The next day, February 26th, we headed west from Khulna to Bayntra in the Asasuni district. We installed GNSS to measure ground subsidence, measured elevation and sediment with RSET-MH (Rod Surface Elevation Table Marker Horizon), and collected core samples using a spacecraft. Augur. Taken together, these will contribute to understanding the balance between sea level rise, land subsidence, and sedimentation that is important for Bangladesh's lowland delta regions. This is the fourth of nine places on the Bangladesh coast that I will visit on this part of my trip.
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It was another long drive so we left at 6am and had breakfast and tea. In this area, we passed many shrimp farms where the soil was too salty for rice. Many fields were left fallow and used for cattle grazing during the dry season. Rice can only be grown during the monsoon season. However, I occasionally saw paddy fields using special salt-tolerant varieties. After many hours of driving, we stopped about 5 kilometers north of the site. From here onwards, the road was so bad that I couldn't take the van. I switched to two electric bike vans. And the roads were as bad as advertised. Bricks on roads were misplaced, washed away or overturned due to the monsoon. The final stretch took him nearly an hour. We finally arrived at the school/cyclone shelter where his GNSS was installed on the roof. Mr. Saqib from BRAC, the world's largest NGO, also participated. BRAC is part of a project in which I am designing interventions to adapt to climate change in southwestern Bangladesh.
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We carried the batteries and equipment up a ladder to the roof. Judging from the results, the battery was still healthy. However, the modem could not connect. I downloaded the data, got phone support from EarthScope, logged into the modem and upgraded the settings, but still couldn't connect. I was hoping it was just poor cell phone reception, but this didn't work out later. I hope to be able to return with EarthScope engineers in the future. Meanwhile, the RSET team can download the data every 6 months if needed.
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From here, we rode in a van down a worse track and joined the RSET and auger teams to measure shallow subsidence and deposition at a second site. This river is outside the embankment but is currently separated from the Kobadak River due to dredging. In 2019, we went up this river and established this site. Currently we are completely cut off to the south by shrimp farms. On the north side, dredging has been completed and a new levee is being constructed along the now smaller channel. Luckily, when we finished, the bike van driver knew of another good route across the river, so we hurried along it and back to the van.
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Saqib took us to the BRAC office and we also had lunch at 5pm and had tea and snacks with the BRAC team members we had met in Dhaka. By the time we finished and headed back to Khulna, it was well past 10pm.
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Luckily, the next day was much easier. Zofur and I set up her GNSS site at Khulna University, 15 minutes away. It was in good condition and did not require any special processing. We toured the university and went for lunch. Masood and I then went to meet the director of the regional forest department. The director was very interested in our work and its impact on the sustainability of Sundarbans mangrove forests.
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Now it's time to go to the Sundarbans, the world's largest mangrove forest.In the evening we went to ghatAt the (dock), we were met by the crew of M/V Bawali. They loaded all our luggage and equipment into a wooden country boat and headed across the river to Bawari Island. For Masood and I, there are a number of familiar faces, but for the rest of our team, the Bawari River and the Sundarbans are new. Massoud's wife, Afroza Mim, also joined us as she had never been to the Sundarbans.
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While we ate dinner, the crew started down the Pusul River before stopping for the night. By the time we woke up, the Bawali had resumed its journey towards Katka and we watched the world's largest mangrove forest pass by. We arrived in the early afternoon and he made his way to RSET, escorted by armed anti-tiger guards. Since we don't have her GNSS here, I mainly accompanied Auger while helping his team. In the soft mud of the forest, it reached a height of 4.4 meters, or nearly 14 1/2 feet.
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After finishing work for the day, I had time to do a little sightseeing. We took a country boat to a viewing platform on the east side of the river. Since it was late, we saw a lot of spotted red deer. In fact, there was a herd of about 200 to the south of the tower. And there were also a lot of monkeys. We looked at them and took pictures. Once we were satisfied, we headed across the river to the Katoka Forest Walk. There were also lots of monkeys here and a few small groups of deer. As the sun set we headed to the beach to walk back. We passed through the remains of a salt kiln from 300 years ago. These have been used to measure subsidence, as they are now no higher than spring high tide levels. We also passed the ruins of a Forest Department building that was destroyed by Cyclone Sidr in 2007. Waiting for us on the boardwalk leading to the boat were two wild boars quietly grazing on the beach. It was a great first day in the Sundarbans.
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During the night, the Bawali sailed west to Tinkona (Triangle) Island. Although she didn't get to see the Sundarbans pass by, she arrived much earlier than planned. The weather was calm in the morning, so she crossed the 10 km wide Pouseur River and headed to Giron Point. Like many tidal streams, the Pusuru River widens towards the mouth of the Bay of Bengal. Hiron Point is located along a small tidal channel, but recently new land has been added to it. To get closer to it, you need to follow the marked channel. While doing so, I realized that I had forgotten her GNSS toolkit in Bawari. After dropping off the RSET/Auger team we had to return to Bawari. We were met by a speedboat to save time, so there wasn't too much of a delay.
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Fortunately, all you need to do is replace the battery at HRNP. All data is collected daily via the internet as it remains online. Monitoring also revealed that the battery was dead. It finished quickly so I was able to cross the channel and join the others. Zohur joined his RSET team and I joined the Augur team. This team currently includes Mim. After finishing we had a snack of bananas and guava and then took a long walk on the elevated walkway through the forest. The broken and crumbling wooden walkways we visited earlier have now been replaced with concrete. There was an observation tower near the end, but since it was daytime, we couldn't see any animals. Nasser and the country boat picked us up at the end of the trail. We then cruised through a long winding tidal channel before meeting up with the Bawari people.
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Our station in the Sundarbans has been completed. We stopped in the Sundarbans for the night and will be sailing tomorrow. Our next station is in a village adjacent to the Sundarbans, and part of RSET is in the Sundarbans. The Sundarbans is a magical place and we will miss it. Thanks to the saltwater flowing into the brackish waters of the mangrove forest, you will also be saddened by the complete absence of mosquitoes.
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