CPD Storm Drainage & Site Utilities Flashcards
6 cards from real CPD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CPD Storm Drainage & Site Utilities flashcards as text
What is a retention pond's primary function in site stormwater management?
Answer: To hold stormwater permanently and release it at a controlled rate
A retention pond holds a permanent pool of stormwater and releases excess volume slowly, reducing peak runoff and allowing sediment to settle.
What distinguishes a detention basin from a retention pond in stormwater design?
Answer: A detention basin temporarily holds stormwater and drains completely between storms
A detention basin temporarily stores stormwater during a storm event and drains completely afterward, while a retention pond maintains a permanent water pool.
Which US federal regulation governs stormwater discharge from construction sites larger than one acre?
Answer: NPDES Construction General Permit under the Clean Water Act
The EPA's NPDES Construction General Permit, issued under the Clean Water Act, requires stormwater pollution prevention plans for construction sites disturbing one or more acres.
What is the purpose of a roof drain overflow (secondary) drain in plumbing design?
Answer: To handle excess rainwater if the primary roof drain becomes blocked, preventing structural overload
Secondary (overflow) roof drains protect the roof structure from ponding overload if the primary drain is blocked, directing excess water to a safe discharge point.
What is an area drain used for in exterior plumbing design?
Answer: To collect surface water in paved or landscaped areas and direct it to the storm system
Area drains are installed at low points in paved plazas, courtyards, or landscaped areas to collect surface runoff and route it into the underground storm drainage system.
In CPD exam contexts, what does 'time of concentration' (Tc) refer to in stormwater hydrology?
Answer: The time for runoff to travel from the most remote point in a watershed to the design outlet
Time of concentration (Tc) is the travel time for runoff from the hydraulically most remote point of the drainage area to reach the design point, and it determines the critical storm duration for peak flow calculations.