Debris Flow Sediment Visualization Video

# Debris Flow Riverbed Change Simulation Model

You are a computational geomorphologist and scientific visualization specialist. Build a complete debris flow simulation model that calculates sediment transport, deposition, and channel evolution over time, then generates visualization code to render the results.

## Terrain Context
{{terrain-description}}

## Simulation Requirements

### 1. Physical Model Implementation
Implement a debris flow model incorporating:
- **Flow dynamics**: Manning's equation or shallow water equations for flow routing
- **Sediment transport**: Entrainment and deposition based on flow velocity thresholds and sediment capacity
- **Mass balance**: Track sediment volume changes at each grid cell over time
- **Topographic evolution**: Update elevation based on net erosion/deposition

Use realistic parameters:
- Debris flow density: 1,800–2,200 kg/m³
- Critical velocity for deposition: 1–3 m/s
- Manning's n: 0.05–0.15 for debris-laden channels
- Time step: adaptive based on Courant condition

### 2. Calculation Outputs
Generate structured data for each time step:
- Elevation change matrix (Δz in meters)
- Cumulative sediment deposition/erosion volumes (m³)
- Flow depth and velocity fields
- Flood extent polygons (areas where depth > threshold)
- Hotspot zones: areas with >0.5m deposition or erosion

### 3. 3D Visualization Code
Create a video rendering script using {{rendering-library}} that shows:

**Visual layers**:
- Base terrain with {{texture-style}} texturing (options: aerial photo-realistic satellite imagery, procedural rock/soil materials, topographic color ramps, or hybrid)
- Color-coded elevation changes: blue (erosion) → white (stable) → red/orange (deposition), with scale bar
- Semi-transparent flow depth overlay during active flow phases
- Flood extent boundaries highlighted with animated contour lines

**Camera & animation**:
- Smooth orbital path showing multiple viewpoints (plan view, oblique angles, close-ups of deposition zones)
- Time-lapse progression with on-screen timestamp and cumulative volume counter
- Before/after split-screen comparison in final frames
- Legend overlay: deposition scale (m), erosion scale (m), flow depth scale (m)

**Technical specs**:
- Resolution: minimum 1920×1080, 30 fps
- Duration: 30–90 seconds covering full simulation
- Vertical exaggeration: 1.5–3× for clarity
- Lighting: directional sun at 45° with ambient occlusion for depth perception

### 4. Code Structure
Organize as:
```
1. Terrain generation/import module
2. Debris flow physics engine (time-stepping loop)
3. Data export (elevation grids, volume time series, flood masks)
4. Visualization renderer (scene setup, material assignment, animation sequencing)
5. Video output pipeline
```

Include inline comments explaining:
- Key equations and parameter choices
- Grid resolution and domain size assumptions
- How to modify initial conditions (source volume, hydrograph shape)
- Where to adjust visual styles

### 5. Clarity Features
**Make deposition zones unmistakable**:
- Aggregate cumulative deposition into 3–5 severity classes with distinct colors
- Add 3D vertical bars or heatmap glows at high-accumulation cells
- Annotate top 3 deposition hotspots with volume labels

**Make flooding obvious**:
- Animate blue translucent water surface during peak flow
- Outline maximum flood extent with bold boundary line
- Show flow direction with animated particle tracers or arrows

## Deliverables
1. **Simulation code**: fully runnable model with sample initial conditions
2. **Visualization code**: complete rendering script ready to execute
3. **README**: parameter guide, execution instructions, output file descriptions
4. **Sample outputs**: at least one rendered video or frame sequence demonstrating the model

Prioritize code clarity and ease of modification—future users should be able to swap terrain data, adjust physics parameters, and re-render within 15 minutes.