Modular drainage systems and water management solutions

Transport for Greater Manchester:
Newton Heath Metrolink
Project Overview
As part of Transport for Greater Manchester's £150 million network improvement programme,
modular drainage system units manufactured by Rosehill Group formed the drainage core of AQUA
Fabrications' Track Enhancement Drainage System (TED) during a major drainage renewal at Newton
Heath Depot.
Working alongside Story Rail and InoRail Design, the project replaced ageing drainage infrastructure
beneath one of the busiest sections of the Metrolink network. A modular drainage system approach was
selected to provide high-capacity water storage, rapid installation during limited possession windows, and
a more sustainable alternative to traditional drainage construction.
The installation demonstrates how modern drainage system engineering can improve network
resilience while reducing maintenance requirements and embodied carbon.
The Challenge
• Insufficient capacity - existing drainage infrastructure was no longer providing the performance
required
• Tightly controlled rail possessions meant water management had to be improved without
extending possession windows
• Repeated rail loading required a system that could withstand dynamic loads while maintaining
hydraulic performance
• Operational light rail environment demanded programme certainty throughout construction
• Long-term resilience - the solution needed to reduce maintenance while supporting future
climate resilience
Project Details:
Client: Transport for Greater Manchester
Principal Contractor: Story Rail
Drainage Partner: AQUA Fabrications Ltd
Design Partner: InoRail Design
Location: Newton Heath, Manchester
Application: Light Rail Infrastructure
Approved Design:
• 210lm of trough,
• 490lm full-height stackers
• 70lm of half-height stackers
Modular Drainage Systems

The Solution
• Modular drainage units incorporated into AQUA Fabrications' Track Enhancement Drainage System
• Approximately 210 metres of modular drainage installed
• Stackable drainage modules provided significant water storage within a compact footprint
• Lightweight recycled rubber components simplified handling and installation compared with
conventional materials
• Rapid modular installation during planned engineering possessions, integrating with the wider track
renewal works
Results
? Improved drainage capacity across a critical section of the Metrolink network
? Climate-resilient design: accommodates rainfall events up to 1-in-1000-year storms with 40% climate
change allowance
? More than 20 tonnes of waste diverted from landfill through the use of recycled rubber
? Approximately 14 tonnes of CO2 emissions avoided compared with equivalent concrete drainage
construction
? Reduced maintenance requirements through a durable, modular drainage system
? Successful integration within one of the largest rail infrastructure programmes currently underway in
Greater Manchester
Copyright ©2026 Civil Water Management Ltd. All rights reserved. Modular Drainage Units manufactured by Rosehill Group.
Constructability
The modular design of the system allows for simple installation in various locations, whether it is CESS, 6ft
or Toe/Crest drainage. Requiring only a minimum 50 mm surround, the system maximises space without
sacrificing performance or rigidity. The units have a male and female profile, allowing them to be stacked to
the height required - typically dictated by the volume of water that will pass through the system.
Combinations of different heights & lengths of porous units allow for greater flexibility and support manual
handling procedures, particularly on more remote sites. The system is also compatible with all AQUA
prefabricated catch-pits.
Why It Matters
Rail drainage is often constrained by limited construction windows, restricted access and the need to
minimise disruption to passengers.
By combining Modular Drainage Systems with AQUA Fabrications' TED system, the Newton Heath project
demonstrates how modular drainage technology can deliver greater hydraulic capacity, faster installation
and lower embodied carbon without compromising long-term performance.
As rail and light rail operators continue to adapt infrastructure for increasingly intense rainfall, modular
drainage solutions provide a practical approach to improving network resilience while reducing whole-life
costs.

