People in the Mountains - Mountain Geography: Physical and Human Dimensions - page 507

FIGURE 10.12 The 50-km-long Tehri Reservoir and Dam (inset) on the Bhagirathi River, a major trib-
utary of the Ganga River, Garhwal Himalaya, Uttarakhand. (Photos by J. S. Gardner.)
Streams, Rivers, and Lakes
Mountain streams, rivers, and lakes have been and remain focal points and corridors for
movement, settlement, and resource exploitation. Within the mountains, they have been
primary water sources for people and settlements, avenues for transporting people and
goods, and sources of mechanical and electrical energy. They are the conduits through
which water is transported from the mountain “water towers” to high water-use areas
beyond the mountains (Vivi-roli et al. 2007). All of the Earth's major river systems gain
some or much of their water from mountain source areas. The importance of moun-
tain streams and rivers thus cannot be overstated (Viviroli and Weingartner 2008). The
hydrology of mountain surface water is described in Chapter 3, and its central role in
sustainable mountain development is described in Chapter 12. Our objective here is
to briefly summarize its complex relationships with mountain people and settlements.
Streams, rivers, and lakes have influenced human use of the mountain environment, and
they have been altered through their relationships with people.
The most obvious point of relationship lies in the fact that rivers and some lakes oc-
cupy valleys that, in many cases, are prime locations for settlements and movement of
people. Floodplains and valley-side terraces and fans provide relatively flat ground for
building, cultivation, and transportation, bringing people into easy contact with water
sources suitable for domestic, agricultural, and industrial uses. Coincidently advantage-
ous is the fact that these lower-elevation sites generally have climate and moisture con-
ditions that are relatively amenable to agricultural activity. Prior to development of the
water turbine generator, rivers and streams provided mechanical power that was used