I've heard this before, and I've tried to imagine how that would work. The lawns I see in just about every city, most of them are surrounded by streets and usually sidewalks and sometimes curbs, too.

I try imagine what'd happen if the grass all just died and soil erosion started to kick in. Where's the soil going that's now going to erode? Is it liquefying in heavy rains and flowing up and away over the roads?

I just can't picture how lawns are doing all that much to prevent soil erosion, but would love a more detailed explanation.