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An Overview of Water Resources Availability in Developing Countries

May 30, 2010

This blog is also available in as a pdf for your convenience: GlobalWaterResourcesBRD.

1. Introduction

It is largely understood that the world’s water resources are becoming increasingly stressed.  Claims are made that the next century’s wars will be fought over water.  Stories abound of communities with large shortages, which become even more horrific in pictures from non-profit mailers showing children dying because they lack safe water.  From an initial glance solving these issues seems like a no brainer.  After all, most of our planet is covered in water.  However, the complexities and intricacies of the water cycle and water use make this much more difficult than it may seem at first glance.  The purpose of this paper is to discuss the state of water resources in the developing world, and to discover if things are as dire as they sound.

The paper will be divided up into two sections.  The first section will be devoted to understanding what water scarcity is, and to discovering what portions of the planet are experiencing it.  The second section will discuss future water resources forecasts, considering both “business-as-usual” conditions and climate change.  For perspective, throughout the paper comparisons will be made between developing and developed countries.

2. Global Water Resources Availability

2.1.   The Big Picture

It must be understood that most of the world’s water reserves are unusable (e.g. ocean saltwater) or inaccessible (e.g. very deep groundwater or glaciers).  Only about 2.5 percent of the global water reserves are available for general, human use.  The current global demand is 3,800 km3 per year.  Compared to rivers, which discharge 45,500 km3 per year to the oceans, demand is a small portion of our sustainable use (Figure 1).  Even though much of this flow must reach the oceans for environmental purposes, this is much larger than what is required to meet mankind’s water needs.  River discharge is used in this comparison because it is the only water source with a generally constant water supply.  While approximately half the world receives its water from aquifers, many of their recharge rates are much lower than is needed to support a large community over the long-term.  There are also other surface water bodies (i.e. lakes, reservoirs, ponds, etc.) available for use, which contain about 7200 km3 (Oki & Kanae, 2006).

Figure 1. Mean Discharge (Oki & Kane, 2006)

Just considering the world’s rivers it would seem that there is plenty of water to meet the world’s demand.  However, upon looking deeper this is not so.  For one, water and population are not equally distributed throughout the planet.  Even if there is enough water globally to meet human demand this may not be true on a regional level (Figure 2).  For example South America has 26 percent of the world’s water, but only six percent of the population.  In contrast Asia has sixty percent of the world’s population, and only 36 percent of the water.

Figure 2. Fresh Water Availability versus Population (Zimmerman, et al., 2008)

Second, it does not matter how much water is available if it is polluted.  Depending on the type/magnitude of the pollution, and the water use, it can be nearly worthless and expensive to clean.  Finally, and on a positive note, water can often be reused, essentially adding to the quantity of water available for use.  This is more common in developed countries because of the treatment technologies employed.  Reuse is easily done with irrigation, though overuse of water for this purpose can lead to saline conditions.  Municipal supply is also largely reusable once it has been treated.  In summary, both quantity and quality of water must be considered in order to understand a region’s water situation.

2.2.   Water Scarcity in Developing and Developed Countries

2.2.1.Water Quantity

A country’s water stress can be compared using a simple demand verses supply ratio.  Within literature this measurement is generally referred to as the water scarcity index (Rws).

Where W is the total annual water used, S is saltwater use via desalination, and Q is the total available freshwater resources (Oki & Kanae, 2006).

It should be noted that the water scarcity index does not differentiate between water uses.  Water used for domestic purposes is not weighted over water used for industrial purposes.  Therefore, the statistic does not provide an accurate picture of water available for human consumption.  However, domestic use of water is generally very small.  The statistic does provide a picture of the ability of existing water supplies to support local communities, and a region’s potential consumption expansion.

A region with an Rws over 0.4 is generally understood to be under water stress and is indicative of a local struggle for access.  Approximately 2.4 billion people are currently living in water stressed regions (Figure 3) (Oki & Kanae, 2006).  These regions include much of India, northern China, middle Asia, and the western United States.  There are also significant portions of the Middle East, southern Europe, northern and southern Africa, and Latin America facing water scarcity.  Upon an initial glance of Figure 3 it is surprising that there is not greater water scarcity in the Middle East and Northern Africa since these are large desert areas.  However, it is important to remember that water scarcity measures demand versus supply.  Even a desert region would not technically be considered water stressed if the demand in the region is low.

Figure 3. Water Scarcity Index (Oki & Kanae, 2006)

Excluding the western United States and southern Europe, most of the world’s water stressed areas are in developing countries.  Similar to experiencing poverty in a developed country versus a developing country, the affects of water stress also differ substantially between the two.  The developed world has much greater resources and technology to cope with water shortages.

