Fort Smith - Cassidy Villeneuve

How is Aquatic Ecosystem Health Measured?

Indicators of water health

The best available information (from traditional, local and western scientific knowledge) needs to be provided to residents of the Northwest Territories (NWT), to allow for informed decisions to be made about how water and aquatic ecosystems are used and managed. For this reason, water health monitoring that includes indicators of water quality and water quantity, as well as biological indicators, is important because it increases the overall understanding of the aquatic ecosystem and this helps to guide water stewardship decisions.

Monitoring activities include the collection, analysis, interpretation, and distribution of information. The information gathered by monitoring programs is often referred to as baseline data. It is used to examine the past and present state of water and aquatic ecosystems. Each additional year of new baseline data collected increases the ability to understand the present and to forecast future environmental conditions.

Baseline data also allow for the assessment of cumulative impacts, setting of limits, and development of mitigation measures for various water users. Cumulative impacts are changes to the biophysical, social, economic, and cultural environments caused by past, present and reasonably foreseeable actions. Knowing the current state of water and projected water uses helps with the detection and evaluation of trends. It also allows for predictions to be made on the impact of future development activities on water and aquatic ecosystems. This predictive ability enables a more effective (and timely) response to potential and actual environmental changes in the NWT and is essential to maintaining the integrity of northern ecosystems.

Climate change affects water quality and water quantity in a variety of ways, such as changes in precipitation patterns, timing and duration of ice on/off periods, and slumping associated with permafrost melting and ground subsidence. All of these changes can affect aquatic ecosystems. Monitoring aquatic ecosystem health indicators allows for the effects of these changes to be determined.

Aquatic ecosystem health indicators are used to assess the state of the water and aquatic ecosystem and to determine if ecosystem processes are being compromised by natural or human-caused environmental disturbances. Aquatic ecosystem health indicators include water and sediment quality parameters, water quantity parameters, flow measurements that look at physical and chemical conditions of the water and sediments, and biological indicators that measure the population, health, or habitat of aquatic species of plants and animals. 

Some examples of Aquatic Ecosystem Health Indicators for the Slave River and Delta are illustrated below:

Aquatic Ecosystem health indicators
Aquatic Ecosystem health indicators

Why measure water quantity?

  • To maintain the health of aquatic ecosystems. Aquatic ecosystems – including people, plants, and animals – require a certain amount of water to be able to survive and thrive. Proper amounts of water also help to sustain the important cycles and processes in an aquatic ecosystem. It is important to protect, conserve, and maintain appropriate levels of water for the health of the entire aquatic ecosystem.

  • For improved understanding. Environment and Climate Change, Government of the Northwest Territories (ECC-GNWT) and Environment and Climate Change Canada (ECCC) measure water quantity across the North. This work includes a data collection program in the NWT, which is important both regionally and nationally in evaluating the state of water and aquatic ecosystems.

  • For informed transboundary negotiations. The W.A.C. Bennett Dam in British Columbia affects water flow on the Peace River in Alberta, which eventually affects the flow of the Slave River downstream in the NWT. Other major rivers flowing across the NWT border are also measured to determine the effects of upstream developments. Transboundary rivers with gauging stations include the Peel, Liard, Petitot, Hay, Tazin, Coppermine, Dubawnt, Thelon, and Back rivers.

  • For river traffic. Transportation companies plan their barge trips when water levels are high enough to get over the shoals and sand bars.

  • For safe ferry operations. Warning of high and low water levels and flows at ferry crossings can be provided.

  • For river crossings. Design of safe bridges and culverts on roads depends on expected flows at river crossings. Pipeline stream crossings also require this type of data.

  • For traditional economic activities. Rivers, lakes, streams, deltas, and wetlands are an important part of traditional Indigenous culture. Land users, such as hunters and trappers, need to know water levels and flows to make sure they are safe when using the land.

  • For design of water holding structures. Sewage lagoons at communities and tailings ponds at mine sites must be designed to hold natural runoff. These amounts are estimated from water flow measurements.

  • For flood monitoring. Water level and flow information is used during spring break-up of the rivers in the communities of Hay River, Fort Liard, Fort Simpson, Tulita, Norman Wells, and Aklavik to give early warning of flooding.

  • For recreation. Canoeists, kayakers and other recreational river users want to know water levels and flows for safety reasons.

  • For assessing developmental impacts. The collection of baseline data allows for the assessment of the impacts of changes in water use on aquatic ecosystems. 

Why measure water quality?

  • To know that water is safe to drink. Source water quality can be affected by a variety of activities, including industrial developments, highways, municipalities and recreational users. Therefore, it is necessary to measure water quality to ensure the protection of source water and to maintain safe drinking water standards for human consumption. The management of drinking water is a shared responsibility of all levels of government. 

  • To protect the health of the fish found in lakes and rivers. Altered water quality can affect aquatic life, including fish habitats. It is important to measure water quality so that steps can be taken to keep all waters clean, which in turn helps to ensure that fish, a major food source for people and animals, can thrive.

  • To contribute to existing knowledge about water quality in order to track changes over time. It is important to have consistent, long-term data about water quality that will allow for the evaluation of water quality changes over time, as a result, for example, of development or climate change.

  • To address community concerns about contaminants in water and suspended sediment. Communicating information about water quality is an important component of measuring and monitoring. A priority of measuring water quality is to inform community members about the state of water and aquatic ecosystems. To access reports on water quality for transboundary rivers, consult the Environment and Climate Change, Government of the Northwest Territories (ECC-GNWT) website.

Why measure biological indicators?

Aquatic ecosystem monitoring generally involves measuring and monitoring several types of water health indicators. These include: physical indicators (e.g., water levels, flood frequency), chemical indicators (e.g., water quality), and biological indicators (e.g., fish health, benthic invertebrates (aquatic bugs) and vegetation). These different indicators provide information about the overall health of the aquatic ecosystem and can contribute to cumulative effects assessment.

Other reasons for measuring biological indicators include:

  • Biological indicators can be affected by the environment they live in and can provide information about changing water quality and quantity over longer periods of time.
  • Species at the bottom of the food web, like benthic invertebrates (aquatic bugs) and algae, can provide early warnings about contaminants and other environmental stressors.
  • Fish health is one biological indicator that is important for many communities in the NWT. Fish health is linked to human health as humans eat fish and other aquatic wildlife.