Earth disturbance, such as construction activities, loosens the earth. During periods of rain, the loose dirt and sediments may wash off the land and into streams and rivers. This runoff is water pollution caused by erosion and sedimentation. The EPA has published a PDF handout - A Citizen's Guide to Understanding Stormwater - that can assist in learning more about stormwater.
To learn more about prevention techniques and requirements, look at the websites below.
In Pennsylvania, the state has generally delegated the implementation of the erosion and sedimentation program to the County Conservation Districts. The Pennsylvania Association of Conservation Districts provides general information about conservation districts on their website.
Specific information about the Montgomery County Conservation District, the District responsible for Erosion and Sedimentation permits in Montgomery County also has a website where you can find contact information and permit application information.
Lower Merion Township lies in the Delaware River Basin. Find out information about the water quality of the Delaware river through the website of the Delaware River Basin Commission.
A DEP information sheet on non-point source water pollution.