Priory Road SuDS projects

This page provides an overview of the three Priory Road SuDS projects in Haringey that reduce surface water flood risk and improve water quality.

 

Where & why were the SuDS projects built?

This SuDS scheme was part of the wider Love the Lea campaign. The campaign aims to improve the water quality of the Lea catchment, which includes the Moselle Brook. It consists of three separate SuDS measures based around Priory Road in the London Borough of Haringey.

Priory Road runs along the culverted course of the Moselle Brook and has a high risk of surface water flooding (it is in a Critical Drainage Area, i.e. identified as contributing to surface water flood risk). In the event of a 1 in 100 year storm, some areas could see up 1.5m of surface water flooding.

Project description

Dale Court rain gardens

Dale Court is a social housing property managed by Homes for Haringey, near the junction of Priory Road and Park Road. Two downpipes at the front of the property were disconnected from the sewer network and diverted into two rain gardens.

These simple depressions in the ground are designed to accommodate the 1 in 100 year plus climate change rainfall event. An overflow pipe from the gardens into the sewer network means the property won’t flood in a severe rainfall event.

New wildflowers have blossomed on the previously featureless lawns of Dale Court.

This 90m2 SuDS measure cost around £23,000 to install, but can be done more cheaply. Thousands of properties across London could benefit from rain gardens like these.

Priory Road rain meadow

The storm drain at the Priory Road / Redston Road junction was often overwhelmed with surface water flowing downhill along Redston Road. This project covered over the storm drain and diverted surface water from Redston Road. This was done through a dropped kerb inlet into a shallow rain meadow dug into the grass verge by the road.

This SuDS measure reduces the amount of water reaching the sewer system. It also increases the amount of time until the water reaches it, giving the sewers time to empty. In addition, it helps to clean and cool surface water run-off as it passes along the rain meadow before entering the Moselle Brook.

The route of the shallow rain meadow is marked with posts, which are engraved with some of the benefits of sustainable drainage. This 85m2 SuDS measure cost around £48,000 to install.

Rectory Gardens rain park

Further east along Priory Road is Rectory Gardens. This large expanse of grassland sits between St Mary’s Church of England Primary School and the road. This has now been landscaped to take polluted surface water from Priory Road via kerb inlets under the pavement.

A series of depressions of varying depths are connected by channels (some under footpaths) to accommodate the 1 in 100 year (plus 20 per cent allowance for climate change) rainfall event. A controlled outlet allows clean water to enter the Moselle Brook. Play equipment (balance beams) is part of the design.

This relatively large (1,000m2) and complex SuDS measure cost around £80,000 to install.

Maintenance

The planting at Dale Court was specifically chosen to reduce upkeep costs. This has lowered charges for Dale Court tenants. The Priory Road rain meadow and the Rectory Gardens rain park are both maintained by Haringey Council’s Highways team.

Outcomes

Environmental improvements

Each sustainable drainage system removes pollutants from roads and roofs. It also stops pollution from entering the Moselle Brook. Future water quality monitoring is planned. The large amount of pollution removed is noticeable at the Rectory Gardens rain park inlet. There silt accumulates after rainfall events before breaking down. This reduces council maintenance costs, as the silt would usually accumulate in gully pots, where it would have to be removed.

This project has helped Haringey Council to develop further SuDS schemes, including Victoria Crescent. Homes for Haringey have also taken SuDS on board and are looking to run more schemes where feasible.

This project has created three native wildflower meadows, providing a total of 320m2 of higher-biodiversity land.

Community engagement

In 2014/15, a booklet was sent to each household in the Critical Drainage Area. This explained how it could help reduce flood risk and improve water quality in the area. The choice of the three Priory Road sites (out of a shortlist of ten possible sites) was partly informed by local people’s views. A series of events, including walks, talks and volunteer activities, helped identify existing strong, active community groups. These are now championing more public space improvements (including SuDS) that were identified and developed during the project.

Three schools were involved with the project, through a total of 36 sessions. Four of these sessions covered the ‘River of Fish’ interpretation by St Mary’s Church of England primary school. Many of the other 32 sessions were designed around key stages, with specific reference to the SuDS scheme.

Main challenges and lessons learned

Planning and procurement

The council’s framework contract had no experience of SuDS schemes. This led to high costs and poor delivery of a previous associated project. So instead, the project partnership decided to use a contractor with experience of SuDS, and tendered these works separately. This caused some issues but meant that the successful contractor was added to the council’s list of approved contractors. This means it will be easier to implement SuDS projects within Haringey in future.

Community engagement

The project engaged successfully with local residents and schools. However, local businesses proved a challenge as the project’s three sites are a fair distance from the shops.

Browse pictures from the Priory Road projects

Photos credit: Thames21 and Katherine Drayson

Priory Road facts and figures

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