Domain: Humanities and Social Sciences — Geography
Target concept: River hydrology: Flood season (rising water level, turbid water) vs. low-water season (falling water level, clear water)

Video generation prompt: This sequence of images illustrates two stages of the river: first, the changes in water level and water clarity during the flood season, and second, the changes in water level and water clarity during the low-flow season.

Evaluation guide:
(i) Target concept: Fluvial hydrological seasonality manifested through observable water level and optical clarity shifts.
Minimum mechanism: River must carry suspended sediment during high flow (causing turbidity), and sediment must settle during low flow (restoring clarity); water level must covary with flow magnitude; both states must be causally linked to the same seasonal regime, not local disturbance (e.g., dam release, rainfall pulse).
(ii)Storyline: Frame opens on stable river view → water level rises gradually (visually anchored to fixed bank marker) while color shifts toward turbid brown-gray → peak flood frame shows maximum submergence and zero bed visibility → water level recedes gradually → low-flow frame shows exposed geomorphic features and full bed visibility under clear water → entire sequence observed from immovable viewpoint with consistent lighting and geometry.

Manual:
Experimental Procedure
1. Film a fixed-viewpoint shot of a natural river channel.
2. First 5 seconds: Show rising water level submerging lower bank features, with water appearing brownish-turbid and opaque.
3. Last 5 seconds: Show falling water level exposing submerged features, with water appearing lower and transparent-clear.
Observation of Experimental Phenomena
- Flood stage: Water level higher, covering rocks/roots; water color brownish-gray; underwater features invisible.
- Low-flow stage: Water level lower, revealing previously submerged rocks/roots; water clear and colorless/transparent; underwater features clearly visible.
Summary of Experimental Principles
River flood season correlates with increased discharge → higher water level + suspended sediment → turbid water. Low-water season correlates with reduced discharge → lower water level + sediment deposition → clear water.

Prompt Grounding rubric:
level_1: No river is shown at all, or the shot depicts an unrelated body of water (a lake, ocean, or urban canal) rather than a flowing river, or only a single static moment is given with no depiction of two different water-level/clarity stages.
level_2: A river is shown, but only one of the two hydrological stages appears: either a high, turbid stage or a low, clear stage, with no second stage of the same channel at a different level and clarity.
level_3: Two stages of the same river channel appear one after another: the first shows a visibly higher water level with turbid, murky-looking water, and the second shows a visibly lower water level with clear water, matching the flood-then-low-flow order named in the prompt.
level_4: Everything at the level below holds, and both stages appear to be filmed from the same camera position and framing (the same bank line and horizon in both shots), with no boats, people, or on-screen text interrupting the water-level/clarity contrast, and the water's edge sits at a consistent place relative to a shared landmark (such as the same rock or tree) rather than the framing being recomposed between the two stages.
level_5: Everything at the level below holds, and the riverbank's shape and surrounding landmarks read as continuous with no cut, zoom, or repositioning between the two stages, and one fixed feature (for example the same partly submerged rock, root, or bridge pier) is shown partially covered by water in the flood stage and fully exposed in the low-flow stage, and the turbid or clear look of the water is conveyed only through the water's own appearance, with no overlay, filter, or color grading that wouldn't arise from real suspended sediment, and the whole flood-to-low-flow transition unfolds within one continuous shot of roughly ten seconds (about five seconds per stage) rather than being compressed or dragged out unpredictably.

Scientific and Causal Correctness rubric:
level_1: The water level does not actually rise then fall across the two stages (e.g., both stages show a similar level), or the clarity contradicts basic river-sediment logic, for instance the higher, flood-stage water looks clearer than the lower, low-flow-stage water, so the turbidity shown has no link to how much water is flowing.
level_2: Water level and clarity both change across the two stages, but they are paired backwards relative to real river hydrology, for example the flood-stage shot shows clear water while the low-flow shot shows turbid water, or a patch of turbid water appears within the low-flow stage with no visible cause such as a nearby disturbance.
level_3: The flood-stage shot pairs a higher water level with turbid, sediment-laden-looking water, and the low-flow-stage shot pairs a lower water level with clear water; the turbidity stays confined to the water itself rather than smearing onto the banks or air, and the clear water in the low-flow shot looks uniformly transparent rather than patchy.
level_4: Everything at the level below holds, and the suspended sediment in the flood-stage water appears spread evenly through the visible water rather than floating only on the surface or settling only near the bottom, correctly suggesting turbulent mixing at high flow, and the clear low-flow water lets the riverbed and any submerged material be seen through its full visible depth rather than only near the surface.
level_5: Everything at the level below holds, and the shift in clarity between the two stages reads as a physically coherent settling process (if any gradient is shown, finer turbidity would sit near slower-moving water at the edges rather than the video showing a hard, uniform boundary splitting turbid from clear water within a single frame), and no coloring artifact (such as a flat color wash or filter-like tint) appears that wouldn't arise from real suspended sediment.

Spatiotemporal Consistency rubric:
level_1: The river vanishes and reappears between the two stages, or the water's edge jumps to a drastically different position in the frame with no visible transition (shifting more than half the frame's width instantly), or the scene switches between daylight and night with no transition, or the riverbank's curve or the landmark used to show the level difference (such as the reference rock or bridge pier) moves or disappears between the two stages.
level_2: The camera's viewpoint itself changes between the flood and low-flow shots (a noticeably different angle or height rather than a fixed position), or the water's surface stutters or skips visibly during the level change, or the fixed rock or vegetation line used to show the level difference looks different in shape or position between the two stages with no visible cause.
level_3: The camera position and the visible riverbank shape stay the same across both stages; the apparent direction of the light does not swing back and forth or vanish between the flood and low-flow shots; the water's surface motion (rippling or flow) looks continuous within each stage rather than jumping or freezing.
level_4: Everything at the level below holds, and foreground elements (such as near-bank rocks or reeds) stay aligned with background elements (such as the far riverbank or tree line) as the camera holds its position, and any moving background elements (clouds, birds, drifting debris) keep moving in the same direction across the transition rather than reversing, and reflections on the water's surface stay consistent in orientation and distortion with the bank features they mirror.
level_5: Everything at the level below holds, and the water's rippling or flow is smooth and continuous with no freezing or skipped motion, and the same partial-occlusion relationships hold in both stages (for example, a reed clump or rock that partly blocks part of the bank in one stage still blocks the same part in the other), and no lens-like artifact (such as a sudden vignette or color fringe) appears at the transition between the two stages.