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Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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4
Water and the Environment

The significance of the environment—including ecosystem services—to the sustainability of water supplies is often ignored in addressing the study area's water-resource planning. This chapter provides evidence, first that environmental quality depends on maintaining water quality and quantity, and second, that high-quality water supplies depend on environmental quality. To a large degree, environmental quality refers to the area's ecosystems, and without the goods and services of natural ecosystems, sustaining supplies of high-quality water for people will be extremely difficult and expensive. Environmental concerns are central to sustainable water resource planning. Water-resource planners in the study area should recognize that the relationships among ecosystem goods and services and water are dynamic and interactive.

In reviewing the relationships among these services, biodiversity, and water supply and quality, this chapter makes four major points. First, maintaining and enhancing ecosystem goods and services is essential for the economic development and welfare of the study area, especially over the medium and longer terms. This stewardship will enhance the quality of life of the study area's inhabitants; and it will maintain environmental quality, including water quality. Second, to achieve such benefits, it is essential to maintain, and where possible, restore ecosystem structure and functioning (sometimes referred to as ecosystem integrity). Third, biological diversity has great moral, cultural, and aesthetic importance to many societies, as reflected in laws and international agreements that express commitments to protect it. In addition, many ecologists believe

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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that maintaining biological diversity is important to sustain ecosystem functioning, although the information on this matter is still very sparse and unclear. Fourth, all these achievements require that, in plans for providing and allocating the study area's water resources, a balance must be struck among environmental, short-term economic, and other objectives. To assess these balances and identify appropriate tradeoffs, a significant amount of new scientific information will be needed.

Ecosystem Services

Ecosystem services are ecosystem processes and functions beneficial to humans, primarily in contributing to the sustainability of people's lives and their intensively managed ecosystems. When activities destroy or impair the ability of natural ecosystems to provide these goods and services, the goods and services must be replaced by artificial means. Examples of such replacements are wastewater treatment plants, water filtration and purification systems, erosion control programs, and so on. Wide experience has shown that the artificial replacements for natural ecosystem goods and services are usually very expensive and often inferior to the natural ones. Because natural ecosystems provide these goods and services at no immediate financial cost, they appear to be free and their value and importance are often underestimated or overlooked entirely. For example, the value of ground water properly includes its extractive values (e.g., municipal, industrial, and agricultural uses) as well as the natural, in-situ services it provides (e.g., providing habitat and supporting biota, preventing subsistence of land, buffering against periodic water shortage, and diluting or assimilating ground-water contaminants) (NRC, 1997). To take advantage of these crucial services, they must be understood and protected.

Ecosystem services can be classified into those related to air, soil, and water. One particular service, absorbing and detoxifying pollutants, can be related to air, soil, water, or some combination of the three. Some services are global in extent and of crucial survival value, namely, the maintenance of the gaseous composition of the atmosphere, and regulation of global air temperatures and global and local climatic patterns.

Although increasing quantities of cash crops are produced on soilless substrates in the study area (using growth chambers, or ''greenhouses"), soil is one universal substrate for terrestrial biological production. Soils are produced by weathering of rocks in the Earth's crust. Organisms directly affect this weathering and also mediate the effects of water and air on weathering. Thus, one important ecosystem service is production and maintenance of soil. Soil can be lost by wind and water erosion at a rate orders of magnitudes faster than it is generated. Normally, soil erosion

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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is slowed down or even totally prevented by vegetation cover. The vegetation of the drylands, through sparse, plays a similar role, which is augmented by a biogenic and soil crust, produced by photosynthetic bacteria, algae, lichens, and mosses (Boeken and Shachak, 1994). Soil retention is linked to water-related ecosystem services, and these are directly related to sustainable water supplies.

Another important ecosystem service is the maintenance of the hydrological cycle. Plants are important for this service, which is especially valuable in drylands. Plant architecture, growth form, and phenology jointly influence the fate of raindrops (i.e., what is retained by the soil, what runs off, and what is returned to the atmosphere) and generate shade, which reduces topsoil evaporation. The overall effect of the vegetation on the water balance of the ecosystem, or even of a country or region, depends on the plant community structure. A plant community is composed of all the species populations that inhabit the ecosystem. The spatial combination of the individuals of all species in the community determines the effect of the vegetation on the water balance of the ecosystem, and effects on the water balance of adjacent and even distant ecosystems as well.

