Bangladesh actually does not have a long coastline. It's coastline is just 580 km compared to The Netherlands 451 km. Three sides of Bangladesh is bounded by landmass, only the south is open to the sea.
Bangladesh actually does not need to do what Dutch had done because nature in our case is doing that. The Dutch actually do not get much of river silt as Rhine is not a big river and it's sedimentation load is much lower. So they had no option but to go for geo-engineering and reclaim land from sea.
On the other land, world's third largest river system Ganges-Brahmaputra passes through Bangladesh carrying billions of ton river silt every year. The source of these silt is the Himalayas and upstearm mountainous areas of India, Nepal, Bhutan and China. This billions of ton river silt is being continuously deposited in the coastal region of Bangladesh because Ganges-Brahmaputra estuary lies there. This deposition is elevating coastline of Bangladesh by a few milimeter every year and expanding coastal land mass by 20 square km per year. This is how World's largest delta formed in the southern side of Bangladesh. Since 1973, Bangladesh gained 1000 sq. km of land by this process.
Bangladesh gaining 20 sq-km land a year
Every year, the country loses 32 sq-km of land due to erosion in rivers and the sea. On the other hand, 52 sq-km of new land emerges from the water
www.tbsnews.net
Coastal water in the Ganges-Brahmaputra estuary of Bangladesh is very shallow and a lot of islands are forming due to this river silt accretion. Look at this island named 'Bhasan Char' where Bangladesh relocated one hundred thousand Rohingya refugees. This island did not exist 30 years ago. It gradually formed by silt accretion and now it has enlarged enough to make home for so many refugees.