2.1.4.1. Human activities threatening to water quantity

Many sectors rely on water resources, e.g. agriculture, fish production, biodiversity, water supply, sanitation, transport and hydropower. The current trend is a shortage of water supply in many areas, including for domestic purposes. Serious competition for water is intensifying between fast growing populations and irrigation development. In this basin, shortages may be provoked by overuse of water because of a lack of infrastructure development. No serious pollution has been reported there.

Geo-hydraulic conflicts resulting from hydropower and dam construction by riparian countries have already arisen because both the quality and quantity of water are affected. Hydropower involves dam building which requires water diversions. Conflict may arise between upstream and downstream countries because of water scarcity and/or unequal allocation. The most crucial issue is perhaps where a basically agricultural country risks losing access to water sources and thereby is deprived of the chance to achieve food security, poverty alleviation, and possible economic growth (Öjendal, 2000). Furthermore, aggressive and hostile capture could lead to tensions and conflicts through population movements, group identity conflicts, economic deprivation and/or civil strife (Ibid).

The trans-boundary implications of hydropower projects on water quality and quantity are numerous. Risks for riparian countries need to be objectively assessed.

The first risk of hydropower projects development in the upstream area of the Mekong River is the negative impact on the environment and society. Those risks have been duly identified as:

- adverse impacts on the ecosystem (aquatic life, animals, birds, vegetation);
- blocking the flow of sediment;
- negative impacts due to changes in a river's flow pattern;
- negative social impacts (resettlement, loss of livelihood);
- loss of scenic landscapes (tourism potential);
- negative impacts on water quality due to storage of water (eutrophication, lower temperatures for discharged water);
- negative impacts on other users of water (navigation, fisheries);
- problems during the construction period (noise, vibration, dust, traffic problems);
- when associated with irrigation, land Stalinization and water logging; and
- danger from sudden and unexpected release of water from flood spilling or hydropower generation.

The second type of risk is geo-political, i.e. the inevitable dependence of countries who do not possess hydropower upon those who develop hydropower projects. Cambodia is particularly vulnerable because it will certainly depend more and more on Thailand, Lao PDR and Vietnam for power supply. A cut-off of power supply by power producers would seriously impede any possibility for Cambodia to achieve its development goals and strategies, e.g. alleviate poverty, improve the population’s livelihood, welcome further foreign investments, sustain tourism development, etc.

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Table of contents > 2. River Basins > 2.1. The Mekong River System (Basin)

2.1.1. Introduction

2.1.2. Mekong River tributaries and Rainfall

2.1.3. Detailed survey of rainfall and surface water in the Mekong catchment

2.1.4. Water environment in the Mekong River systems

2.1.4.1. Human activities threatening to water quantity

2.1.4.2. Human activities threatening to water quality

2.1.4.3. Case study on human factors threatening to the water environment

2.1.4.4. Transboundary issues