This paper presents key findings from a case study on the Grand Coulee Dam conducted by the authors for the World Commission on Dams. The analysis demonstrates that the distribution of project benefits has been tilted in favour of irrigation interests and hydroelectric power users and that the project's major cost bearers have been riparian-based indigenous tribes of the Upper Columbia River. The study identifies lessons learned that are applicable to many large multi-purpose water resources development projects. Within the paper, the impacts of the following factors are discussed: low stakeholder participation in decision making; absence of just compensation to Native Americans and Canadian First Nations adversely affected by the loss of fishery resources; modernization of agricultural technology; differing stakeholder perceptions of project costs and benefits; and changes in values attached to anadromous fish. These lessons highlight the need for careful, broad-based a priori assessments of the irreversible and cumulative impacts of large water resources development projects as well as planned re-evaluations of water allocations and project operations.

As water demand surpasses water availability, the problem of who will have access to water and who will be rationed, is inevitable. This is already the case in arid regions or where the economic uses of water exceed water capability. This work contributes to the understanding and resolution of this decision-making process. Several allocation mechanisms are discussed and an allocation model based on the opportunity cost of water for different users is presented. This model leads to both a water pricing scheme and a method for compensating rationed parties.

This paper evaluates the relationships between sediment production, economic losses and land cover change in Costa Rica. Results suggest that the relationship between sediment production and the deterioration of land resources in Costa Rica is less understood than expected, and that new sediment monitoring systems must be implemented in order to be able to detect the overall impact of tropical deforestation and habitat fragmentation on sediment production. The results also indicate that the correlation between economic losses due to flooding and landscape fragmentation can be counteracted by promoting 'payment for environmental services' initiatives; a new concept that takes into consideration the role that tropical ecosystems play in protecting the environment.

A dynamic programming-based neural network model is developed for analysing the water sharing between two reservoirs in a multi-reservoir system catering for irrigation. To study the water sharing between two downstream reservoirs from an upstream reservoir, a modified dynamic programming algorithm with three state variables and four decision variables is proposed. The operating policies are derived from the three state variable dynamic programming algorithm using a neural network. The new dynamic programming neural network model gives a very good performance for the multi-reservoir system case study considered. The performance of this model is compared with the improvised standard operating policy and constrained dynamic programming neural network model previously suggested.

This paper assesses the chemical and bacteriological quality of drinking water in three districts of the Chittagong Hill Tract (CHT), a region within Bangladesh. Drawing water samples from tubewells, chharas/springs, lakes/canals, wells, and ponds, analysis was done on pH, alkalinity, arsenic, phosphate (PO4), sulphate (SO4), ammonium-nitrogen, conductivity, and faecal coliform bacteria. The PO4 and SO4 concentrations were within the permissible limits. In contrast, 100% of the water samples contained alkalinity below 400 mg/l. Varied proportions, ranging from 14% to 50%, of tubewells, chharas/springs, lakes/canals, and well water had a pH of less than 6.5. Three out of 16 (18.8%) tubewell water samples tested had arsenic contamination and 18% of the chhara/spring and 11% of the well water samples had an unacceptable level of conductivity. In addition, faecal coliform bacteria contaminated almost all sources of water, ranging from 81% to 100%. The water used for drinking in CHT in general is harmful for health.

South-to-north water transfer schemes are considered a strategic and ambitious approach to resolving water shortage problems in the north of China. This paper discusses the proposed south-to-north water transfer schemes, which would deliver water from the south of China to the water-short north of China. The three potential water transfer routes are discussed in detail, emphasizing the different water regimens of the water export and water import regions, political and institutional implications, and environmental protection. A water balance study conducted according to the principle of integrated water resources planning and management has shown that, without water transfer, the water deficit in the north of China will continue to be an obstacle to sustainable development from now to 2050. Also, the analysis on the asynchronism-synchronism for the two regions concerned has implicated the uncertainty of future water resource availability in the water transfer regions.

Many countries invest public funds in large-scale drainage projects to alleviate problems of waterlogging and salinization, and to enhance agricultural development. The estimated returns on those investments are substantial when crop yields are expected to increase significantly with drainage service. However, if the need for drainage is caused largely by inadequate water management, then the efficient strategy for enhancing agricultural productivity will include investments both in irrigation and drainage facilities and in policies that motivate improvements in water management. The policy implications that follow from this perspective are described using an empirical example from Egypt.