SuDS (Sustainable Urban Drainage Systems) are innovative systems for the sustainable management of rainwater in urban areas. The acronym, which originated in the Anglo-Saxon world, is gaining increasing attention in Italy in response to growing problems linked to climate change, urbanisation and the inadequacy of traditional sewerage systems.

The problem of rainwater run-off in urban areas

Massive urbanisation has drastically reduced the soil's ability to naturally absorb rainwater. Impermeable surfaces (asphalt, concrete, roofs) hinder the natural water cycle, generating excessive rainwater run-off. As this water is not absorbed, it flows rapidly into the sewerage system, often causing it to become overloaded and increasing the risk of flooding.

Hydraulic invariance: a key principle in SuDS projects

The concept of hydraulic invariance was developed to ensure that, after construction or urban development, the amount of rainwater discharged into the drainage system remains the same as before. This means restoring the natural capacity of the soil to retain, infiltrate or manage rainwater, avoiding sudden increases in runoff.

How SuDS work

SuDS systems seek to mimic the natural processes of the soil: absorption, infiltration and filtration. The most common interventions include:

• draining green areas
• permeable paving
• infiltration reservoirs
• filtering channels and drainage trenches
• attenuation reservoirs
• reuse tanks

All these elements work together to slow down and regulate runoff, filter pollutants and return water to the ground or to reuse systems.

The environmental and urban advantages of SuDS systems

SuDS offer numerous benefits:

• Reduced risk of flooding
• Improved water quality
• Groundwater recharge
• Integration with green areas and public spaces
• Reduced environmental impact of cities

In addition, SuDS improve the resilience of urban areas to increasingly frequent extreme weather events.

Aquanest: a modular and efficient SuDS solution

Aquanest allows the creation of underground collection basins (i.e. reservoirs) for rainwater. It is a modular system made of recycled polypropylene, designed to ensure high mechanical resistance, quick installation and versatility.

It can be used for:

• Infiltration: promoting dispersion into the ground
• Lamination: regulating the flow towards the sewers
• Storage: for reuse of water in irrigation, toilets or firefighting

Aquanest fully complies with hydraulic invariance criteria and contributes to the restoration of the natural water cycle, even in highly urbanised areas.

The future of urban drainage is sustainable

With the intensification of the effects of climate change and the need to reduce the environmental impact of cities, SuDS represent a concrete, technological and integrated response. Not just an alternative to traditional sewers, but an ecological vision of urban design, capable of combining efficiency, sustainability and quality of life.