Japanese Water Management Systems from an Economic Perspective: The Agricultural Sector - Water and Agriculture: Sustainability, Markets and Policies - page 45

natural river streams causes serious uncertainties compared with tropical/semi-tropical
countries. Irrigation systems both in terms of physical and social infrastructures have
been continuously developed for hundreds of years.
The irrigation systems are comprised mainly of canals to deliver water from rivers to
the rice production site and to allocate the water inside. From 50 to 500 farmers at the
most belong to each production site and make up a community or village. Though water
allocation in the community had been managed based on the principle of equal usage
among farmers, water battles frequently took place among villages in years of low
precipitation. Many efforts were made for efficient use of irrigation water in each
community and among villages. Areas that have relatively low precipitation or extremely
short rivers often constructed irrigation ponds for supplementary uses. Groundwater use
has been very limited in agricultural production in Japan.
The roles of forests both in villages and upstream areas should not be neglected in
agricultural production. Forests, well managed ones in particular, have a high potential to
buffer rainfalls, stabilise river flows and prevent or mitigate disasters caused by floods,
landslides and drought, as well as provide forestry products such as timbers and fertiliser.
Japanese society has placed more importance on the roles of forests. The principle of
'replant when cutting' has been widely accepted and the forest cover in 2000 was
maintained at 64% of the total land area, while many of the village forests have been
converted into golf courses and other non-agricultural uses in recent years.
2.2 States of water use and water rights
Around 420 billion cubic meters (m 3 ) of water a year is available for human activities
in Japan, of which 85.2 billion m 3 , or 20%, is actually utilised. The annual average
precipitation is 1,718 millimetres (mm). Depending heavily on annual rainfall, Japan
often faces problems of shortage due to annual and seasonal fluctuations, as well as
frequent occurrences of disastrous floods. Agriculture is the primary user of water
(Figure 1).
Property rights to water, i.e., water rights, were traditionally established by
community according to customs based on prior occupation. Although rainfall and natural
water flows from rivers fulfill most of the basic demand for agricultural production in
years of normal precipitation, water rights become meaningful mainly when the
precipitation is lower than average.
Competition with non-agricultural sectors has taken place since the Meiji Era (since
1868). Industrialisation and the population increase in urban districts expanded the
demand for water. Legislation on water rights has been gradually drafted along with
capital investment in water resources development to meet increasing demand from
hydropower generation and industrial, municipal and agricultural sectors. Water rights to
be newly issued should be connected to the construction of facilities so as to protect
historically entitled rights. Water rights have not been free in this sense. They are not
considered to be normal private properties from a legal perspective, although they may
seem to be private properties that are excludable in consumption from an economic point
of view. Economies of scale in water management have enhanced multi-sectoral
investments. Water rights are to be revised by the water authority every ten years, and
commercial trading has been legally banned because of the public nature of water.