Hydrology Subsystem
The global water cycle: flow, basins, moisture, and surface water dynamics.
The Hydrology Subsystem models the behavior of water across the planetary surface.
This includes flow direction, accumulation, basins, moisture distribution, and the dynamic relationships between terrain and water.
Hydrology is one of the most visually expressive and foundational subsystems in the simulation.
Purpose
The purpose of the Hydrology Subsystem is to simulate how water moves across the planet’s surface, how it accumulates, and how it influences climate, terrain, and life.
It provides both physical realism and intuitive visual feedback for educational, scientific, and gameplay contexts.
Core Principles
- Topology-Driven Flow — water movement follows geodesic gradients.
- Directed-Edge Logic — asymmetric flow representation for natural transfer.
- Multi-Domain Influence — hydrology drives moisture, climate, and ecosystems.
- Deterministic Flow Computation — same inputs always produce the same flow patterns.
- Continuous Feedback — hydrology responds to terrain and climate changes.
System Model
Primary Fields
- Flow Magnitude (directed-edge) — how much water moves from one tile to another.
- Flow Direction (directed-edge) — path determined by elevation and slope.
- Water Accumulation (tile) — rivers, lakes, surface accumulation.
- Moisture Field (tile) — condensation, evaporation, soil moisture.
- Basin Classification (tile) — watershed identity and flow destinations.
Temporal Behavior
Hydrology updates on the medium clock, balancing responsiveness with stability.
Influence Model
Hydrology interacts with:
- elevation → determines flow
- atmosphere → determines evaporation
- ecosystems → determines biomass viability
How It Interacts With Other Systems
- Geology — elevation and slope drive all flow logic.
- Atmosphere — evaporation/precipitation loops influence moisture.
- Ecology (future) — water availability drives biome and resource distribution.
- Civilization (future) — water access determines settlement feasibility.
- Overlays — flow vectors and basins visualize hydrological behavior.
What This Enables
- realistic river networks
- watershed and drainage mapping
- moisture gradients for climate modeling
- emergent weather patterns
- compelling visual overlays
- rich educational demonstrations
Visual Examples (Optional)
- directed-edge flow visualization
- basin coloration overlays
- moisture distribution heatmaps
Public Extensibility Notes
Future SDK features may allow:
- custom hydrology models
- external precipitation datasets
- advanced flow experiments
- educational water-cycle scenarios
Hydrology is one of the most extensible and expressive subsystems in the engine.