Jensen Biofilter tree box with a cast iron tree grate and curb inlet opening, planted with shrubs beside a parking lot.

Jensen Biofilter Stormwater Treatment

Jensen Biofilter – High Performance, Low Impact Stormwater Treatment Solutions for Urban Areas

Jensen Biofilter

Low Impact Development permits want green infrastructure that actually performs — and proves it.

Formerly the StormVault Biofiltration System, now the Jensen Biofilter: a new name to avoid confusion with StormVault detention, built around the same “Sierra Blend” media. It mimics natural filtration to capture sediment, trace metals, nutrients, oils, and trash, and retains them even under high-flow bypass.

NJCAT verified, NJDEP certified, and Washington State TAPE (GULD) approved.

Green Infrastructure With Verified Performance

Bioretention is the LID approach regulators want — but generic “rain garden” soil is hard to verify and easy to clog.

The Jensen Biofilter solves that with an engineered media. Runoff slows over rip rap, ponds, and passes through a mulch layer that removes gross debris, then through 18 inches of Sierra Blend bio soil media (BSM) that filters fine solids, adsorbs metals, filters oils, and breaks down nutrients — before an underdrain conveys treated flow out, or floor blockouts let it infiltrate.

Units install online or offline with internal or external bypass, sized to a design treatment flow, and retain captured pollutants under high-flow bypass with no scour.

Applications: residential, commercial, roadway, industrial, parking lots, and new or existing urban development.

01

Inflow

Curb / Pipe / Grate

02

Pond & Pre-Treat

Rip Rap + Mulch

03

Sierra Blend BSM

Engineered Media

04

Bridging Stone

Distribute Flow

05

Underdrain

Collect Treated

06

Discharge

Drain / Infiltrate

01

Inflow

Curb / Pipe / Grate

02

Pond & Pre-Treat

Rip Rap + Mulch

03

Sierra Blend BSM

Engineered Media

04

Bridging Stone

Distribute Flow

05

Underdrain

Collect Treated

06

Discharge

Drain / Infiltrate

The Jensen Biofilter is a treatment stage of a complete system — Jensen builds the pretreatment, detention storage, and reuse pumping too, so the whole system is engineered together.

How the Jensen Biofilter Works

The Biofilter recreates a natural bioretention process in a precast vault — slow the water, screen the coarse material, then filter it through engineered media.

Slow, Pond & Pre-Treat

Rip rap controls velocity and erosion, a ponding area provides head and sediment storage, and a mulch layer removes gross debris — protecting the media below.

Sierra Blend BSM

18″ of bio soil media is the primary treatment layer — filtering fine TSS, adsorbing metals, filtering oils, and breaking down nutrients. It exceeds the 2 gpm/ft² loading rate.

Biological Nutrient Removal

Nutrients are removed by filtration, volatilization, denitrification, and plant uptake, and the process also captures bacterial pathogens.

Slow, Pond & Pre-Treat

Rip rap controls velocity and erosion, a ponding area provides head and sediment storage, and a mulch layer removes gross debris — protecting the media below.

Sierra Blend BSM

18″ of bio soil media is the primary treatment layer — filtering fine TSS, adsorbing metals, filtering oils, and breaking down nutrients. It exceeds the 2 gpm/ft² loading rate.

Biological Nutrient Removal

Nutrients are removed by filtration, volatilization, denitrification, and plant uptake, and the process also captures bacterial pathogens.

Underdrain or Infiltrate

Bridging stone distributes flow to an underdrain that conveys treated water out; floor blockouts let all or part of the treated volume infiltrate.

Jensen Biofilter: In-Depth

Cross-section of a Jensen Biofilter planter box showing the inlet, internal bypass pipe, mulch layer, Sierra Blend media, bridging stone, and perforated underdrain.

Biofilter Cross-Section Explained

1. Inlet

Configurations include grated, piped, and curb inlet

1. Inlet

Configurations include grated, piped, and curb inlet

2. Internal Bypass Pipe

Conveys excess flow past the treatment chamber. External bypass configurations available

3. Mulch Stabilization Layer

Captures large trash and debris; protects media from scour, water retention for vegetation

4. Sierra Blend BSM

Inorganic components remove TSS and metals; organic components remove nutrients and facilitate biological uptake

4. Sierra Blend BSM

Inorganic components remove TSS and metals; organic components remove nutrients and facilitate biological uptake

5. Bridging Stone

Allows for even drainage; protects effluent pipe from clogging

6. Perforated Underdrain Pipe

Conveys treated flow to storm drain system or infiltration blockout

What the Jensen Biofilter Removes

Oils are filtered directly by the media, metals are adsorbed, and nutrients are removed through filtration, denitrification, and plant uptake.

