A well-known Saskatchewan environmentalist is raising the alarm about the impact of Alberta's oil industry on the North Saskatchewan River.

Sandra Finley says the 1,300-kilometre-long river that runs through Alberta and Saskatchewan faces increased demand from oilsands expansion.

But it's not just the Fort McMurray area that's a problem, she says — Edmonton is, too. That's because there could soon be nine heavy oil upgraders near Edmonton, each using millions of litres of water from the river every day.

Finley worries that people in Saskatchewan may not be aware of the increasing demand on the river that winds through Edmonton, North Battleford and Prince Albert before connecting with the Saskatchewan River east of that city.

She's concerned the result would be less water available for people on the Saskatchewan side of the border, including less groundwater. 

"It is really a time now when people have to stand up and say 'no' or 'whoa' or 'this is not sound public policy,'" said Finley, a longtime community and environmental activist who is leader of the Green Party of Saskatchewan.

The Alberta government is studying the capacity of the North Saskatchewan River. And it suggests that new upgraders won't be built if the river can't meet demands.

"We're not looking at projects as one-offs any longer. We're looking at the cumulative impacts of development in our province," said Lisa Grotkowski, a spokeswoman with the Alberta Environment Department.