The recent town centre flooding made me cast my mind to one method of mitigating the effects of sudden downpours, namely Sustainable Urban Drainage Systems (SuDS). Sustainable urban drainage systems (SUDS) have been developed to improve drainage and reduce the volume of surface runoff in urban areas. They include retention systems that delay the discharge of surface water to watercourses by providing storage within ponds, retention basins or wetlands.
While much has been written about incorporating SuDS into private development plans I wonder whether any thought has gone into including SuDS into our public highways? Recently pavements on Robin Lane have been renewed with smart looking but completely impervious tarmac which will just direct water down to the town centre with no delay. I couldn’t help being reminded of the pavements and pedestrian areas I have seen being laid in Karlovy Vary, Czech Republic, where they really take SuDS seriously.
For example, some extensive pedestrian areas close to the river have two grades of paving stones but both have gaps to allow rainfall to pass between them. The area shown is strong enough to also take vehicular traffic. [see photo 1 below: pedestrian area].
I captured the construction of SuDS paving in a more residential area, notably on a hill, where pavements were being renewed with small rectangular paving stones and, where wide enough, alongside a cobbled strip over quite a deep retention trough. [see photo 2 – Pavement substrate layers’ and photo 3 – ‘Pavement nearly complete’ ] Note that the substrate is particularly rough as any smooth round gravel or soft sand would allow the top cobbles or paving stones to shift under foot or vehicular traffic. [see photo 4 – Coarse Substrate holds paving securely] This is something I’ve observed being done badly in south London, where a substrate that was mostly only sand or sand-like allowed the paving stones to tilt, guaranteeing the contractors renewal work every few years. Our repeat visits to Karlovy Vary over many years have shown their SuDS paving remaining completely smooth, with no tilting.
I also include two photos of an old cobbled residential street which is still resilient after what must be many years of vehicular traffic. You can see grass growing between the cobbles.[see photo 5]. In this case the pavement is tarmac and the roadway is SuDS.
No doubt we’re not going to see cobbles in this country and certainly in Bentham we don’t have wide enough pavements for such a dual surface system, but is such Czech smooth paving adaptable to UK streets? [see photos 6 and 7] My residential street example appears to direct roadway water onto their SuDS pavement which is unlike anything we have here but some type of SuDS needs to be adopted to make us more resilient to the effects of climate change and heavier rainfall, if not an exact copy of the Czech system. What are North Yorkshire’s plans?
