It is still litter on the bottom and pollutes the clear water. In addition to packing out your own garbage, you can help out by policing the lakeshore for litter. Garbage bags are available at boat ramps. Fill a bag with litter and inform rangers at the visitor center or ranger station nearest to the area you cleaned. Don't use glass containers.
Broken glass is a real hazard to beachgoers.
If you break a bottle, pick up all the pieces and dispose of them at one of the marinas. Fire remains are also litter. Charcoal and ash take hundreds of years to disintegrate in this arid environment. Fires near rock faces can also cause the sandstone to crack and fall. If you must build a fire, do so in an area that will not mar the scene, use a fire pan, and remove all fire remains.