1. Rake up leaves from lawns and street gutters so they don't wash into the storm drains and then into the lake;
  2. Eliminate or reduce lawn fertilization, pesticide and herbicide;
  3. scoop the poop.....it's the right thing to do!;
  4. Replace hillside lawns with buffer |riparian plantings] to absorb and filter runoff from the lawn before it reaches the water.
  5. Don't blow grass clippings/leaves into the street or lake.

These are some of many Virginia Tech homeowner publications regarding water quality: Storm Water Management for Homeowners on Buffers: https://pubs.ext.vt.edu/SPES/SPES-14/SPES-14.html
What is a Water Shed?: http://digitalpubs.ext.vt.edu/vcedigitalpubs/4364617117137241/MobilePagedReplica.action?pm=2&folio=1#pg1