Up to 100 metres deep in places, yet also as shallow as 16 metres in others, the mekong is a mighty force that defines the geography and supplies life to many parts of Asia. Some parts of the river reach 16 kilometres wide, while others shrink to just 50 metres. The Mekong basin is also one of the richest areas of biodiversity on the planet and its waters provide a home to some of the the biggest fish species ever discovered.  These include the the Mekong Freshwater Stingray that can have a wingspan of up to 4.3 metres, the giant river carp that can grow up to 1.5 metres and weigh 70 kilograms, and the Siamese giant carp and the endemic Mekong giant catfish, both of which can grow up to about 3 metres in length and weigh 300 kilograms. Sadly, the combination of dams and flood control, plus commercial fishing is having a serious impact and all these species are now seriously depleted.

In the Tibetan plateau, close to the Mekong's source the water is generally clear as snow melts into the river's fast flowing waters. Further south, the murky depths hide a  huge variety of species, including the famous Irrawaddy Dolphin, once a common sight in the river but now very rarely seen. Other wetland mammals that live in or close to the river include the smooth-coated otter and fishing cat. The endangered Siamese Crocodile has also been sighted on banks of the Mekong, but only very occasionally. When the monsoon brings torrential rains, the entire Mekong River Basin becomes an enormous fish pond teeming with aquatic life, but by April and May, the entire region dries out and water levels drop dramatically.

The Mekong provides a natural source of irrigation for farmers who produce enough rice every year to supply around 300 million people. Farmers first began devising ways to use the river's plentiful waters back in the first century and today, thanks to the 1200 irrigation networks that extend from the river's banks, in some regions they are able to produce three crops every year.  Economic expansion has drawn some farmers away from rice production and into other crops which provide a better income. But the effects of increased production are  having a negative impact on the river itself in some locations. Extensive irrigation schemes place undue demand on the river, worsening droughts and disrupting fish migration patterns and soil replenishment.

Tourism is another economy for people living along the Mekong and in countries such as Laos, international visitors already provide people with an alternative income. Riverside villages are regularly visited by passenger boats on river cruises, while small hotels and restaurants are opening as the Mekong's residents learn to offer their services to visitors. Farmers and fisherman act as guides on treks and tours of the area's natural attractions offering insights into their traditional way of life. Cruising the Mekong is therefore a fascinating experience and with careful planning, tourism may eventually make an important contribution to the region by helping protect both the human and natural environment along the river.