Calculation of Recurrence Interval using Weibull Plotting Position:

• Formula: According to the Weibull formula, the return period / recurrence interval ($T$) for an event of rank $m$ in a record length of $N$ years is:
  $$T = \frac{N + 1}{m}$$
• Given Data:
• Total years of record ($N$) = $16$
• Rank of the event ($m$) = $10$
• Calculation:
  $$T = \frac{16 + 1}{10} = \frac{17}{10} = 1.7\text{ years}$$
  (Note: Probability of exceedance $P = m / (N+1) = 10 / 17 = 0.588$).

Atmospheric Dynamics of Cyclones and Anticyclones:

• Statement (A) is Correct: An anticyclone is a weather system with high atmospheric pressure at its center around which air circulates clockwise in the Northern Hemisphere (due to the Coriolis deflection to the right) and counter-clockwise in the Southern Hemisphere.
• Statement (B) is Incorrect: Anticyclones are high-pressure systems, not low-pressure systems.
• Statement (C) is Correct: A cyclone is an intense low-pressure system surrounded by closed isobars with counter-clockwise inward circular wind motion in the Northern Hemisphere.

Definitions of Standard Hydrological Graphs and Plots:

• Mass curve matches with (II) Cumulative precipitation vs time: A graphical plot of accumulated rainfall depth plotted continuously against time.
• Unit hydrograph matches with (III) Discharge rate vs Time: Direct runoff hydrograph resulting from 1 unit ($1\text{ cm}$ or $1\text{ mm}$) of rainfall excess occurring uniformly over a catchment at a uniform rate.
• Depth area duration (DAD) curve matches with (IV) Average depth of rainfall vs area: Depicts the maximum average depth of rainfall over different area sizes for specific storm durations.
• Hyetograph matches with (I) Rainfall intensity vs time: A bar chart or plot showing the distribution of precipitation intensity or hyetographic depth over discrete time intervals.

SCS-CN Antecedent Moisture Condition (AMC) Analysis:

• Assertion (A) is True: In the USDA Soil Conservation Service (SCS) Curve Number method, AMC-I designates dry soil condition preceding the storm event, having the lowest curve number ($CN_I$) and therefore lowest runoff potential and highest infiltration capacity.
• Reason (R) is True: USDA defines AMC-I as soils that are dry, but not to the wilting point; when cultivated, soils are dry enough for satisfactory plowing/cultivation without smearing.
• Explanation Link: The physical reason AMC-I generates low runoff is high matric suction and available unsaturated pore volume for infiltration, not merely agricultural plowability. Hence, (R) is a true descriptive property of AMC-I but not the causal scientific explanation for low runoff potential.