The Maine Department of Environmental Protection (DEP) routinely tests streams throughout the state to determine the water quality in a stream. When the waters of the stream are determined to not meet their standards, the DEP considers them impaired. There are six Urban Impaired Streams that are within the City of Bangor.
The Urban Impaired Streams in the City of Bangor include Arctic Brook, Birch Stream, Capehart Brook, Penjajawoc Stream, Shaw Brook, and Sucker Brook. Each of these streams is delineated by its watershed. A watershed is a land area that drains to a certain waterbody, such as a stream. The land within a stream's watershed can influence the health of the stream through land uses and activities. Of all of the land in Bangor, more than 44% of the land area is within a watershed of an Urban Impaired Stream.
Many of these impairments are attributed to a high amount of impervious cover in these watersheds. The impervious surfaces (such as roofs, driveways, roads, parking lots, and sidewalks) allow pollution such as soil, oil and grease, excess nutrients from fertilizers and pet waste, and litter to enter the stream. The stormwater acts as a broom, pushing pollutants across the pavement and into the stormwater systems which lead to the stream. This "non-point" source pollution usually isn't from one individual, business, or activity, but is a collection of many small inputs of pollution that can have a larger impact on a waterbody.