Recent rains may have helped lawns and gardens, but they didn’t do much for river flows and reservoir levels in the Grand River watershed.
Flows are still below normal for this time of year, meaning it remains important to practice water conservation.
The entire Grand River watershed remains in a Level 2 Low Water Condition. At that level, water users are asked to voluntarily cut their consumption by 20 per cent.
Lawn watering is always a big water use during the summer, but there’s little need to water lawns at this time of year. Cooler temperatures and dewy mornings help lawns bounce back naturally.
This has been the driest year in more than 50 years and most of the watershed has recorded only about 60 per cent of normal precipitation in the last six months. That works out to a rainfall deficit of about 150 mm to 200 mm (six to eight inches).
As a result, water levels in GRCA reservoirs remain far below normal for this time of year. The GRCA has reduced the amount of water it releases from the reservoirs on a daily basis to ensure it has enough to get through the rest of the year should the dry weather continue.
The water released from the seven reservoirs – particularly Conestogo, Belwood and Guelph – is critical to the operation of municipal sewage treatment plants. The river needs enough water to be able to assimilate the treated effluent from sewage treatment plants. It’s also important to maintain flows to support the communities that take some or all of their drinking water from the river: Region of Waterloo, Brantford and Six Nations.
And the water helps to maintain habitat for fish and other aquatic life.
Normally, the GRCA would release enough water from the reservoirs to ensure that there is a minimum of 9 cubic metres per second (m3/s) flowing down the Grand at Kitchener. However, there’s only enough water in the reservoirs to maintain a flow of 6 m3/s – a reduction of about one-third.
If the dry spell continues through the fall, the GRCA may reduce releases from the reservoirs even more.
On the Speed River in Guelph, the normal summer target is 1.7 m3/s but it has already been reduced to 1.1 m3/s where it is expected to stay the rest of the year. Normally, that reduction doesn’t happen until October.
The more water in a river, the easier it can assimilate the treated effluent from sewage treatment plants. Lower flows can result in higher concentrations of nutrients in the rivers – chemicals such as phosphorous, nitrate and ammonia – from sewage treatment plant effluent and overland runoff.
Fishing ban lifted
Higher concentrations of ammonia, in particular, can pose problems for aquatic life and can complicate the treatment process at drinking water plants.
The GRCA has asked the managers of sewage treatment plants to ensure they are operating their systems to ensure that the effluent coming out of the plants is as clean as it can be.
Meanwhile, the Ministry of Natural Resource has lifted a voluntary fishing ban on Whiteman’s Creek west of Brantford. While flows remain low, ministry staff judged that lower water temperatures and higher oxygen levels in the creek have reduced the stress level on fish.
