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Module 5 Assignment- Hydraulics

Location Map

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Site Location

The site for this data collection event was located on a tributary to Fanno Creek (unnamed). Fanno Creek is located west of Portland, Oregon in the Tualatin River Watershed. This creek is in an urban area with an adjacent walking trail. 

Planform Site Sketch

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Figure 3. Planform drawing of the stream channel with various features identified. 

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Photo 1. View looking upstream 

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Photo 2. View Looking downstream 

Discharge

Observations

Estimated wetted width: 1.5 meters

Estimated average depth 0.2 m

velocity measurements: 

a. 4.5 m/ 13 =0.35 m/s

b. 4.5 m /12= 0.375 m/s

c. 4.5 m /14 = 0.32 m/s 

Average velocity= (a+b+c)/3= 1.045/3=0.35 m/s

Calculations

Q= average cross sectional area*velocity

Q= (1.5 m*0.2m)(0.35m/s)

 

Q= 0.105 m^3/s

Q= 0.105 m^3/s *(35.32 ft^3/m^3)= 3.7 cfs

According to the USGS gauge at Fanno Creek in Portland, the value at the time of sampling was 3.2cfs. 

Hydraulic Jump

There was very limited cobble at this site so it was difficult to find any good examples. After the fact, I realized the culvert is a great representation of a hydraulic jump (hydraulic jump 2). The supercritical flow is the area around where the water hits the surface, it is shallow and fast (waves do not propagate upstream). The subcritical flow is in the culvert itself and downstream of where the waves are occurring (the transition zone). Waves propagate upstream.  

Site Pictures

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view from upstream of piece of wood
view from downstream of  wood
view from downstream of middle and river right culvert
view from downstream of  river right culvert
Upstream view of glide and pool
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