What does the variable P represent in the water balance equation?

Precipitation

True or False: The Rational Method is suitable for watersheds larger than 200 acres.

False. The Rational Method is limited to small watersheds, typically less than 200 acres.

Which method uses the formula: P_avg = (1/n) × Σ P_i?
A) Thiessen Polygon
B) Arithmetic Mean
C) Isohyetal
D) IDF

B) Arithmetic Mean

In the Rational Method, Q = C × i × A. What does C represent?

Dimensionless runoff coefficient

Fill in the blank: Time of concentration is the time for water to travel from the _____ point to the outlet.

Hydraulically most distant

What are typical runoff coefficient values for dense urban areas?

0.70 to 0.95

True or False: Higher CN values indicate lower infiltration capacity and greater runoff potential.

True

Which hydrologic soil group has the highest runoff potential?
A) Group A
B) Group B
C) Group C
D) Group D

D) Group D

What is the initial abstraction formula in the NRCS method?

I_a = 0.2S

Fill in the blank: The NRCS equation S = (1000/CN) - _____ calculates potential maximum retention.

10

True or False: Runoff occurs when P ≤ I_a in the NRCS method.

False. Runoff occurs when P > I_a.

What does a unit hydrograph represent?

Direct runoff hydrograph from 1 inch of excess rainfall

In flood frequency analysis, what does T = 1/P calculate?
A) Risk
B) Return period
C) Discharge
D) Probability

B) Return period

Fill in the blank: The Log-Pearson Type III uses the formula: log Q_T = X̄ + K_T × _____

S_x

What is the final constant infiltration capacity in Horton's equation?

F_c

True or False: In detention basins, storage volume increases when inflow exceeds outflow.

True

Which equation describes orifice discharge?
A) Q = C_w L h^1.5
B) Q = C_d A √(2gh)
C) Q = CIA
D) Q = KXI

B) Q = C_d A √(2gh)

Fill in the blank: Manning's equation includes the factor _____ for US customary units.

1.486

When Froude number equals 1, what type of flow occurs?

Critical flow

True or False: Supercritical flow occurs when Fr > 1.

True

What is the typical range for the weighting factor X in Muskingum routing?
A) 0.5 to 1.0
B) 0 to 0.5
C) 1.0 to 2.0
D) -0.5 to 0

B) 0 to 0.5

Fill in the blank: Lag time equals _____ times the time of concentration.

0.6

What does the discharge coefficient C_d typically equal for orifices?

0.6 to 0.65

True or False: Hydrologic Soil Group A has high runoff potential.

False. Group A has low runoff potential and high infiltration.

In the Kirpich equation, what exponent is applied to slope S?
A) 0.77
B) -0.385
C) 0.5
D) 1.5

B) -0.385

Fill in the blank: Base time T_b = _____ × T_p in NRCS dimensionless unit hydrograph.

2.67

What principle allows superposition of unit hydrographs from equal duration storms?

Principle of superposition

True or False: Retention basins have surface outlets while detention basins do not.

False. Retention basins have no surface outlet; detention basins have controlled outlets.

Calculate peak discharge: C=0.8, i=5 in/hr, A=10 acres. What is Q in cfs?

40 cfs