Many people, entire families, live and work on these boats.  They are used for many purposes, from fishing to hauling freight to ferrying passengers to dredging sand. 

A telltale of the speed with which the economy is expanding past its infrastructure is that there is such demand for sand for construction that many families survive by dredging sand from the rivers and transporting it to construction sites for use in concrete. 

They dredge by hand using a large woven bucket on the end of a very long bamboo pole, scooping up sand and brining it to the surface, the levering it up onto the deck of the boat and dumping it.  You will see these dredging boats with only a couple of inches of waterline heading to sell their load.