HydroCAD Supports DeepRoot Silva Cell™
HydroCAD provides direct support for
the Silva Cell™, manufactured by DeepRoot.
This allows the Silva Cell to be easily used within any HydroCAD model for
stormwater storage, detention, or infiltration.
The Silva Cell can be modeled with
HydroCAD-9.1, which also provides an interactive
chamber wizard for easy layout, pricing, and modeling of underground storage
systems. (Please contact DeepRoot for current pricing to
use in the chamber wizard.)
Note: You will find the Silva Cell listed alphabetically by
manufacturer as "DeepRoot Silva Cell". Early shipments of 9.1 may require a
chamber update to provide the
necessary Silva Cell definitions.
How chambers are modeled
In a HydroCAD model, stormwater chambers typically appear as part of the
storage definition for a "pond". In the simplest case, HydroCAD
calculates the available storage for use with other calculations.
But more often, it 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.
Special modeling considerations
1) Unlike most
"chamber" products, the Silva Cell is normally filled with a bioretention soil
to support the growth of trees in an urban environment. The Silva Cell
definitions that are supplied with HydroCAD automatically allow for the 20%
available storage provided by the void space in the bioretention media, as well as the minimum required
cell spacing of 1".
Important: When using the chamber wizard, the "spacing"
parameter must be set to zero in order to prevent stone backfill from being
placed between the cells. The cell definitions already include the 1"
space between cells, and the 20% voids in the bioretention media, so additional
spacing in the model is not required.
2) Because of the bioretention media, water will not enter the Silva Cell as
rapidly as a conventional open-cavity chamber. For this reason, additional
modeling elements may be required to properly simulate the delayed inflow.
Specific modeling recommendations and sample HydroCAD project files are
available upon request.
3) Dewatering of the Silva cell is typically achieved by root absorption and
evapotranspiration, rather than infiltration into the adjacent ground, or
overflow to a storm sewer system. However, any combination of these
"outflow" mechanisms can be modeled, depending on the design objectives and site
details. Please contact DeepRoot for further details.
4) Specific modeling recommendations and sample HydroCAD project files are
available from DeepRoot upon request.
Flexible storage options
In addition to
storage within the Silva Cell, HydroCAD can model almost any imaginable storage
arrangement, such as auxiliary storage from
adjacent pipes and catch basins, and even the above-ground areas (parking lot)
that may provide overflow storage for certain events.
Each "pond" can include an unlimited number of storage definitions as required
to describe its overall storage characteristics.
If appropriate to your application, HydroCAD can also embed (bury) chambers in a
bed of crushed stone, and automatically calculate the combined
storage at any water surface elevation. This makes it easy to determine
the storage for virtually any configuration of chambers and stone, without
resorting to manual calculations.
Modeling the DeepRoot Silva Cell
Setting up a pond to use Silva Cell chambers is a simple process: Just
pick the desired Silva Cell unit from the drop-down list, and specify the
total number of chambers. Since the Silva Cell is used in heights of 1 to
3 units, separate definitions are provided for each height. As noted
above, the Silva Cell definitions automatically allow for the 20% voids in the
bioretention media, as well at the 1" minimum required spacing between cells.
For chambers that are installed in a stone bed, you can describe the shape and dimensions of the
outer excavation, plus the stone voids (porosity), and the composite storage is
calculated automatically. Or you can use the new
chamber wizard for automatic chamber layout,
modeling, and cost estimating.
Detailed Silva Cell information
For detailed chamber specifications and design information, please visit the
DeepRoot Silva Cell page.
For more information about HydroCAD
Please see the following pages for further HydroCAD information:
Pond storage calculations
Storage chamber modeling
(includes step-by-step instructions)
Exfiltration calculations
General support page
HydroCAD features and capabilities
Free evaluation program
Pricing and ordering
Images courtesy of DeepRoot Partners LP.
Silva Cell™ is a trademark of DeepRoot Partners LP.
HydroCAD® is a registered trademark of HydroCAD
Software Solutions LLC.