The water-related services above are "input" services, which include soil moisture recharge and retention, aquifer recharge, and control of soil salinization and erosion. With respect to "output," one important ecosystem process is returning water to the atmosphere. On a global dimension, this process is clearly a service. However, on the local and regional scale in dryland countries like those of the study area, this is more a "disservice." The balance of this "service''/"disservice" is not known. For Israel, Stanhill (1993) calculated that 10,000 years ago, when the dry subhumid part of the country (receiving 400 to 800 mm annual rainfall) was mostly a natural, scrubland ecosystem, the potential water yield (volume of rain falling in a given year on a given surface area, minus volume of water returned to the atmosphere from the same area and year) was 1,590 km3/year, lower than the current 1,846 km3/year, with most of the area consisting of cropland, a highly managed ecosystem. Natural scrubland ecosystems appear to evaporate more soil water than intensively managed ecosystems in Israel. However, the positive contributions of that scrubland and other less managed ecosystems—such as scrubland's contribution in recharging aquifers—to the water balance of Israel, compared to the contributions of intensively managed ecosystems, must be calculated too, and weighed against the losses due to evapotranspiration from the same ecosystems.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Services Provided by Water Bodies

Open-water body ecosystems are spatially more homogeneous and better delimited than most terrestrial ecosystems. Being mostly a dryland, the study area is inherently poor in water bodies. Furthermore, many of these aquatic ecosystems are under intensive management or have been totally replaced by terrestrial ones. The following section addresses ecosystem services of the study area's streams, lakes, and wetlands.

Streams

Currently, the most significant ecosystem service of streams is the natural treatment of wastewater. The wastewater-treating service of most of the aquatic organisms in streams is facilitated by the oxidizing properties of the stream current and its velocity. Other components of the food web, such as aquatic herbivores and predators, are instrumental in regulating the populations of these wastewater-treating species, and in this way become involved in the quality of the wastewater treatment service of streams.

Lakes

Of the two study area's major lakes, one (the Dead Sea) is globally unique in its apparent lifelessness, and the other (Lake Kinneret, Lake Tiberias, or Sea of Galilee) serves as an operational open water reservoir for supplying water of drinking quality to most parts of Israel, with recent allocations to Jordan and the West Bank and Gaza Strip. The "service" of this ecosystem is thus to store water and to help maintain its quality as drinking water. Lakes in general, including Lake Kinneret/Lake Tiberias/Sea of Galilee, also provide the ecosystem service of wastewater treatment, although not as effectively as streams.

Wetlands

Wetlands are lands where the water table is usually at or near the surface, or lands covered by shallow water, that have characteristic physical, chemical, and biological features reflecting recurrent or sustained inundation or saturation (Cowardin et al., 1979; NRC, 1995a). Most major wetlands of the study area have been drained totally (coastal wetlands of Israel) or partially (Hula in Israel, Azraq in Jordan). Others, especially around the Dead Sea, are still relatively intact, though small. Wetlands are characterized by the slow rate of water movement in them. This

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

feature reduces their oxidizing capacity, making them ineffective in wastewater treatment. However, the slow water movement promotes the deposition of suspended material and provides ample time for the complete biological mineralization of organic compounds and biodegradation of synthetic toxic chemicals (NRC, 1992). The slow water movement also supports typical wetland vegetation, which further slows water movement, and reduces the depth of the wetland, thus contributing to its spatial expansion. This expansion provides a unique ecosystem service: water storage during floods and a slow downstream release. Wetlands therefore lower flood peaks and their detrimental economic and environmental effect, such as soil erosion (NRC, 1992). While this service is not provided by landlocked wetlands such as Azraq, it was an important (although underestimated) function of the Hula wetland before its drainage.

