Saw Mill Br. is a highly developed headwater watershed located in Burlington, MA. This watershed has a lot of residential and commercial development, characterized by many impermeable surfaces such as roads and rooftops. There are very few wetlands located in this watershed.

The Saw Mill Br. watershed is being studied because it is the most highly developed small watershed in the Ipswich and Parker River watersheds. Because of the high amount of development, this watershed is most likely to show the impact human development has on water quality.

Why study small watersheds such as this one? Most rain falls on land surfaces that are drained by small streams. Although any given headwater stream is relatively unimportant, put together they contribute a lot of water. An understanding of how water quantity and quality differs in headwater streams is therefore important. Land use in small watersheds is often the most important factor determining water quality in small streams. When water from small watersheds flows downstream it influences drinking water sources, as well as water quality of lakes, larger streams and rivers, and the coastal zone.

Compare the water flow and water quality parameters with those measured in Cart Cr., a mostly forested headwater watershed, by clicking on the "Paired Site" link. Take an especially close look at the data following a storm runoff event (you can find these by looking for spikes in the discharge).