Water Quality Testing

In order to track the health of Renfrew Ravine, we try anddelete-after test the water whenever possible. Generally, testing takes place by the part of the ravine beside the land bridge at east 17th avenue. To see our latest results, please click here.

Our testing equipment

  • Hach Nitrate Test Kit, Model NI-11
  • Hach pH Test Kit, 5.6 – 8.4 pH, Model 17F
  • Hach Phosphorus, Orthophosphate (Reactive) Test Kit, Model PO-19A
  • Hach Dissolved Oxygen Test Kit, Model OX-2P
  • Dynamic Aqua Armored Thermometer

What we measure


Water temperature changes throughout the year. Organisms often thrive at a specific temperature range. The temperature affects the amount of dissolved oxygen present (high temperatures reduce dissolved oxygen, while cooler temperatures are better at retaining oxygen in the water), the rate of photosynthesis by aquatic plants, and the sensitivity of organisms to toxic wastes, parasites, and disease.


pH tests for the amount of hydrogen in solution, which is the level of acidity or alkalinity. The pH scale ranges from 0-14, with values above 7 being basic, 7 being neutral, and values below 7 being acidic.

Ideally, a pH range of 6.5-8.2 is ideal for most organisms. Generally speaking, organisms will have biological functions to adapt within a small margin of change in pH, but tend to thrive at a very specific pH.

Several different influences can alter the pH of the ravine. Natural waters generally range anywhere in between pH 5 to 8.5. Freshly fallen rain is acidic and can range from pH 5.5 to 6, while alkaline soils and minerals can raise the pH to 8 to 8.5.


Nitrogen in water can be nitrate, nitrite, or ammonia. For plants, nitrate is a valuable nutrient. However, if the nitrate levels are too high, plants and algae will grow excessively, creating water quality problems.

Unpolluted water generally have nitrate levels below 4 ppm. Levels above 40 ppm are considered unsafe for drinking.

Nitrate is found in human and animal waste, decomposing organic material, and run-off from fertilizers.


In water, phosphorus is found as phosphate. Phosphate is a nutrient for plants and can cause plants and algae to grow excessively when levels are high enough, thereby creating water quality problems.

Ideally, phosphate levels should be below 1 ppm, however, any amount below 4 ppm is fair.

The most common sources of phosphate in water are detergents and commercial fertilizers that have run-off into the waterways.

Dissolved oxygen

Even aquatic animals, plants, and bacteria need oxygen to survive, except in their case, the oxygen is dissolved in the water.

Oxygen requirements depend on the type of species and the stage of life. Ideally, 5 to 6 ppm are usually required for growth and activity, while levels below 1 to 2 ppm are not enough to support fish. Levels between 3 and 4 ppm are stressful to aquatic organisms.

Oxygen is readily diffused from the atmosphere into the water until it can no longer contain anymore oxygen (saturated). Oxygen is also produced by aquatic plants, algae, and phytoplankton through photosynthesis.

Bacteria from sewage or the rotting of plants can consume the oxygen in the water, thereby lowering saturation. This consumption can significantly change the amount of oxygen depending on the time of day.