Evaluation of On-Farm Irrigation Efficiency Metrics:

• Statement (I) is Correct: Water storage efficiency ($\eta_s = V_s / V_{req} \times 100$) quantifies how completely the root zone storage capacity is replenished. When water allocations are constrained or in slow-permeability clay soils requiring protracted ponding, monitoring storage efficiency is crucial to prevent chronic under-irrigation.
• Statement (II) is Correct: Water application efficiency ($\eta_a = V_s / V_f \times 100$) compares water stored in the crop root zone ($V_s$) to total water delivered to the field ($V_f$). Applying excessive depths of water beyond root zone field capacity causes proportional increases in deep percolation losses and surface runoff tailwater, thereby driving application efficiency down.

Statement (I) is correct: Measuring flumes (such as Parshall, cutthroat, and trapezoidal flumes) are engineered contractions formed in open channels to accurately measure irrigation discharge rates. Statement (II) is incorrect: The operational hydraulic principle of measuring flumes is based on the conservation of specific energy (Bernoulli equation) by contracting the flow cross-section to induce critical flow, allowing discharge to be determined from an upstream head measurement alone, rather than being based on the concept of kinetic energy alone. Option analysis: (A) Statement (II) is incorrect. (B) Statement (I) is correct. (C) Statement (I) is correct but Statement (II) is incorrect is the correct answer. (D) Statement (I) is true.

Statement (I) is correct: A standard Parshall flume consists of three primary zones: an upstream converging section, a throat section with parallel vertical walls, and a downstream diverging section. Statement (II) is incorrect: In a standard Parshall flume, the floor of the converging section is horizontal (level), the floor of the throat slopes downward at a slope of $3:8$ (vertical to horizontal), and the floor of the diverging section slopes upward at a slope of $1:6$. Hence, stating that the throat floor inclines upward is physically false. Option analysis: (A) Statement (II) is false. (B) Statement (I) is true. (C) Statement (I) is correct but Statement (II) is incorrect is the correct answer. (D) Statement (I) is true.

Assessment of canal conveyance and cross-drainage structures: (A) Culverts are standard closed conduit structures installed under roads when the road embankment fill is sufficiently elevated above the canal invert; (B) Inverted siphons convey flow under hydrostatic pressure across wide depressions or shallow road cuts where minimal headroom precludes culverts; and (C) Elevated open flumes (aqueducts) span across natural drainages, ravines, and streams. Statements (D) and (E) are incorrect because cross-drainage structures are vital in irrigation layout, and a siphon is a pressure conduit, never termed a flume. Option analysis: (A) (A), (B) and (C) only is correct. (B) Includes false statement (D). (C) Includes false statements (D) and (E). (D) Includes false statement (D).