Drainage Systems Inspection Flashcards
6 cards from real CTQP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Drainage Systems Inspection flashcards as text
What is an 'inlet' in a storm drainage system?
Answer: A structure that collects surface runoff and directs it into the underground pipe system
A drainage inlet is a structure (curb inlet, grate inlet, junction box) that collects surface water and channels it into the underground storm sewer system.
What is the minimum longitudinal slope required for storm drain pipes to maintain self-cleaning velocity?
Answer: 0.50%
A minimum pipe slope of approximately 0.5% is generally required to maintain a self-cleaning velocity of about 2.5 feet per second in storm drain pipes.
What is a 'French drain' or 'underdrains'?
Answer: A subsurface perforated pipe system that collects and removes groundwater or infiltrated water
Underdrains (French drains) are subsurface systems using perforated pipe surrounded by filter aggregate to intercept and remove groundwater that would otherwise weaken the pavement subgrade.
What does 'hydraulic gradient' refer to in storm drainage design?
Answer: The slope of the energy line in a pipe system under pressure or gravity flow
The hydraulic gradient is the slope of the pressure or energy line through a drainage system, and must remain below the rim of manholes and inlets to prevent surcharging.
When inspecting a reinforced concrete pipe (RCP) joint, what is the inspector checking for?
Answer: Proper gasket installation, joint gap, and alignment between pipe sections
At RCP joints, the inspector verifies that the rubber gasket is properly seated, the joint gap is within tolerance, and the pipe sections are properly aligned without offsets.
What is 'endwall scour' and how is it prevented?
Answer: Erosion at the outlet of a culvert caused by high-velocity flow; prevented by riprap or energy dissipators
Outlet scour is erosion at the downstream end of a culvert caused by high-velocity discharge; it is controlled by placing riprap, concrete aprons, or other energy dissipators at the outlet.