PaveDrain®
permeable paving
supported by HydroCAD
HydroCAD provides direct support for the PaveDrain system of permeable articulating concrete block mats. This allows the storage and infiltration capabilities of PaveDrain installations to be easily modeled with HydroCAD.
The PaveDrain can be modeled with HydroCAD-10 or later, which provides an interactive chamber wizard for easy layout, pricing, and modeling of modular storage systems. Earlier versions will require a program update in order to model PaveDrain systems. If you're already using HydroCAD-10, make sure you have "build 3" or later in order to get PaveDrain support. Details here.
How chambers are modeled
In a HydroCAD model, stormwater storage, such as the internal PaveDrain tunnel, typically appears as part of the storage definition for a "pond". In the simplest case, HydroCAD calculates the total storage for use with other calculations. But more often, HydroCAD is used to generate a complete inflow or runoff hydrograph and route it through the pond. The resulting analysis indicates the water levels attained throughout the rainfall event, as well as any discharge that may occur through outlet devices or infiltration into the surrounding ground.
Flexible storage options
Each pond can include an unlimited number of storage definitions as required to describe its overall storage characteristics. This makes it easy to model complex storage arrangements, such as a combination of multiple chambers, pipe storage, catch basins, or other contributing volumes.
In the case of a PaveDrain block, HydroCAD calculates the internal storage of the PaveDrain arch, plus the underlying stone bed. This determines the total storage available in the "pond", as well as the area available for exfiltration calculations.
The HydroCAD model can also include auxiliary storage provided by adjacent pipes and catch basins, plus above-grade areas (e.g. parking lot) that may provide overflow storage for certain events.
Modeling PaveDrain systems
Setting up a "pond" with PaveDrain storage is a simple process: Just select the Chamber Wizard, pick PaveDrain from the drop-down list, and set the number of rows and the row length. Check the "Default" box to set the minimum 6" stone bed, or set a custom depth as required.
Based on this information, the chamber wizard calculates the dimensions of the underlying stone bed and the total volume of stone. Storage is then calculated based on the stone voids (porosity) plus the internal PaveDrain storage, and the storage in the 1/4" gap between blocks. The wizard can also be used to estimate the total installed cost, including the PaveDrain blocks, stone base, and other elements.
Note: In addition to the stone base, HydroCAD models stone fill in the 1" waists of all the perimeter blocks, as well as the half-block area at the end of each row. In practice, a solid half block will normally be inserted in this space, resulting in slightly less storage than predicted by HydroCAD.
In addition to calculating the total storage in the PaveDrain system, HydroCAD can perform runoff and routing calculations to verify the behavior of the PaveDrain system under any desired rainfall conditions.
Detailed chamber information
For detailed PaveDrain specifications and design information, please visit the PaveDrain web site.
For more information about HydroCAD
Please see the following pages for further HydroCAD information:
Pond storage calculations
Storage chamber modeling
Exfiltration calculations
General support page
HydroCAD features and capabilities
Free evaluation program
Pricing and ordering
HydroCAD® is a registered trademark of HydroCAD
Software Solutions LLC.
PaveDrain® is a registered trademark of PaveDrain.