In 1980 EGAT, the Energy Council of Thailand built a hydroelectric dam in an area of Khao Sok National Park which caused the natural river that flowed through the valley to build up into a man made lake shielded by 3 dams and natural limestone cliffs called Cheiw Larn Lake.

As they built the hydroelectric dam it was decided to relocate several villages and towns, leaving buildings and structures behind to be flooded. As the water rose to above 60m it submerged, according to rumour from locals; a temple - otherwise known as a ‘wat’, fire station, houses, school and a police station.
Big Blue Tech have been doing Cavern and Cave diving monthly in Khao Sok this year and while looking for new caves we heard more and more about this feature.

On our last trip we took a translator to the administrative offices of the energy council for the dam in search of a map or survey prior to when the water rose. We we’re lucky to find an old comparative map of a submerged river, villages and the overlying lake we now dive in. With a few weeks of planning and consequent phone calls; a technical diving expedition was arranged in search of these villages and anything else of significant difference.

Diving in Khao Sok is unlike diving anywhere else in the world. For many at Big Blue Tech the thrill of coral reefs and their associated marine life isn’t quite the thrill it used to be. Underwater exploration and the discovery of something new and unique is the ultimate thrill for us.

For someone who has yet to dive in the Khao Sok national park, the best way to envision the experience is to imagine flying through the woods at night, around the trees, over the clearings, across a river and under enormous suspended vegetation covered in freshwater matter or “mung” as referred to in the NSS-CDS Cavern Diving Manual. And then, in the midst of it all: houses with chairs and tables, walkways with fences, buildings with roofs. A feeling much like finding Atlantis perhaps, although this is only about 20 years old of course and it’s pitch black conditions in 22 degree freshwater.

The expedition consisted of 6 team members: James Thornton-Allan, Hannah Lusby, Oskar Sjostrom, Tim Klein, Christos Kardana and Cory Lewis; all technical divers with different backgrounds, disciplines and diving styles. The logistics for this trip would require more technical gear than our usual trips to the same location, including an oxygen booster, double the amount of torches, shot lines and buoy lines and of course enough nitrox and oxygen for 6 dives to 60m, for up to 30 minutes bottom time. Although the oxygen booster is not essential, we needed it to get every drop out of our big 50L oxygen tanks, thus allowing every oxygen cylinder a fill of at least 130 bar.

We all agreed that this trip would be dry, which means no alcohol! Due to the remote nature of the diving and the lack of immediate or speedy emergency support, any risk of a diving related injury or illness had to be minimized. Despite a few grumblings all agreed that this is the correct attitude for such an expedition and this decision was kept until the trip home, which was messy by any standard.

The day of departure was much like normal; taxi fully loaded and off to the pier to catch the night boat to Chumphon. Once there it’s a mini bus ride to the resort with the big blue gear taxi following. Arriving at the resort there is a fury of activity with equipment checks, logistical and mission briefings and everyone kitted up and down to the lake for a check dive. The check dive would introduce conditions new to some team members and make sure all their skills and drills were sharp for the diving ahead. A short moderate dive exposed everyone to the conditions below the freshwater surface and brought everyone back on the longtail boat with laughter and smiles of which many haven’t shown in a while. This dive also allowed James to show Cory and Christos how to shot a mark and tie on. This was essential so our longtail could remain on the site and surface support could respond with short distance if needed.

This was a long first day in a new environment. The recent weather in Koh Tao had been rainy and cloudy, so quite a few were suffering from the new found heat and sun they were suddenly exposed to on the opening day. We finished the day with a quiet dinner and off to bed early in our spacious air-conditioned rooms with large balconeys facing the  stunning park view. Tim -our local multimedia guru- even brought his playstation 3 along just to pass the time while the compressor roared through the night, forcing every possible litre drop into the 6 twin 12L tanks.

Waking at 6am proved too much for some. It was clear Tim was not a morning person and needed a good couple of hours after waking up before anyone could talk to him…a charming chap indeed. A breakfast of eggs, toast and cereal was prepared by Cory and then it was off to the lake for an early morning dive. We brought the compressor with us this time so we could fill our tanks during lunch at a floating resort during the surface interval. During these dives we explored different areas of the villages, some found a hut while others found a chair but still had yet to find the large concrete structures reported by the locals. Although finding man made buildings was great, it was not exactly what we were looking for and it didn’t help us get closer to the centre of the village. We could have been 500m away, which at 60m might as well be 10 miles. With staggered diving for surface cover the day was long but with plenty of food and water it flew by quicker then most expected.

The next day we decided to explore a different mark of the map which indicated  a cluster of villages. Speaking to the locals we realised more and more that they have less and less of a definitive idea of what lies beneath and realized that a small village in a jungle over 20 years ago wouldn’t look the same as what we recognize Thailand villages today. With that in mind we lowered our expectations of submerged roads and shopping malls to simply looking for bamboo huts, pathways and woodland clearings and the new search patterns and mission briefings were completed. The dives that followed proved successful as we started to find, still at 60m in pitch-black conditions, wardrobes, chairs, simple man made structures, clearings of purpose cut trees and pathways. Unfortunately they were all surrounded by heavy forest and covered in freshwater detritus making it hard to follow an individual pathway. In agreement with the local stories, it was clear that they were all connected by a deeper path, in this case the old river that supplied the water to build the lake. By this time everyone was tired and a bit sun kissed but very excited and satisfied with the days diving. We still had one more place to look, which would be on our final day, consisting of a big dive with 30 minute bottom time.

The wind had picked up and the waves were crashing over the bow of the longtail as we arrived on site the next morning. Broken into groups to explore for one last effort, the divers’ descents down the line were staggered, with surface cover at the ready. After a 70minute exploratory Oskjar and Cory returned to the surface, while Hannah had a longer bottom time and was still doing her decompression on a lift bag. Retrieving the nitrox tanks the second group descended down the buoy line, while Hannah surfaced with good news, finding a concrete pillar and signs of a town. This definitive sign of man made dwellings, was what we have been searching for all along and Tim who had yet to dive could return down her reel line, and conduct a further search within proximity of all these newly found structures. Tim was successful; his sightings allowing us to positively identify the temple area.  Among other things Tim found a large water reservoir and concrete structures including a 10m by 10m square block with 3 steps rising to a plateau. On this plateau were steel pipe supports for a roof and a concrete pedestal.  Typically Thai temples in small villages have a simple concrete centre with a Buddha or relic where offerings are placed. In speaking with the locals they confirmed that we had found the village near the temple and that we needed to look further south in search of the old building. Further research and interviews with locals bought new information to light. The temple was primarily made of wood. This would suggest the intergrity of the temple is most probably reduced to its concrete foundations. However, the discovery meant we had an exact gps mark to the village that was home to the temple.

Despite the trip having a somewhat bitter sweet finish, our discovery leaves us with so much more to be explored and discovered. Returning to the resort, it was kit break down and equipment sorting. The usual farewells ensued before departure to Chumphon for the night boat back to Koh Tao.

For the team we head back to Koh Tao for more technical diving activities and expedition planning, as we look forward to more exploration and discovery in the future.

If you would like to join us on the next expedition to The Khao Sok National Park contact us at info@bigbluetech.net

More info here and here