975 Indian Landing Road
Millersville, MD 21108
tel. 410-222-3822

Bio-retention Areas -Simulated Costal Plain Bogs

A bog is one of nature’s ways to filter rain- water runoff from non-point sources.  If bogs are preserved/restored the overall health of the Bay will improve.

The L.A.W.S.S.of the BOG

Lack of nutrients: because of the lack of oxygen and the acidic chemistry of bogs, they lack many nutrients, such as nitrogen, that are food for plants.  The lack of nutrients restricts the growth of competing plant species.  Carnivorous plants such as pitcher plants, sun dews, and bladderworts obtain their nutrients from the meat (insects) they digest.

Acid: Bogs are great environments for plants to decay, which adds organic acids to the soil and water.  Since this makes it so harsh for most nutrient-loving plants, bog plants have adapted to be acidophilic, using the natural acids as food.  Examples: cranberry, Atlantic White Cedar, sphagnum moss.  Acidophilic plants need little nutrients to survive.

Water: Bogs are wetlands! Coastal plains bogs form near the edges of still or slow- moving water, near ponds, lakes, slow streams, or springs.  The water in bogs is normally clear and cool.  Technically speaking, the coastal plain bogs of Anne Arundel County are called Fens because water passes through them rather than being contained.

Sandy soil: Maryland’s bogs are unusual because they rely on a sandy soil that is part of the Magothy sand lens, which begins in Europe and continues along the Atlantic, surfacing only for 30 miles long & 10 miles wide in Anne Arundel County.  Coastal plains bogs associated with this sand lens can be found from Gibson Island in Pasadena to Bowie near the Patuxent River.  This sand combined with the high concentration of surface carbon from plants, provides a great filtering medium for cleaning the water associated with bogs.  Leaves from acidophilic plants such as Atlantic White Cedar are slow to decay and add to this filtering mat.

Sun: Due ot the of the lack of nutrients, most plant growth is restricted.  Most bog plant species are low growing so they do not compete for the sun.  Bog associated trees such as Atlantic White Cedars and Sweet Bay Magnolia grow on the edge of bogs allowing light to penetrate the center of bogs.


Bogs are open, acidic, nutrient poor wetlands.  Bogs form when a mat of vegetation (moss)develops on the edge of a pond, lake, wetlands, or slow-moving stream and grows over the surface of the water.  As time passes, the dead, decaying plants make a dense, fibrous layer that is called peat.  When plants die they become part of the peat layer. Most plants, that you know, cannot grow in bogs.  That is because the still or slow-moving water is too acidic and does not contain nutrients, such as nitrogen that are needed for plants to grow.  There are some unusual plants that can grow in bogs.

Pitcher Plants and Sun dews- carnivorous plants that attract and digest insects.

Atlantic White Cedars- rot resistant tree that needs wet soil and can grow to be 80-100 ft tall

These plants are endangered in Maryland because there are only a few bogs remaining.  AA County has the most bogs in Maryland but that number is less than 10.


What can be done to protect our threatened bogs?

Changes in the quality of water is one of the major threats to bogs.  If a bog dries out, rare bog plants will be replaced with plants more tolerant of dry conditions.  Development too close to bogs changes flow patterns of water and the amount of water entering the bog.  With the water comes sediment that fills in the bog, changes soil conditions and provides habitat for woody plants (trees).  All these changes destroy the bog.  Some pollutants, such as herbicides, can damage or kill bog plants directly or by changing the acidity or nutrient levels in the bog.

Bog Lesson
(.html file)
Pearls of the Magothy
(presentation download)
(e-mail our staff)
Supplement A
(.html file)
Supplement B
(.html file)
(.html file)


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Special Thanks

Keith Underwood (Underwood & Associates)
Phil Sheridan (Meadowview)
Judy Cole (MDE)