Artificial Aquatic Ecosystems

All types of artificial open water bodies function as intensively managed ecosystems. These bodies include fish ponds (mainly in Israel), wastewater treatment plants (e.g., the Shifdan plant in Israel), water carrying systems' open canals and reservoirs (the National Water Carrier in Israel and the Ghor Canal in Jordan), and other open air reservoirs (e.g., floodwater reservoirs in Jordan and Israel). Soon after construction, such bodies are colonized by aquatic microorganisms, plants, and invertebrates, and they are used by waterfowl and insectivorous bats (Carmel and Safriel, 1998). Thus, the water bodies, constructed for the sole function of water treatment or supply, become intensively managed ecosystems, with ecosystem functions shaped by the wild species that successfully colonize them. Like natural and less intensively managed ecosystems, constructed aquatic ecosystems provide the ecosystem service of promoting wastewater treatment. Many of these water bodies are also important habitat for birds, especially birds that migrate or that use it for wintering. Constructed wetlands for wastewater treatment can also provide wildlife habitat (U.S. EPA, 1993). In Israel, the major wastewater treatment facility, Shifdan, has become a waterfowl sanctuary that attracts hundreds of bird-watchers every year and is used to university teaching. Nearly all constructed water bodies in the study area significantly support bird and other aquatic and riparian biodiversity.

Biological Diversity

Biological diversity means the diversity of genotypes within a species, species diversity, and the diversity of ecological communities: in short,

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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biological diversity (often abbreviated to biodiversity) is the diversity of life on Earth. (See the similar definition by the 1992 United Nations Convention on Biological Diversity [Anonymous, 1992]). The protection of endangered species and biodiversity in general has been important to many people for a long time, and as a result, many have looked to science to provide quantitative assessments of the value of biodiversity. Although that endeavor has been difficult, there are other good reasons to protect biodiversity. For example, Sagoff (1996) described how difficult it is to establish on a purely economic basis that biodiversity or indeed most individual species should be protected, but he argued that the best reasons—and they are very powerful—for protecting biodiversity in most cases are ethical, moral, cultural, and aesthetic. Societies around the world have, in their laws and international treaties, reflected this view. Thus the United States's Endangered Species Act of 1973 declares it "to be the policy of Congress that all Federal departments and agencies shall seek to conserve endangered species and threatened species…" (Section 2 {b [c]}). The act further specifies that the determination as to whether a species is endangered or threatened must be based "solely on the basis of the best scientific and commercial data available," i.e., without reference to economic considerations (Section 4 {b[1]) (see NRC 1995b for a description and history of the act and its scientific underpinnings). In the study area, Annex IV of the Israel-Jordan Peace Treaty (see Appendix A) includes commitments to protect natural resources and biodiversity; the presence of parks and other protected areas throughout the study area is further indication of the study area's commitment to protecting biodiversity.

The above discussion does not suggest that biodiversity has no economic value or that it is not important in maintaining ecosystem goods and services. Clearly, some species have enormous economic value and ecological importance, and some ecosystems have economic—especially tourism—value because of their biodiversity. Within the study area, several ecosystems have recreational and hence economic value. For example, woodland ecosystems are relatively rare in the study area, but their sharp contrast with the more common deserts make them important recreationally and inspirationally. Aquatic ecosystems are even more valuable in these respects, especially when they occur in deserts, such as the Azraq Oasis or wetlands and oases around the Dead Sea. Lake Kinneret/Lake Tiberias/Sea of Galilee, although it is in a relatively fertile area, is a major site for tourism and leisure activities, especially in summer. On the other hand, the study area's deserts and their own biodiversity contrast sharply with the landscapes that are home to most foreign tourists in the study area, and hence deserts are major sources of tourist income.

Without some minimum amount of biodiversity, ecosystems would

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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function poorly, even if the general relationship between biodiversity and ecosystem functioning is unclear (see Grime, 1997 for a clear summary of this matter and citations to recent literature). In addition, many have cautioned that just because we cannot at present quantify relationships between biodiversity and ecosystem functioning, that does not mean we should be cavalier about extinctions: a species lost is gone forever, and we might discover too late that it had great ecological or economic importance (e.g., Perrings, 1991). Sagoff (1988) warned that if we wait to establish the economic and survival value of biodiversity, it may be irreversibly lost.

