We have devised a smart and sustainable way to deal with our city’s rainwater to guard against flooding and provide water for the plants and trees.
Why can’t the old drainage system remain?
The old drainage system is showing its age. It is a post war combined sewer system – surface and foul water – that was never really designed to deal with the capacity it currently has to cope with, given the demands of modern plumbing in residential and commercial properties.
The SuDS system is not replacing the old drainage system but takes pressure off it as it is diverting rain and surface water away from the current drainage system.
We have also been working with South West Water to help upgrade sections of their system in Armada Way in advance of work starting.
What is a SuDS and why is it important to include it in Armada Way?
We want to create a SuDS (sustainable urban drainage system) to manage all surface water which falls on Armada Way, mimicking where possible, a natural drainage system. The system has been designed to reduce the amount of run off into the sewer system by up to 77%. This will involve the use of rain gardens and underground storage tanks which will fill with rainwater after being filtered through natural reed beds instead of using chemicals.
The water will be recirculated around Armada Way through an ornamental stream which will run along the length of the scheme. The water will be used to irrigate the trees day and night. Through this process, we will reduce the strain on the combined sewer system, clean our surface run off and reduce discharge events into Plymouth Sound. The system is more climate resilient as it is designed to handle extreme weather events and is considered critical and best practice for handling urban water run off by the Environment Agency and South West Water.
What benefit will the SuDS bring?
The sustainable urban drainage system has a number of benefits for the new trees, for the city centre and for Plymouth Sound. It:
- Reduces maintenance and watering costs - The system uses rain gardens which will be installed beneath the ground level, which combine with large underground storage tanks, and will retain rainwater that can be used to feed the plants and trees above the ground.
- Reduces the amount of rain and foul water that ends up in the Sound - The system will ensure that rain and surface water will not go into the existing combined sewer system.
- Frees up capacity in the existing combined sewer system - Reducing the risk of flooding in the city centre.
How will the SuDS be powered?
It will be partially powered by solar canopies that will be based at Place de Brest. The system also has a ‘back-up’, linking to the main power-grid, in case not enough power is generated by the sun. The use of solar power will also help the Council with its Net Zero aspirations.