Hartlepool Borough Council:
Burn Valley Gardens
Project Overview
Burn Valley Gardens is a historic Edwardian park following the course of a channelised burn through
residential Hartlepool. As part of Hartlepool Borough Council's Town Centre to Catcote Road cycle route -
one of the Tees Valley Combined Authority (TVCA) cycle schemes - the park's terraced paths off Colwyn
Road were renewed, and 600m of Grip Strip drainage units were installed to solve a long-standing runoff
problem that was eroding the embankment and undermining the park's original stone retaining walls.
Working with contractor BCE Northern Ltd, the terraces were resurfaced in porous asphalt laid to falls, so
that rainwater passing through and across the surface is directed to flush Grip Strip drainage lines at each
terrace edge. The strips collect the water and carry it to discreet outlets cut through the existing walls,
taking it safely down the slope to Burn Valley Beck.
The result is a fully draining path network with no gullies or gratings to maintain, no standing water, and
controlled outfalls in place of the uncontrolled runoff that was washing out the banks - delivered without
deep trenches, without heavy excavation plant, and without disturbing the roots of the mature trees that line
the paths.
The Challenge
• Uncontrolled runoff from the terraced paths was scouring the grass embankment and washing out
material from behind the park's historic stone retaining walls
• Heritage structures - deep excavation for conventional piped drainage alongside the old walls risked
disturbing their foundations
• Mature tree roots spread beneath the path edges throughout the park - traditional drainage
trenches would have cut straight through them, and the large excavation plant needed to dig them
would have compacted root zones and torn up the surrounding parkland
• Heavy leaf litter beneath the park's mature trees would quickly block conventional gullies and
gratings
• Public open space demanded a flush, trip-free finish safe for pedestrians, buggies, bikes and
mowers
• Steep terraced site - water needed collecting and conveying to the burn at the valley floor in a
controlled way
Project Details:
Client: Hartlepool Borough Council
Contractor: BCE Northern Ltd
Location: Burn Valley Gardens, Hartlepool
Scheme: TVCA Town Centre to
Catcote Road Cycle Route
Application: Cycle Route & Park Path Drainage
System Used: Grip Strip 100mm
Modular Drainage Systems
Copyright ©2026 Civil Water Management Ltd. All rights reserved. Modular Drainage Units manufactured by Rosehill Group.
The Solution
• Full-depth porous construction laid to falls - 30 mm porous asphalt surface course and 70 mm
porous binder over an open-graded sub-base, directing rainwater through and across the surface
towards the drainage lines
• 600m of flush Grip Strip drainage units - slimline 100 × 200 mm recycled rubber blocks installed
directly into shallow gravel-filled trenches, typically just 250 mm deep, staying above the tree roots
that conventional drainage trenches would have severed
• Compact plant, minimal damage - the shallow trenches were excavated with small machinery
rather than the heavy construction plant deep piped drainage demands, keeping disturbance to root
zones, lawns and established planting to a minimum
• Interceptor lines at every terrace edge, capturing runoff before it reaches the embankment
• Discreet outfalls to Burn Valley Beck - Stakkabox catchpits set beneath the Grip Strip runs, with
100 mm pipes down the embankment and vitrified clay outlets mortared through the beck wall
• Gravel and cobble dressed finishes blending the drainage lines into the park landscape
Results
? Runoff captured at source on every terrace, ending the scour and washout that was damaging the
embankment and walls
? Heritage retaining walls protected - the shallow 250 mm trenches avoided disturbing wall foundations
? Mature trees unharmed - shallow trenching stayed above the root zones, avoiding the root severance
that deep drainage trenches would have caused along the tree-lined paths
? Flush, trip-free finish throughout - safe for all park users and maintenance machinery
? Nothing to block - the porous rubber strips have no gratings or slots for leaf litter to clog
? SuDS-friendly drainage using porous surfacing and recycled rubber, discharging at a controlled rate to
the watercourse
? Rapid installation alongside the resurfacing works, with drainage lines trenched, laid and dressed in
the same visits using only compact plant
Copyright ©2026 Civil Water Management Ltd. All rights reserved. Modular Drainage Units manufactured by Rosehill Group.
Why It Matters
Parks and greenways are difficult places for conventional dra

