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A PAPER FROM THE URBAN IMPERATIVE [Table of contents] [Buy the book] [PDF version]
The role of forest protected areas in supplying drinking water to the world’s biggest cities
NIGEL DUDLEY AND SUE STOLTON
The authors are partners in Equilibrium Consultants, Bristol, England. Citation: This paper may be cited as: [Authors.] 2005. [Article title.] In Ted Trzyna, ed., The Urban Imperative. California Institute of Public Affairs, Sacramento, California. 1. Introduction: THE GROWING WATER CRISIS FOR CITY DWELLERSWater is a renewable resource. Yet, the carelessness and profligacy with which it has been used, the speed of human population growth, and the increasing per capita demands for water together mean that provision of adequate, safe supplies of water is now a major source of concern, expense and international tension. At the World Summit on Sustainable Development in Johannesburg in 2002, over 80 percent of the participating decision-makers identified water as a key issue to be addressed by heads of state from countries throughout the world (World Bank, 2002). Municipal water – the focus of the current chapter – accounts for less than a tenth of human water use, but is of critical importance to the growing proportion of the world’s population who live in cities. An estimated one billion city dwellers still live without clean water or adequate sanitation. Annually, 2.2 million deaths, four per cent of all fatalities worldwide, can be attributed to inadequate supplies of clean water and sanitation (McNeil, 2000). These problems will increase in the future as the rapid processes of population growth and urbanization continue. In India, for example, World Bank forecasts are that demand for water in the urban and industrial sectors is likely to increase by 135 percent over the next 40 years (Brandon and Ramankutty, 1993). Most of the world’s drinking water comes from surface waters (rivers, lakes, or artificially constructed reservoirs) or from underground aquifers; an increasing number of countries are also investing in desalination plants. All sources face costs and problems, the latter including over-exploitation and pollution. Currently, most cities rely on the collection and diversion of existing freshwater sources, with minor amounts, on a global scale, extracted directly from rainwater or from the seas. All major water supplies face problems. Some countries already have genuine shortages, although in many others the problems of supply relate more to access and transport. Withdrawal of water from transboundary sources, such as the Nile or rivers in the Middle East are creating political tensions and are causing rivers to dry up far from their outlets to the sea, with a range of ecological and economic consequences. Over-exploitation of groundwater resources is occurring in many developed and developing countries – for example in the American Great Plains, China, India, Mexico, and the southern states of Central Asia. Saline intrusion into groundwater sources is a problem for many coastal cities, such as Jacksonville, Florida; Dakar in Senegal; and several Chinese cities. Pollution of all water sources creates major health costs, with pollutants coming mainly from agriculture, sewage, industry, and activities such as mining. Until recently, the main focus of efforts to improve urban water sanitation and supply have taken place within cities themselves, and have focused on better distribution systems, treatment plants, and sewage disposal. However, throughout the world, municipal authorities are now increasingly looking at ways in which improvements can be made at source through changing management practices in watersheds. This is the starting point for the study related below. 2. WHAT FORESTS CAN PROVIDE There is a widespread assumption that forests help to maintain constant supplies of good quality water. Loss of forests has been blamed for everything from flooding to aridity and for catastrophic losses to water quality. In fact, the hydrological role of forests is complex and the precise impact on water supply varies dramatically between places and can also vary in one place depending on such factors as the age and composition of the forest. Forests in watersheds generally result in higher quality water than alternative land uses, if only because virtually all alternatives – agriculture, industry and settlement – are likely to increase the amounts of pollutants entering headwaters. In some cases forests also help to regulate soil erosion and hence reduce sediment load, although the extent and significance of this will vary (Aylward, 2000). While there are some contaminants that forests are less able to control – the parasite Giardia for example –forests usually reduce the need for treatment. Where municipalities have protected forests to protect water supply, it is issues of water quality that have generally been the primary driving force. The situation with regard to quantity of water is more complex. The precise interactions between different tree species and ages, soil types, and management regimes are still often poorly understood. Many studies suggest that both in very wet and very dry forests, evaporation is likely to be greater from forests than from land covered with other sorts of vegetation, leading to a decrease in water from forested catchments as compared with, for example, grassland or crops (Calder, 2000). Planting new forests, particularly of species with high evapotranspiration rates, can often lead to reduced water flow. The Food and Agriculture Organization of the United Nations concluded that eucalypts are likely to reduce water yield and that in the humid tropics, young eucalyptus plantations may consume more water and regulate flow less well than natural forests (Poore and Fries, 1985). This conclusion has been echoed by