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CON/SPAN® Concrete Detention and Infiltration

CON/SPAN is a modular, precast concrete arch system designed to provide economical, large volume stormwater detention or infiltration below grade. CON/SPAN’s distinctive arch top and vertical side walls maximize storage volume while providing enhanced structural integrity.

Flood Control

Contech's CON/SPAN® and UrbanPond® precast underground storage systems are designed to maximize storage volume and capture peak storm events to minimize downstream flooding and erosion.

Precast Systems for Stormwater Detention and Infiltration

Contech's CON/SPAN® and UrbanPond® concrete stormwater detention and infiltration solutions provide the versatility to accommodate any footprint needed. These patented precast structures are engineered to maximize storage and ensure structural integrity.

Technical information for this product is centrally located in the technical guides section.

View Technical Information

CON/SPAN Detention and Infiltration Features and Benefits

Distinctive shape; arch top and vertical side walls
Maximizes storage space; superior durability and structural integrity
Full range of span & heights
Versatile design capabilities
Precast continuous foundation
Ensures structural integrity and eliminates differential settlement
Manufactured in a quality controlled environment
Superior quality over cast-in-place
Base slab, strip, or pedestal wall foundations
Foundation versatility

CON/SPAN Detention and Infiltration Installation

  • The CON/SPAN precast elements are three-sided arch units that offer rapid set-in place construction.
  • Systems are installed on top of cast-in-place concrete foundations.  Precast elements are set in a keyway that is cast into the foundation.
  • The system can also be installed on top of a pedestal wall foundation if additional vertical rise is required.

CON/SPAN Detention and Infiltration Maintenance

  • Manhole and other access openings can be located in the center of the units or along walls to allow for ladder access.
  • CON/SPAN can be equipped with a large opening between units that allow for maintenance equipment to be lowered into the system.


HydroCAD Stormwater Modeling

Contech CON/SPAN Detention Systems can be easily modeled with the HydroCAD Stormwater Modeling system, allowing simplified analysis of the devices' behavior in a drainage and stormwater management system.  The HydroCAD chamber library includes detailed storage data for each Contech product allowing automatic determination of their unique stage-storage characteristics. Click here for details.

HydroCAD® is a registered trademark of HydroCAD Software Solutions LLC.

Large Volume Stormwater Storage

CON/SPAN is a modular precast system designed to provide economic, large volume stormwater detention or infiltration below grade.  CON/SPAN’s distinctive arch top and vertical side walls maximize storage volume and provide structural integrity. Combining the CON/SPAN arch unit with precast walls and cast-in-place foundations allows for an array of configurations to meet nearly any site need.

Construction of cast-in-place strip footings beneath CON/SPAN legs and end walls allow for a large open area in the center of each cell. These cells can be filled with crushed stone or granular material to allow for stormwater infiltration or recharge by percolating runoff through the granular material inside of the foundation.

CON/SPAN system provides efficient stormwater detention in a variety of footprints. Installation on a base slab foundation can be made watertight, which is ideal when dealing with high water table issues or subgrade soils sensitive to water infiltration.

CON/SPAN can be combined with the Stormwater Management StormFilter to provide high-volume stormwater treatment. 

The Contech Advantage

Agency/Regulatory Guidance

Our team is ready to provide you with expert advice and assistance on local regulatory requirements, resulting in faster approvals.

Solution Development

Our engineers can review your requirements, weigh all options, and recommend the optimal solution to integrate with your site designs.

Technical Expertise

Our engineers can assist by providing product specific engineering calculations such as hydraulics, buoyancy, foundation reactions, and unit sizing.

Cost Estimates

We can quickly provide engineer’s cost
estimates to assist with your solution
selection process.

Site Specific Drawings

Our engineers can provide site-specific drawings for proposals, project meetings, and submittals, helping you be more efficient with your time.

On-site Assistance

Contractors know time is money, so we provide preconstruction meetings, delivery coordination, and on-site installation support to ensure a timely, smooth installation.