Wednesday, November 4, 2015

Field Site Visit on the Downstream Reach of Bago River and Confluence Area with Yangon River and a small tributary

This is Ralph ACIERTO, project researcher of Kawasaki group from River and Environmental Engineering Laboratory. The site visit to Bago River Basin in Myanmar was done from 27-31 October 2015. The objective of the site visit was to establish the impact of tidal fluctuations and get some observations in Bago River basin primarily near the confluence of Bago River and Yangon River. The map below shows the areas visited during the field site visit.

Figure 1. Annotated Bago River Field Site Visit locations from MotionX Offline map. (1)Excel River View Hotel; (2)Star City Site; (3) Thilawa Site; (4)Yangon Site; (5) Midstream bridge crossing in Bago River; (6) Bago City site observation; and (7) Tawa sluicegate 

27 October 2015

The Japanese team was composed of Kawasaki-sensei (Figure 2, 7th from the left), Shimozono-sensei (Figure 2, 4th from the left), Tajima-sensei (Figure 2, 5th from the left), myself (Figure 2, rightmost), and Shota Seto(Figure 2, 2nd from the left), and Masahiro Kambara (Figure 2, 3rd from the left). We were guided by Myanmar counterparts from 27-30 of October for the entire field survey as shown in the group photo below.

Figure 2. Group picture of the site field survey from 27-29 October, 2015

We arrived in Yangon at around 5:20pm (local time). We headed to check-in at Excel River View Hotel. Then, we head for dinner and made plans for the next morning’s site visit to observation sites. There are two main observation devices, pressure sensor and camera as shown below. Pressure sensor was for measuring tide and wave fluctuations while camera was used for observing surface river velocity.

Figure 3. Pressure Sensor and Camera used for Site Observation near the confluence of Yangon River and Bago River

28 October 2015

On the second day of field survey, three pressure sensors were deployed on three sites. The three site include Excel River View Hotel (site 1 in Figure 1, upstream of Bago River before confluence), near Thilawa port (site 3 in Figure 1, downstream of confluence), and near the Yangon River mouth (site 4 in Figure 1, upstream of Yangon River before confluence).

In Excel River View Hotel site, pressure sensor was also deployed. The river bank on this site was also very muddy and slippery to deploy the pressure sensor. The tide fluctuations from low to high tide was estimated to be around 5-7meters based on the wet markings of the structure near the river bank. Also, salt meter was also used to check the salinity of the river.

Figure 4. Deployment of pressure sensor on the (3)Thilawa port site

On the Thilawa port site, it was quite difficult to go to the river bank and deploy the pressure sensor because of the thick mud and silt layer on the river bank due to the combination of significant tide level fluctuation and significant fine particle bedload (indicated by the brown colloidal turbidity of water) of the river. 

Figure 5. Deployment of pressure sensor on the (1) Excel River View Hotel site. Left picture shows the low tide condition in the site. Middle picture shows the deployment of pressure sensor. Right picture shows the measurement of salinity suing a salinity meter

Additionally, a camera was set-up for observing the river velocity through observing floating objects on water and additional post-processing of the images taken. Figure 5 shows the deployment of pressure sensor and Figure 6 shows the setting up of camera observations on Excel River View Hotel site.

Figure 6. Setting up of camera for observing river velocity in (1) Excel River View Hotel site

29 October 2015

In the morning, the group went to check the site near Star City for observing confluence area of Yangon River and Bago River. Camera observation was installed on a guard post as shown in Figure 7.

Figure 7. Setting up of camera for river velocity observation at (2) Star City site

30 October 2015

In the morning, the group was divided into boat team and land team. The boat team was tasked to get additional GPS points for the post-processing of images taken by the camera observations for the three sites – Excel River View Hotel site, Star City site, and Yangon site.  In addition, the boat team collected the pressure sensor for the Yangon site. On the other hand, the land team was tasked to gather the deployed pressure sensors from Thilawa site and Excel River View Hotel site.

Figure 8. Near (4) Yangon site boarding the boat for getting additional GPS points for image analysis of the camera observations near the confluence of Yangon River and Bago River

Figure 8 shows the boat used for the survey that was located near the Yangon site(site 4 in Figure 1). Figure 9 shows the view from the boat of the Excel River View Hotel site (left picture) and signaling to camera as marker for the additional GPS points taken along the river. The marker serves as reference point to transform the pixels in images by the camera to coordinate system. Figure 10 shows the upstream and downstream view from the boat of the bridge nearby upstream of Excel River View Hotel site. 

Figure 9. View of (1) Excel River View Hotel site from the boat (left picture) and signaling to camera (indicated by raising the bright orange vest) of the GPS point for image analysis of camera observations.

Figure 10.Upstream and downstream view of the bridge near (1) Excel River View Hotel site

In Yangon site, the camera was collected and additional measurements regarding the camera level in reference to the water level. Figure 11 and 12 shows the location of the Yangon site where camera was installed. 

Figure 11. (4) Yangon site for camera observations as shown in the right picture and left picture shows additional measurement to establish the height of the camera used in observation in reference to water level

Figure 12. (4) Yangon site showing the additional measurements and checking for the camera observations

This concludes the field site survey for the downstream of  Bago River basin focusing on the confluence of Bago River, a tributary, and Yangon River. The field observations were done to investigated tide and water levels and river velocity. An additional post will be released regarding the observations on the midstream reach of Bago River during the field site visit from 27-31 of October, 2015.

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