Module 5 Assignment- Hydraulics
Location Map
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
Figure 3. Planform drawing of the stream channel with various features identified.
Photo 1. View looking upstream
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.