Silt Traps, Leaf & Treatment Filters

One of the topical issues with Attenuation and Infiltration systems is how to prevent silt entering the system and how to manage silt that does enter the system. Prevention is the obvious first choice.

Additionally minimising pollution of the natural watercourse, in line with new legislation and guidelines such as the Water Framework Directive is becoming increasingly important. This is where the use of a Treatment Filter is necessary.

Silt Traps

These bespoke fabricated solutions stop the ingress of silt and debris through the use of specific filters designed to suit particular requirements.


All SUDS solutions

Features & Benefits

  • Prevents ingress of debris into structure, extending its useful life
  • Lightweight chamber design
  • Tough and durable product
  • Pre-fabricated off-site and delivered ready to install
  • Choice of chamber sizes from 1050mm, 1200mm, 1500mm, 1800mm and 2100mm
  • Inlets and outlets supplied with integral sockets as standard
  • Provides easy access maintenance points for silt collection prior to the attenuation structure

Leaf Filters

As with the Silt Traps, Leaf filters are a bespoke fabrication to stop the ingress of leafs through the use of specific filters. Their use is predominantly in conjunction with GRP Attenuation Tanks.


Used with GRP Attenuation Tanks

Features & Benefits

  • Self cleaning
  • Low maintenance
  • Filters for roofs up to 3000m2
  • Pre-fabricated off-site and delivered ready to install
  • Tough and durable product

Treatment Filters

New legislation and guidelines such as the Water Framework Directive calls for stricter water quality discharged into the environment. JDP offers regulatory-compliant solutions for dealing with the issues of water quality from surface water run-off from roofs, car parks, and the most polluted roads, even in heavily trafficked areas.

These products are not a substitute for use as Oil Seperators, see Surface Water Drainage section for Oil Seperators.


  • Highway runoff
  • SUDS projects
  • Vehicle maintenance wash down
  • Car parks
  • Industrial commercial areas
  • Wetland projects

Features & Benefits

  • 4 stage filtration for oil retention, chemical separation, filtration and sedimentation
  • Low maintenance
  • Source control
  • Easy to install
  • Off site solution
  • 3 versions for, traffic, heavy traffic and roof applications

Downstream Defender®

The Downstream Defender® is an ideal solution for the prevention or reduction of solids and pollutants entering water storage areas where settlement can occur, leading to a build up over time. The system is a hydrodynamic separator which is incorporated into a reinforced concrete chamber.

The design of the internal components directs stormwater downwards and around the periphery of the chamber inducing a rotational flow. A unique flow pattern created within the chamber encourages the solids separation, the silt sediment sinks and floatable debris floats. Both are then prevented from re-entering the main flow path.

Whilst this product has an oil retention element it is not a substitute for Oil Seperators, see Surface Water Drainage section for Oil Seperators.

Features & Benefits

  • Available in sizes 1000mm to 3000mm diameter
  • No moving parts
  • Highly effective with minimal head loss
  • Inline & same level inlet & outlet pipes
  • Small footprint
  • No concrete backfill required
  • 1000mm & 1200mm sizes delivered complete
  • Other sizes delivered in easy to construct component systems