The application of CCME Water Quality Index in the Mackenzie River Basin: A summary*.

Environment Canada and the Canadian Council of Ministers for Environment (CCME) collaborated to develop the CCME Water Quality Index (based on initial work by BC) to quantify the quality of water through the use of a single measure, which integrates the frequency, time and sampling strategies of a number of elements in the water. The WQI is a method of providing consistent procedures for Canadian jurisdictions to report water quality information.  A Freshwater Quality Indicator based on the CCME WQI has been identified as one of the national set of six indicators of sustainable development created through a multi-stakeholder consultative process led by the National Roundtable on the Environment and Economy (NRTEE). This Freshwater Quality Indicator provides a nationally consistent measure of the overall state of water quality as measured against objectives related to major water uses in Canada such as water for aquatic life, recreation, drinking and agriculture

In this study, the CCME water quality index has been applied as a tool to monitor the changes in water quality in the Mackenzie–Great Bear sub-basin, Northwest Territories (NT).  The purpose was to evaluate the water quality of the only sub-basin within the Mackenzie River which lies within a single jurisdiction and to test the application of CCME WQI by a new approach through employing different protocol. The CCME WQI is a candidate indicator for the 2003 (first-ever) Mackenzie River Basin Board’s State of Aquatic Ecosystem Report.

The 4241 km long Mackenzie River is the second largest river in the North America, draining into the Arctic Ocean.  The Mackenzie-Great Bear sub-basin lies north of 60° latitude and has a limited number of vegetation species due to its extremely cold climate.  The mineral and petroleum wealth of the Mackenzie basin makes the river significant both environmentally and economically. The Western Canadian Sedimentary Basin portion of the Mackenzie River basin is underlain by vast reserves of oil and natural gas developed for production and transportation via the Canol Pipeline from Norman Wells to Whitehorse, Yukon during World War II. The Norman Wells oil field currently produces 11 to 12 million barrels per year. Another major resource is the natural gas with an estimated reserve of 66 trillion cubic feet.The basin is also known for its uranium, gold, diamond, lead, zinc and silver mines.

The current population of the Mackenzie-Great Bear Sub-basin is about 10,000 people living in communities, with the greatest concentration at Inuvik followed by Fort Simpson. Fur remains important to the local economy while mining has been dominant in the eastern region and the shield.

The water quality at the following six sites has been evaluated by employing two modes of objective functions (threshold values): one based on the CCME guidelines and the other based on site-specific values that are determined by the statistical analysis of the historical data base.

1. Mackenzie River near Fort Providence

2. Mackenzie River at Strong Point

3. Mackenzie River at Norman Wells

4. Mackenzie River above Arctic Red River (Tsiighetchic)

5. Camsell River at the Outlet of Clut Lake

6. Great Bear River at the Outlet of Great Bear Lake

The CCME based objective functions were applied on 8 specifically designed protocols, each representing a typical scenario to evaluate the water quality employing the CCME WQI Macro. Each protocol consists of a set of water quality parameters, designated herein as variables, to reflect the specific scenario representing a particular water use. The site-specific thresholds, however, were applied only on one set consisting of 28 variables that can be regarded to represent the scenario of overall water use. The site-specific objective functions were invoked through three combinations of the statistics of the data series: mean + 2 standard deviation, the upper 90^th percentile values of the entire data series, and mean +2 standard deviation of the data during the freshet. Thus, an additional three protocols were created, which were processed using the CCME WQI Macro.

The protocols and the accompanying scenarios are as follows:

Protocol # l consists of 28 water quality variables/parameters (such as physical, major ions, metals and nutrients) to evaluate the overall use of the water.

Protocol # 2 consists of 22 variables/parameters (all protocol # 1 minus 6 variables/parameters such as color, temperature, turbidity, aluminum, copper and iron) and this represents a hypothetical scenario as if these variables have been corrected to the acceptable CCME recommended limits.

Protocol # 3 consists of physicals, major ions and some metals as variables and this represents the scenario for drinking water use using source waters.

Protocol #4 consists of nutrients, physical and some metals as variables/parameters and represents the scenario for freshwater aquatic uses.

Protocol #5 consists of physical variables/parameters only.

Protocol #6 consists of nutrients as variables/parameters only.

Protocol #7 consists of major ions as variables/parameters only.

Protocol # 8 consists oftotal trace metals only as variables/parameters.

Protocol # 9 evaluates the CCME WQI using “Mean value + 2 * standard deviation” as statistical tool.

Protocol # 10 evaluates the CCME WQI using mean value + 2 standard deviations for the freshet period (May and June)” as statistical tool.

Protocol # 11 evaluates the CCME WQI using “90th percentile” as statistical tool.

This evaluation revealed:

• The quality of untreated water is categorized as marginal to fair along the Mackenzie River for overall, drinking and aquatic water uses. The water quality is excellent to good when analyzed under Protocol # 2.

• The water quality declines downstream to the Mackenzie Delta for the above uses.

• The water quality of the Camsell River that was fair to good in 60s to 80s, has deteriorated in the 90s (marginal to poor)

• The water quality is excellent forall the sites when evaluated by protocol # 7 for major ions.

• The high turbidity in Mackenzie River Basin always attributed towards nlowering the water quality and can be controlled by adopting appropriate watershed management strategies. 

The CCME WQIs analysis reflected that the water quality of the Mackenzie River basin had deteriorated over the 1990s due to an increase in the level of the trace metals. The excessive presence of trace metals can be attributed to natural and anthropogenic sources. Several mines were decommissioned around that period, which might have encouraged uncontrolled runoff from that area.  In this report, CCME WQI calculations are based on total concentrations of metals in the water. Had the study used the dissolved bio-available trace metals instead of total metals (as do the water quality indices employed in Quebec and Alberta), the overall, freshwater aquatic life and trace metal CCME WQI would certainly be higher indicating improved water quality.

Increased erosion and weathering of trace metal-rich and trace organic-rich bedrock (possibly related to increased access roads and survey lines, and/or climate change/climate variability) may be the main natural or part natural/part anthropogenic reason for higher metal concentrations. Mining is not expected to be a major cause from relatively small areas.

The categories of water quality evaluated by CCME WQI based on site-specific objectives and CCME guidelines showed no difference in their conclusive results, therefore, no preferential use of either of them can be emphasized. However, site-specific objectives allow the use of more water quality variables, indicating their potential in water quality categorization

This study demonstrated that using different Water Quality Index protocols to evaluate water quality does identify the specific problematic variables/parameters that may be contributing towards lowering the quality of water. This information can be of great value for water users (public), water supplier (municipalities and city councils) and the planners.

For the full report contact eman@ec.gc.ca

*Sharma, T.C., 2002,”Canadian Water Quality Index Determination for 4 Sites in the Mackenzie River Basin”, (Contract KW405-02-0308) Ecological Monitoring and Assessment Network, Environment Canada, CCIW, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6

*Lumb. A, Halliwell. D and Sharma T.C, 2002, “The Application of Canadian Water Quality Index (CWQI) in the Mackenzie River Basin”, Proceedings of the 29^th Annual Aquatic Toxicity Workshop: October 21-23, 2002, Whistler, British Columbia, Canada.

*Lumb. A, Halliwell. D and Sharma T.C, 2003, “Application of Canadian Water Quality Indexes (CWQI): A Case Study of the Mackenzie River Basin in Canada” (In press)