2.3 Distribution of Transboundary River Basins in the World
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ever forming a common border (through-border or contiguous rivers), while 17 rivers
have been identified that define the entire border between two countries without ever
entering either of those (border-creator rivers) (Dinar 2008).
Rivers and lakes that are shared by the constituent units of federal or quasi federal
countries serve around 40% of the global population (Garrick et al. 2014). They
include some of the world’s largest river basins (Indus, Ganges-Brahmaputa, Amazon, etc.), a great number of which are international rivers at the same time.
2.4 River Basin Typology
Naturally, all river basins, transboundary or not, vary largely with regards to their
particular hydro-climatic conditions. Yet, on the basis of these natural conditions
rivers can be clustered into three broad categories (Sadoff et al. 2015):
– highly variable/monsoonal basins are characterised by extreme intra-annual variability (unpredictable seasonal and annual rainfall and runoff) and, consequently,
a high degree of hydrological uncertainty that often implies severe floods and
droughts. As their name suggests, they are mainly located in tropical monsoon
areas. Historically these rivers have been a major source of rainfed and floodplain agriculture so the basins tend to be very densely populated (e.g. GangesBrahmaputra or the Mekong basins). Monsoonal basins also happen to be relatively
poor and underdeveloped,
– arid and semi-arid basins face challenges of high freshwater variability and,
ultimately, absolute scarcity. Chronic scarcity normally leads to intensive groundwater exploitation and extensive surface water infrastructure development, putting
the ecological conditions of the river under severe strain. Arid and semi-arid basins
are scattered in both developed and developing regions of the world. Examples
include the Aral Sea basin in Central Asia, the Murray-Darling system in Australia,
the lower Nile or the Colorado river in the US, etc.,
– temperate basins are relatively evenly watered with moderate seasonal variations
both in terms of precipitation and river flow. Many of such rivers systems can be
found in the western hemisphere (e.g. the Rhine, the Great Lakes, the Danube)
and have contributed significantly to the development of modern economies and
statehood.
The above typology also provides a rough indication about the character and magnitude of the hydrological complexities—a combination of natural and human-induced
water challenges—that are associated with particular river basins. Thus, temperate
basins, especially with no radical and/or rapid changes in water use by riparian states,
are relatively easy to govern collectively. On the other end of the spectrum lie those
shared arid basins where fierce competition for water resources often lead to complex collective action problems, rendering political cooperation over transboundary
basins cumbersome or almost impossible.
13
ever forming a common border (through-border or contiguous rivers), while 17 rivers
have been identified that define the entire border between two countries without ever
entering either of those (border-creator rivers) (Dinar 2008).
Rivers and lakes that are shared by the constituent units of federal or quasi federal
countries serve around 40% of the global population (Garrick et al. 2014). They
include some of the world’s largest river basins (Indus, Ganges-Brahmaputa, Amazon, etc.), a great number of which are international rivers at the same time.
2.4 River Basin Typology
Naturally, all river basins, transboundary or not, vary largely with regards to their
particular hydro-climatic conditions. Yet, on the basis of these natural conditions
rivers can be clustered into three broad categories (Sadoff et al. 2015):
– highly variable/monsoonal basins are characterised by extreme intra-annual variability (unpredictable seasonal and annual rainfall and runoff) and, consequently,
a high degree of hydrological uncertainty that often implies severe floods and
droughts. As their name suggests, they are mainly located in tropical monsoon
areas. Historically these rivers have been a major source of rainfed and floodplain agriculture so the basins tend to be very densely populated (e.g. GangesBrahmaputra or the Mekong basins). Monsoonal basins also happen to be relatively
poor and underdeveloped,
– arid and semi-arid basins face challenges of high freshwater variability and,
ultimately, absolute scarcity. Chronic scarcity normally leads to intensive groundwater exploitation and extensive surface water infrastructure development, putting
the ecological conditions of the river under severe strain. Arid and semi-arid basins
are scattered in both developed and developing regions of the world. Examples
include the Aral Sea basin in Central Asia, the Murray-Darling system in Australia,
the lower Nile or the Colorado river in the US, etc.,
– temperate basins are relatively evenly watered with moderate seasonal variations
both in terms of precipitation and river flow. Many of such rivers systems can be
found in the western hemisphere (e.g. the Rhine, the Great Lakes, the Danube)
and have contributed significantly to the development of modern economies and
statehood.
The above typology also provides a rough indication about the character and magnitude of the hydrological complexities—a combination of natural and human-induced
water challenges—that are associated with particular river basins. Thus, temperate
basins, especially with no radical and/or rapid changes in water use by riparian states,
are relatively easy to govern collectively. On the other end of the spectrum lie those
shared arid basins where fierce competition for water resources often lead to complex collective action problems, rendering political cooperation over transboundary
basins cumbersome or almost impossible.