Water is vital to the survival of ecosystems. In turn, ecosystems help regulate the quantity and quality of water necessary for the survival of all species. Policies that ensure water quality are critical for numerous reasons, including the need to protect aquatic biodiversity and drinking water sources. The development of a composite index of water quantity and water quality will allow for assessment of the overall adequacy of inland surface water resources for aquatic ecosystem health. There are currently no internationally recognized targets for pollutant concentrations in water supplies that are designed to protect either human or ecosystem health. Nor are there globally uniform standards for the unsustainable extraction of water resources from surface or ground water sources for economic activities or human needs. These two areas, called water quality and water stress, are in dire need of greater international policy attention. This section of the EPI focuses on the ecological aspects of these critical water issues.
Increasing demands to supply water for domestic, agricultural, and/or industrial use to a growing population has extensively modified inland waters (UNEP GEMS/Water 2006), leading to habitat and biodiversity loss, pollution, the introduction of invasive species, and the construction of dams and levees (which themselves impact water quality). The monitoring of water quality on a global basis is essential to the identification of areas with declining water quality and to the establishment of successful best practices.
Water issues are, by nature, interdisciplinary and multi-faceted. No single index can provide comprehensive information about water availability, use, quality, and equity. The 2008 EPI contains two indicators, one for Water Quality based on data for the five commonly evaluated water quality factors (dissolved oxygen, pH, conductivity, and the nutrients nitrogen and phosphorus), and one for Water Stress based on oversubscription of water resources.
The availability, quality, and regional resolution and dissemination of water data all have serious limitations. Aggregating different measures into a single metric is attractive, but single aggregate measures can be misleading and uninformative. Composite metrics are more valuable and flexible, allowing different kinds of comparisons to be made at different regional scales.
Comprehensive water-use data are particularly hard to find. For example, in regions where water is shared internationally, nations are tempted to restrict information when there is a perceived political advantage in doing so. We have previously commented on this problem (Gleick 2000), and believe that open sharing of water data is critical for proper and effective water planning and management. Further, the development of informative, comprehensive metrics is not possible unless data are collected and shared. Last, some water uses or needs are currently unquantified or unquantifiable. Nevertheless, these water uses and activities will eventually need to be quantified if they are to be included in measures of water quality and overall availability. Excluding them from analysis would mean excluding critical factors related to human and ecological well-being.
New Zealand, Finland, Lithuania, Latvia, and Slovenia have the highest ranking water quality among the 149 countries examined, with index scores ranging from 96 to 99. By comparison, the countries with the lowest ranking water quality included Kuwait, Yemen, Syria, Saudi Arabia, and United Arab Emirates, all with scores of zero.
The majority of top-ranked nations are European, although the highest-ranked New Zealand is an exception. Many of these countries have numerous data collection locations and/or enhanced awareness of, and cooperation on, water quality protection. In the middle of the pack, along with Indonesia and Myanmar, are the United States, the Netherlands, France, and China. Note, however, that much of the surface water in some countries, such as the Netherlands, is derived from upstream countries; the poor water quality detected in the Netherlands is at least in part due to pressures placed on water quality outside of the country’s borders. In others, intensive industrial sectors negatively affect water quality. Many of the countries with the lowest rankings are geographically located in arid regions or suffer from conflict or other such stresses. Some of these countries lack sufficient data, while others, with all five data points reported, simply suffer from dismal water quality due to factors such as poor management and lack of sanitation or pollution mitigation systems.
Forty-two countries meet the target set by the Water Stress indicator, including many Central American and northern European nations, as well as some African nations. Many other nations come very close to meeting the 100 score, including Russia and numerous Asian and western European countries such as the Philippines, Viet Nam, France, and the United Kingdom. The United States, China, and the Netherlands have scores in the seventies, along with Djibouti, Zimbabwe, and Iraq.
Overall, arid and semi-arid countries perform poorly. The percent of territory that is oversubscribed is in these regions at least in part determined by climatic factors and natural endowments, with many arid countries showing more than 50% of their territories oversubscribed. Yemen, Armenia, Jordan, Israel, and Kuwait rank the lowest in this category, with a wide spread from zero (Kuwait) to 38 (Yemen). Other countries with low rankings include Australia, Belgium, Spain, India, and numerous African nations. Also, densely settled or agricultural exporting countries also show high levels of deposition due to high-input agriculture. These include Mexico, China, Australia, the United States, and Argentina. Water use in the agricultural sector is the most significant factor contributing to oversubscription.
Finland, New Zealand, Latvia, Slovenia, and Sweden, along with other more-industrialized northeastern European nations, have the highest combined water rankings, with scores ranging from 94 to almost 99. Uruguay, Laos, Croatia, Canada, and the United Kingdom also rank high, as did island nations such as Indonesia, Japan, and Fiji. Some of these nations have ample and/or extremely pristine water reserves. Others have strong water quality protection programs in place, are located in non-arid regions, or have low population density.
The United States ranks 57th, in close company with Cuba, Russia, Kenya, China, and Venezuela. Many of the lower ranked nations are those in arid or conflict-riddled regions, including Jordan, Armenia, Iraq, Israel, and Côte d’Ivoire. Some of the lower rankings are also due to intensive agriculture or resource data, such as the case with Kuwait.
EPI 2008 provides a valuable snapshot of surface water issues for the countries for which data were available. However, the obvious lesson learned is the need for improvement in data scope, availability, reliability, and quality for indicators of Water Quality and Water Stress. Recent data from additional countries for all of the parameters included here are needed to better track and rank environmental performance as it relates to water quality and quantity on a global scale.
Increased global demand for fresh water will make achieving targets for the two water indicators increasingly difficult. Non-water policy pressures – air pollution, land management, poverty alleviation measures, etc. – can greatly affect many aspects of water quality and quantity, thus making the prioritization of water resource protection and management a prerequisite to the success of these exogenous development efforts. As populations and demands on water resources continue to grow globally, countries must implement serious reforms to both water policy and exogenous policies that affect water.
Growing demand for freshwater availability, in conjunction with the global push to meet the UN Millennium Development Goals for hunger, water, and sanitation, suggests that the target of zero percent oversubscribed territory will be difficult if not impossible to meet. However, continued over-abstraction (and particularly abstraction of fossil ground water) cannot be sustained indefinitely. More effective measuring, reporting, and tracking of global water quality and quantity, on a country-by-country basis, must occur in order to better inform policymaking and international efforts toward sustainably meeting the Millennium Development Goals and the basic needs of all species.
The histograms above represent indicators used to calculate this policy category score. Each dot is a single country’s proximity-to-target value for this indicator. The tinted box represents the inner quartile range of country values, or points lying between the 25th and 75th percentiles. The small triangle marker at the bottom of the chart indicates the median of country scores.
