Excellent polution filtration

More efficient than gravel counterparts, and 30 year filter guarantee

Excellent water storage

Double the capacity compared with gravel systems

Streamlined installation

No temporary shoring works, less excavation, fewer lorry trips required

Highly configurable

Modular nature allows extra capacity to be added. In-ground problems can be negotiated 'live' during installation

Highly effective infiltration
Top blocks act as inlet channel
Fast, simple installation

Swales are shallow, broad and vegetated channels that store and/or convey road surface runoff and remove pollutants. Hydrorock natural aquifer block swales can be designed as conveyance structures to pass the runoff to the next stage of the Hydrorock treatment train, or to buffer run off and promote infiltration where soil and groundwater conditions allow.


In all cases, Hydrorock swale solutions mitigate flooding caused by run off and prevent rainwater overloading the sewer system where clean water becomes contaminated.

  • More efficient than gravel counterparts
  • Excellent filtration of pollution
  • No possibility of blockages
  • 30 year filter guarantee
  • Double the water storage capacity compared with gravel
  • No temporary shoring works required
  • 15% less soil excavation  (by volume and weight)
  • 60% less infill weight (far fewer vehicle loads required with Hydrorock)
  • 33% bigger infiltration surface area (much more efficient than gravel system)
  • 30 year filter life (double gravel 15 year filter life)
  • Free recycling by Rockwool (gravel needs expensive cleaning)   
  • Full integratable with other Hydrorock infiltration or attenuation systems
  • Excellent load bearing up to 40 tonnes and life time system integrity
  • Uniquely high absorption to volume ratio (94%)
  • 100% natural product
  • Recyclable

Design detailing


Installation is very simple and quick with minimal disruption.
Blocks are pre-wrapped with filter membrane, so the excavation needs to be only as large as the system (no access is required to fit the membrane).

  • No specialist installation engineering or equipment is needed, with simple push-together blocks and snap-together fittings which require no special skills or tools
  • Hydrorock natural aquifer blocks can be used in single or multiple layers, on a 100 mm layer of sand. This increases the surface area of the bottom of the system
  • Multiple block configurations are possible to suit site requirements
  • Extra capacity is provided by adding further blocks, which, on contact with others, become unitary aquifers
  • Hydrorock BD blocks have integrated perforated pipes allowing rapid inflow and storage water in each block underground.
  • Additional capacity can be rapidly and easily achieved by the addition of further Hydrorock BD blocks or Hydrorock B blocks (pre-wrapped but without integrated pipes)
  • The system can be placed around existing infrastructure, such as pipes and cables unlike crated sumps. This flexibility allows for optimisation of the site.
  • Placing the system on a 100mm layer of sand will permit infiltration from the module into the surrounding soil and facilitate the discharge of water from the Hydrorock blocks.




Click here to use our calculator and quickly calculate the number and volume of Hydrorock natural aquifer blocks needed for your application.


Hydrorock natural aquifer blocks are available to provide 100% sustainable, 100% recyclable water management solutions.

D Block
D Block
BD Block
BD Block
DHD Block
DHD Block
BDHD Block
BDHD Block
BD Block
IR Block
LG Block
LG and SL Blocks
IP Range
IP Range
Filter units
Filter units
Hydrorock fixings and connectors
Hydrorock fixings and connectors