Low-water flows related to drought on the Koksilah River south of Duncan have prompted the province to take the rare step of restricting water use in order to protect fish populations.
David Robinson, an assistant water manager with the ministry, said the measures being taken with the Koksilah are the first under B.C.’s Water Sustainability Act, which was enacted in 2016.
Prior to that, the only other similar case in the province involved the Coldwater River in 2015.
“Never before,” Robinson said of the regulatory step. “Definitely the first time on Vancouver Island.”
The fish, including steelhead, coho and trout, are important to local First Nations groups.
“By restricting water use for the irrigation of forage crops, such as hay and corn, but allowing water use for stock watering and irrigation of perennial crops and vegetables, water flows should be restored to a level sufficient to maintain fish populations while minimizing effects on users, such as the agricultural sector,” the Ministry of Forests said in a statement.
Robinson said the Koksilah can be susceptible to flow issues for a number of reasons, including that it is a rain-dominated system without a lot of snow runoff and has many agricultural users.
“We have seen over decades fish declines.”
He said orders were being issued Monday, and would be going to 32 people on about 50 parcels of land to restrict the irrigation of crops.
Water levels in the Koksilah are so low that habitat conditions are severely degraded and fish numbers could be threatened, the ministry said.
“The flow of water in the Koksilah River has dropped below 180 litres per second [less than two per cent of mean annual discharge] and may be trending downward.”
Restrictions could be in place through Sept. 30, when water licences have expired.
Ministry staff will be doing compliance checks in the Koksilah River watershed for the duration of the fish population protection order, which could be revoked if water flows rise above 180 litres per second on a sustained basis following significant precipitation.
The process of developing a water-sustainability plan for the river is underway.
Other waterways under watch are the Chemainus River, Tsolum River, Black Creek and Fulford Creek on Salt Spring Island.
Environment Canada meteorologist Matt MacDonald said May and June were especially dry in the capital region, and only July approached monthly norms for precipitation. So far in August, much of the rainfall on the Island has come from a system that hit the central area Aug. 1 and 2, with very little since.
“If we look at Victoria, Gonzales has seen 9.2 millimetres this month, Victoria airport’s seen 4.2,” he said.
The monthly average for Gonzales is 19.7 mm and for the airport is 23.8 mm.
Coming up in the Duncan area, expect 2 to 3 millimetres on Wednesday and perhaps some weekend drizzle, MacDonald said.
“It’s been very dry,” he said of the south Island. “There’s not much rain on the way.”