Interactive engineering model
Permeable pavement layer stack
Explode the paver, bedding, reservoir, and subgrade layers and compare conservative stone storage against run-on volume and subgrade drawdown.
Preparing the 3D model...
A layered pavement section shows rainfall entering open joints, water standing in the reservoir voids at the level the storage balance solves for, subgrade infiltration, and surface ponding when the required storage exceeds the reservoir. An optional underdrain can be drawn but its discharge is not included in the water balance.
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
A layered pavement section shows rainfall entering open joints, water standing in the reservoir voids at the level the storage balance solves for, subgrade infiltration, and surface ponding when the required storage exceeds the reservoir. An optional underdrain can be drawn but its discharge is not included in the water balance.
Important: The underdrain toggle is schematic only and does not change storage, drawdown, or any numeric result. Use the calculator for system design.
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.