Water Resources and Environmental
This area covers the movement and management of water: open-channel and pipe hydraulics, stormwater runoff, and hydrology. The exam tests continuity, energy, Manning's equation, and runoff estimation.
Continuity and Hydraulics
Discharge is Q = V·A and is conserved in steady incompressible flow. Open-channel velocity follows Manning's equation V = (1/n)·R^(2/3)·S^(1/2), so velocity scales with the square root of slope. Hydrostatic force on a submerged surface acts at the center of pressure, one-third of the depth above the base for a vertical rectangle.
Runoff and the Rational Method
The Rational Method, Q = C·i·A, estimates peak runoff for small watersheds, with i in in/hr and A in acres yielding cfs directly. Peak flow occurs when storm duration equals the time of concentration, when the entire watershed contributes to the outlet simultaneously.
Stormwater Management
Storm sewers, culverts, and open channels convey runoff, while detention and retention ponds attenuate peak flows to protect downstream areas. Runoff analysis uses the Rational or SCS/NRCS methods, considering storm frequency, rainfall distribution, and erosion control.