How much water we can flow down the Black River system, which feeds Gaspereau River, is regulated by our environmental permits. Those rules are in place to protect fish and fish habitats.
Under our environmental permits, we have to run the system 24 hours a day from April 15 to June 15 to enable fish migration – because the river has populations of smelt, gaspereau, salmon, and bass. We want to keep them healthy. But running strong river flows 24/7 drains a lot of water from the system.
At the same time, our permits also require us to maintain a certain water level on Black River Lake between Victoria Day and Labour Day – so mid-May to early-September. That’s to maintain high enough water levels for cottages along the lake, as well as for the end of the bass nesting season.
Each summer, we reach a point where those two environmental requirements intersect – we’ve drained a lot of water maintaining flows for fish migration, and so we have to reduce the flows for a few weeks to keep the water levels up in Black River Lake for the cottages and bass.
It used to be that we could flow water year-round. But in 1998, our environmental permits were revised and modernized, because there just wasn’t enough water entering the system to maintain good fish habit, and also for cottagers on Black River Lake. That’s when the flow reductions that happen each summer began.
It would definitely be better for tubing if we could run strong water flows straight through the summer. Tubing is one of the many great recreational uses of our river systems. But we have to remember the fish too. They were here first. And it’s important for us to be good stewards of that ecosystem. By late August, we often have enough water in Black River Lake that our permits will allow us to start flowing more water and generating power again. So tubing is usually able to resume for what’s often the hottest part of the summer.
Sometimes people think that we slow the flows each summer to do maintenance, but it’s actually due to those environmental requirements. The misunderstanding is understandable, because when the flows are slowed and we’re not generating electricity, we do our annual inspection and maintenance work on the turbines and generators, and any other upgrades to dams and other infrastructure. It’s a matter of trying to make the best use of the time, so that we don’t have to have generation interruptions at other times of the year. But it’s the flow reduction that triggers the maintenance work, not vice versa. And the flow reduction is triggered by environmental permit requirements.
There’s lot of interesting history involved in this. Our dams and other infrastructure – most of which dates back to the 1920s to 1940s – along the Black River system actually create the water levels that allow tubing downstream on the Gaspereau. Without it, there would be a lot of flood water with the spring thaw and rains, and then it would run pretty shallow through the summer. Black River Lake used to be much smaller than it is today, before the initial dam and canal works began. It used to actually be two lakes: the upper part of the lake was a separate lake, and it emptied into the Avon River system, but they dammed that off and joined the two to create a bigger reservoir.
The Black River system is one of the most important river systems for hydro-electricity in Nova Scotia. It generates about 23 megawatts, which is similar capacity to a good sized wind farm, like the ones in Pubnico, Point Tupper, and Digby. So, it’s important to renewable electricity generation in Nova Scotia. In 2015, 25% of the electricity Nova Scotians use will come from renewable sources, mainly hydro and wind – about 9 or 10% is hydro each year, depending on rainfall amounts.