Page 21 - Water and DSİ

Basic HTML Version

20
CHAPTER II - LAND & WATER RESOURCES
2.8. Water Resources
The total water in the world is 1.4 billion km
3
, 97.5% of which is saline water in the oceans and
seas, 2.5% of which is fresh water in the rivers and lakes. Since 90% of fresh water exists in the
South and North Poles, human beings have very limited readily exploitable fresh water resources.
Mean precipitation in Turkey is 643 mm/year amounting to 501 Bm
3
(billion m
3
)/year. A volume
of 274 Bm
3
water evaporates from water bodies and soils to atmosphere. 69 Bm
3
water leaks
into groundwater, whereas 28 Bm
3
is retrieved by springs from groundwater contributing to
surface water. Also, 7 Bm
3
water comes from neighboring countries. Thus, total annual surface
runoff amounts to a volume of 193 Bm
3
of water.
Including 41 (69-28) Bm
3
net discharging into groundwater (covering safe yield extraction,
unregistered extraction, emptying into the seas, and transboundary), the gross (surface and
groundwater) renewable water potential of Turkey is estimated as 234 (193+41) Bm
3
. However,
under current technical and economic constraints, annual exploitable potential has been
calculated as 112 Bm
3
of net water volume, as 95 Bm
3
from surface water resources, as 3 Bm
3
from neighboring countries, as 14 Bm
3
from groundwater safe yield.
Water Resources versus Water Consumption
Turkey is not a “water-rich” country as it is often presumed. To the contrary, the country is
vulnerable to facing water shortage problems in near future unless necessary interventions are
made. This problematic status of the country in regard to water derives from several actors
including the following: Difficulty of controlling resources as a result of a problematic
topography; unbalanced regional distribution of resources and precipitation; and utilization of
water resources through regional, discrete and short-term projects instead of long-term planning
for integrated water management on catchment basis.
Per capita water usable is 1,600 m
3
. Looking at some other countries and the world average, it is
seen that Turkey is among those facing water shortage in term of per capita usable water
endowment. Today, it is accepted that a country should have annual per capita water potential of
more than 5,000 m³ so as to be classified as “water rich.” Population of Turkey is expected to be