Water Users Association and Irrigation Management - Institute for ...

"twin problems" (Details of general characteristics are given in Appendix 1.1). UNEP
(1987) estimated that the rate of loss of agricultural land is approximately 5-7 million
hectares per year and overall, salinization is the second major cause of such losses 3 • In
irrigated areas it is the primary cause. In India, an estimated 7 million hectares has gone out
of cultivation because of excess salts (Umali 1993).
Many major irrigation projects are found to be deteriorating due to waterlogging, salinity,
water pollution and the spread of vector-borne diseases (Pallas 1993). Whitecombe (1972)
presents a bewildering array of adverse effects associated with the introduction of canal
irrigation. The World Commission on Dam Knowledge Base indicates that problems of
waterlogging and salinity for irrigation systems have reached serious levels globally and
have long-term and often-permanent impacts on land, agriculture and livelihoods. Despite
the fact that soil salinity and waterlogging endanger sustainability of agricultural
development, the information available on the extent of soil salinity and waterlogging and
externalities associated with these problems are scanty and partial. Hence this aspect must
receive greater attention.
Global magnitude of irrigation-induced salinity and waterlogging
Availability of data on waterlogging and salinity is a major bottleneck at the macro level.
Available definitions and estimates of damaged area vary considerably because different
agency and researchers use different norms. This is because neither a standardized
methodology nor a set of uniform criteria exists to assess the problem. Furthermore, due to
lack of appropriate information, it is also not known whether all waterlogging and
salinization are irrigation induced. The general lack of regular monitoring of saline and
waterlogged areas is also clearly evidenced by the dearth of field level information.
Nonetheless, the available information based on various estimates indicates alarming
signals on the extent and severity of the problem at a global level.
Estimates of annual global losses of agricultural land due to waterlogging and salinization
range from 160,000-300,000 hectares (Barrow 1991) to almost 1.5 million hectares (Kovda
1983). Most of the waterlogging and salinization has occurred in irrigated croplands of high
J Soil erosion is the primary cause of the decline in agriculture land area.
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