For all the above reasons, the committee concludes that it is important to protect biodiversity, and that water-resource planning should take this into account. Furthermore, protecting biodiversity often requires the protection of ecosystems, as does the protection of ecosystem goods and services. Thus, maintaining biodiversity and ecosystem goods and services can often be treated as a single goal, as the committee does in the following sections of this chapter.

Economic Values of Individual Species

In general, economic values of species derive from their provision of food, fuel, and fiber. In addition, some species provide medicinal, ornamental, and aesthetic goods. All human food consists of species and their direct products. Most of the species consumed by the global human population are domesticated and cultivated, which is also to say derived from species provided by biodiversity, or wild species. Many domestic species, and especially the food species, do not exist anymore in non-manipulated ("natural") ecosystems, namely, in the wild. But their progenitors, and more often their wild relatives, still occur in natural ecosystems. It is the genetic diversity of these progenitors and relatives that is one of the most critical benefits of biodiversity.

Ironically, domestic species are the most endangered species, despite the huge sizes of their populations and their large geographical extent. Efforts to increase their production have led to erosion of their genetic variability. These species gradually lose their resistance to environmental changes, competitors, pests, and parasites. The high densities and uninterrupted spatial expanses of their populations, and the "globalization" that leads to widespread uniformity of their genetic structure and to high transmissibility of their mortality agents, make them increasingly prone to extinction (Hoyt, 1992). Their wild progenitors and relatives provide a repository of transferable genetic variability, variability that can counteract the ongoing genetic erosion of the domestic species, thus reducing their extinction risks.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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The study area of this report is one of the Earth's richest areas in progenitors and relatives of domesticated species (Zohary, 1983). Land uses depending on supplies of irrigation water deny these biogenetic resources their natural habitats where they dynamically evolve under our changing environment (Zohary, 1991). Because this genetic diversity is the insurance against agricultural disasters, its loss through excess water use jeopardizes the long-term sustainability and contributes to non-sustainability in the use of the study area's water supplies.

Many wild species, both terrestrial and aquatic, are of commercial value. Wild plant species are often heavily sought, collected whole or for their parts, for their herbal, aromatic, medicinal, and ornamental properties. Many wild plant species are labeled prime pasture species, because they are critical for range-dependent livestock. Expansion of irrigated agriculture is at the expense of this economically significant biodiversity.

At the same time, most species do not have current, short-term economic value. Of the approximately 266,000 species of plants known (Raven and Johnson, 1992), about 5,000 are used as food plants, 2,300 are domesticated, and 20 provide most of the food for the global human population (Frankel and Soulé, 1981). Food production is currently limited by land and water resources and losses to pests, but not by the lack of food species. However, should current food species fail because of the risks identified above, alternative species, currently wild, will be sought for domestication. The natural species pool is thus a repository of potential food and utility species for humans.

Farmers often view the natural ecosystems adjacent to their croplands as sources of pests. But these and other natural ecosystems are also, and sometimes mostly, sources of enemies of agricultural pests. Thus, natural ecosystems provide important services that have economic value. Use of synthetic chemicals to control pests also controls their enemies, so this potential ecosystem value (pest control) is often not realized.

Conflicts Between Water Resource Development and Ecosystem Goods and Services

All species of realized or potential economic benefit to humans, globally and in the study area, are land users, and this type of land use competes with irrigated cropland. Improved water supplies for the study area may reduce not only the economic benefit of any expanded agriculture, but also the sustainability of existing irrigated and rain-fed agricultural production. This potential conflict requires evaluating that part of biodiversity that is of economic significance, but even the fraction and magnitude of that part of biodiversity have not yet been anywhere identified (Lawton, 1991). All species and their different populations must be

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

considered possible members of this economically important class, at least until a large part of the useful species are identified as such. Their benefits must then be weighed against the benefits of developments driven by water supplies in the study area.

