How Do We Measure Aquatic Ecosystem Health?

Why is Monitoring Important?

Why Measure Water Quantity?

Why Measure Water Quality?

Why Measure Biological Indicators?


Why is Monitoring Important?

In order for Northerners to make informed decisions about how water and aquatic ecosystems in the Northwest Territories (NWT) are used and managed, we need to have as much information available as possible. For this reason, aquatic ecosystem health monitoring that includes indicators of water quality and quantity, as well as biological indicators is important because it increases our 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 our ability to understand the present and to forecast future environmental conditions.

Baseline data also allow us to assess cumulative impacts, set limits and develop 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 us to detect and evaluate trends. It also allows us to predict the impact of future development activities on our water and aquatic ecosystems. This predictive ability enables us to respond more effectively and in a timely manner 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 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 us to determine the effects of these changes.

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

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



Why Measure Water Quantity?

1) To maintain the health of our aquatic ecosystems

Aquatic ecosystems – including people, plants and animals – require a certain amount of water in order 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.

2) For improved understanding

We want to know how much water there is. Environment and Natural Resources, Government of the Northwest Territories (ENR-GNWT) and Environment Canada (EC) 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 our water and aquatic ecosystems, an important aspect of our lives.

3) For informed transboundary negotiations

The Bennett Dam in B.C. affects the flow of the Slave River. 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, Hay, Coppermine, Thelon and Back rivers.

4) For river traffic

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

5) For safe ferry operations

Warning of high and low water levels and flows at ferry crossings can be provided.

6) 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.

7) 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.

8) 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.

9) For recreation

Canoeists and rafters on the rivers want to know water levels and flows for safety reasons.

10) For assessing developmental impacts

The collection of baseline data allows us to see how changes in water use impacts water and aquatic ecosystems.


Why Measure Water Quality?

1) To know that our water is safe to drink

Our source water quality can be affected by a variety of activities, including various industrial developments, municipalities and recreational users. Therefore, it is necessary to measure water quality to ensure we protect our source water and maintain safe drinking water standards for human consumption. The management of drinking water is a shared responsability of all levels of government. For more information click here

2) To protect the health of the fish we eat from our lakes and rivers

Altered water quality can affect aquatic life, including fish habitat. It is important to measure water quality so we can take steps to keep our water clean, which in turn helps to ensure that fish, a major food source for people and animals, can thrive in our waters.

3) To contribute to the 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 us to evaluate how water quality has changed, as a result, for example, of development or climate change.

4) 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 our water and aquatic ecosystems. To access reports on water quality for transboundary rivers click here.


Why Measure Biological Indicators?

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


Why Measure Biological Indicators?

  • 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.


A brochure has been developed to highlight biological aquatic ecosystem health indicators for the Slave River and Slave River Delta.