The Columns of Wonder
The Hong Kong UNESCO Global GeoPark remembers Hong Kong in a way that none of us does. Hexagonal rock columns line the slopes at the Eastern Dam of the High Island Reservoir in Sai Kung. They span a total area of 100 square kilometers including sea areas. Rows and rows of these rock formations surround the buffer zone of the reservoir. They are the living testaments of Hong Kong’s pre-settlement history.
Back in those pre-settlement days, there were active volcanoes in Hong Kong. Eruptions of these volcanoes 140 million years ago have made possible the forming of these columns. The following is a description of how they formed:
“Whenever there was an eruption, great lava flows gushed out along with scorching volcanic ash. They spread across the ground surface and formed lava layers. During the cooling period, the rock contracted very uniformly and gave rise to the marvelous hexagonal columnar joints seen today.”[i]
The vertical columns already create a magnificent testament of the geological movements hundreds of millions of years ago. Yet nature has not stopped there. Subsequently, movements in the earth has created a bent to the vertical columns into “S” shapes:
And the description explains this phenomenon thus:
“When the hexagonal rock columns were first formed, they cooled down slowly inside the caldera. Their texture would have been similar to that of putty. Most probably earthquakes or regional subsidence caused them to become contorted into the S-shape columns seen here.”[ii]
I highly recommend the GeoPark to any nature enthusiasts travelling to Hong Kong. The hexagonal columns, as a non-basaltic kind, is really quite unique to the hexagonal columns in the world.[iii]
Surely, one visiting the area would be drawn to the columnar formations, but there are a few other wonders worth seeing at the site. Lying at the very end of the trail at the buffer zone is the Sea Cave. It was formed from the erosion of the waves. The construction of the coffer dam has shielded the area from the consistent erosion of sea waves so the cave remains a cave, instead of a sea arch.
One can also see afar the Po Pin Chau, a stack island that split from the mainland due to the erosion of sea waves. It now shows a steep cliff.
Finally, the East Dam’s coffer dam itself is an infrastructural wonder. It is lined and protected by thousands of t-shaped dolos blocks, made of concrete and weighing 25 tons each. When you arrive at the long upper edge of the dam, you will see a giant blue dolos block that commemorates those who died in the construction of this dam. An Italian firm constructed the dam.
For a leisurely stroll in the area with time to read the exhibits, one should reserve at least 1.5 to 2 hours. A gentle but crucial reminder to visitors: if you are travelling during the summer, two bottles of water would not suffice. Bring three at least. The area has very few shades throughout, and even though the walk is very short, it does involve a strenuous climb up. Therefore, be certain to bring a hat and a number of bottled water with you.
This following is perhaps the best way to get to the area:
- At Pak Tam Chung, take a green taxi. Tell the driver you are going to the East Dam of High Island Reservoir. If no taxi’s are at the stand, you might have to call one. One-way from Pak Tam Chung should cost you less than $75.
- Taxi back is even trickier, especially if you are leaving at around 3 to 4pm because that is when the taxi drivers change shifts. Watch the time, and try to leave before 3pm. That is when there is a good chance that taxis can take you back after they drop off other tourists. You most likely will have to call one, and if the driver asks for a top-up (some would ask for as much as double the cost), you might just have to pay it.
Do note that the area is off-bounds to private cars and the mini buses only go on the weekends. On all my past visits I have taken taxi’s in. After every visit, however, I thought it was well worth the trouble. The scenery there never ceases to amaze me.
Finally, for the hikers, from Pak Tam Chung to hike to East Dam, the trail will take at least 3, 3.5 hours each way.
[i] Internationally rare acidic polygonal volcanic rock columns － High Island.
[ii] A Landmark Produced by an Exogenous Force, an introductory display at the GeoPark.