Irrigation Water Management & Drainage

• Latin Square Design (LSD): A single-factor experimental design where a single set of treatments is arranged in a square grid to eliminate two perpendicular sources of extraneous soil heterogeneity (row blocking and column blocking simultaneously). (Correct answer: Option 3)
• Factorial RCBD: Multi-factor design studying two or more factors and their interaction effects.
• Split-plot Design: Multi-factor design where main-plot factors require large operational plots and sub-plot factors require smaller precision plots.
• Strip-plot (Split-block) Design: Two-factor design where both factors require large contiguous strips perpendicular to each other.

• Statement (I) is true: A mass curve of rainfall is a cumulative plot of rainfall depth against time ($P$ vs $t$). The instantaneous slope at any point along the curve represents the rate of rainfall depth per unit time ($\frac{dP}{dt}$), which directly defines the rainfall intensity at that interval.
• Statement (II) is true: A hyetograph is a bar graph of rainfall intensity versus time intervals, which is mathematically derived directly from the step-wise slopes of the cumulative mass curve.
• Conclusion: Both Statement (I) and Statement (II) are true. (Correct answer: Option 1)

• Chronology of National Watershed Development Programmes in India:
• NWDPRA: National Watershed Development Project for Rainfed Areas launched in 1990 - 1991 (VIII Five-Year Plan) $\rightarrow$ (I)
• DDP: Desert Development Programme launched in 1977 - 1978 based on recommendations of the National Commission on Agriculture $\rightarrow$ (II)
• IWDP: Integrated Wastelands Development Programme initiated in 1989 - 1990 $\rightarrow$ (III)
• ORPs: Operational Research Projects on Watershed Management initiated by ICAR in 1974 - 1975 $\rightarrow$ (IV)
• Systematic Match: (A)-(I), (B)-(II), (C)-(III), (D)-(IV) corresponds to Option 2.

Correct option: (2) (A) - (IV), (B) - (I), (C) - (I), (B) - (1)

• Hydrograph Baseflow Separation:
• The Fixed Base Length Method (N-day method) is widely deployed in engineering hydrology.
• Baseflow is assumed to decline to the lowest point under the hydrograph peak and then rise linearly over an empirical duration $N = A^{0.2}$ days to rejoin the recession limb. (Correct answer: Option 2)