Stream velocity
Stream velocity is how fast the water is moving. You measure it using a flow meter. When counting revolutions it is per forty second intervals. If you are trying to find the stream discharge, which is the amount of water moving though and area, you would use another method called an orange test.
Terminology
-A riffle describes the flow of water in shallow areas where similar rocks create a white cap effect.
-Rapids is a word used to describe fast moving water with large rocks and a greater volume of water.
-A pool is a deep, slow water in the main channel.
-An eddy is still water behind a large object in the channel.
-A glide is a straight run in the river.
Rock Analysis
Rock analysis’s are important because you can tell a lot about what plants and animals are living in a steam or river based on the size of the rocks present. In areas with larger rocks there will be larger fish. The more variety of rocks found the more diversity or organisms will be found. A stream with of fine sediment is not as stable as a stream with larger varied rocks. Sediment can starve eggs of oxygen.
When doing a rock analysis you randomly choose 10 rocks at three different locations on a site. With those rock you measure the length, width and height, and determine the average. Then you would use that number to classify the rock. You also need to determine the percent embedded at each site. The percent embedded is the average amount of sediment around the rock. You find this by observing the rocks as you walk out into the water, and estimating.
Benthic Invertebrates
These organisms will tell you about the quality of the water by the kinds that are living there. Some types can tolerate poor conditions, other can not.
(for more information see benthic invertebrates)
Water Quality Testing
There are four aspects to finding the water quality:
Dissolved Oxygen: if the steam is healthy there will be a large amount of dissolved oxygen available for aquatic life. Oxygen levels will fluctuate, due to photosynthesis and cellular respiration. During the day when plants undergo photosynthesis oxygen is created and there is a larger variety then during the night when cellular respiration occurs and oxygen is used up. To find the lowest dissolved oxygen level you will have to take your reading early in the morning. Steam back vegetation also helps to increase oxygen levels.
Temperature: Temperature directly impacts the oxygen levels. If the water temperature is high there will less oxygen in the water. If there is a slow surface flow then oxygen from the air will not be able to mix into the water. Temperature effects more then just the oxygen content, it also effects the organisms living in the water. Most of the organisms are cold blooded, or exothermic and match the temperature of the water. If the water temperature is high it can increase disease in fish, even if the plant life is uninfected. The temperature can also show you the type of fish and invertebrates that will survive, for example trout, salmon and mayflies are all found in cold water.
PH/Acidity/Alkalinity: These determine the growing conditions for river life. There are lots of things that can effect them, like sewage, manure, rain or dissolved minerals making their way into a stream or river. A pH between 6-8.5 is necessary for the aquatic food web. PH is related to geology, alkaline means high mineral content, while acidic means coniferous.
Turbidity: Turbidity means cloudiness of the water, and it can effect general health of aquatic animals (for example clogged gills) or fish spawning habitat. Landslides into water cause turbidity and they can have immediate and/or long time effects on an ecosystem.