many other researchers. However, some natural forests appear to increase flow rates. The most significant example is cloud forest, where leaves collect water from clouds and this additional water may exceed transpiration losses. Recent work in northern Costa Rica suggests that the pattern of cloud formation above forested and cleared areas differs (Nair et al., 2000). In addition, some very old forests also apparently increase available water. For instance, research suggests that mountain ash (Eucalyptus regnans) of 200 years or more in Australia increases water flow (Langford, 1976). As important as total water is constancy of flow, both in terms of maintaining dry season flow and reducing flooding. There is little evidence that forests regulate major floods, although flooding was the reason for introducing logging bans in, for example, Thailand and China. One important exception is flooded forests, which do appear to have a role in regulating water supply, both lowland forests such as the Varzea forests on the Amazon and swamps in the uplands. Forested catchments can also have important local impacts in regulating water flow, for example for communities in upland areas. In addition, the undisturbed forest with its leaf litter and organically enriched soil is the best watershed land cover for minimizing erosion by water. What forests provide depends to a large extent on individual conditions, species, age, soil types, climate, and management regimes. Information for policy-makers remains scarce, but the role of forests in the cost-effective protection of water quality is now generally accepted. 3. THE ROLE OF PROTECTION As a result, natural forests are increasingly being protected to maintain high quality water supplies to cities. Protection within watersheds also provides benefits in terms of biodiversity conservation, recreational, social, and economic values. Many municipalities and other users already cite maintenance of water supply as a reason for introducing forest protection or reforestation. Sometimes this is recognized and watershed protection has been a major reason for establishing the protected area: the cities of New York and Quito are both famous for their use of protected forests to maintain their high quality water supply. Watershed protection has sometimes bought critical time for biodiversity, by protecting natural areas around cities that would otherwise have disappeared: for instance around Santiago in Chile and Singapore. Around 85 percent of San Francisco’s drinking water comes from the Yosemite National Park (Natural Resources Defense Council, 2003). The Mount Makiling Forest Reserve, around a hundred kilometers south of Manila in the Philippines is a 4,244 ha area of forest administered and managed by the University of the Philippines, and its forested ecosystem supplies water to five water districts and several water cooperatives (University of the Philippines, 1999). However, in other cases, the watershed values of protected areas are largely unrecognized and the downstream benefits are accidental. 4. THE STUDY Specific case studies linking forest protection and drinking water have been well documented and frequently repeated and created interest. But how representative are these of the situation in most countries and most cities? We wanted to find some statistics about how important forests are to urban water supplies, and therefore looked at the world’s top 100 cities and assessed how many relied on water from protected areas for a substantial proportion of their drinking water. (Actually, we looked at the top 105 by population, divided between the Americas - 25, Africa - 25, Europe - 25, Asia - 25, and Australia - 5.) What appeared initially to be a fairly simple question became more complex in its unraveling. Finding the information proved a challenge and revealed many layers of complexity. What exactly constituted a forest protected area? We had assumed official protected areas, as designated by IUCN - The World Conservation Union, but found many other categories of protection, some specifically aimed at watershed protection and often with their wider values only poorly understood. In some catchments (for example around Beijing), “protection” actually means integrated management, with controls on the type of farming and other land uses. Not all forests set aside for catchment protection also have high biodiversity values. In some areas, governments recognize the need for restoration, or have reforestation projects already underway in important catchments. The results should still be considered preliminary: we are well aware of the gaps and uncertainties in our data. Nonetheless, we found that around a third (33 out of 105) of the world’s largest cities obtain a significant proportion of their drinking water directly from protected areas. At least five other cities obtain water from sources that originate in distant watersheds that also include protected areas. At least eight more obtain water from forests that are managed in a way that gives priority to providing water. Several other cities are currently suffering problems in water supply because of problems in watersheds, or draw water from forests that are being considered for protection because of their values to water supply. Some of these statistics are outlined below. Cities drawing some or all of their drinking water from protected areas Our study showed that the drinking water supplies from the following cities all had important links to forest protected areas:
Cities managing forests for drinking water In addition, there are a number of other major cities where a proportion of forest is managed specifically for watershed protection while not being officially within protected areas, and key examples are listed below (note that some of these cities also have forest protected areas for watersheds as noted above).
