I'm going to add pics from my phone, of my stairwell 'filtering' mat...
We started with the black mat which caught leaves well. It was a pack of ten squares that snap together. Then we recently added the blue mat- because it was on the curb in somebody's trash, brand new, and decided we might find a use. It catches the grit and sludge, some. Of course we have to clean the area now and then. But I don't remember the last time we had overflow here.
Now, infiltration on the block walls here and there, whole nother thing. This house was set too low. We've really worked to get the water to go around to the street where it is lower... rain is usually not too bad knock on wood. Unless one gets an extra 15 inches of rain in a year..hahaha.. Snow and ice events see me out there compulsively creating channels for drainage to the sides, out of the central yard area. This despite neighbor in back whose whole yard slopes well away from us.
