Tuesday, August 7, 2012

Ponds around the world--New York State

Coastal plain ponds...

...are a unique and rare ecosystem found from New Jersey north along the Atlantic coast.  They include the amazing ponds of Cape Cod.  Some people consider seepage ponds in Midwestern states--formed along the glacial margin like those on the Cape-to be close relatives.

A pond in New York State (Long Pond, Sag Harbor), by Steven Young

"The first thing you might notice about a coastal plain pond is that there is no stream flowing in and none flowing out. Water levels of the pond, and therefore the size of the exposed pond shore, are due only to changes in an underground aquifer.

During the wetter parts of the year this aquifer is high and water levels in the pond are high which translates into a very narrow pond shore. Conversely, during the dry months (late summer) the aquifer is low so water levels are low but there is a large expanse of pond shore. Every 5 years or so there is an exceptionally dry year with a lot of pond shore exposed. Plants that may not have been seen for a decade will now germinate and grow.

There are over 50 documented occurrences of coastal plain pond shores in New York. They are restricted to the coastal plain of Long Island. Many of these separate occurrences that occur near each other may actually be combined into pond systems because they are hydrologically connected and should be considered as one occurrence. As of now, there are an estimated 15 separate sites and about 6 pond systems documented. 

Many of these systems continue to be threatened by development, invasive species, changes to hydrology, and recreation (e.g.off-road vehicles and trampling)."


The numbers and acreage of coastal plain ponds in New York have declined in recent years. There are less than 400 acres currently mapped with probably less than 1000 acres extant. The total, historical, acreage is unknown but was probably less than 2000 acres. The decline is due primarily to development and the increasing demand for freshwater.

"The numbers and acreage of coastal plain ponds have declined from historical numbers primarily due to settlement of the area and the corresponding agricultural, residential, and commercial development causing both a displacement of this community and a lowering of the water table due to an increased demand for freshwater."

Conservation strategies

"Where practical, establish and maintain a natural wetland buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the wetland. Buffer width should take into account the erodibility of the surrounding soils, slope steepness, and current land use.

Roads and trails should be routed around wetlands, and ideally not pass through the buffer area.

Minimize actions that will change what the water carries and how water travels to this community, both on the surface and underground. Water traveling over-the-ground as run-off usually carries an abundance of silt, clay, and other particulates during (and often after) a construction project. While still suspended in the water, these particulates make it difficult for aquatic animals to find food; after settling to the bottom of the wetland, these particulates bury small plants and animals and alter the natural functions of the community in many other ways. Thus, road construction and development activities near this community type should strive to minimize particulate-laden run-off into this community."


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