Here's a neat tool from the EPA to calculate how much rain water is running off your yard and into the creek.  http://www.epa.gov/nrmrl/wswrd/wq/models/swc/

As you may know, the biggest threat to our creek (and the Bay for that matter) is the volume and velocity of water entering the creek whenever it rains.  Water isn't soaked into the ground by trees or landscaping,  runs directly into the creek.  The big volume erodes the stream bed and covers the rocks and hiding places for fish and water creatures with dirt.  The water also carries pollutants into the creek which make their way into the Bay.  Anything you can do to keep the water on your property will go a long way to helping the environment.  The EPA tool is a wonderful help in showing you how much water is running off. 

For information about what you can do to help get the water back in the ground, in Montgomery County visit - www.rainscapes.org.  In DC, visit http://ddoe.dc.gov/riversmarthomes   Both DC and the County have a nice rebate programs for implementing some very simple landscaping changes. 

For information on how much rainwater a tree can soak up, visit http://www.treebenefits.com/calculator/  

Sarah Morse
Co-President
Little Falls Watershed Alliance