Introduction

Water is essential for many ecosystem services, and supports wetlands, biodiversity, wildlife habitat, and other important natural ecosystems. In particular, aquatic ecosystems are often heavily impacted by diversions of water for other uses. Healthy and resilient aquatic and terrestrial ecosystems provide a diverse range of services to humans that are essential in securing food and livelihoods security, especially of the rural and peri-urban poor. However, such ecosystems typically remain poorly integrated within land and water resources management systems. Further, the factors required for the maintenance of system ecological character are seldom met and the overall socioeconomic value of ecosystems to people living in basins across the world is underestimated. As a result, many ecosystems, in particular inland and coastal wetlands, are subject to increasing degradation, with serious attendant implications for human well-being, especially in the longer-term. Agriculture and irrigation, in particular, have been singled out as major drivers, reducing the capacity of the ecosystems they alter to deliver services to people, so that inevitably, continued widespread degradation will threaten the very sustainability of agricultural systems themselves. As in the case of human health, environmental concerns have often been neglected in the move towards rapid development. Yet, unless issues of environment sustainability are firmly placed on the water and land resources and agricultural agendas, we risk marginalizing a critical element of the broader landscape supporting agriculture and pathways out of poverty and extreme hunger.

Background

The PODIUM Policy Dialogue Model, includes an analysis of environmental trade-offs resulting from water use by other sectors, namely agriculture, and demand for the domestic and industrial uses. , However, it is critically important that at least a certain minimum volume of water is left after diversions for the maintenance of the environment, particularly freshwater ecosystem functions and the services they provide to humans. These volumes of water are referred to as Environmental Water Requirements (EWR). The total EWR are assumed to consist of ecologically relevant low-flow and high-flow components (Smakthin et al, 2004). Environmental water scarcity is determined in the model using a water stress indicator, which shows what proportion of the available water is withdrawn for direct human use and where this use is in conflict with EWR. In general, EWR required to maintain a fair condition of freshwater ecosystems ranges globally from 20 to 50 percent of the mean annual river flow in a basin. Even at estimated modest levels of EWR, parts of the world are already or soon will be classified as environmentally water scarce or environmentally water stressed. The total population living in basins where modest EWR levels are already in conflict with current water use, is over 1.4 billion, and this number is growing.

Use the model :http://podium.iwmi.org/

Environmental Water Requirement

In every country, there is certain amount of water which is taken out of the natural water system, and diverted for use by human beings. This water is for irrigation, domestic and industrial uses. The total amount of surface water within a country can consist of runoff from precipitation falling within that country, and water flowing into that country from adjacent areas. The total amount of water in that country is referred to as the mean annual runoff (MAR). We distinguish three kinds of water use in the PODIUM Policy Dialogue Model;

• Agriculture
• Industrial, used for production/cleaning/cooling.
• Domestic

Environmental Issues

High population growth is among the main drivers of environmental degradation:

• A very high increase of the world population, with high population densities in several places in the world.

As a result of breakthroughs in technical and scientific advances, and in many places, an increase in prosperity, many people are living longer than ever before. With rising standards of living, people have changed their consumption habits and diets, started to eat in a different way (particularly more meat and fish), and radically increased their consumption of natural resources. Waste and pollution are the most evident by products. However, changing diets and increasing agricultural production have led to a massive expansion of agriculture, deforestation and land degradation.

(In)direct consequences of high increases in world population and high population densities:


• Increase Food consumption.
• Increase Material consumption First basis needs (Houses, clothes, vehicels), Later (depend on the prosperity level) more luxury products (Television, DVD Player) etc.
• Increasing possibilities of conflict and war:


• Poverty is another important driver of environmental and related problems. When people are focused on meeting basic needs, for example, struggling to get food and water to survive, environmental issues may take a lower precedence. Likewise, when countries are poor, environmental concerns often are neglected.
  

Links

Organizations / Institutions

• http://www.iwmi.cgiar.org/dialogue/
• http://www.enviroliteracy.org/
• http://www.globalissues.org/TradeRelated/Development/
• http://www.environmentaldefense.org/
• http://www.nrdc.org/international/
• http://www.global-issues.net/