SIMMS makes their Intruder boots with integrated gravel guards. Per pair they're like 2.6lbs. I bought them intending to use them only for hike-in trips but I use them all the time. These are now my go-to wet wading boot. Oversized, they'd go over waders fine. Their Freestone is also light. Super-light are the Riprap Shoe, but they're like low-cut tennis shoes and so don't offer any ankle support.