We purchased our late 60's house two years ago. The previous owners replaced the grass between the rather downward slopping concrete driveway with tuscan toppings. Everytime we have heavy rain, much of the toppings move down the driveway and cover the drain in front of our garage resulting in it flooding once and coming close half a dozen times in two years (we have been home the other times and cleared the drain cover). We can't afford to concrete the entire drive yet as there are other renovation priorities but are toying with something like the Surepave plastic paving system you can get at Bunnings and using a slightly larger pebble than we currently have. Has anyone used this system? Do you think the top layer of pebbles would still have the same runoff issues? Thanks in advance.