Sustainable drainage systems
SUDs
The Adult Learning Centre employs use of a Sustainable Drainage System (SuDS) to control rainwater run off, reduce the risk of flooding on site, and help to treat and prevent water pollution.
Rainwater gardens are used on site, a system whereby rainwater is directed through drains down into plant beds and is slowly released into the soil. Further to the SuDS solution, a permeable surface is used in the car park and outdoor paving, allowing storm water to slowly drain, and preventing the overburdening of drains. In very extreme weather conditions when the rain gardens cannot manage the volume of water, there is outflow pipe to a conventional drain.
1. Constructed landscape mounds
Turf a
Lightweight soil layer b
Filter fleece c
Drainage/storage layer d
Root barrier e
Waterproof membrane f
Concrete base cast in-situ g
2. Open cell masonry pavement
Open cell masonry, 600 x 400mm a
Bedding course, 50mm b
Base reservoir, 75mm c
Free draining
granular sub-base, 150mm d
Filter membrane geo composite e
Sub grade, 150mm f
3. Permeable pavement solution
Permeable surface a
Bedding course b
Choker layer c
Resevoir layer, 150mm d
Perforated drainage pipe e
Filter membrane f
Sub-grade g
1. The constructed landscaped guides rainwater into the surrounding rain gardens, and the mounds have the ability to absorb and slowly diffuse some of the moisture, as they have been composed similarly to a green roof system.
2. In the car park open cell masonry pavement has been installed to prevent both flooding and replenish the soil beneath. This pervious surface can passively control the water on site, while not impeding on the user experience. Beneath this surface is an under drain system, which disposes of any overflow that the system cannot support, transporting it to the rain gardens on site.
3. Lead up to the buildings entrances are tiled with a permeable pavement solution, similar to that used in the car park, although aesthetically it more closely resembles typical pavement systems. Voids in this pavement surface allow rainwater to seep through into a sub-base, storing the water until it saturates into the ground below. This paving system can also remove and diffuse pollution from rainwater runoff.
4. Rain gardens
Stone kerb a
Concrete b
Concrete haunching c
Concrete block d
In-situ concrete foundations e
Filtered soil f
Undisturbed soil g
Perforated pipe h
Stone i
The constructed landscaped mounds directing rainwater into the rain gardens.
Plants used in the rain garden are good for water retention:
1) Wild Daffodil
2) Golden Woodrush
3) Marsh Marigold
4) Purple Loosestrife
5) Meadowsweet
6) Water Mint