Canals USBR Flashcards
Trapezoidal is the most accepted shape for earthern canals
T or F?
True
Side slopes of 3:2 for smaller canals and laterals and 4:2 for larger canals is generally adequate for most earth materials and should be considered when determining the side slopes of canals
T or F?
True
3.0 fps for smaller canals up to 1.5 fps for larger are the range of permissible velocities considered for sizing a canal water section
T or F?
False
What considerations must be made when canal construction is to utilize “cut and fit” methods?
- The water prism should be kept a safe distance into the natural ground
- Generally the ground water surface above the downhill cut take should not exceed approximately one-fourth the water depth
- On steep sidehills the entire water prism should be entirely in the natural ground for safe consideration
- All above
All above
Steel flumes are seldom used today due to High maintenance costs
T or F?
True
Alone uphill terrain concrete bench flumes are most commonly used
T or F?
False
What shape of flume gives the maximum velocity for a given area?
- One that has a bottom width 4 times the depth of the water depth
- One that has a bottom width 2 times the depth of the water depth
- One that has a bottom width 3 times the depth of the water depth
- None above
One that has the bottom width 2 times the water depth
Encountered falling rock and debris are ideal conditions to make precast concrete pressure pipe for flume service
T or F?
True
Buried precast concrete pipe and monolithic concrete pipe are considered common types of construction for siphon service
T or F?
True
Why is concrete pipe predominantly used for canal siphons?
- Hydrostatic heads encountered are generally less than 150 ft
- Bridges supporting canal sections across drainage channels, over highways and railroads, are generally more expensive
- Sizes from 12 to 96 inches are available in most localities
- All above
All Above
Monolithic construction is generally considered for siphons smaller than 96 inches in diameter
T or F?
False
Factors that may dictate construction of elevated steel pipe siphons could be where costly rock excavation is encountered and limited space for handling river flows during construction
T or F?
True
What essential design features, in addition to the pipe itself, must be considered for inverted siphons?
- Inlet and outlet transitions
- Blowoff structures
- Non pressured lines
- Both A and B
Both A and B
Inlet and outlet transitions serve for the purpose of maximizing head loss and erosion damage
T or F?
False
A pump type, gravity pump, and pressure turnout type, are all considered blowoff structures
T or F?
True
When feasible, blowoffs should be located at the low points of siphon where water is drained into natural drainage channels
T or F?
True