3. Results and discussion
The five monitoring of Mekong mainstream are as following;
1st Monitoring : In the early morning on May 30, 2015, on the upstream, both parties of participators and researchers has started to install 2 rows of 4-inches diameter of wooden pegs which spacing of 20 meters in between each rows. The pegs in the same row has spacing of 2-4 meters which are started from toe and go up to top slope of the river bank to ensure that the installed pegs can be monitored the changing of bank slope. In the afternoon the team has moves to downstream to install another 10 wooden pegs. 2nd Monitoring: On June 30, 2015, the team has observe and survey on site, and found that nothing change from 1st monitoring due to the same drought period and water level also has not change, the height of every wooden pegs still 500 millimeter vertically above the existing ground level of bank slope.
3rd Monitoring: In the monsoon period, the team has observe and survey at site on August 07, 2015, and found that every wooden peg in both upstream and downstream are under the water due to rainy season and flood period, and impossible to record the height of all wooden peg under water.
4th Monitoring: at the end of monsoon period, the team has visit the site to observe and survey the changing of river bank on September 16, 2015, and found that few of wooden pegs are above the water level and some are still flooded due to the end up of the rainy season and Mekong River water level still high. And the team has found the ripple mark of water level that shown along river bank. The team has take picture and also record the height of few wooden pegs which appears both shorter and longer than 50 cm to present both eroding and depositing along river bank as illustrated in Table 1.
Figure 4 5th Monitoring of wooden peg in Line B at Ban Na
Nong Bok (upstream) Figure 6 5th Monitoring of wooden peg in Line D at Ban
Tan Pak Nam (downstream)
Table 1 Monitoring and Analysis of Wisdom Vertical of Bank Erosion Rate per year