Sketch A Stretch
Know Before
The sinuosity of a watercourse is a measure of its ‘wiggliness’. The course of a stream naturally changes as sediment is picked up and deposited by energetic flowing water. Stream banks erode as material is carried away and gets deposited further downstream. Streams maintain a dynamic equilibrium as long as there are no major changes to the system. In Twelve Mile Creek, with extra overland runoff from urban areas, the system has become unstable and is transitioning to a new equilibrium. This is affecting the water quality, habitat and adjacent property.
The way stream features are arranged creates habitat that provides food, water, shelter and space for the different life cycle stages of Brook Trout and other critters that live in the water. If certain features are absent or deteriorated, the stream may not be able to support trout and other aquatic organisms. Understanding the integrity of these features can inform decisions to conduct ecosystem restoration.
To assess the condition of the creek it’s helpful to draw and record the structure and habitat features of different sections.
Get Out The Door
Select a section of the stream to sketch. An ideal section would include two complete bends.
Record the date and the coordinates for this location.
Sketch an outline of the streambanks. Use an arrow to indicate the direction of the stream flow.
Where suitable, a tape measure can be used to measure distances, such as the cross section width, or the distance between the start and end point.
Considering the size of your paper, determine a suitable scale, recording it as a ratio __:__
Orient the paper to the land and indicate North with an arrow.
Label any of the following features found in this stretch of the stream.
Pool: Deepest area with slow moving water. Pools are used by larger trout for refuge and protection from predation.
Riffle: Swift, shallow portion of the stream where the flow is broken, often with gravel, rubble or rocks protruding above the surface. Young trout live along riffle margins, especially where logs, rocks and plants can offer shelter.
Run: Swift and deep portion of the stream. Month old trout move to these areas, resting in eddies behind rocks and logs.
Flat: Shallow and slow moving portion, usually where a stream has widened.
Point bars: Deposits of sediment located on the inside of a bend.
Think Some More
Can you see evidence that the meanders of the stream have moved over time?
Do you notice any patterns as you observe Twelve Mile Creek?
What factors could affect the movement of rocks and sediment in a stream?
How might a young river and old river differ in sinuosity?
What may happen to sediment where 12 Mile Creek enters Lake Ontario?
Bring Along:
paper
pencil
GPS or what3words app
compass
tape measure