Slide 65 of 75
Notes:
With a decline in watershed quality, there is a corresponding decline in both the total number of aquatic species and number of sensitive species. This is illustrated by an examination of four small watersheds in the Anacostia. The impervious cover of the four watersheds is as follows: Good Hope watershed at 10%, Nursery Run at 12%, Hollywood Branch at 25%, and Wheaton Branch at 55%. As can be seen, half the fish community is lost at 25% impervious cover and is down to two fish species at 55% impervious cover. The same finding has been replicated in many other regions of the country.