In developed countries, industrial water users can take advantage of exhaustive recycling technologies, and agricultural users are able to precisely calibrate their techniques for irrigation efficiency.  (It should be noted that agricultural waste of water is often incentivized in the developed and developing world by agricultural subsidies for less than ideal crops, and various government water projects which supply water at less than cost.)  Municipal water use is available to be largely recycled, often discharging treated wastewater to the same body it was initially drawn from.

Developing countries often have a much lower economic ability to implement effective recycling and reuse programs.  Industrial and municipal water is often not recycled or treated.  When it is discharged back into the environment it contaminates the entire water body, largely limiting its use.  Agricultural users often, but not always, do not implement the most efficient irrigation practices.  Under stressed conditions it is the poorer domestic user that often suffers in the developing world; as competition for clean water becomes increasingly fierce, their cost for just a small portion is driven up.

An example of the damage caused by water stressed conditions in the developing world can be found in Gujarat, India.  For the last portion of the twentieth century government irrigation projects were implemented to encourage large agricultural increases.  These projects could not keep up with the demand, and farmers put in groundwater pumps operating off of subsidized electricity to feed their crops.  As groundwater was pumped at alarming rates, new wells were driven to depths a 1,000 feet more than was necessary 50 years ago.  Due to this decreasing supply some farmers are mining the groundwater and selling it instead of growing crops, as it is more profitable.  In addition, this water is often purchased from textile industries which discharge their wastewater largely untreated.  The poor, who once could sink a well 30 feet to find water, are now required to purchase the water at a larger cost than the textile industries (Pearce, 2006).

Though the Midwestern United States faces similar water stress levels, the issues that ordinary people face are completely different.  Aquifer levels in this region have sometimes fallen hundreds of feet in the past 50 years.  Still, all people have plenty of water for personal use.

2.2.2.Water Quality

As mentioned, even if a region possessed enough water to meet its demand, that does not mean that the water is of sufficient quality.  Documenting water quality is much more complex than water quantity.  Efforts must be taken to identify different pollutant categories (e.g. organic matter, organic compounds, heavy metals, pathogens and microbes, and nutrients).  For each pollutant, various concentration benchmarks mean different things.  Once all of this is done regular testing must be performed.

Biochemical oxygen demand (BOD) is an indicator of the level of organic matter in a given water sample.  This organic matter often includes feces and food.  BOD is generally present in the discharge of agricultural, industrial, and municipal waste.  The Organisation for Economic Co-operation and Development (OECD) is comprised of 30 mostly developed countries including Western Europe and the United States.  A study by the United Nations comparing OECD member countries and non-OECD countries (essentially developed countries and developing countries) showed that non-OECD countries have much higher agricultural and household levels of BOD discharge to waterways (Figure 4) (Zimmerman et al., 2008).  This can be indicative of largely untreated sewage being discharged to waterways, which can have significant environmental and downstream use implications.

Figure 4. BOD Discharge Level by Sector (Zimmerman et al., 2008)

The contrast between the water quality issues faced by the developed and developing world can be seen on the Rio Grande between El Paso, Texas and Juarez, Mexico.  Shortly downstream of these two cities the Rio Grande often runs dry.  Accordingly, flows by the city are generally low.  El Paso, abiding by the U.S. standards for wastewater effluent, discharges highly treated water to the river.  Juarez, however, discharges mostly untreated sewage to the river.  Due to the low flow already present in the river, water downstream of this site is rendered largely useless to local downstream communities (Far West Texas Water Planning Group, 2006).  Downstream colonias, on the U.S. side of the border, use this water for drinking untreated, while richer communities are able to recover some of it through treatment (Mendoza et al., 2004).  Once again it is demonstrated that while facing the same conditions, developing communities have larger hurdles to overcome than developed.

2.2.3.Water Scarcity in Developed versus Developing Communities: A Summary

As we have seen, the developing world often deals with larger issues of scarcity and pollution than the developed world.  Aside from these issues, given the developing world’s larger constrictions in technology and other resources, they would still face a larger hurdle.  These issues are also not always the result of natural consequences.  Unhealthy institutions provide little regulation for the use and environmental treatment of water in developing countries.  Though the institutions in developed countries may not be perfect, they do provide more effective regulation on the use and discharge of water.

3. Future Water Availability and Use Projections

3.1.   Business as Usual

Under “business-as-usual” conditions, projecting out trends in population, GDP, energy agricultural, and water demand, it is possible to forecast water use and availability into the future.  Alcamo et al. (2003) and Rosegrant and Cai (2002) are one of the many to do so.  Their projections and others’ often do not consider climate change, preferring to work with more traditional model inputs before encountering the uncertainty that is climate change.  This section will discuss their conclusions.  The following section will discuss some of the water resources implications for developing countries considering climate change.

