Dark Harbour, Barrier Beach EarthCache

Dark Harbour, Barrier Beach

Dark Harbour, located on the west side of Grand Manan Island, New Brunswick, is the only suitable haven for fishing craft along the island's western shore, which is dominated by high cliffs. It is relatively isolated from the communities on the more hospitable eastern side facing the Bay of Fundy.

Dark Harbour Pond is a naturally occurring pond fed with fresh water from the surrounding 120 metre cliffs and with salt water from the ocean which seeps through the seawall that contains the pond. It is the only indentation in the cliffs on the entire western side of Grand Manan Island that shelters boats. 

Barrier Beaches

Barrier Beaches are narrow and elongate beaches situated parallel to the shoreline. By definition, the beach provides a barrier between the mainland and adjacent nearshore wetland, such as a salt marsh or mudflat and marine waters offshore. Barrier beach systems are comprised of several distinctive topographic elements: the beach and dune complex, tidal inlets, and wetlands such as mudflats or salt marsh.

Sand Transport in Barrier Beaches

In a natural barrier beach system the primary process of sediment distribution is longshore transport. In longshore transport, waves breaking on shore carry sand parallel to the coast, helping to create the elongated form of the barrier beach. Sediment transport in barrier beaches relies heavily on the morphology of the beach and what is referred to as "wave climate" which includes wave height and period (time between waves). These factors can vary seasonally or during storms.

In the case of Dark Harbour the force of the Bay of Fundy along with the help of storm surges the barrier beach is a stone wall. The natural harbour has been augmented by a sea wall thrown up by the waves that rings the harbour. The natural seawall of stones keeps the pond in place as the force of the ocean pushes the stones up from the ocean floor and the fresh water from the brook pushes the stones on the inner side.

To log this Earthcache visit the viewing location. Please answer the following questions and send in a timely manner to my geocaching profile or email. Answers not received will result in deleted logs.

Questions:

1. Estimate the length of the barrier beach?

2. Is the water in the lagoon fresh or salt, why?

3. What do you think the barrier beach is made of?

4. What is the elevation at ground zero?

5. Post a picture in your log with a personal item or hand in picture to prove you were there.

[REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please provide a photo of yourself or a personal item in the picture to prove you visited the site.