Current land use in the Prettyboy Reservoir Watershed reflects more than three centuries of social, economic, and demographic change. Over time this once pristine wilderness has been transformed into a relatively prosperous and ever growing suburb of Baltimore City . The price for this shift, however, is higher and higher as we face the problem of declining clean water in the region.

According to data gathered by the Maryland Biological Stream Survey dated 2003, two of  the Prettyboy Reservoi r's three subwatersheds , Georges Creek and Graves Run , was recorded as having  'fair' stream water quality , while the Upper Gunpowder, the third sub-watershed,  has recorded "good" water quality, which is the highest rating given. It is not certain why  the two  streams have "fair" status,  but presumably it is because they are more developed and there are more impervious surfaces creating sheet runoff into the streams. In addition, the Maryland Department of the Environment lists half of  the drainage s that flow  directly into the Reservoir as impaired.

The loss of forests, farms and riparian (stream side) vegetation, coupled with increased storm-water runoff, leaking septic tanks, roads and increasing deer populations, has caused concerns about water quality. Changing land use in the Prettyboy Watershed is a direct threat to the health of this watershed if left unchecked. Below are some of the major issues facing the Reservoir:

Loss of Forests
The watershed is only 34% forested, a low percentage for a drinking water watershed.  Studies have shown that when forest levels drop below 75%, water quality suffers.  In addition, much of the emergent under story (our future forest) has been destroyed by the increasing deer population.

Loss of Riparian (Stream Side) Banks
Many of our streams lack any (or have minimal) forested buffer areas along the stream bank.  These buffers play a crucial role in reducing surface runoff, stabilizing stream banks, reducing water temperatures and nutrient load, trapping sediment, mitigating floods and providing habitat for all types of stream life.

Increase in Impervious Surface
The amount of impervious surface (roads, houses, parking lots, etc) is directly related to the quality of a stream in a watershed.  It has been established that amounts exceeding 20% result in very poor quality streams.  In fact our Maryland Brook Trout cannot tolerates levels higher than 3%!

Excess Nutrients
High phosphorus and nitrogen levels are present as a result of failing septic systems, over fertilization of lawns and gardens by homeowners and of fields by farmers.

Increased Salinization
Strong increases in the baseline concentration of chloride in rural watersheds in Maryland have occurred over the last several decades. These increases are such that, if they continue at the same rate into the next century, many rural streams will exceed levels that are toxic to freshwater life and will not be potable for human consumption.

Stormwater
Rainwater that does not seep into the ground flows over the land creating what’s known as stormwater runoff.  Impervious surfaces increase the amount of runoff that makes its way directly to our streams via storm drains. (It is important to know that this water is not treated before entering a stream.)  Large storm events can generate so much runoff that streams are unable to handle the increased load and significant erosion of streambanks occurs.

Click here to find out what you can do to address these threats to the Prettyboy Watershed