full storage,” Houle explained, last week. “The river level has definitely been ramping down.”

To blame is the raising of the weir; a necessary step in ensuring the lake hits its full storage level by operators’ goal of Saturday, July 9. The Cowichan Lake is comparable to a bath tub, with the weir its plug. Should the lake reach full storage level by this time, Houle said that there should be enough water available to drain into the Cowichan River to ensure the seven cubic meters per second flow, until heavy rains start up again in the fall.

Currently, the lake is two inches below the full storage level.

“We suspect that with the snow pack we will be able to maintain more than seven cubic meters per second,” he said.

The seven cubic meters per second minimum Cowichan River flow is important, Houle said, as it ensures there’s enough water for fish populations.

As discussed during various water stewardship and water board meetings over the past year, the minimum flow also ensures that there’s enough water to properly dilute sewage, as well as ensure there’s enough water for stakeholders down-river.

Once the lake hits full storage, July 9, the weir will ramp down, allowing the minimum flow, or better, during the dry summer months.

Change in river flows is regulated very closely, Houle said, out of fear of stranding fry in drying up creek beds.

Overall, he suspects that things will go quite well this summer.

“Who knows what tomorrow will bring, but right now it’s looking great,” he said.

Last year was a different story, with river flows dropping all the way down to six cubic meters per second, at its lowest point.