Water runoff is the biggest contributor to degrading water quality, and development increases runoff. It brings silt and phosphorus into the lake, turning sandy bottoms into muck and increasing plant growth. Non-porous paved driveways can be really bad, but gravel driveways can cause problems too, as they are not very porous. No matter what you install, think about how you can divert water into the woods, or into a holding pond, before it goes into the lake. This can be done with an angled ditch in a gravel driveway or a speed-bump like mound built into the paved driveway. For gravel, you can also use a "rubber waterbar". Directions on how to make them are
here. Anything you can do to slow down water's run to the lake will help more of it infiltrate into the ground instead.