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Fascinating stuff, I am probably the only person who will actually read it. I can see the sense in urban areas which are pretty much all impervious surfaces. In my mainly rural area 99% of anything I pave drains into a surrounding garden of which the paving forms less than, say, 5%. In the few cases where drainage is needed I either use soakaways or fanned permeable pipes into surrounding woodland or fields. In one case where flooding was an issue around a house built on clay in a valley bottom I constructed an automatically pumped system into a series of reed ponds. In 20 years I have only twice sent water into the main groundwater drains. I do have my doubts about the permeable membrane/ resin and gravel joints system as surely this would be overwhelmed by any heavy or persistent rain, but I suppose something is better than nothing.
ColinTheBald-
Yes, it would be helpful if the concept of SuDS actually incorporated minimum permeability figures. Round here, outer north west London, flooding in June 2016, Nov 2019, the best pavers offer is a thin line of Aco-Drain at the threshhold to the pavement.
The local authority, who uses a term contractor to 'do' all the dropped kerbs,
routinely just 'tarmacs' the driveway across the pavement.
Its all an uphill struggle.
Many more people now wished they lived uphill.
mespilus
A little light reading.
'Drainage' when increasing the built environment no longer works.
Simply connecting a new building and its impervious surrounds to the storm water drainage system simply floods someone else downstream.
Rain, when it does rain, is becoming increasingly intense, and altered patterns of weather mean we are experiencing periods of rainfall never previously recorded.
This Spring we had three successive storms, Ciara, Dennis & Jorge. Each on their own would have been extraordinary. 3 on successive weekends was previously inconceivable.
The built environment needs pervious surfaces to allow rain water to sink, (hopefully), deep through the soil into the clay, and in the south east into the underlying chalk aquifer.
I don't know about your local authority, but here in LB Hillingdon you cannot have a paved (front) garden that discharges rain water into the highway.
How many front gardens are still being paved over and how many Enforcement Notices are being applied is a question that is yet to be answered.