TSS & Sediment
Trace heavy metals (Cu, Zn)
Nutrients (N, P)
Oil & Grease
Trash & Debris
Bacterial Pathogens

Biofilter Configurations

Featured - Planter Box

Planter Box

An above-ground planter or swale box, vegetated over the Sierra Blend media. Flow enters above the mulch/rip-rap — piped in or distributed through a curb inlet.

Tree Box

A planter box with an attached tree well. With the bottomless option, a tree can root and grow for decades, and deep media replacement doesn’t require re-planting it.

Underground Box

A fully underground vault with no plants or trees — the Sierra Blend media performs without vegetation, for sites with no room for surface planting.

Engineering Support

Get specs, drawings, or application support from our engineering team.

Engineering Support

Get specs, drawings, or application support from our engineering team.

Tested. Certified. Approved.

NJCAT Verified

Independently verified for ≥80% TSS removal at a 2 gpm/ft² loading rate, online and offline, with no scour under high-flow bypass.

NJDEP Certified

Certified as a Manufactured Treatment Device in April 2020, based on the NJCAT verification.

WA DOE TAPE — GULD

Washington State Department of Ecology TAPE approval at the General Use Level Designation.

NJCAT Verified

Independently verified for ≥80% TSS removal at a 2 gpm/ft² loading rate, online and offline, with no scour under high-flow bypass.

NJDEP Certified

Certified as a Manufactured Treatment Device in April 2020, based on the NJCAT verification.

WA DOE TAPE — GULD

Washington State Department of Ecology TAPE approval at the General Use Level Designation.

Honolulu Accepted

Jensen is also listed by the City and County of Honolulu as an accepted biofiltration provider.

80%

TSS removal (NJCAT / NJDEP)

84%

Total phosphorus

96%

96% copper · 93% dissolved / 98% total zinc

80%

TSS removal (NJCAT / NJDEP)

84%

Total phosphorus

96%

96% copper · 93% dissolved / 98% total zinc

2 gpm/ft²

Design loading rate

Built for Long-Term, Low-Cost Upkeep

The mulch layer is a sacrificial first screen that protects and extends the life of the media, and the system is designed so deeper servicing is straightforward when it’s eventually needed.

01

Mulch Protects the Media

The top mulch layer removes coarse solids and is refreshed periodically — preserving the Sierra Blend media and extending service intervals.

02

Media Replacement

Over the long term, the Sierra Blend media can be removed and replaced to restore full treatment capacity.

03

Tree Well Sustainability

With the bottomless tree well option, deep media maintenance happens without removing or re-planting the established tree.

01

Mulch Protects the Media

The top mulch layer removes coarse solids and is refreshed periodically — preserving the Sierra Blend media and extending service intervals.

02

Media Replacement

Over the long term, the Sierra Blend media can be removed and replaced to restore full treatment capacity.

03

Tree Well Sustainability

With the bottomless tree well option, deep media maintenance happens without removing or re-planting the established tree.

Biofilter Installation

Crew setting a precast Jensen Biofilter tree box vault with a cast iron grate and curb inlet.

Jensen Biofilter - Installation

A young tree set into the open tree well of a Jensen Biofilter tree box, with one grate panel removed.

Jensen Biofilter - Installation

Jensen Biofilter - Tree Box

How to Get Started

You have your workflow. We fit into it — not the other way around.

01

Request Sizing

Share your drainage area, treatment flow, and site layout. We’ll size the media bed, pick a configuration, and return a preliminary layout.

02

Get Drawings Fast

With sizing confirmed, we turn around project-specific drawings and submittals in days — not weeks.

03

Engineering Review

We confirm hydraulics and loading rate, verify agency compliance and certifications (NJDEP, TAPE), and provide stamped submittals.

04

Delivery & Installation Support

Precast vaults arrive ready to set — we coordinate delivery, media, and planting, and support installation through final inspection.

Complete Your System

The Jensen Biofilter is one treatment stage of a complete stormwater system. Add pretreatment upstream to extend media life, detention storage for volume control, and a pump station for reuse. Jensen engineers and manufactures all of it — one partner, one set of drawings.

01

Conveyance In

RCP / Box Culvert

02

Pretreatment

JDS / SV Baffle Box

03

Jensen Biofilter

Biofiltration

04

Detention

StormVault / Panel Vault