The heat becomes almost unbearable around 10 am, which means getting up really early and using the cooler morning hours for working on and around the lake. Usually a light breeze starts around 11 am and the sky becomes overcast around noon. Both make the heat more tolerable.
We finished coring on Lake Pa Kho today. Now we have a nice surface core and an almost 7 m long sediment sequence. Lake water and plant samples were next on the list, as well as water samples from inflowing rivers and creeks. We wanted to get as close to the source of one of the creeks to obtain a sample and started following it through thick woods and understory. Walking close to the creek was not really possible and walking upstream in the channel itself was not a good choice either given the many broken trees, the dense vegetation and the steep sides. For a while we could still be sure that the creek was somewhere on our left side, but after a while we lost track of the little stream. Not much water was actually running in it, but the steep sides suggested that high water flow during the rainy season. We struggled through dense vegetation, across sugar cane fields and through rubber plantations, but could not find any water anymore. Instead we completely lost direction! Luckily we found a small path leading to a house, which turned out to be a Wat (temple) with a rather unfriendly monk, but a friendly charcoal burner.
Both of them directed us somewhere along the dirt road, where they said the stream would run. We did not find a stream, but came to another house, whose owner directed us back on the dirt road, where we would find a small bridge over a channel, she said. Finally we found the bridge and the channel, but there was not a drop of water in it! Just dry vegetation. This was really disappointing. Having walked for several kilometers, we still had not found the source of the water! It would certainly have been much easier during the rainy season, when the dry river channels are full of water.
After two or three kilometers we reached the lake again and made another attempt to follow the creek upstream. We only managed a few hundred meters and then it was stop.
The area around Kumphawapi and Pa Kho is known for the high salt content in the soils, due to the underlying evaporitic bedrock. Farmers use the salt containing soil to extract salt by first washing the soil through a net. The salty water is then boiled for some time. During boiling it evaporates and what remains is white salt. This is in a way perfect recycling –salt that comes and goes, from the bedrock into the soil, from the soil into the water, and later back into the soil.