The study shows, we believe fairly conclusively, that protection of forests for drinking water is not a minor or a special-case issue, but one that relates to a high proportion of urban dwellers around the world. 5. IMPLICATIONS – FINANCIAL Those who manage forests typically receive little or no compensation for the services that these forests generate for others. Recognition of this has encouraged the development of “payment for environmental services” (PES) systems, which propose mechanisms for compensating those who provide environmental services This means that if particular management systems are needed in watersheds to maintain the quantity or quality of water supply, the users – like drinking water or hydropower companies – should pay for these. These benefits are known to be enormous. A team of researchers from the United States, Argentina, and the Netherlands has put an average price tag of US$ 2.3 trillion on water regulation services from the natural environment (Costanza et al., 1997). Recent studies calculated that the presence of forest in Mount Kenya National Park saved Kenya’s economy more than US$20 million through protecting the catchment for two of the country’s main river systems, the Tana and the Ewaso Ngiro (Emerton, 2001). The issue for policy makers is how to translate these values into money that can help to support particular types of land management in catchments and thus address some of the potential social issues outlined in the previous section. Projects using water resources as a springboard for PES schemes have been most thoroughly developed in Latin America. In Costa Rica, for example, the government has been involved in a scheme to help users such as hydropower companies to pay farmers to maintain forest cover in watersheds, while in Quito, Ecuador, water companies are helping to pay for the management of protected areas that are the source for much of the capital’s drinking water. PES has raised great hopes that protected areas can be supported through the environmental services that they provide. Although this is clearly possible, and there are some successful examples, it is also no universal panacea to the questions of support for protection. Schemes only work when conditions are right: ideally when a relatively small amount of money used to support a particular management regime results in major economic benefits to a small group of users – like a water company. But users have different needs; for example a hydropower company will be interested in quantity and freedom from sediment while a water company will have much wider quality interests. It may be difficult to identify and hence negotiate with people upstream. There are risks of a few users paying for services enjoyed by many. Clumsy use of payment schemes can create perverse incentives, for example, by raising hopes of payment in other areas and hence blocking other ways of reforming management. Nonetheless, such schemes are already working in several places and are receiving a high level of attention from governments and from donor agencies. 6. IMPLICATIONS – SOCIAL Water catchment management offers benefits to people living downstream, including millions of city dwellers who rely on water from forested watersheds. But what of the people living in the catchments themselves? Setting aside an area of land for forest protection or restoration might be good for water, but could have severe implications for the lives of people who live there and who have their own ideas about what it should be used for. For example, Mount Elgon National Park in Uganda is an important source of drinking water and water services were a major incentive for protection. But this caused conflict with local people who had used the forests for generations and abruptly found themselves excluded, creating problems that required considerable efforts to address (Scott, 1998). Because urban interests are more politically powerful than rural interests, watershed protection has often ignored rural people’s rights, with negative impacts for millions of people. At worst, watershed protection has been a thinly disguised excuse for resettlement or social control of politically and culturally marginal groups. This has caused resentment and many programs that established strict forest reserves or attempted to reforest farm and grazing lands have failed to achieve watershed objectives. If watershed protection is going to benefit