Walk Wheel Cycle Trust: NCN Route 6
Milton Keynes City Council
Case Study
Project Overview
Working with the Walk Wheel Cycle Trust and Milton Keynes City Council, a 1km upgrade and widening scheme was
successfully delivered on National Cycle Network Route 6 between Castlethorpe and Wolverton.
Persistent flooding had rendered sections of the route inaccessible during wet weather and winter periods, creating
challenges for commuters, families and other users. Conventional drainage and excavation approaches were unable
to provide an acceptable solution to the site's planning and environmental requirements.
To address these challenges, a combined pathway construction and integrated surface water management solution
was developed using permeable Drainage Edges, Drainage Spurs and Drainage Mats. The resulting modular drainage
system enabled the route to be widened, resurfaced and drained using a reduced excavation methodology whilst
supporting accessibility, environmental stewardship and long-term route resilience.
The completed project demonstrates how integrated surface water management can help unlock active travel
infrastructure where flooding, drainage and environmental constraints might otherwise limit delivery.
Key Outcomes
1km extension completed in June 2025
Zero flooding recorded through camera
monitoring
Operational performance approaching two
years in service
Improved year-round accessibility and route
performance
Up to 50% reduction in carbon and estimated
19% cost reduction vs traditional methods
Forecast social value of £3.1 million over
10 years across the full route
Repeatable methodology capable of
supporting planning, drainage and
environmental objectives
Modular Drainage Systems

The Challenge
Persistent flooding issues made the 2.5km
route impassable in wet weather and winter
periods.
Families, commuters and disabled users were
unable or reluctant to use the path.
Conventional sustainable drainage plans and
excavation methods were unable to provide an
acceptable solution to planning approvals.
A sustainable drainage solution was required
to improve route resilience and support long-term
active travel use.
Planning and environmental considerations
required a solution capable of managing surface
water whilst minimising excavation and protecting
existing environmental assets.
Engineering Solution
Modular drainage system units installed to form
the path body construction, and simultaneously
manage surface water drainage.
Path widened and resurfaced with minimised
excavation to maintain environmental stewardship
best practice, and improve route accessibility and
user experience.
Sustainable drainage approach 2.5km approved
through environmental assessment and planning
processes.
Lower-carbon installation methodology
compared with traditional drainage alternatives.
Repeatable design suitable for wider deployment
across active travel networks.
Open-void drainage framework (avg. 45% void
ratio) enabling connected vertical, longitudinal
and lateral movement of water.
Reduced excavation construction methodology
supporting route widening, drainage performance
and tree root protection objectives.
Project Details
Client: Walk Wheel Cycle Trust,
Contractor: CIJO Ltd


Milton Keynes City Council, Rosehill Group
Integrated modular drainage path construction system with Drainage Edges/Grips/Spurs and Drainage Mats
Location: National Cycle Network Route 6, Milton Keynes


After: accessible, drained route
Why It Matters
National Cycle Network Route 6 demonstrates how integrated surface water management can help unlock active travel
projects where flooding, drainage and environmental constraints present barriers to delivery.
The project demonstrates how a single integrated construction methodology can simultaneously address route
accessibility, drainage performance, reduced excavation requirements and environmental stewardship objectives
whilst providing a repeatable model for future active travel infrastructure schemes.
Benefits for Route Owners, Local Authorities and Active Travel Teams
Flood resilience Eliminates persistent waterlogged pathway and supports year-round route performance.
Low impact construction No major trenching or pipework, reducing disruption in sensitive public spaces.
Sustainable materials Uses recycled rubber drainage components with a low-carbon design approach.
Scalable application A repeatable solution for local authority footpaths, cycleways, parks and public realm routes.
Discuss Your Project
Talk to our specialist drainage team.
E: [email protected] T: 0203 189 1468 W: www.civilwatermanagement.com