A permeable paving solution from Brett Landscaping has delivered an effective Sustainable Drainage solution to a social housing development in Pontefract, for a comparable cost to traditional paving.
Stump Cross is an ambitious project built by contractor Jack Lunn Construction for developer Synergy Housing.
Due to an existing drainage infrastructure already working close to capacity – and therefore unable to cope with additional run-off – Wakefield Metropolitan District Council demanded that a Sustainable Drainage System (SuDS) be incorporated into the access road to Stump Cross.
A feasibility study confirmed that a permeable pavement was the most cost effective solution because the high density of the housing project precluded alternative SUDS devices such as swales and ponds which require additional land take.
Brett Landscaping was asked by Jack Lunn to devise a suitable solution and, following initial site investigations, determined that the permeability of the sub-grade was good enough to allow surface water resulting from rainfall in the area to infiltrate totally into the sub-grade.
Brett designed a permeable paving solution for the site using its PermCalc software, which assesses projects based on calculations of variables such as rainfall, traffic volumes and land composition to determine the appropriate sub-base composition. These design suggestions were then submitted to Wakefield Metropolitan District Council for approval.
The permeable pavior selected was Omega Flow from Brett Landscaping (80mm for the roads and 60mm for driveways), whose classic rectangular profile and purpose designed nibs ensure optimum permeability in addition to an eye-catching contemporary aesthetic.
Unlike other surface water management and attenuation systems, the use of permeable paving enables the structure to capture up to 95% of pollutants within the surface water runoff. This significantly improves the quality of the water leaving the site and is a key feature of a true SuDS system.
Based on the PermCalc design, Brett Landscaping recommended the use of a series of containment dams running across the carriageway to compartmentalise the road into individual permeable pavements. This helps to prevent the surface water flowing to the bottom of the site and flooding the lower houses on the development during periods of heavy rainfall.
Brett also worked with Jack Lunn to design a service strip which fed the individual plots with gas water and electricity.
Rob Martin, Marketing Manager at Jack Lunn Construction, said a close working relationship from an early stage with Brett helped ensure the project ran smoothly – and came in at a comparable cost to traditional paving.
One particular benefit was that there was no need for traditional road drainage on the site, which helped to reduce additional groundwork during construction. This ensures that the overall cost of the project came in approximately the same as they would have been for constructing a conventional pavement.
“Permeable paving is often seen as being a significant departure from conventional pavement construction incurring more time and, inevitably, more costs,” said Mr Martin. “However, working closely with Brett Landscaping on the design and construction of the permeably paved areas on this site, we found that it was no big deal, just a bit different from normal pavement construction.”
The section 38 officer from WMDC who approved the designs prior to construction confirmed that the authority would take legal ownership of the road upon completion of the initial 12 month maintenance period.
Based upon this experience Jack Lunn Construction has stated that it certainly would have no concerns about using permeable paving on future projects to provide an effective way to manage the dispersal of surface water.