Water Supplies, Biodiversity, and Desertification

There is a critical relationship between ecosystems, desertification, loss of biodiversity, and climate change in the context of sustainable water supplies. Desertification is land degradation in drylands caused by mismanagement and overexploitation. Overpopulation and increased demands, mostly in semiarid regions, bring about overstocking and overgrazing and trampling, transformation of woodland to rangeland (e.g., the deforestation for railway ties and fuel in the study area by Turkish forces in the early part of the century) and the overexploitation of rangeland for the fire wood. The reduced vegetation cover and breakage of the soil crust, lead to water and wind erosion of the topsoil, and with it an irreversible loss of productivity-desertification. The loss of vegetation cover reduces aquifer recharge and increases losses of floodwater. At the same time the loss of vegetation cover reduces the global carbon sink, thus exacerbating global warming.

Another type of land degradation is associated with the transformation of rangelands with year-round vegetation cover, to croplands that if not irrigated, have only intermittent cover, leading to further soil erosion. If the croplands are irrigated, irrigation brings about salinization of the topsoil: water scarcity does not permit application of quantities sufficient for leaching, and the high evaporation leaves the salt in the topsoil. Such croplands, when abandoned due to salinization, cannot revert to their original function as rangeland, since most range species are intolerant of the increased salinity. Thus, either due to loss of topsoil or due to salinization or both, land degradation may reach the point of irreversible desertification. To conclude, increasing the water supply allows the intensified use of rangelands and their conversion to croplands in semiarid regions. This leads to loss of biodiversity, reduced ecosystem services such as soil conservation, aquifer recharge, and the maintenance of carbon sink, thus exacerbating desertification and global warming.

Desertification often has roots, typically a large external disturbance (Puigdefabregas, 1995), that began some years, or even decades, before crises manifest themselves (e.g., the Dust Bowl in the United States in the 1930s and the Sahel crisis in the 1970s). For this reason, it is important to try to prevent desertification by avoiding nonsustainable use of water, before it manifests itself by loss of biodiversity and the impaired provision

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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of ecosystem services such as aquifer recharge, leading to reduced sustainability of water supplies.

Environmental Costs of Water-Resource Development

Policy makers, planners, and individuals in the study area need to make many decisions about activities ranging from international development projects to individual actions concerning water use, waste disposal, and what to plant in a garden or field. To make decisions about these activities and allocate water resources to different uses in the study area, a balance must be struck among environmental, economic, and other objectives when those objectives do not represent the same uses of water. To assess the balance and to identify acceptable tradeoffs, current scientific information should be used; a significant amount of new scientific information will also be needed.

The preceding sections explained how environmental quality depends on the goods and services provided at no cost by natural ecosystems and explained how economic well-being, quality of life, and maintenance of water supplies depend on environmental quality. This section describes some of the specific consequences that follow from failure to maintain ecosystem goods and services by losing the land that is needed for ecosystems to persist.

The section illustrates some of the factors that must be considered in making assessments and identifying sound tradeoffs, by describing interactions among environments, ecosystem goods and services, water quality and quantity, and human activities in the study area. First, we characterize the study area's biodiversity in the context of water supplies, we then describe the effects of water-resource development in biodiversity and on ecosystem services; and finally, we address ways to mitigate negative effects in achieving sustainable water supplies for the study area.

Biodiversity of the Study Area

Biodiversity relevant to water use in the study area has the following features:

  1. The ecology of the study area as a whole is that of hyperarid, arid, semiarid, and dry subhumid dryland ecosystems. The area's biodiversity is therefore that of drylands, with terrestrial vegetation directly limited by water, and all other components of biodivesity affected directly or indirectly by the variability and the unpredictability of water availability (Noy-Meir, 1973).
Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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  1. Humans have had an extremely long and persistent influence on the environment. It is highly likely that the recent evolution of the study area's biota took place in the presence of humankind, and that human activities and practices have acted as selection agents, like other agents of natural selection.

    Attributes (1) and (2) imply that many of the study area's species have been selected to withstand water scarcity, fluctuations in water supply, and human interventions, and hence that the study area's ecosystems are resistant and resilient.

