Why this Earthcache is here
Mattawoman Creek is an interesting area in Southern Maryland. When you arrive at ground zero you will find a man made barrier to prevent the erosion of the creek. Take a good look around the water and you will need to make some observations in order to answer the questions. Our goal is to provide some history of the geology of this area, a lesson on how important this area is, how to prevent further erosion and to enjoy your trip.
What is Erosion?
In the terms used in geology and geomorphology, the actions of exogenic process which remove rock and soil is called EROSION. Erosion is when rock and soil is removed from the Earth’s crust and moved to a different location. When speaking in these terms of Mattawoman creek, sediment that has eroded may be transported just a few inches, or for hundreds of miles.
There are 5 main types of Erosion:
1. Erosion due to water
2. Erosion due to wind
3. Erosion due to gravity
4. Erosion due to soil
5. Erosion due to glaciers
WATER EROSION - from rain or another source exposes water-sensitive areas which can decay, or the force of very hard droplets which can also erode hard sedimentary surfaces. As water builds up run off picks up soil exposing roots and rock underneath which can lead to destabilization. [1]
WIND EROSION - Excessive amounts of wind can cause top soil or sand to be blown away and expose other soils and rock underneath. [1]
GRAVITY EROSION - Mass movement of soil occurs on steep slopes under the influence of gravity. The process involves the transfer of slope forming materials from higher grounds due to its own weight. [1]
SOIL EROSION - A result of gravity pushing down on soil that may rest on hills, as well as water, wind and glacial melting, which can cause soil to wash away and tree roots to be exposed. [1]
EROSION DUE to GLACIERS - Snow and ice will melt causing water to run down hills and mountains - this water has the tendency to cause stream-ways and ditches. [1]
History of Mattawoman Creek and the Indian Head Rail trail
At the posted coordinates you will see that the Army Corps of Engineers has worked to prevent the erosion of the banks to save the Indian Head Rail Trail. In the summer of 1918, in the midst of World War I, the U.S. Navy needed a reliable land route to bring supplies to and from its gunpowder factory at Indian Head, Md. A route was surveyed from the naval facility along the Mattawoman Creek valley to the nearest existing rail junction, 14 miles away in White Plains, Md. In May 1919, only about six months after the first tracks were laid, trains began rolling to and from the powder factory. The rail line stayed in use for a few more decades, but as the county's road system developed and the functions of the naval base shifted away from gunpowder production to weapons research and testing (the base is today known as Naval Support Facility-Indian Head and is the county's largest employer), the trains eventually stopped running. [2]
Mattawoman Creek is a tributary to the tidal Potomac River with a mouth at Indian Head, Maryland. Mattawoman drains the town of Indian Head, the town of Bryans Road, and most of Waldorf, the largest community in Charles County. Its watershed remains over 50% forested but is approaching a 10% impervious cover, often cited as a threshold for significant degradation as measured by water quality and species diversity. Continued loss of forest and increases in impervious cover are anticipated, as most of the watershed in Charles County falls within a designated development district, which at about 83 square miles is larger than Washington D.C. With respect to projected growth, the Mattawoman Creek Watershed Management Plan authored by the U.S. Army Corps of Engineers notes that:
“these intense development practices would have severe repercussions on the biological community and would decrease the habitat quality within the estuary.”
The quality of Mattawoman’s living resources are acknowledged by Charles County government, while the juxtaposition of high quality and high vulnerability to development are recognized by state and federal agencies. For example, the Mattawoman Creek Watershed Management Plan states:
“The Mattawoman Creek represents an important natural resource, with a diverse network of forests, tributaries, and wetlands, providing tremendous fish and wildlife habitat. The ecological integrity of the Mattawoman is at risk from current and future development pressures within the watershed.”
The juxtaposition of value and vulnerability has caused the creek and its watershed to become a focal point for regional and local conservation organizations that work to restore the Chesapeake Bay in the face of growing urbanization, which studies find contribute to the decline of the Bay.