urban dwellers, it must therefore be practiced in ways that do not further disadvantage the urban poor. In some urban watersheds, protecting or expanding forest cover will be essential for water management. Here, every effort should be made to embed biodiversity conservation and livelihood benefits into forest protection. Multiple-use community forestry can provide local income, and communities and landowners can be paid to conserve resources and monitor water quality. Planting or regeneration can focus on the most critical sites for watershed services. Local people can identify sites producing unusual levels of sediment or contamination, or areas of compacted soil or barriers to water flow, that may not show up through remote sensing. They can also identify areas where there are strong community motivations to increase forest, such as around local water sources or cultural sites. While natural forest can often provide these functions most effectively and at a low cost, well-designed mosaics of other land uses may also do much the same. Where the “opportunity cost” of protection is very high for local people, alternatives should be explored. Timber and non-timber forest products can be produced commercially, under standards of certification. Crops may be produced using good erosion control or in agroforestry or organic systems. Rules can require wide strips of natural vegetation be left at intervals on contours on steep slopes. Examples of all these approaches already exist and can help decisions in other cities. 7. IMPLICATIONS – BIODIVERSITY This study started with issues of protected areas and then deliberately moved away, to look at the wider implications of drinking water and forests. But to return to our starting point: the use of protected forests for drinking water is also a perfect opportunity to combine utilitarian needs with good biodiversity protection. At a time when protected areas rightly need to justify their designation and management more and more, combining watershed and wildlife management can provide an excellent argument for protection, and one whose need is likely to increase further in the future. 8. REFERENCES Aylward, B. 2000. Economic analysis of land-use change in a watershed context. Presented at a UNESCO Symposium/Workshop on Forest-Water-People in the Humid Tropics, Kuala Lumpur, Malaysia. 31 July - 4 August, 2000. Brandon, C. and R. Ramankutty. 1993. Toward an Environmental Strategy for Asia. World Bank Discussion Paper No. 224. The World Bank, Washington, D.C. Calder, I. R. 2000. Forests and hydrological services: reconciling public and science perceptions. Land Use and Water Resources Research 2 (2), 1-12. Costanza, R, et al. 1997. The value of the world’s ecosystem services and natural capital. Nature 387. Emerton, L. 2001. Why forest values are important to East Africa. Innovations 8 (2). African Centre for Technology Studies, Nairobi. Johnson, N., A. White, and D. Perrot-Maître. Undated. Developing markets for water services from forests: Issues and lessons for innovators. Forest Trends, Washington D.C. Langford, K. J. 1976. Change in yield of water following a bushfire in a forest of Eucalyptus raglans. Journal of Hydrology 89, 87-114. McNeill, J. 2000. Something New under the Sun: An Environmental History of the Twentieth Century. Penguin, London. Nair, U. S., R. M. Welch, R. O. Lawton, and R. A. Pielke. 2000. Influence of surface characteristics on the development of cumulus cloud fields. Paper presented at the 15th Conference on Hydrology, American Meteorological Society, 9-14 January, Long Beach, California. Natural Resources Defense Council. 2003. What’s On Tap? Grading Drinking Water in U.S. Cities. NRDC, Washington, D.C. Poore, M. E. D. and C. Fries. 1985. The Ecological Effects of Eucalyptus. FAO Forestry Paper 59. Food and Agriculture Organization of the United Nations, Rome. Scott, P. 1998. From Conflict to Collaboration: People and Forests at Mount Elgon, Uganda. IUCN - The World Conservation Union, Nairobi. University of the Philippines. 1999. Economic Instruments for the Sustainable Management of Natural Resources: A Case Study on the Philippines’ Forestry Sector. United Nations Environment Programme, New York and Geneva. World Bank. 2002. Water – Priority for Responsible Growth and Poverty Reduction: An Agenda for Investment and Policy Change. World Bank, Washington, D.C.
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