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Wednesday, 23 April 2014

Tasik Chini Fieldwork - Hydrology (part two)

Our Dr. Nor Rohaizah whom I have never met before. She seemed fearless when crossing the 'river' (feeling ashamed, could we even call that river?).
Many of us made a mistake during this fieldwork. As we thought that we were going to get our feet wet, we wore slippers which gave poor protection (that almost equivalent to no protection) to our feet as we walked into the forest to reach the river. I got some minor wounds on my feet scratched by branches or thorns (that's why I bought myself a pair of hiking shoes now, which is good for hiking and also getting into the river, yay) and the mud was the most annoying part of the river. It makes you slip or traps your foot, ugh. The downstream part of the river was chosen as our fieldwork site as this was the shallowest river where we would not disturb the life of orang asli living there (there was another river with the depth of 3m, so...hmm...).

The very shallow water of the river. At the middle of the river it was mainly sand but at the river bank it was full of mud, annoying mud.
So yeah, it was the downstream part of the river.
This was more about the quantity measurement of the river. Firstly we need to set up a safety rope across the river (during this fieldtrip we used nylon string which was unsafe at all, haha. After all the depth of the water did not even reach half of my calf) for us to hold on to in case we lose balance. The height of the safety rope indicates also the maximum height of the river water during rainy season. Then the meter tape is set up too along the safety rope.We have to decide whether we measure the physical parameters of the river from the left or the right bank. The direction is decided by which we face the direction the water flow of river. After that, the width of the river is 'cut' into several section with 1m per section. The current river depth and the maximum depth of the river are recorded at each of the point. The velocity of the current is measured at those points as well by inserting the propellent at half of the depth of the river.

The 'safety rope' and meter tape. They were tied across the original width of the river. The size of the river shrunk due to the previous drought. The effect was really big towards the river.
The staff gauge which can be extended to measure the depth of the river.
Again, the GPS which is placed on the ground to measure the elevation of the site, according to the sea level.
The non-waterproof current meter. It is another expensive device that we cannot afford to drop it into the water.
The propellent which is the detector for the current meter. It should be pointed at the direction of the river flow without any obstacle at front. Due to wind or other factors, the water at surface will flow at a faster rate, so we should take the measurement at the half of the depth. But if the depth is more than 1m, we take the reading at 0.2m and 0.8m then get the average reading. That should represent the velocity of river flow.
I did not write down notes at all during this session as we were rushing to finish the fieldwork. So many of the details I have forgotten (ugh). Measuring the river could be dangerous and yet we have to do it as these physical conditions of the river will definitely affect the water quality. I believe there would be much more river adventures we will go through one day.

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