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. This is the latest dispatch from a five-year project to understand the hazards and the possible hidden links among them. 

By Mike Steckler

Our group returns on the country boat, the M.V. Sundari, from their morning fieldwork.

My critical equipment repairs were now done. Chris and Dan still had several days of work in the area, but Humayun and I were interested in traveling to Hiron Point near the coast in the Sundarban Mangrove Forest. We want to take advantage of being so close to We hoped we could do it in a day, with the tides and broad open channel to the south, it would take two, too much for Chris to spare. We worked out that Humayun, Liz and I could take Bachchu’s smaller boat, the M.B. Mowali. Mowali are the honey collectors in the Sundarban and Bawali are the wood cutters.

Before we leave, we have one day with Chris and the others. After, Matt and Tanjil, our forest guide from 2015 who stayed with us for a day, departed, I went out with them to Polders 32 and 31 for their afternoon run. They are

Chris measuring the reflectance spectra of the ground while some local woman look on.

making soil salinity measurements to see if it is possible to determine soil salinity from satellite imagery. Saline soils are a large problem in this part of Bangladesh. We took the country boat to shore and scouted for the appropriate place. At each one Chris and Dan laid out a grid of probes to measure salinity and moisture content. Kingston and Zahan did similar measurements at the surface and at the root level. As always, we attracted a crowd of onlookers curious as to what these foreigners were doing.

Later, after dinner, the M.B. Mowali arrived and our group split once again. We traveled to the edge of the Sundarbans that night, to pick up our guide and our armed guard for the tigers. The Mowali is much smaller. I haven’t seen her since she was renovated. Now there is one

Dan measuring the salinity of the soil.

cabin, which Liz got, and a larger room for Humayun, myself and our guide. In the early morning we headed south. Once the fog lifted and we entered smaller channels, we started seeing deer and monkeys on the banks and in the forest. We stopped in a small side channel and had lunch before crossing the over 10-km wide estuary in our speed boat, a 40-min ride. I could see that a lot on fresh land had grown at the mouth of the channel with the forest station and our GPS since the last time I was here, two years ago. We brought along lots of extra equipment in case anything had broken down. Humayun and I worked on downloading the GPS data while Liz and the guide went for a walk and climbed the observation tower. They got to see deer, wild boar and a

Chris providing a detailed explanation of what he is doing in English to people who only speak Bangla.

monitor lizard, while Humayun and I sat in a dark room. As usual, we struggled to remember how to connect and download data exacerbated my unfamiliarity with the Windows OS on the PC we were using.

Eventually, we got it right and were happy to see that the system was working perfectly, data files for every day since I last visited. Obviously, because we had brought all the equipment along, we didn’t need it. We downloaded all the data and then changed the SIM card in the modem. We had set up cellular communications when we installed the station, but the signal was too weak to every collect any data. Now there is a good signal here from a different cell phone company. When we get back we will have UNAVCO check to see if it works. In any case, we now have enough data to measure the subsidence here.  The

Liz gets photographed with two young girls. Blonde women doing field work are not that common here.

sinking of the land exacerbates the impact of rising sea level. Only the vast sediment supply of the delta counters it to maintain the land. And that is at risk from human intervention.

We had tea and cookies with the forest ranger and then headed back before low tide trapped us in the channel. As things went well, we stopped on the newly emerged char land and Liz and I walked around examining the sediments, surprisingly sandy for a tidal estuary. Back in the speed boat, we crossed the broad channel and then paused to watch the sunset on the water. Once on the Mowali, we sailed to where we would spend the night in the Mangrove Forest and now I got to see deer and boar on the way before darkness descended. There was even a herd of 9 or 10 just across from where we rejoined the Mowali.

The M.B. Mowali, our home for the next two days for the run to Hiron Point and back.

In the morning, we started heading north. Because it was very foggy, we stayed in smaller channels for a few hours before entering the main channel of the Pussur River. I spent the early morning before breakfast watching the forest go by and spotted a few more deer. By noon we were out of the Sundarbans and ready to drop off our guard. I actually hadn’t seen him for the entire trip. We continued past the Rampal power plant. This a coal-fired plant being built less than 20 km from the Sundarbans. Most of the coal for it will likely be transported up the Pussur River through the Sundarbans. It is the subject of a lot of protests, including the hartal we had last week, but they are not likely to stop it from being built. A short time later we met up with the Bawali and moved back across. Then, work here being done, both ships sailed up to

Humayun having tea in the morning on the Mowali.

Khulna for the night. Tomorrow morning we disembark for the next phase of the trip.

Sundarban Mangrove Forest at low tide.

One of the many chital, or spotted deer, we saw along the way.

Getting into the speedboat to sail across the channel to Hiron Point.

Having tea with the forest ranger after completing our work.

Al fresco dinner on the Mowali.

Sunset over the Sundarbans and one of the many ships plying the waterway.

This post was originally posted on the Columbia University Earth Institute State of the Planet blog.