Dhaka and beyond
The spacious new office of Humayun, as VC of Bangladesh Open University.
The following week I spent countless meetings with colleagues and partners in the capital, Dhaka, only limited by the terrible Dhaka traffic. Two events stand out. I went north to Ghazipur to live with my colleague and main partner S. Humayun Akhter, who has worked in Bangladesh for over 20 years. Last summer, he became vice-chancellor of Bangladesh Open University, 7th The largest university in the world. A vice-chancellor is equivalent to a university president in the United States, because the president is a ceremonial position. He now has a huge office and residence where I live with him.
Chris and I in Punjabi for a photo with Babu who drove us to the wedding.
The real highlight of the week came last night when Chris Small came to me for my first wedding reception in Bangladesh, Nafis Sazeed. Nafis, a graduate student at the New Mexico Institute of Technology, is involved in a project that will bring me back to Bangladesh in March — mapping saltwater and freshwater groundwater using electromagnetic tools. We talked multiple times over Zoom and email, and I was on his thesis committee, but because of COVID, it was also the first time I saw him in person. It turned out that Humayun also attended the wedding. His current wives, Georgina and Nafis, are students in the Department of Disaster Management at Dhaka University. Humayun was invited by her.
Georgina poses for a photo in her wedding dress.
Early the next morning, we set off for southern Bangladesh, where I will spend the rest of my journey. I now have 9 GNSS stations in this part of Bangladesh and all seem to have failed batteries. We will replace the battery and see if there are any other issues that could be causing the problem. The stations are examining land subsidence in the Ganges-Brahmaputra delta. All deltas sink due to the weight of the accumulated sediments and the compaction of the sediments. The sinking rate is even greater than the rate of sea level rise, greatly exacerbating the problem in this densely populated low-lying region. However, the Ganges and Brahmaputra rivers here still bring a lot of sediment to fill the newly created space. As a result, Bangladesh is still gaining land, but due to the changing location of rivers, some areas are getting enough sediment while others are facing problems due to lack of sediment.
Watching a car ferry go in the opposite direction as we cross the Padma River t Aricha
The survey is currently supported by the Bangladesh Water Development Council as part of “Long-term Monitoring, Research and Analysis of Coastal Areas in Bangladesh (Polders for Sustainable Development Adapted to Coastal Dynamics)”. In Bangladesh, they use the Dutch term “polder” to refer to the banks that protect coastal islands. In addition to Chris who will validate his remote sensing observations, Sanju and I are joined by 5 other people. Masud Rana and Sharmin (Pinky) Akhter from Dhaka University will be servicing the RSET-MH (Rod Surface Elevation Table – Mark Horizon) equipment that we will be installing with GNSS in 2019. These devices measure elevation changes and sediment accumulation. The difference is the shallow subsidence of the poles at these locations above the 80-foot depth. GNSS, on the other hand, measure deep settlements, but miss some shallow settlements due to the foundations of the buildings on which they are installed. This combination is a very effective way of understanding the dynamics of a delta. This work was the basis for their master’s thesis.
Typical scene along the “highway”. Most are one lane in each direction and have no restricted access. We share the road with trucks, buses, cars, auto rickshaws, rickshaws, lagunas, bike trucks and more, constantly passing slower vehicles.
We recently published a paper on our results so far here. In addition, Pinky also brought another female student, Tanjina Fedous Ira. Finally, two employees of IWM (Institute of Water Modelling), one of our partners in this project, also came to the land part. As part of the technology transfer part of the project, Sheikh (Nahid) Nahiduzzaman and Upal Mahamud will be trained together in our methods and equipment. In 2019, Nasheed was with us too. The pair will visit New York and Louisiana in April for further training.
Chris was standing at the ferry (pier) filming us climbing up the Khepupara tide gauge to temporarily install an active GNSS.
The Padma River has two crossings, the Ganges and Brahmaputra together, one at Mawa south of Dhaka and one at Alicha near the confluence of the three rivers. Despite the Mawa’s shorter distance and shorter overall travel time, the drivers chose to cross the road at Aricha due to the severe delays at the Mawa. While this route saves time overall, we didn’t reach Kuakata on the coast of the Bay of Bengal until 9pm. On a stop at Barisal University, we picked up my colleague Hasnat Jaman and one of his students.
We climbed onto the metal structure, placed the antenna on the proximal end of the arm holding the radar water level gauge, and set up the receiver and solar panels.
Now we can start working on the website. We headed back north to Barisal, stopping at two locations on the way. Masud and Pinky’s team will serve RSET and Sanju, while my team will be responsible for the GNSS site. The RSET team was worried about finishing all the stops and getting to Barisal, so they left at 7am. After breakfast at 8am, we followed at a more leisurely pace. Since we have an active GNSS suite, we stopped at the tide gauge near the GNSS station in Khepupara. We originally put the GNSS here to be close to the tide gauges, which showed irregularities and sometimes large subsidence. On my last trip of 2019, we soldered a commemorative pin to the tide gauge. Now, as we work on continuous sites, we’ll put an active GNSS here. After a few phone calls for permission, we took the ferry to the steel structure and hoisted the equipment with ropes. The signals recorded by GNSS bouncing off the water will allow us to determine the offset of the local datum to measure tides at global mean sea level.
Sanju worked hard on receivers at PSTU (misnamed PUST). We finally got it fixed and working, although it took a lot longer than expected.
Then we went to the continuous GNSS at the local weather radar station. Everything seems to be working fine except the battery is dead. The log looks like it was slowly failing last summer. A possible explanation is that the solar panels were unable to charge the batteries due to the rainy days. The battery power is drained enough to damage the battery. A quick call to Keith Williams at UNAVCO in Colorado to confirm everything is OK. We packed up, retrieved the activity kit from the tide gauge, and headed north with confidence.
We stopped for a light lunch instead of the snacks we often eat on the road, then reached our second stop at Patu Akali University of Technology and got to work. We changed the battery, flipped the switch, and…nothing. After many tests and some false starts, we determined that the solar charger was faulty and replaced it. Now we have power, but the modem can’t connect to the network. Fortunately, we had another spare modem and changed it.run up and down from 4th I got a lot of exercise in the floor office that received the receiver. Finally, since the copper rods were stolen, we installed new ground rods and we were done. We spent 4 hours. By the time we finished, RSET had already settled in at the hotel in Barisal. We are the late team. Sanju and I finally had dinner at 10pm.
