2009 Shoal Lake water quality test results
Our staff test Shoal Lake and the intake at the west end of Indian Bay (where the water enters the aqueduct) as part of our routine water quality testing program.
For more information on Winnipeg's drinking water and our impact on Shoal Lake, visit the web page on Shoal Lake - Our Water Source.
Testing
We take samples at the intake every week during the open water season and every two weeks during the rest of the year. We also take samples from the Shoal Lake watershed from May to October. We test the intake samples for:
- routine water chemistry
- taste and odour compounds
- metals
- disinfection by-products
- bacteria and protozoa
- toxins produced by algae
By taking these samples, we track seasonal changes in water quality and determine the effects (if any) of human activity within the Shoal Lake watershed.
The intake for the aqueduct is at the west end of Indian Bay. Water entering the intake passes through screens before being disinfected by chlorine. We add sufficient chlorine to maintain a free chlorine residual of about 0.3 milligrams per litre in the water in the aqueduct when it enters Deacon Reservoir.
| What is being measured |
How it's measured |
Guideline or regulation |
Shoal Lake average |
Shoal Lake range |
Comments |
| Odour | units | Inoffensive | 115 | 60 to 200 | Raw water - guideline does not apply |
| Geosmin | parts per trillion | no guideline | 3.3 | <1.0 to 6.0 | Common taste and odour compound |
| IPMP - 2-isopropyl-3-methoxypyrazine | parts per trillion | no guideline | <0.8 | <0.5 to <5 | Common taste and odour compound |
| IBMP - 2-isobutyl-3-methoxypyrazine | parts per trillion | no guideline | <0.8 | <0.5 to <5 | Common taste and odour compound |
| MIB - 2-methylisoborneol | parts per trillion | no guideline | 4.5 | <0.5 to 6.4 | Common taste and odour compound |
| 246 TCA - 2,4,6-trichloroanisole | parts per trillion | no guideline | <0.8 | <0.5 to <5 | Common taste and odour compound |
| 236 TCA - 2,3,6-trichloroanisole | parts per trillion | no guideline | <0.8 | <0.5 to <5 | Common taste and odour compound |
| 345 TCV - 3,4,5-trichloroveratrole | parts per trillion | no guideline | <0.8 | <0.5 to <5 | Common taste and odour compound |
| MTBE - methyl tertiary-butyl ether | parts per million | no more than 0.015 | <0.0008 | <0.0005 to 0.001 | Raw water - guideline does not apply |
| NDMA - N-nitrosodimethylamine | parts per billion | under review | <2 | <0.8 to <5 | Guideline under review by Health Canada |
| Plankton (algae) count | cells per millilitre | no guideline | 39,661 | 2,000 to 316,900 | Algae contribute to odours and may cause filter clogging |
| Chlorophyll-a | parts per billion | no guideline | 3 | <1 to 7 | Chlorophyll is found in algae |
| Microcystin LR | parts per billion | no more than 1.5 | <0.2 | <0.2 to 0.2 | Raw water - guideline does not apply |
| Cryptosporidium | oocysts per 100 litres | no guideline | <1 | <1 to <1 | 13 samples taken in 2009 - no positive results |
| Giardia | cysts per 100 litres | no guideline | <1 | <1 to 1 | 13 samples taken in 2009 - one positive result |
| Turbidity (clearness) | Nephelometric turbidity units | no more than 1.0 | 0.79 | 0.26 to 1.70 | Raw water - guideline does not apply |
| Colour, Apparent | units | no more than 15 | 2.7 | 2.5 to 5.0 | Coloured water may be offensive |
| Total Dissolved Solids | parts per million | no more than 500 | 97 | 73 to 169 | Raw water - guideline does not apply |
| Conductivity | microsiemens per centimetre | no guideline | 141 | 122 to 159 | Another measure of dissolved solids |