Alcamo et al. (2003) project a 15 percent increase in global water demand from 1995-2025.  Though there is an increase in water demand generally the projected the number of regions considered water stressed will fall globally.  Large regions of China, India, the Middle East, and northern Africa will no longer be considered water stressed largely due to an increase in water use efficiency.  However, other portions of Asia, most of Africa, South America, and Russia will become water stressed or will be rapidly approaching it because of population and industrial growth.

Over the same period of time Rosegrant and Cai (2002) project a 23 percent overall increase in water use, and 28 in developing countries.  They assert that the increase in developing countries will largely be due to the fact that the vast majority of the world’s population growth will occur there.  This increasing population will also increase their per capita water usage.  There will also be a significant industrial component to the increased water demand.  Their study does not consider water scarcity.

3.2.   Considering Climate Change

It should be stated that the weakest part of climate change science is forecasting the implications of warming.  Therefore, more specific questions lead to more uncertain answers.  However, in this period of a changing climate, which could have large implications for the hydrologic cycle, it is imperative to consider the possibilities of what this could mean for the already stressed water situation felt by many countries.  Most likely a warmer planet will mean some snowfall will become rain, snow melt will occur earlier, and sea level rise will cause increased sea water intrusion into coastal aquifers (Oki & Kanae, 2006).  Generally the globe will experience more intense and extreme precipitation patterns (The World Bank, 2010).  We do not know how these changes will affect demand.  The World Bank sums up the affects of climate change to the hydrologic cycle in the following figure:

Figure 5. Typical Affects of Climate Change on the Hydrologic Cycle (The World Bank, 2010)

As the future of the world’s water resources are uncertain, a large number of models have been run under different climate change scenarios to determine what conclusions can be made about future supplies.  Figure 6 displays the impacts of climate change on annual runoff.  The conclusions are uncertain in a large portion of the globe.  However, many developing countries in Africa, the Middle East, South America, and others will face a decrease in precipitation.  There will be an increase felt in portions of China, India, Southeast Asia, South America, Africa, among others.  Initially this may be perceived as a good thing.  However, larger intensity storms will provide larger floods, and more flood casualties and damages if better infrastructure is not developed in concert with these changes.

Figure 6. Projected Changes in Water Runoff by the Middle of the 21st Century (The World Bank, 2010)

3.3.   A Summary of What the Future Holds

Models predict decreases in water scarcity in portions of India, China, and the Middle East due to improved efficiency.  However, due to population growth and larger per capita demand many other parts of the developing world will have become or will be approaching water stress.  Climate change only casts more uncertainty into these conditions.  It is agreed that more extreme rains and droughts will be seen, increasing both water scarcity and floods.  It is unknown how demand will be affected as a result of climate change.  These increases in demand and the uncertainty of climate change provide more difficulties for developing communities to overcome.

4. Conclusions

Water stress can be found in both developing and developed countries.  However, developed countries have better resources to deal with the problem.  The implications of this in developing countries, is that fierce competition arises, limiting access of households to safe drinking water.  In developed countries, water resources are stretched to get more use, and there is not a problem supplying general households.  In the future most of the increase in demand will occur in developing countries, pushing more regions into water stress as they deal with the uncertainty of climate change.  Creative solutions are needed to help solve these issues.

References

Alcamo, J., Doll, P., Henrichs, T., Kaspar, F., Lehner, B., Rosch, T., & Siebert, S. (2003). Global estimates of water withdrawals and availability under current and future “business-as-usual” conditions. Hydrological Sciences-Journal-des Sciences Hydrologiquers, 48, 339-348.

Davis, M. L. & Masten S. J. (2004). Principles of environmental engineering and science. New York, NY: McGraw-Hill.

Far West Texas Water Planning Group. (2006). Far west Texas water plan.

Mendoza, J., Botsford, J., Hernandez, J., Montoya, J., Saenz, R., Valles, A., Vazquez, A., Alvarez, M. (2004) Microbial contamination and chemical toxicity of the Rio Grande, BMC Microbiology 4(17).

Oki, T. & Kanae, S. (2006). Global hydrological cycles and world water resources. Science, 313, 1068-1072.

Pearce, F. (2006). When the rivers run dry: Water-the defining crisis of the twenty-first century. Boston, MA: Beacon Press.

Rosegrant, M. W. & Cai, X. (2002). Global water demand and supply projections part 2. Results and prospects to 2025. Water International, 27, 170-182.

The World Bank. (2010). World development report 2010. Washington, DC.

Zimmerman, J. B., Mihelcic, J. R., & Smith, J. (2008). Global stressors on water quality and quantity. Environmental Science and Technology, 42, 4247-4254.

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