Source: SacBee - Scientists who for decades reported that famously clear Lake Tahoe was turning murkier have discovered that its clarity actually has been stabilizing since 2001.  Using a new, more sophisticated statistical analysis of environmental data, researchers also determined that a reduced rate of visibility loss in the lake was likely the payoff from decades of erosion control, purchases of environmentally sensitive land and restrictive building rules designed to curb runoff.  NPDES rules and regulations require the use of erosion control blankets, turf reinforecement mats, hydraulic mulch, silt fence, straw wattles and other erosion control products to eliminate sediment from leaving a jobsite >1 acre in size.  Sedimentation ponds, lined with high-strength geomembrane liners, help control high flow areas from overburdening these erosion control measures during large storm events.