| pH | units | between 6.5 and 8.5 | 8.13 | 7.80 to 8.69 | Raw water - guideline does not apply |
| Temperature | degrees Celsius | no more than 15 | 8.0 | 2.0 to 19.0 | Raw water - guideline does not apply |
| Total Alkalinity | parts per million as calcium carbonate | no guideline | 74 | 67 to 82 | - |
| Total Hardness | parts per million as calcium carbonate | between 80 and 100 | 77 | 65 to 92 | Raw water - guideline does not apply |
| Total Organic Carbon | parts per million | no guideline | 10 | 8 to 14 | - |
| Soluble Organic Carbon | parts per million | no guideline | 10 | 8 to 12 | - |
| Total Kjeldahl Nitrogen (TKN) | parts per million | no guideline | 0.47 | 0.30 to 0.60 | TKN is a combination of ammonia and organic nitrogen |
| Total Phosphorus | parts per million | no guideline | 6 | <2 to 16 | Phosphorus can contribute to algae growth |
| Total Soluble Phosphorus | parts per million | no guideline | <2 | <2 to 3 | - |
| Fluoride | parts per million | no more than 1.5 | 0.08 | <0.08 to 0.20 | Raw water - guideline does not apply |
| Nitrate Nitrogen | parts per million | no more than 10 | 0.014 | <0.003 to 0.037 | Raw water - guideline does not apply |
| Chloride | parts per million | no more than 250 | <9 | <9 to <9 | Raw water - guideline does not apply |
| Sulfate | parts per million | no more than 500 | <9 | <9 to <9 | Raw water - guideline does not apply |
| Trihalomethanes | parts per billion | no more than 100 | <0.5 | <0.5 to 1.5 | Raw water - guideline does not apply |
| Bromodichloromethanea | parts per billion | no more than 16 | <0.5 | <0.5 to <0.5 | Raw water - guideline does not apply |
| Haloacetic acids | parts per billion | no more than 80 | <2 | <2 to <10 | Raw water - guideline does not apply |
| Aldehydes | parts per billion | no guideline | 5 | 3 to 7 | - |
| Calcium | parts per million | no guideline | 20.7 | 18.6 to 23.0 | Contributes to hardness |
| Magnesium | parts per million | no guideline | 6.02 | 5.51 to 6.91 | Contributes to hardness |
| Sodium | parts per million | no more than 200 | 2.1 | 1.9 to 2.4 | Raw water - guideline does not apply |
| Potassium | parts per million | no guideline | 1.22 | 1.07 to 1.38 | Raw water - guideline does not apply |
| Iron | parts per million | no more than 0.3 | 0.01 | <0.01 to 0.03 | Raw water - guideline does not apply |
| Copper | parts per million | no more than 1.0 | <0.001 | <0.001 to <0.001 | Raw water - guideline does not apply |
| Lead | parts per million | no more than 0.01 | <0.001 | <0.001 to <0.001 | Raw water - guideline does not apply |
| Aluminum | parts per million | no more than 0.1 | 0.003 | 0.001 to 0.006 | Raw water - guideline does not apply |
| Arsenic | parts per million | no more than 0.01 | <0.001 | <0.001 to <0.001 | Raw water - guideline does not apply |
| Chromium | parts per million | no more than 0.05 | <0.001 | <0.001 to <0.001 | Raw water - guideline does not apply |
| Nickel | parts per million | no guideline | <0.001 | <0.001 to <0.001 | - |
| Cadmium | parts per million | no more than 0.005 | <0.001 | <0.001 to <0.001 | Raw water - guideline does not apply |
| Manganese | parts per million | no more than 0.05 | 0.004 | 0.001 to 0.007 | Raw water - guideline does not apply |
| Zinc | parts per million | no more than 5.0 | 0.001 | <0.001 to 0.003 | Raw water - guideline does not apply |
| Mercury | parts per million | no more than 0.001 | 0.0000093 | 0.0000011 to 0.000028 | Raw water - guideline does not apply |
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This page was last updated on April 15, 2024 |
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