Welcome to Pantai Kulambu
In northern Sabah, Kudat boasts the highest number of beautiful beaches in the region, many of which feature unique geological characteristics beyond just stretches of white sand. Kelambu Beach, also known as Kulambu Beach, is a sandbar that connects an island to the mainland, making it a rare and remarkable sight in Sabah.
About Tombolo
A tombolo is a coastal formation that means, when translated from Italian, “mound”. It appears to be a small island that has not fully separated from the mainland. This island-like landform is actually attached to the coast by a thin sand bar or spit. Tombolos are sometimes referred to as “tied islands”, because they seem to be tethered to the coast. This formation can be either solitary or found in clusters. When clustered, the sand bars may form a lagoon-like enclosure near the coast. These types of lagoons are likely to fill with sediment over time.
The Formation of Tombolo
The shoreline moves toward the island (or detached breakwater) due to accretion of sand in the lee of the island where wave energy and longshore drift are reduced and therefore deposition of sand occurs.
Longshore Drift
Longshore drift occurs as waves push sediment (which may consist of sand, silt, and clay) towards the coastline at an angle. Instead of landing on the beach, this sediment begins to build up between the beach and an island, creating the bar mentioned above and effectively “tying” the island to the mainland. This drift is often influenced by the wind direction. When created by longshore drift, these formations are sometimes not considered a true tombolo.
Wave Diffraction and Refraction
A true tombolo is formed by wave diffraction and refraction. Waves move toward the coastline and are slowed down as they enter the shallower water. They first reach the islands that are close to the shore. Because these waves are moving at a slower than normal pace, they move around the island instead of over it. As the water moves more slowly around the island, it picks up sediment along the way. When the waves meet on the other side of the island (the side facing the coast), sediment is deposited. This sediment continues to build up until it creates the sandbar that connects the island to the beach.
Changing Tombolos
Because of its unique shape, a tombolo tends to be more likely to change over time due to weathering and tides than the regular coastline. Sometimes, the island at the end of the bar, or spit, is large enough that it supports commercial or residential activity. In order to prevent changes to the tombolo, the bar is reinforced with cement roads or parking lots. This prevents wind and waves from washing away the finer sediment on top of the bar.
Diagram Formation of Tombolo:
Additional Information:
1. Spit or Sandspit (Landform)
A spit or sandspit is a deposition bar or beach landform off coasts or lake shores. It develops in places where re-entrance occurs, such as at a cove's headlands, by the process of longshore drift by longshore currents. The drift occurs due to waves meeting the beach at an oblique angle, moving sediment down the beach in a zigzag pattern. This is complemented by longshore currents, which further transport sediment through the water alongside the beach. These currents are caused by the same waves that cause the drift.
2. Deposition
Deposition is the geological process in which sediments, soil and rocks are added to a landform or land mass. Wind, ice, and water, as well as sediment flowing via gravity, transport previously eroded sediment, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment.
3. Tied Island
Tied islands, or land-tied islands as they are often known, are landforms consisting of an island that is connected to land only by a tombolo: a spit of beach materials connected to land at both ends.
How to get here?
Kelambu Beach is accessible by tar road (mostly), it is located about 31km to the north-west of Kudat town and 8km south of the Tip of Borneo. There is no public transport going there.
How to claim this EarthCache?
Send me the following;
1. The text "GC7715N Kulambu Beach (tombolo)
2. The answers to the following questions;
- Estimate the distance and the width of the sand bar (Tombolo) in meter.
- Feel the water. Which is warmer, the left or the right side of the sand bar?
- When standing on the coordinates and looking towards Kulambu Island, explain why you think you see tombolo instead of spit.
3. Take a selfie (optional) and/or a photo of a thumbs-up, peace-symbol (V) or personal item, while standing in the middle of the tombolo, and attach it to your log.*
References
- https://en.wikipedia.org/wiki/Tombolo. - www.worldatlas.com/articles/coastal-landforms-what-is-a-tombolo.html. - www.sabahtourism.com/destination/kelambu-beach
Finding the answers to an EarthCache can often be challenging, and many people tend to shy away from these caches because of this. However, it is my opinion that geocaching is also meant to be a fun family experience that simply aims to introduce interesting and unique locations such as this one. Flexibility on logging requirements, however, can only be applied if it can be established that you have actually taken the time to visit the site. For this reason, a proper log describing your adventure accompanied by a good number of photos would be much appreciated.
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