Interactive engineering model
Rational Method watershed
Watch rainfall split across roof, pavement, lawn, and woodland and converge at the watershed outlet as Q equals C i A.
Preparing the 3D model...
Four land-cover strips drain across one solid catchment whose footprint follows the drainage area and whose grade comes from the flow path length divided by the time of concentration. Sheet-flow film thickness follows the surface runoff coefficient times intensity, five-minute travel bands cross the parcel, and the collector channel at the outlet carries the Manning normal depth for the peak discharge.
Focus the 3D view and use the arrow keys to orbit, plus or minus to zoom, and Home to reset the view.
Text explanation and non-WebGL fallback
Four land-cover strips drain across one solid catchment whose footprint follows the drainage area and whose grade comes from the flow path length divided by the time of concentration. Sheet-flow film thickness follows the surface runoff coefficient times intensity, five-minute travel bands cross the parcel, and the collector channel at the outlet carries the Manning normal depth for the peak discharge.
The numeric controls and readouts remain usable if WebGL is unavailable. Drag or swipe the 3D view to orbit and use a wheel or pinch gesture to zoom. With the 3D view focused, use the arrow keys to orbit, plus or minus to zoom, and Home to reset. The complete numeric lesson is also keyboard-accessible in the adjacent controls and readouts. This model is an educational aid and does not replace applicable design standards or professional review.