Why this matters for the Dart: rain that soaks into your garden arrives in the river slowly and clean; rain that races off paving arrives fast, dirty, and all at once.
When rain falls on a natural surface, most of it soaks in. When it falls on concrete or standard paving, nearly all of it runs off, picking up oil, rubber dust, sediment and anything else in its path, and hurries into surface drains that lead to a watercourse (see how your home connects to the river). The Royal Horticultural Society notes that using non-porous materials in hard landscaping can increase rainwater run-off by as much as 50% 45. Multiply that across a town and you get flashier floods, more storm overflow spills from combined sewers, and a dirtier river. The general name for features that soak up or slow down rainwater where it falls is SuDS, short for sustainable drainage systems. You do not need to remember the acronym; you just need a garden that drinks.
Know the paving rule before you pave. In England, you do not need planning permission to surface your front garden, whatever the size, if you use a permeable surface such as gravel, permeable block paving or porous asphalt, or if the water drains to a lawn or border. But laying a traditional impermeable surface of more than five square metres that does not drain to a permeable area does need planning permission 43 44. Why it helps the Dart: the rule exists precisely to stop front gardens becoming run-off chutes. How hard: a planning fact to know, not a job.
Choose permeable surfaces for drives and paths. Gravel, permeable block paving, reinforced grass grids and porous asphalt all let water through to the ground beneath 43 45. If you are relaying a drive anyway, this is the moment. A cheaper trick from the water industry: pave only the wheel tracks and leave the rest green 47. Why it helps the Dart: every square metre that drinks its own rain sends nothing to the surface drain. How hard: a bigger project when replacing a drive; the tyre-track version is moderate.
Disconnect a downpipe into a water butt or the garden. Where your ground slopes away from the house, a simple diverter can send roof water to a butt, a border or a lawn instead of the drain 47. Why it helps the Dart: it takes your roof out of the storm surge that triggers overflow spills. How hard: easy to moderate.
Build a rain garden. A rain garden is a shallow planted dip that receives run-off from a roof or hard surface and lets it soak away among plants that tolerate both wet and dry spells. The RHS notes a rain garden can absorb up to 30% more water than the same area of lawn, reduces erosion by slowing heavy rainfall, and avoids the need for a soakaway 46. Why it helps the Dart: it turns a run-off problem into a habitat, and it works hardest in exactly the downpours that make overflows spill. How hard: a bigger project, a weekend or two of digging, but cheap.
Wash the car on grass or gravel, or at a commercial car wash. Car shampoo, road grime and traffic-film remover are a potent mix, and if you wash on the road or a paved drive the dirty water runs to a surface drain and very likely to a watercourse 16. Wash on grass or gravel so the water filters through the ground, or use a commercial car wash, which must dispose of its water properly 17 16. Why it helps the Dart: this is one of the most common ways detergent enters rivers from homes. How hard: easy.
Go easy on garden chemicals. Use pesticides and weedkillers sparingly if at all, never apply them when rain is due, never near a drain, ditch or stream, and take leftovers to the recycling centre rather than pouring them away 26 37. Why it helps the Dart: what rain washes off your garden is part of the river's diet. How hard: easy.