Disaster and moving on
It looks like we lost the deep well. The morning started off as planned. We would finish the calibration of the strainmeters, installing the GPS and training Shaheen for the weekly measurements. Should be out by noon for the 8-hour drive to Dhaka followed b the 5 hour ride to Khulna the next day. Then one of the fibers broke. Multiple splices meant there was not enough Kevlar strengthening fibers. Scott D. had to redo the entire top of the well, but this time in daylight. With the column in place, he worked higher off the ground, took his time each splice was better than the last. The well was saved, or so we thought. Pulling up the fiber for tensioning it, it became clear that it had broken free from the cement at the bottom of the well. It was getting late and we made the poor decision to try to pour a new layer of cement from the top, without the long tube. It didn’t work, the cement got stuck in the tube and we could only partially get it to go down. Time will help, but unlikely the cement we reach the bottom before setting. In retrospect, we should have pulled the entire fiber and started from scratch. That would have required staying at least one extra day. That mindset led us to try the quicker, unsuccessful route, instead of the more longer, safer choice.
Even with the fast choice, by the time we backed up and loaded the truck, it was 8 PM. Too late to drive to Dhaka. We drove over the bad roads to Sylhet and stayed in a hoel there. Left early for the long drive to Dhaka, stopping for breakfast in the middle. Unfortunately Dhaka traffic reared its ugly head and we spent almost two hours for the last part of the trip. Lunch with Humayun, a few hours at the university while Babu visited home and we were back on the road again. More Dhaka traffic and then free again. I’m now on the long ferry ride from Mawa Ghat crossing the Padma River – the 14 km wide river formed by the joining of the the Brahmaputra and Ganges. Then 3 hours to Khulna.
While here, we noticed that there is an interesting mixture of Bangla and English developing in Bangladesh. When people tell each other phone numbers they always use English numbers, one, two three, rather than ek, dui, tin. I practice me little bit of the Bangla alphabet and see many transliterated English words. The rest house we are staying in says “Hostel” above the door. Restaurants use the English word “Restaurant”, in the Bangla alphabet. It certainly helps me that the word is familiar as my vowels are still shaky.
We feel confident from our experience in Jamalganj that the site at Khulna will go well. The we hav a better idea of the pitfalls, having fallen into some of them, and the lithology, the types of sediment that they are finding, will make our job easier. This is the first time anyone has tried to put this type of instrumentation in the weak sediments of an actively growing basin. It should provide completely new data monitoring the compaction of sediments as it happens. The deep well in Jamalganj is a big loss, but we will still break new ground. Our GPS shows very rapid (by gologic standards) subsidence in Bangladesh over the last few years. Five mm/year in Jamalganj and 9 mm/year in Khulna. However, drilling records of the layers deposited over the last 10,000 years of show a much lower rate. I am convinced that a large part is due to compaction – the squeezing of the sediments as they get buried. In a few years, we will know.