Summary of Surface Water Monitoring Results in Ottawa
Water quality in the Ottawa, Mississippi and Rideau Rivers is generally good to excellent. This is largely due to the relatively low proportion of urban development and agriculture upstream of Ottawa.
The exception to the overall “good to excellent” assessment of the City’s major rivers are the two sites located in the most downstream stretch of the Rideau River (at the Bank Street Bridge and St. Patrick Street Bridge), which are rated fair.
Levels of phosphorus in the Rideau River are generally much higher than in the Ottawa and Mississippi Rivers.
Water quality in the City’s major tributaries varies. The Jock River has a water quality index ranging from fair to good depending on the location; the Castor is rated marginal to fair; the Carp is poor to fair; and Bear Brook is marginal. Levels of metals in the streams are generally good to excellent; E. coli levels are fair to good in the Jock River, poor to fair in the Carp, and poor to marginal in the other major tributaries. Phosphorus levels are poor to marginal in the Jock River and mostly poor for the other three major tributaries.
Water quality in the City’s smaller tributaries varies from poor to excellent depending on the pollutant. Levels of metals are good to excellent in the majority of areas, with marginal to fair ratings observed in more urbanized settings. For the most part, phosphorus and E. coli levels are rated as poor to fair in both rural and urban creeks, with good to excellent ratings observed in areas upstream of the City.
In terms of meeting water quality targets, urban creeks are worse than rural creeks. Higher levels of metals in urban creeks reflect urban runoff from roads and parking lots.
Areas of Concern
Six creeks were identified during the trends analysis as areas of concern: Bilberry Creek, Green Creek, Bear Brook, Beckett’s Creek, Cardinal Creek and Casey Creek. These monitoring stations show high levels of phosphorus, E. coli and metals. Some of these tributaries drain urban areas, some drain rural areas, and some drain areas with mixed land use.
Surface Water Quality Trends
With the exception of the main channels of the Ottawa and Mississippi Rivers, and naturalized areas upstream of the urban area, phosphorus is a concern in all of the City’s rivers and streams. In all watercourses other than these exceptions, phosphorus levels are rated mostly as poor or marginal and average concentrations exceed water quality targets.
E. coli is not a concern in the Ottawa and Mississippi Rivers. Increasing levels of E. coli are seen in the Rideau River with distance downstream. However, differing levels suggest the influence of local sources rather than a cumulative effect. A significant increase in phosphorus levels is noted when the river reaches the Black Rapids. This is likely the influence of some rural tributaries which empty into the Rideau upstream from Black Rapids.
Increasing levels of phosphorus and E. coli have been found in the Ottawa River, downstream of the urban area. This is due to the influence of the Rideau and Gatineau Rivers, stormwater run off from the Gatineau and Ottawa urban area, and the wastewater treatment plants that serve Ottawa and Gatineau. Increased levels of pollutants are seen in Ottawa’s tributaries during the spring melt when runoff picks up pollutants from farms, yards, roads and parking lots.
Overall, water quality tends to improve as the size of the watercourse increases. Patterns in water quality in the rural and urban areas are somewhat inconsistent, with locations of high water quality found in both rural and urban areas and vice versa. However, there is some evidence that rural tributaries flowing through natural areas (forests or wetlands) are of higher quality than those flowing through agricultural and urban areas.
In addition, water quality index values have generally been better when comparing the index values from the last five years against earlier results, suggesting that water quality may be improving across most water courses within Ottawa.
City of Ottawa Baseline Water Quality Monitoring Program
Why do we monitor?
Water quality monitoring is important and helps answer questions about the condition of a body of water (i.e., the levels of pollutants), stresses on water and the effectiveness of our protection, mitigation and restoration programs. The data collected at program monitoring locations sheds light on trends and is used as baseline information to measure the condition of other water bodies.
Understanding the health of our rivers and streams is vital to protect the natural environment. Water quality data and information collected by WEP is used by internal City departments for investigations, planning, and restoration and remediation efforts. It is also used by external agencies such as the Ministry of Natural Resources and Forestry (MNRF), the Department of Fisheries and Oceans (DFO) and the three Conservation Authorities in Ottawa.
Through monitoring we can identify water quality problems, and then develop strategies to address them. Ongoing monitoring allows us to see if our efforts have been successful, and then adjust or adapt activities, if necessary, to achieve our objectives.
How do we evaluate water quality data?
Water quality data is evaluated against three sets of criteria – the Provincial Water Quality Objectives (PWQO), the Canadian Water Quality Guidelines (CWQG) for the Protection of Aquatic Life, and the Canadian Council of Ministers of the Environment (CCME) Water Quality Index. The provincial objectives and federal guidelines protect all forms of aquatic life and recreational uses. The CCME Water Quality Index translates complex water quality data into simple terms (e.g., excellent, good, poor) for reporting.
Similar to the Provincial Air Quality Index, the Water Quality Index gives information on overall water quality. The end result is a single index score between 0 and 100 that describes the overall water quality.
Index values closer to 100 indicate higher water quality, while values closer to zero indicate poorer water quality. For an explanation of what a specific Water Quality Index score means, see the table below.
The following water quality categories are recommended by CCME (2001):
What it means
Water quality is protected and is virtually threat or impairment free; conditions very close to natural or pristine levels. These index values can only be obtained if all measurements are within objectives virtually all of the time.
Water quality is protected with only a minor degree of threat or impairment; conditions rarely depart from natural or desirable levels.
Water quality is usually protected but occasionally threatened or impaired; conditions sometimes depart from natural or desirable levels.
Water quality is frequently threatened or impaired; conditions often depart from natural or desirable levels.
Water quality is almost always threatened or impaired; conditions usually depart from natural or desirable levels.
How and what do we monitor?
The City’s Baseline Monitoring Program monitors water quality across Ottawa and identifies long term trends. Six rivers, four lakes, and forty creeks are monitored on a monthly basis unless prevented by site conditions (such as ice cover). Each sample is analysed for 50 different parameters:
These parameters are measured using hand held equipment while at the monitoring site:
- Dissolved Oxygen
Samples are collected and transported to a laboratory for analysis on the following parameters:
- Dissolved Organic Carbon
- Total Suspended Solids
- Total Kjeldahl Nitrogen
- Phosphorous, total
- Phosphorous, reactive
Where can I find Ottawa’s baseline water quality data?
For an overview of the water quality of Ottawa’s rivers, lakes and streams please see our Interactive Water Quality Map. For specific monitoring results from 1998-2014, please visit the Water Quality – Baseline Surface Water Monitoring Program data set found on the City of Ottawa’s Open Data archive.
Water Quality in Ottawa’s Rivers, Lakes, and Streams
Interactive Water Quality Map
The summaries for more than 130 monitoring stations are mapped on the interactive water quality map below. This information reflects conditions in 2014 and has been provided by the City of Ottawa’s Baseline Surface Water Monitoring Program. Monitoring results obtained between 1998 and 2014 can be viewed by accessing the Water Quality – Baseline Surface Water Monitoring Program data set found on the City of Ottawa’s Open Data archive. For an explanation of what each Water Quality Index rating means, please see How do we evaluate water quality data?