  2. The study area is not only a crossroads of continents (Africa, Asia, and Europe), but also of biogeographical regions—the Saharo-Arabian (African), Irano-Turanian (Asian), and Mediterranean. The area also shows intrusions and relicts of Euro-Siberian (northern European and Ethiopian (tropical African) species.
  3. Attributes (1) and (3) have three implications: overall species richness is very high; most species are presented by peripheral populations, and, although most of the species are not unique (endemic) to the region, the communities, that is, the regional assemblages of species, are. In this region, species of Asian steppes interact in the study area with species of Saharan deserts, for example.

    Effects of Water Use on Regional Biodiversity and Ecosystem Services

    It is clear from the preceding that biota and ecosystem services depend on water. Water-resource development in the study area usually entails six major practices: transportation of water from lakes and river sources; pumping from sources of springs as well as impounding springs by enclosing them in concrete structures; drainage of wetlands and large ponds; drainage of ephemeral ponds; pumping from aquifers; and damming floodwater courses to construct floodwater reservoirs. Each of these practices has notable effects on biodiversity and ecosystem services of the area, as discussed below.

    Management of Lakes and River Sources.

    Large water-development projects have dramatically affected the regional economy by promoting year-round intensive, pressure-irrigated agriculture as well as urban development. These development projects are associated with the management of river systems. The coastal Yarkon River1 fed by Ein Afek springs at the Judean foothills generated the Yarkon-Negev Line. The Rift Valley's Jordan River Basin management generated the Israeli National Water

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

Carrier System and the King Abdullah Canal. These projects revolutionized agricultural and rural development at the cost of biodiversity and ecosystem services, many of them related to water quality.

As Appendix C shows in greater detail, a watershed-management approach for the whole Jordan River Basin could be essential to achieving overall sustainability of water-resource development in the area. This approach could achieve a sound balance between providing water supplies to the study area, and maintaining and promoting ecosystem services related to water quality—those of both the Hula wetlands and Lake Kinneret/Lake Tiberias/Sea of Galilee—as well as the biodiversity of the lower Jordan River and around the Dead Sea coasts.

Impoundment of Springs.

Springs in the study area vary from those sustaining small ephemeral or even permanent ponds, to those supporting ephemeral or permanent streams. Many springs are pumped and impounded within a sealed concrete construction, to prevent evaporation and to protect the pumps from vandalism. These practices affect both the riparian biodiversity along the stream, mostly of plants, and the aquatic biodiversity of the ponds and streams themselves, mostly of invertebrates, some of which are unique to the study area. The effect of drying streams and obstructing access to ponds also cascades to the terrestrial biodiversity adjacent to the springs and streams, and ultimately even farther.

Drainage of Wetlands and Ponds.

At the end of the nineteenth century there were 200,000 dunams of wetlands2, west of the River Jordan, 97 percent of which have now been drained. The motivations for this drainage were to reduce water loss by evaporation, collect water for agricultural development, increase land resources for agriculture, and eradicate malaria. Management intensity has ranged from complete transformation of the wetland to agricultural land, with a total loss of aquatic biodiversity, to initial draining, with subsequent engineering of a wetland nature reserve in part of the drained area and final reconstruction of another part by reflooding. The effects of draining wetlands, too, cascades to adjacent and remote ecosystems, by affecting animals of an amphibian life style, animals who prey on aquatic organisms, and so forth. The Kebara wetlands on Israel's coastal plain were used by the prey of prehistoric humans (Tchernov, 1994) and inhabited by the Nile crocodile at the turn of this century. Also, the study area serves as a flyway of

1  

This river has been called "Yarkon River" for the last 60 years on international maps. However, it is also known as Wadi Abu Butrus.

2  

A dunam, 1000 m2, is a unit of land used in the study area.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Palearctic migratory birds, used just before or after crossing the Sahara desert. The study area's wetlands, either at the edge of deserts (the Hula) or well within them (Azraq) function for refueling prior to the desert crossing (fall migration), or rights after completing it (spring migration) (see Boxes 4.1 and 4.2). Thus, the loss of these wetlands affects European and African birds, and may modify the birds' patterns of cross-desert migration.

