Gilbert Run Watershed EarthCache
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During the summer months Gilbert Run charges $5 dollars per car on the weekends and holidays. During the off season the gates are closed, but you can walk into the part from the gate.
Why this Earthcache is here
Operated by the Charles County Department of Recreation, Wheatley Lake, also known as Gilbert Run, was constructed as one of three flood water management impoundments in the 1960's and 70's. Of the three structures, Wheatley was also designated as a "multi-purpose" structure which would allow it to be used as a recreational facility in addition to providing flood and watershed protection. The main source of water for the lake is Wheatley Run, part of the Gilbert Swamp Run drainage. Gilbert Swamp Run flows into the Wicomico River which eventually enters the Potomac River near Cobb Island.
WATERSHEDS
A watershed is the geographic area that contributes water runoff into a stream. How is this geologically important, you ask? A watershed, a.k.a. drainage basin, is the primary transportation system of water carried sediment. It also provides nutrients for vegetation and wildlife that live here, which may also affect the local geology. An example is rainstorms: When it rains, the water naturally flows downhill, until something blocks its path. This "something" can be land, vegetation, man-made structures, debris, and even more water. The Wheatley Run is one of 150 rivers and streams that drain into the Chesapeake Bay. The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia.
The Chesapeake Bay's drainage basin covers 64,299 square miles in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. More than 150 rivers and streams drain into the bay. The soil, sand and rock found in the ground acts as a filter or sponge for the rain and surface water. Contaminants from roads, oils, pesticides re mixed with the rain water and absorbed into the soil. As the contaminated water filters through the soil, sand and rocks, it purifies the water so that when it reaches the ground water (the underground rivers) it has less contaminates to pollute the rivers and lakes that it flows into.
Geology, Shape and Form
Drainage Basin
A drainage basin or watershed is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point at a lower elevation, usually the exit of the basin, where the waters join another water body, such as a river, lake, reservoir, estuary, wetland, sea, or ocean.
A tributary stream of a brook which joins a small river, which is tributary of a larger river is thus part of a series of successively smaller area but higher elevation drainage basins (watersheds).
A drainage basin provides a limited surface area within which physical processes pertinent to the general hydrology may be considered. The climatic variables and the water and sediment discharge, water storage, and evapotranspiration may be measured; from these measurements, denudation rates and moisture and energy balances may be derived, each of which is useful in the consideration and understanding of landscape formation.
QUESTIONS
To receive credit for this Earth Cache, answer these questions in an email to the cache owner. Please do not post the answers in your online log.
Optional: Please post a photo of you and/or your gps at the listed coordinates with the dam in the background.
1 How tall is the dam?
2 What is the retarding stage of the dam?
3 What is the volume fill of the dam?
4 How much storage is at the emergency spillway crest?
5 What other flood prevention methods do you see in this location? How do these methods protect the Chesapeake from becoming polluted by foreign particles? And materials?
Citations: Wikipedia http://en.wikipedia.org/wiki/Structural_basin
Angeler Web: http://www.anglerweb.com/fishing_spots/wheatley-lake-gilbert-run
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Treasures
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