water supplies for both surface and
Large cities are facing both a rising
groundwater sources.
demand for water in a time of scarcity
and threats to the quality of the water
Unfortunately none of the large Indian
cities with over one million population
leave alone Bangalore which draws
heavy ground water cannot have the
vision to build their way out of scarcity.
One must learn from Los Angeles case
study;.
supply. Improving the way watersheds
are managed, would have an immediate
effect on water quality and, in the longer
term, water quantity. Urban dwellers
around the world face two common
threats to water-supply quality. The first
threat
Los Angeles city draws more water from
outside its natural watershed than any
other in the world. To safeguard its
water, Los Angeles owns about 315,000
acres in the Sierra watershed, yet with
warmer temperatures, more frequent
forest fires and decreased snowfall, the
supply is in jeopardy. The region is in a
state of “water stress”: It uses more than
comes
from
erosion
and
sedimentation, which can reduce the
storage
capacity
of
reservoirs
and
increase the cost of filtration and
pumping for water utilities. Erosion
typically occurs at a higher rate on
barren
lan d,
which
lacks
rooty
vegetation to keep the soil from washing
away. So Los Angeles started land
conservation,
including
protecting
existing forests and reforesting cleared
40% of the water available to it.
areas to prevent erosion. In addition,
Recognizing the need for a new path,
uncontrolled forest fires can leave an
Rob
area denuded of vegetation, so proper
McDonald,
The
Nature
Conservancy’s senior scientist for urban
management
sustainability, and Daniel Shemie, the
important strategies.
of
forests
are
also
director of water funds, led a study in
which more than 30 researchers studied
different large cities water use pattern
and conservation strategies. .
A second threat to water quality comes
from farms and ranches, which release
nutrient pollution from livestock waste
and fertilizer runoff and increase water
6
Integrated River Basin Management Society