WetlandMod® is built upon the concept of horizontal flow biofiltration, just as the MWS Linear – screening, separation, & biofiltration – combined with the capacity to reduce and control water volume in a more efficient way when compared to traditional downward flow bioretention systems. The WetlandMod® can utilize various media blends to meet the local stormwater bioretention specifications.

BMPs Advantages

  • Horizontal flow biofiltration
  • Pretreatment chamber
  • Volume Reduction & Control
  • Peripheral Void Area
  • FLow Control
  • No Depressed Surface


The WetlandMod is designed to accept various 5-inch per hour media blends to meet local agency LID requirements. They system is also available with an organic-free WetlandMEDIA to prevent nutrient leaching and maximize pollutant removal.

Downward Flow Systems Have an Inherent Flaw

Water Flow Unimpeded

Water Flow Impeded

Downward Flow Systems or Bioretention Systems have an inherent flaw. The force of gravity. As stormwater runoff carries pollutants into the system, including sediments and hydrocarbons, they are deposited on top of the bioretention media. Sediments in stormwater accumulate on top of downward flow systems, eventually clogging the filter media and system.

Sediments in stormwater accumulate on top of downward flow systems, leading to clogging

It has been documented that sediment accumulation from just a few storm events can completely clog a bioretention system. This leads to drastically reduced infiltration rates, expensive maintenance burdens, and safety issues associated with standing water, depressed landscaping and vector control.

The WetlandMod overcomes these challenges by utilizing pre-treatment, a horizontal flow biofiltration bed and orifice flow control. The initial surface of the media bed in the WetlandMod is oriented on a vertical plane as opposed to horizontally. The vertical planes run parallel with the force of gravity as opposed to perpendicular to it. This simple concept increases surface area, reduces BMP footprint, prevents clogging and leads to an enhanced overall system with lower maintenance costs.



WetlandMEDIA is an organic free alternative to traditional bioretention media. It offers higher infiltration rates and a sorptive media mix with high ion exchange capacity. This makes it ideal for nutrient removal. WetlandMEDIA also supports robust vegetation and prevents standing water.

Bioretention Mix

The WetlandMod is designed to utilize any type of bioretention mix required to meet local requirements and specifications, including a 5-Inch Per Hour sand compost mix found in most LID manuals.