Upali A. Amarasinghe

Water scarcity in the twenty-first century

As we approach the next century, more than a quarter of the worlds population or a third of the population in developing countries live in regions that will experience severe water scarcity. This paper reports on a study to project water supply and demand for 118 countries over the 1990-2025 period. The nature and geographic focus of growing water scarcity are identified. In the semi-arid regions of Asia and the Middle East, which include some of the major breadbaskets of the world, the ground water table is falling at an alarming rate. There is an urgent need to focus the attention of both professionals and policy makers on the problems of ground water depletion, which must be seen as the major threat to food security in the coming century.

Land and water productivity of wheat in the Western Indo-Gangetic Plains of India and Pakistan: a comparative analysis

In Kijne, J. W.; Barker, R.; Molden. D. (Eds.). Water productivity in agriculture: limits and opportunities for improvement. Wallingford, UK: CABI; Colombo, Sri Lanka: International Water Management Institute (IWMI)Comprehensive Assessment of Water Management in Agriculture Series 1

The Indus and the Ganges: river basins under extreme pressure

The basins of the Indus and Ganges rivers cover 2.20 million km2 and are inhabited by more than a billion people. The region is under extreme pressures of population and poverty, unregulated utilization of the resources and low levels of productivity. The needs are: (1) development policies that are regionally differentiated to ensure resource sustainability and high productivity; (2) immediate development and implementation of policies for sound groundwater management and energy use; (3) improvement of the fragile food security and to broaden its base; and (4) policy changes to address land fragmentation and improved infrastructure. Meeting these needs will help to improve productivity, reduce rural poverty and improve overall human development.

PODIUM: Projecting water supply and demand for food production in 2025

Abstract Since 1997, IWMI has been developing models to investigate future food and water requirements. Since the initial results were published (Seckler et al., 1998), the data and methodologies were refined substantially, evolving into the PODIUM model. The model estimates projected increases in water demand in 2025 resulting from the expected population growth and changes in consumption pattern, for individual nations. The PODIUM model provides a user-friendly means to analyze alternative future scenarios and conduct sensitivity analysis. As part of the World Water Vision 2025 exercise, the PODIUM model was used to test a range of scenarios related to food and water demand. In the IWMI base scenario, 33 percent of the population of the studied countries will face absolute water scarcity. These countries will not have sufficient water resources to meet water needs. Another 45 percent of the population live in countries that will face economic scarcity. Countries in this category may not have the capacity or financial resources to develop sufficient water resources. Globally, water diversions to agriculture will grow by 17 percent. Fifteen countries, mainly in the Middle East and Africa, will rely on cereal imports for more than 25 percent of their grain consumption (Seckler et al., 2000). This paper presents the modeling strategies adopted in the PODIUM model and the results obtained during the development of the World Water Vision (Rijsberman and Cosgrove, 2000). These results indicate the need for substantial investment in water resources development, improving agricultural water use and expansion of both irrigated and rain-fed agriculture.

Water productivity and water footprint: misguided concepts or useful tools in water management and policy?

Water productivity (WP) and water footprint (WFP) are popular concepts in research and discourses on water management. Yet there are concerns about their theoretical validity and practical value. This paper shows that the water production function, the concept with a sound theoretical foundation, is the basis for WP. Total WFP is the reciprocal of WP. The practical value of WP and WFP depends on the context of water use and stress. Maximizing WP, not a panacea to all water problems, mainly suits arid rainfed areas. In other regions, economic and marginal WP for increasing overall production should take precedence in water management and policy decisions.

Water–milk nexus in India: a path to a sustainable water future?

This paper examines the nexus between milk production and water use in India. The nexus is examined in the context of extended consumptive water use (CWU) of milk production beyond drinking water. It includes the real CWU (evapotranspiration (ETa) that occurs during the production of green fodder and feed grains) and the virtual CWU (ETa embedded in by-products for animal feed). The real CWU appears as large as that of sugarcane, and the real and virtual CWU combined is as large as that of rice. However, milk production generates more value than the outputs of rice and sugarcane combined. Sustainable water use and agricultural growth in major milk-producing areas require a drastic reduction in groundwater CWU, which, at present, exceeds natural recharge. It is suggested that diversifying to a mix of milk and high-value (but low water consuming) crops can reduce groundwater CWU while ensuring higher total output.

Impact Assessment of Organizing Farmers in the Gal Oya Left Bank Irrigation Scheme, Sri Lanka

The nature and intensity of institutional interventions at the secondary unit level in the rehabilitation of the Gal Oya Left Bank irrigation system were different. The focus of this paper is to examine the impacts of these different interventions on the performance of secondary units using a time-series impact assessment model. The impact assessment model appears to be able to describe with some precision the trends in the system as a whole, as well as distinguish between different impacts in different units. The results of the analysis demonstrate that areas that were intensively organized showed the greatest capacity to adopt improved management techniques quickly. However, these well-organized areas also happened to be more favoured before rehabilitation and have realized least satisfactory overall benefits. Tail-end areas, even though they were less intensively organized, showed the best overall performance in terms of water use, production and water productivity. But they took longer to respond full...

Groundwater quality issues and management in Ramganga Sub-Basin

Groundwater quality receives increasing attention in water management in India. The purpose of this paper is to highlight the emerging issues of groundwater quality in the Ramganga Sub-Basin (RSB), a tributary joining the Ganga River from the northern plains, which extends over 30,839 Sq. km and covers 15 districts in both Uttarakhand and Uttar Pradesh. The groundwater in most of the districts of the RSB has high concentration of nitrate, iron, salinity and fluoride, which exceed the standards prescribed for drinking water by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). Arsenic contamination in groundwater is an emerging issue in few groundwater development blocks. Moreover, groundwater with substantial hardness, high sulfate, and high manganese is emerging issue in some districts. Additionally, shallow aquifers have high concentration of ions. In the RSB, the quality of groundwater, especially in the shallow aquifers, is influenced by the contamination of poor quality surface water, due mainly to poor sanitation, improper disposable of domestic sewage water, manures and irrigation return flows. To reduce deterioration of water quality further, the RSB requires proper sanitation facilities, efficient usage of agrochemicals, as well as an awareness program of water-related disease.

Projections of irrigation water demand in India: What do recent trends suggest?

Abstract Projected increases in irrigation water demand required to feed Indias population have been a significant component of the justification for the ambitious and highly contentious Indias National River Linking Project (NRLP), which, in its ultimate form, seeks to transfer water from relatively water‐rich basins to those basins where demand has already outstripped supply. This paper re‐examines some of the key assumptions underlying the irrigation demand estimations of the NRLP project, and concludes that a number of key assumptions are not consistent with recent trends. Major changes from earlier projections include rapidly changing consumption patterns and the dominance of groundwater as the source of irrigation water choice where available. The major challenge facing the agricultural water sector in India today and over the long term therefore is how to increase the groundwater stock (supply enhancement) to arrest declining groundwater tables, and how to sustain water use by minimizing uncontrolled groundwater pumping (demand management). While large‐scale water developments, including inter‐basin transfers, are likely still necessary, the characteristics of agricultural water demand and realities of available supplies need to be carefully reconsidered.

Strategic Analyses of the National River Linking Project (NRLP) of India, Series 4. Water productivity improvements in Indian agriculture: potentials, constraints and prospects

In International Water Management Institute (IWMI). Strategic Analyses of the National River Linking Project (NRLP) of India Series 5. Proceedings of the Second National Workshop on Strategic Issues in Indian Irrigation, New Delhi, India, 8-9 April 2009. Colombo, Sri Lanka: International Water Management Institute (IWMI).