How to calculate stream order Another way to look at a drainage system is to treat it as a hierarchical network Stream order m order increases by 1 each time two streams of the same order join ange in stream order occurs when two streams of different order join 3 rd order stream receiving a 1 st order stream remains a 3 rd order strea
17
Embed
How to calculate stream order Another way to look at a drainage system is to treat it as a hierarchical network Stream order Stream order increases by.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
How to calculate stream order
Another way to look at a drainage systemis to treat it as a hierarchical network
Stream order
Stream order increases by 1 each time two streams of the same order join
No change in stream order occurs when two streams of different order joinEg a 3rd order stream receiving a 1st order stream remains a 3rd order stream.
1 km
x
Outline the Watershed of thissmall tributary to Threepoint Cr. at
the point x
First study the altitudinal contours
Locate the 5000’5500’& the 6000’Contours
What are the highest points in the area
How to map a watershed
1 km
o
o
o
o
o
o
o
Now ask yourself which way would water flow from various points around the creek?
The flow path is perpendicular to the contours.
The area that delivers water to the point x includes all of the points that flow toward x, and none of the points that flow away from x
x
1 km
o
o
o
o
o
o
o
Start at x , and extend a line up to the east ridge, and follow the ridgetop up to the top of Mt. Barwell, and then extend the line through the saddle and onto the small peak west of the mountain, and along the west ridge back to
the point x
All points that drain into the creek, and down
to point x will be contained within this area, and all points that drain away, should be outside the area
x
1 km
o
o
o
o
o
o
o
x
The area of this watershed is 4.5 km2.
What is the avg annual discharge at
the point x?
From the runoff map we assign a value of 0.6 m/year
0.6m/yr x 4.5 x 106m2= 2.7 x 10 6 m3/yr
=0.1 m3/s
What are the units of flow measurement?Discharge (R or Q)—L3/timeVelocity (v)—L/time
Discharge can be measured by X-sectional area (L2) of the stream at a point times mean velocity (L/s)
Mean depth (L) x width (L) x mean velocity (L/s)
If the mean discharge of the creek is 0.1 m3/sec, and the mean width at the point “x” is 4 m, and the mean depth is 0.2 m, what is the mean water velocity?