Gold River Liming, Maria Brook
Southern Nova Scotia has been heavily impacted by acid rain deposition over the years; and with combination of the low buffering capacity of bedrocks and soils, acidification occurs in many rivers that support Atlantic salmon (Salmo salar). The Committee on the Status of Endangered Wildlife in Canada (COSEWC) lists the Atlantic salmon as Endangered under the Species at Risk Act and acidification is considered one of the main contributors to the Atlantic salmon declines in Southern Nova Scotia.
One solution apart from stopping the pollution source of acid rain, is liming. The application of lime or calcium carbonate (CaCO3) chemically neutralizes acidic waters. Coastal Action and Dalhousie University’s Department of Environmental Science team up in a project of catchment liming in the Gold River watershed, which has had a reduction of Atlantic salmon population. Catchment liming is a mitigation method used to neutralize acidification in rivers by placing lime directly on the soils. Catchment liming can have a long-term effect after a small number of applications, if done correctly.
Maria Brook is part of the Gold River watershed and has Catchment Area of 0.47 km2. This site is being used as somewhat of a test site for the effectiveness of catchment liming. May 2012 the first application of 30 tonnes of powdered limestone. The following year 60 tonnes of limestone was added in June 2013, and another 30 tonnes in June 2014. This site is being monitored by Dalhousie University’s Department of Environmental Science to observe positive changes in the pH of the area.
For more details of results of the catchment liming check out the reports prepared by Dalhousie (links coming soon).