This is an Earthcache – as such, there is no physical cache. Instead after examining the shoreline at the posted coordinates you will answer 7 questions and message me the answers. This earthcache is located in Belle Isle State Park with permission. For more information about hours of operation, entrance fees, and park rules please visit this Belle Isle State Park LINK.

Belle Isle State Park is a peninsula with about 8.6 miles of shoreline surrounded by the Rappahannock River to the southwest, Deep Creek on the south east, and Mulberry Creek on the north east. This Rappahanock River flows almost 184 miles from the Blue Ridge Mountains into the Chesapeake Bay. Here at the posted coords you will find a small beach along the shore of that river.

RIVER BANK EROSION

At the posted coordinates you can see some examples of river bank erosion. Shore erosion in the tidal Rappahannock River is mostly caused primarily by wind-driven waves and slope processes. Unlike ocean waves, which are largely created by wind, these river waves are formed either by water flowing quickly downstream over a drop in elevation. These waves cut steep banks along most of the shoreline which are interrupted by low-lying areas of marsh and swamp that occupy small stream valleys flooded by rising sea level.

A cut bank, also known as a river cliff, is an erosional feature of streams and rivers. They are shaped much like a small cliff, and are formed by the erosion of soil as the stream collides with the river bank. Typically, these cut banks are nearly vertical and often expose the roots of nearby plant life. Often, particularly during periods of high rainfall and higher-than average water levels, trees can fall into the river due to mass wasting events.

Vertical or undercut bank- a bank that rises vertically or overhangs the stream. This type of bank is resistant to erosion. However, if seriously undercut, it might be vulnerable to collapse.

Steeply sloping- a bank that slopes at more than a 30 degree angle. This type of bank is very vulnerable to erosion.

Gradual sloping- a bank that has a slope of 30 degrees or less. This type of stream bank is highly resistant to erosion, but does not provide much streamside cover. Beaches along these eroding bank sites are generally 6 to 18 feet wide at local mean sea level, with gentle slopes from 4 to 7 degrees. These beaches usually have a limited supply of sand that form them.

LIFE IS A BEACH

A beach is a landform made of very small loose particles that gather at the shore of a body of water. These particles are typically made from rock, such as sand, gravel, pebbles, or shingles. About 31% of the world’s beaches are sandy. Sand comes from erosion of rocks both far away from and near the water. These rocks can be remnants of old mountains, eroded under water rock beds, or even coral reefs can be even source of sand.

The color of the sand particles can tell you more about how a particular beach is formed and the minerals of the rocks of which they are composed. Beaches along the Chesapeake Bay have sand colors that run from a deep orange to nearly white. It all depends on the minerals from the rocks which they came. For instance, a deep orange sand originates from feldspar rock that was high in iron, while a whiter sand is made up of many grains of quartz.

Sometimes black sand collects along the beach surface. This sand is combination of dense minerals, such as magnetite and garnet, create a purple, black or reddish sand. The black sand is heavier than the usual beige-colored sand and is always under the beige, sandy beach. Sand “layers” according to a grain’s size and weight. Storms will disrupt the layers and that layering process starts all over, with the black sand exposed for a bit until the beaches recover, literally. If you use a magnet on the black sand, the magnetite will stick. NOTE: a permit is required for any collecting activities, including metal detecting, per 4 VAC 530-50 which states that “No person shall remove, destroy, cut down, scar, mutilate, injure, take or gather in any manner any tree, flower, fern, shrub, rock or plant, historical artifact, or mineral in any Park. Special permits may be obtained for scientific collecting.”

THE FUTURE

Belle Isle State Park has been targeted for a Living Shoreline Management at this location. A living shoreline uses a combination of planting native marsh plants to control sediments and a series of offshore rock structures to serve as a breakwater.

The conceptual design of the beaches at this Picnic Area may one day have Sills and 2 breakwaters installed to slow down wave energy and protect shore, as well as using sills to trap sand and build up the beach. Bank grading was suggested for the sandy beach, that will provide a gentle gradient for public access to the beach rather than stepping down the eroded steep cuts that are there today.

LOGGING REQUIREMENTS:

To log this Earthcache: Read the geology lesson above. Answer all seven questions posted below. Answers can be sent via e-mail or messenger contacts on my Geocaching profile within a reasonable time. Group answers are fine, but please include the members of the group you are with.

QUESTION 1. Is Belle Isle State Park an island or a peninsula?

QUESTION 2. How tall is the sloping cliff from the beach below to the grass on top?

QUESTION 3. Do you see any evidence of bank under cutting here near the posted coords? If so, how deeply cut in to the cliff do you think it is?

QUESTION 4. Look at the cliffside and the sand. Does the sand appear to be originating from the bank cut, or does it look completely different as if it was carried from further up river and deposited here?

QUESTION 5. Take a close look at the beige sand that makes up a majority of the beach. Would you describe the color of this sand as being:
A. More Quartz based
B. More Feldspar based
C. An even mixture of quartz and feldspar

QUESTION 6. Did you see any black sand on the beach at the time of our visit?

QUESTION 7. How can this location benefit from a Living Shoreline?

OPTIONAL PHOTO: Posting a photo that readily indicates that you (and anyone else logging the find) are at the location.

Awesnap has earned GSA's highest level:

REFERENCES: