Detention & Infiltration

Detention & Infiltration2017-04-05T00:57:25+00:00

Jensen Stormwater Systems offers a variety of convenient, flexible, and cost effective methods to manage stormwater detention, retention and infiltration as well as engineered controlled release valves.  Jensen precast reservoirs, vaults, battery tanks, single tanks and manholes are engineered into modular systems that are installed quickly and easily below grade.  Jensen’s large variety of precast geometry and modular application of these shapes allow for nearly limitless configurations to fit a required storage volume within a specific project footprint.

Jensen Detention Reservoir (JDR)

The Jensen Detention Reservoir (JDR) is a precast modular stormwater storage system comprised of reinforced box culvert (RBC) Sections to meet large detention and infiltration needs for all development projects.  The JDR system is a perfect design solution for satisfying Hydromodification Plans (HMPs) to comply with the Standard Urban Storm Water Mitigation Plan (SUSMP).  The JDR system is a straight-forward means of ensuring that stormwater runoff rates from post-construction match pre-development runoff conditions and a practicable means of extending detention flow duration and maintaining discharges below erosive thresholds.  JDR systems can be arranged in many configurations to meet stormwater volumetric control storage or infiltration needs.

Jensen Detention Reservoir - Type 1 Reinforced Box Culvert Sections

Units that aren’t intended for infiltration can be made watertight, allowing for use in areas where groundwater is near the surface or with sensitive soils.  Stormwater can enter and exit the JDR through single or multiple inlets and outlets, either on the ends or cast as portals in sides of units.  Access openings that communicate with manhole and riser sections are engineered into the system as needed for simplified vactor-truck cleanout and maintenance.

Holding Tanks, Cisterns, and Manholes

Jensen Precast 16 foot manhole

Jensen Precast has been manufacturing and fine-tuning an entire line of traditional water storage and conveyance products since 1968.  Our vaults, holding tanks, cisterns, and manholes represent a large menu of geometric shapes that are readily available, economical solutions well-suited to serve in stormwater detention and infiltration applications.

Precast tanks and manholes come in a variety of size options.  Our readily available, off the shelf, precast vaults, holding tanks and manholes are ideal for project detention needs calling for 2,000 cubic feet (approximately 15,000-gallons), or less.  Depending on capacity, vaults and holding tanks are available in a monolithic or battery style. For larger detention and infiltration needs, assembling tanks and vaults together in a battery system provides an economical, scaling option.  Jensen Stormwater Systems can help evaluate the many available options to develop the best suited, most economical option for a development project.  In addition to tanks and cisterns, we offer standard manholes with internal diameters from 4 to 12-ft. To our knowledge, we are also unique in offering the only available 16-ft internal diameter manhole in the region.

Our traditional systems have been in use for many decades and have a proven track record of performance and ease of maintenance. A variety of loading options combined with the modular application of our vaults, tanks, and manholes to detain, infiltrate, and store stormwater is a powerful, yet simple solution for design engineers to meet a project’s volumetric needs.

LID Infiltration Shafting

LID Infiltration Shafting

Infiltration is an often-preferred low-impact development (LID) Best Management Practice (BMP).  In addition to minimizing the impact to the stormwater system, it emulates pre-development conditions where water has a chance to recharge groundwater.

In developed high-density urban areas, matching pre-development conditions is usually difficult to achieve.  The proximity of infrastructure, buildings, and property lines preclude opening large spaces to install above or underground storage and infiltration units. Jensen LID Infiltration Shafting systems solve this dilemma with an ability to achieve large infiltration volumes in a small footprint for high density areas or redevelopment projects having extremely limited space.  A properly designed infiltration system combined with in-situ soils having high infiltration rates may completely eliminate any stormwater discharge from a given development.

Infiltration Shafting comes in 3.5, 4 or 4.5-ft internal diameter precast circular shafts in solid and perforated walls to serve as vertical drywells.  This shafting enables stormwater to be infiltrated into the ground in a very small diameter.

Concrete Arches

Jensen Stormwater offers precast concrete arches for culverts and bridges that are frequently applied to stormwater storage.  These arches are designed with 3-sided precast arch-shaped, vertical-walled units.  The arched geometry optimizes the compressive strength of concrete to resist large bearing stresses over great span widths, allowing deep burials, traffic, rail and aircraft loadings. Arch units come in in span widths from 26 to 60-ft, with large interior heights when pedestal walls are used.

Arch system designs are flexible. In addition to right angles, ends can be finished skewed to create curved radius installations.  End walls seal the unit into a single reservoir and internal baffle weirs can be incorporated to create sedimentation zones.  Inlets and outlets can be created in either the ends or side walls, providing additional configuration and flow options. Due to arch systems’ typically large sizes, pretreatment systems as well as flow-control discharge systems can be configured within them. Sections can be installed on continuous precast or poured strip footings, stem walls, or pedestal walls.

The concrete arch systems are designed to be installed quickly, using an interlocking joint system.  As with other Jensen Stormwater precast systems, backfill can often be done with less expensive, local materials without complicated compaction procedures, which speeds installation.  Precast manholes in the surface of select arch roofs provide easy access for maintenance and vactor truck clean-out as needed.

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Jensen Water Resources

Jensen Water Resources is comprised of three specialized teams: Jensen Pump Stations, Jensen Stormwater Systems, and Jensen Advanced Onsite Wastewater Systems.

The Jensen Pump Stations team provides high-quality pump stations for municipal, commercial, industrial, and residential applications. The Jensen Stormwater Solutions team provides products and systems for a diversity of stormwater best management practice applications.
Jensen Advanced Onsite Wastewater Systems creates advanced treatment systems for removing pollutants from wastewater.