Proposals for two four-lane highways that would cross the fluvial stream, and the expected attendant development, have generated debate. The first, the Western Waldorf Bypass, is one of three alternatives being considered by state and federal agencies for the U.S. 301 Waldorf-Area Transportation Improvements Project. This highway would divide lengthwise about one-half of the Mattawoman watershed. The second, for which controversial wetlands permit applications have been submitted, is a proposed extension of Charles County’s Cross County Connector, which would cross the width of the watershed. [3]
While erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. Excessive (or accelerated) erosion causes both 'on-site' and 'off-site' problems. On-site impacts include decreases in agricultural productivity and (on natural landscapes) ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses. Water and wind erosion are now the two primary causes of land degradation; combined, they are responsible for about 84% of the global extent of degraded land, making excessive erosion one of the most significant environmental problems world-wide. [4]
The water being drained from the local communities is polluting Mattawoman Creek which is speeding up the erosion process. The banks of the Mattawoman Creek are made up of rocks, sand and clay, but as they erode, the plant life on the banks of the Creek are washed away. These plants help prevent greenhouse gases. When distributed in our atmosphere, a greenhouse gas like CO2 traps heat much as a pane of glass does in a greenhouse: it is transparent to sunlight but blocks Earth’s radiant heat from escaping into outer space. In addition to the documented increase in global surface temperatures, the price of disturbing our atmosphere with excess greenhouse gases is predicted to include altered patterns of storm frequency and intensity, new rainfall distributions with attendant drought and desertification. In two words: climate change.
Mattawoman exemplifies the connection between global warming and land use because its watershed is being rapidly converted from forest, a CO2 sink, to sprawl, a CO2 source.
As the water erodes the soft sands underneath the harder rock, cracks form. The cracks begin to grow and become small caves. The caves begin to grow until the land breaks off from the banks. See Photo Below:
How do we correct the damage we’ve done and prevent erosion?
The banks of Mattawoman Creek have become protected. Barriers have been erected along Mattawoman Creek to prevent further damage. The Army Corps of Engineers placed steel barriers along this section because the damage was so severe, planting vegetation or piling rocks would not slow down because the pollution was accelerating the process.
In some areas you will see barriers erected such as the photo below to prevent erosion in the short term:
Temporary barriers have been erected in flood and erosion areas such as New Orleans to prevent further damage.
The barriers installed at the posted coordinates are permanent metal barriers that will prevent the erosion while planting new vegetation along the banks to help keep the creek from crumbling.
To log this earthcache as found, first e-mail me the answers to the following questions (don't post them in your log!). You may log it as found before hearing a response from me, but e-mails with missing or poor answers to the first three questions may be deleted, and the cacher notified as to the reason(s) why.
- At the posted coordinates, the metal barriers were erected to prevent the cliff from eroding. If you look to the sides of the barriers, you can see unprotected sections. Here, at the edge of the cliff, you can observe a vertical fracture in the rock, which may one day result in the formation of a new cave below. Measure or estimate the width and height of this fracture. (For the height, get an elevation reading at this spot and at any point along the edge of the water, such as a nearby bank.)
- While standing at the posted coordinates on the observation overlook, what type or types of major erosion do you see?
- Do you think that this type or types of erosion at this location can be stopped?
- (OPTIONAL) There are many Bald Eagles in this location as well as Egrets. Post a picture if you happen to see one or one of yourself at the banks of the Creek.
References:
[1] What are the Different Types of Erosion? (2004, January 1). Retrieved September 4, 2014, from http://www.odec.ca/projects/2004/derk4d0/public_html/differenttypesoferosion.htm
[2] Roland, T. (2011, July 1). Rails-to-Trails Conservancy:: Trail of the Month: Indian Head Rail Trail, Md. Retrieved September 4, 2014, from http://www.railstotrails.org/news/recurringFeatures/trailMonth/archives/1107.html
[3] Anonymous. (2012). About the mattawoman. Retrieved from http://www.mattawomanwatershedsociety.org/about
[4] Wikipedia. (2014, August 31). Erosion. Retrieved from http://en.wikipedia.org/wiki/Erosion
Congrats to CacheClown for the FTF on this Earthcache and providing excellent answers to the questions!