Water and Soil Management for Water Conservation in a Watershed - Water and Agriculture: Sustainability, Markets and Policies - page 290

Introduction
The land in Korea consists of approximately 64% mountainous terrain. Paddy fields,
as the main arable lands, are mostly located in the plains or valleys, in the form of levees
or terraces that help to reduce soil erosion. As the Korean Peninsula belongs to the Asian
monsoon belt, the annual precipitation is about 1500mm in the southern part of Korea and
1300mm in the central part. More than half the annual precipitation falls during the
summer season, and sometimes there are severe short-term droughts during the early
stage of rice growth in Korea. For the rainy season, paddy rice farming which can be
resistant to floods has been developed. Because most of the water resources are derived
from rainfall, techniques for the storage of rains have become the most important ones in
water use. But, human life and general industry do not contribute to storing water, and
just consume it differently from farmland. With an economic development, agriculture is
facing increasing competition for surface and groundwater from urban and industrial
demands. Also there is a growing desire to meet environmental needs through re-
allocation of water resources for the protection of the environment from down-stream
impacts caused by agricultural pollution. Some indicators relating to water use were
proposed by the OECD, but we think that the OECD has overlooked regional differences
in climate, the social and economic meanings of irrigation or water use, and water
conservation in the development of these indicators. Therefore, a new recognition on the
perspective of water use and water conservation will be required to understand more
clearly the status of each country. It will be fruitful, in finding more efficient and
effective ways of water management, to consider the issues related to water in some other
aspects, through a few case studies on water resources in Korea.
Overview of water resources in Korea
1. Characteristics of water resources in Korea
The climate in Korea is under the effect of both continental and marine climate, and
variations in seasonal temperature and rainfall are therefore great. As well, there is a rainy
season for about one month because the Korean Peninsula is located in the Asian
monsoon belt. As an average of precipitation for 30 yrs (1971-2000) in Korea was
1310mm (Figure 1), it was 1.3 times greater than the annual average precipitation in the
world. But, when the precipitation per capita in Korea, about 2,705m 3 , was compared
with the average amount of the world, 26,800m 3 , the precipitation per capita in Korea was
only 11% of the average amount of the World. Also, the range difference of annual
precipitation having a width from minimum 745mm to maximum 1683mm is about
930mm. A trend of average precipitation is close to regular value, but the amplitude of
change is becoming greater.
There was a great variation in precipitation depending on local areas as well as
seasons. Two thirds of annual mean precipitation was concentrated in June through
September, and precipitation in October through March of the next year was only one
fifth of the annual average precipitation. Therefore, it is not easy to manage and use water
resources efficiently since water deficits from droughts and disasters from flood or
typhoon caused by the great seasonal variation of climate happen frequently. Especially,
river basins in Korea having a large mountainous area, which covers 64.3% of the total
land, have a small area of steep gradients and short lengths so that a large amount of