The Ganges River flows across most of northern India, draining the Himalaya Range.  Near its eastern/lower end it is joined by the Brahmaputra River.  Then the mighty river flows into the head of the Bay of Bengal.[1]  Along the way, the rivers carry immense mounts of earth.[2]  When the river approaches the waters of the bay, it slows down and the silt gets deposited along the shores.  This has created a huge delta.  Actually, it is the biggest delta in the world.  It is more than 200 miles across at its widest point and covers more than 40,000 square miles.  Bigger than the Nile delta, or the Mississippi delta, or the Amazon delta, or the Google delta.  Like other great deltas, the flow of water-born sediment has pushed the delta out toward the sea.  Over time, the delta has advanced an estimated 250 miles to the south.

The silt is rich in minerals and nutrients, so that the soil that builds up is excellent farm land.  With the river and many streams close at hand, it is easy to irrigate the land.  The soil is so rich that between 125 and 145 million people live in the delta.  (That is two-thirds of the population of Bangladesh.)  That works out to about 520 people per square mile.[3]  They grow rice, tea, and sisal.[4]

In addition to the human beings, the islands are inhabited by deer, pythons, eagles, crocodiles, elephants, woodpeckers, leopards, and some Bengal tigers (which occasionally invade villages for take-out).

The delta is not one big mass of land.  It is a maze of islands separated by rivers and streams.  The many islands are connected by “traditional” wooden ferry boats, rather than by bridges.[5]  Most of the delta is between 30 feet above sea-level and sea-level.  Indeed, if global warming caused enough of the polar ice pack to melt to raise the sea-levels everywhere by 20 inches, then 6 million delta residents would lose their homes and land.

The delta gets a lot of rain.  The monsoons drop from 59 to 79 inches of rain on the western part of the delta and from 79 to 118 inches in the eastern part.  All that rain is one of the things that makes rice-farming possible.  The run-off causes streams and rivers to rise.

Lying at the head of the Bay of Bengal, the Ganges delta is the frequent target of tropical cyclones.  In the Atlantic these are known as hurricanes.  High winds (typically about 80 miles per hour), lots of rain, and big storm surges (water pushed ashore by the storm).  Tropical cyclones start in the south of the Bay of Bengal, then move northward toward the head of the bay at the Ganges delta.  This shoves a lot of water from deep water toward shallow water.  When it reaches shore it is called a storm surge.  Another problem is that the Ganges delta is densely populated (compared to the Jersey shore during hurricane season).  If they get a big storm, the water level suddenly rises, and many people drown.

What we see here is human beings living at the edge of two great natural physical processes.  The river has created a land that can support many people.  The monsoons of the Bay of Bengal make farming possible, but the cyclones push back the line of safe settlement.

[1] Bengal is in north-eastern India, so the Bay of Bengal is on the eastern side of the Indian sub-continent.

[2] Also, the remains of dead people who were cremated upriver and cast into the stream.

[3] The population density of Conshohocken, PA, is about 13,000/square mile.  However, Conshy is purely residential while the Ganges delta is mostly devoted to farm land.  So the concentration of people in farm villages is much greater than it sounds.

[4] Sisal is a fiber used to make twine.  I bought a roll in the Dollar General to tie up a bunch of small branches that had come down in the yard for trash day and to attach gingerbread cookies to the Christmas tree.

[5] If you read the New York Times, the ferries are overloaded all the time, and capsize all the time, and lots of passengers drown all the time.