Earthquakes, floods, sea-level rise and sudden shifts in river courses threaten many of the 150 million Bangladeshis living in the low-lying Brahmaputra River delta. Scientists from Lamont-Doherty, Dhaka University and other institutions have begun a five-year project to understand the hazards and the possible hidden links among them. Lamont geophysicist Michael Steckler keeps us up to date on the work.
Geohazards in Bangladesh
North to Patuakhali and Barisal for the end of the fieldwork
The next morning we headed north and stopped at Khepupara. After seeing the site, the SET team continued on. Ashraf had to get back to Dhaka for an exam and they had to scout the next and last location near Patuakhali Science and Technology University (PTSU). John and Sanju climbed the structure to weld on the monument. I joined them with some additional materials after taking pictures.
Then, we also continued north to PTSU. We met our contact and he introduced us to the relevant professors. The old vintage GPS was no longer working. We would scrape everything but the monument and rebuild the station. While a seismometer site was on the ground floor, the GPS was on the third floor close to the roof. Removing the old dated equipment we went to work constructing a new one, with a break to meet with the vice chancellor of the university. We had a number of purchases to make with our dwindling supplies, so we left early to shop in Barisal, where we would be staying. The small city of Patuakhali could not accommodate us. This means we have a two-hour commute, including a ferry each day.
Meanwhile the SET team had a difficult time finding good easily accessible locations for their equipment. Still, they managed to locate the two sites they needed. Since we were now ahead of schedule, we have plenty of time for this installation.
We walked around the downtown with a local Barisal University student buying nuts and bolts and a box to keep the station in, and arranging for a solar panel. We saw various areas selling steel, clothing, automotive parts, peppers and turmeric, shoes, jewelry.
This is known as retail clumping, where sellers of the same items are all near each other. However, we could not find any angled aluminum for the solar power frame after wandering a long time. We decided to take an auto rickshaw to an aluminum place we spotted outside of town after dropping our purchases at the hotel. Then, 100m from the hotel, we found what we had been searching for, and got the rest of the stuff we needed.
The next morning the SET team tried to leave before dawn to be able to install the outside the polder (embankment) because of needing to work during low tide. Although the driver of their van overslept so they got out late, they were still on the road well before the rest of us woke up. We got to the university at Patuakhali later that morning and set to work rebuilding the GPS station.
We ordered a good quality solar panel by a Bangladeshi brand we trust. Since they have no official distributor in Barisal, we had arranged for it to be sent by bus to Patuakhali, a short ride from the university. However, the shop owner wanted to go to Friday prayers before sending it and the bus would then take some time. We decided to drive ourselves to the small town of Galachipa, where his shop was, to pick it up to save time.
The first part of the journey was on the main highway, but we then turned off onto some bumpy dirt local roads. We wound our way through then to the river and then continued south. At one point, we hit a bypass road around some road construction that had a line of waiting buses. We found we could just barely make it across the temporary bridge. We continued on and reached the ferry. The shop was in the town on the other site.
However, the car ferry was not running because the high tide submerged the dock. We hopped on a country boat people ferry, then an electric rickshaw and found the small shop. When we got back to the dock, a ferry had just left. To save time, we hired a boat for ourselves (less than $1) and crossed back. I suggested a longer route with better roads, but was told the bridge was out so we could not go that way. We went back the way we came, but now a Caterpillar backhoe was blocking the route.
We could not get by. We went to the other route that we had suggested and asked people along the way how to go. We found a small road around the missing bridge. It included crossing a bridge with holes in the concrete and squeezing through an open air cow market for the upcoming Eid al-Addha (Feast of the Sacrifice) holiday. We finally made it back to larger, more drivable roads and hurried back. This adventure had taken us over four hours, but given the ferry and bypass road situation, was actually necessary to get the solar panels.
When we got back, the GPS station was mostly assembled. We installed the solar panel on the roof and a few remaining bits of wiring and headed back. My long-term collaborator Humayun Akhter was in Barisal to supervise some exams. Importantly, he had brought an antenna and power cable we need to complete the station. When we got to Barisal, we found the SET team had competed both installations with their early start.
However, the second one had lots of leeches at the site. I’m glad I didn’t go there. We had a large celebratory dinner that included Humayun, some professors from Barisal University and our team.
The next morning we headed back to Patuakhali and completed the site while the SET team slept in. Later in the day, they visited the sights of Barisal, including a mosque and floating market. It took 2.5 hours to finish the site, although John was not able to double check the VPN internet connection to UNAVCO. Back at Barisal University, we decided to install two GPS monuments using leftover material. One was a braced monument on the ground using leftover SET rods. This will give us a shallowly anchored site to compare to the deeply anchored site on a long SET rod at our first location.
We also put a threaded rod on the roof so we have a monument that matches most of our other sites in Bangladesh. Hasnat will occasionally borrow the Dhaka University campaign system to make measurements.
We were done, almost. John found the VPN wasn’t working, so he and Sanju headed back to Patuakhali in the morning as the rest of us started the long drive back to Dhaka. They will take the overnight launch from Barisal and arrive in Dhaka at 6 am.
For me and the others, fieldwork was over. We had installed four new GPS stations and upgraded five others. Shortly, all but Hiron Point will have working data downloading to UNAVCO. We also added four unplanned campaign monuments. The SET team installed 12 systems at 6 sites and made the first measurements at a seventh. We also made new friendships among the people in the team and connections to others in the places we visited. It was a very successful trip, and amazingly it took exactly the amount of time we estimated.
We had feared nearly continuous rain during the monsoon, but it has been a relatively dry monsoon season and we had good weather much of the time. Happily most of the heavy rains happened overnight or while we were driving and we caught in only a few downpours. We even saw the Milky Way a couple of nights in the Sundarbans. The trip will end with several days of meetings in Dhaka related to this and our other projects here before the long flight home.