Run off can be a problem, but I often think how much of a problem is it.
Has 92% of the country not been built on?
However run off is more to do with drainage especially in built up areas!!.Ask the people of Oakey ,Toowoomba,the darling downs,Gatton and the Brisbane River valley about run off problems!! in 2011/2012 an area aslarge as germany and half of france was flooded by run off, caused by overdevelopment on the great dividing range from Crows nest to Stanthorpe, complete villages washed away, over 250 dead,100s of families left homeless,when natural water ways are built over the water finds the easiest way out, in our case Toowoomba the main roads became raging rivers sweeping everything before them, to say we were not prepared is putting it mildly, of course the geezers in charge of water management panicced because the dams were full, sothey opened the damgates
successfully flooding the Gatton Plains and the brisbane river valley,bodies of victims from the gatton area were recovered in moreton bay 150kms away from flood source, we think run off is a PROBLEM!!!!!!!!!!!!!!!!!!
Even if the drains can’t cope, the water goes elsewhere but isn’t captured where it’s needed.
ISTR that Staffordshire is overcoming a water shortage by pinching water from Birmingham who in turn get it from Wales.
Water company’s are reducing leaks, and also doing the tried and tested method of curtailing customer use by charging for it.