Typical Data
Here we look at daily and yearly trends of a few water quality parameters that were measured on the East Canyon Creek (Weber River Watershed).
When we make field measurements we only see what is happening at that location at that point in time. Patterns emerge when sites are monitored hourly, daily, monthly, and yearly. Thanks to technology, we have the ability to collect high frequency data. We can use this to understand the trends of the parameters we measure for water quality.
Next time you collect data, think about the time of day and year you are sampling. Although your data won’t numerically match the data from East Canyon Creek, you can expect it will follow the same pattern.
In western mountain areas, stream flow typically increases in early spring as snow melts and runs off into the streams. Summer storms may cause a brief increase, but flow is generally much lower and constant during the rest of the year. This “base flow” is fed by water that has soaked into the ground and slowly drains back to the stream.
Flow will decrease during the day as water is evaporated from the stream and used up by plants for photosynthesis. At night the flow will increase as evaporation and photosynthesis is discontinued.
A stream heats up from direct sunlight and from heat in the surrounding land and water temperatures vary widely throughout the seasons, especially in mountainous regions in northern Utah.
On a daily basis, the stream will heat up and cool down due to mainly incoming radiation and air temperature.
Dissolved Oxygen is often higher in the winter than the summer because less oxygen can dissolve in warm water than in cold water.
Dissolved oxygen is lower during the night than the day. During the day, photosynthesis by plants creates oxygen. At night, photosynthesis discontinues because there is no light. Oxygen is still being used by the organisms living in the water. Dissolved oxygen levels are much lower at night.
pH is relatively consistent throughout the year.
pH is higher during the day than the night. Plants living in streams use carbon dioxide (a weak acid) they need for photosynthesis from the water. This increases the pH of the stream during the day, when plants are growing.
Turbidity increases when stream flow increases in the spring. This is natural; however, human activities, fires or other events may increase erosion, which can increase turbidity.
Turbidity is usually quite low (water is very clear), during base flow, when stream flows are low.
Specific conductance in East Canyon Creek is highest during winter months. Concentrations of salts in the water are greater during this time due to diluting of the stream during runoff months.
Let’s apply what we have learned about the patterns formed by these water quality parameters. It is around 11:00 am on a summer day. The temperature of the stream reads 61.1°F. When you compare this to the pattern established by our East Canyon Creek data, you can see at this time of day, stream temperature is climbing. We can assume the max temperature for the stream has not been reached for that day. If you sampled in the afternoon, during the hottest part of the day, you could assume your reading was approximately the highest temperature for the stream that day.