Loss of Ephemeral Ponds.

The study area's rainy winters generate ponds that often completely dry out during the long, dry summers. Many were created by ancient damming and quarrying, and were used for generations to water livestock in early summer. They harbor unique biodiversity, adapted to the ephemeral conditions, usually by having an amphibian lifestyle or leaving dormant propagules in the soil of the dried-up bottoms of the ponds. When wet, the ponds attract wildlife that come to drink or to prey on other animals. Most of these ponds have been cut off from their runoff sources and drained, to be transformed to agricultural land. Other ponds have become sinks for wastewater of high toxicity or high organic load. Many have been drained intentionally or are sprayed to control mosquitoes. Spraying of existing ephemeral ponds, and their spatial rarity, which prevents migration between them, have reduced their biodiversity. For example, Hadera Pond had 56 aquatic plant species in 1906, of which 30 persisted until the 1950s, and only 16 in 1982 (Mador-Haim, 1987). Implicating the ponds as a mosquito threat is flawed, because mosquitoes are controlled by the ponds' natural predators—tadpoles in the winter and predatory insects that live in the ponds as long as they have water. These animals maintain mosquito populations at low levels. The use of pesticides to control mosquitoes aggravates the situation: their natural enemies are destroyed, and the mosquitoes evolve resistance to the pesticides. Fortunately, because of the dormancy and high dispersibility of the propagules (airborne or transported by birds), the biodiversity of such ponds can be established and promoted once they are reconstructed, by seeding the constructed ponds with soil from the few existing, healthy ponds. The most important ecosystem services of these pools are recreational, educational, and scientific, given the unique nature of their biodiversity and their dynamic ecology. The interest in Israel's ephemeral ponds has generated surveys and plans for rehabilitating and constructing ephemeral ponds, rather than permanent artificially maintained water bodies (Gazith and Sidis, 1981).

Pumping from Aquifers.

There is no evidence that lowering the water table through pumping aquifers in the study area poses risks to terrestrial biodiversity. Such pumping was blamed for the deaths of acacia trees in

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

the Israeli section of the Arava Rift Valley (Ashkenazi, 1995), but the issue is not yet resolved (Ward and Rohner, 1997). Pumping from aquifers, however, can reduce the discharge of springs, and thus transform permanent spring pools into ephemeral ones or curtail the flow of streams. For example, pumping from the Yarkon-Taninim aquifer reduced the discharge of the Ein Timsah spring into the Taninim River 3 such that the flow in the lower part of the river was reduced from about 84 to 88 million m3/yr between 1953 and 1956 to 24 million m3/yr between 1984 and 1986 (Ben-David, 1987). This and other factors have adversely affected the biota of this stream, despite its legal status as a nature reserve.

Damming Runoff Courses and Constructing Reservoirs.

The objective of dams in the study area is to prevent runoff to either the Mediterranean Sea or the Rift Valley. The floodwater is stored in reservoirs or used to recharge aquifers or directly for irrigation. Unlike all other practices, which have a strong local effect (mostly on aquatic and riparian biodiversity), and a smaller regional effect on nonaquatic species, this management practice has a regional, whole-watershed effect, mostly on terrestrial biodiversity. The closer the dam is to the water divide, the larger the area of watershed affected. Dams and reservoirs can promote very successful agriculture, but also adversely affect downstream channels in various ways. Dams can reduce soil moisture in these channels and their immediate surroundings, adversely affecting the richest parts of dryland watersheds. In hyperarid dryland watersheds, the channel is the only element that has perennial vegetation. Putting dams in these drylands has a stronger effect on biodiversity than putting them in less arid drylands of the study area. Damming also reduces the subsurface runoff in the channel, which lasts longer than the surface runoff and is critical for the persistence of the channel vegetation. Finally, the reservoirs enrich the desert with water bodies that dramatically affect the behavior, population dynamics, and structure of the desert's annual-plant communities. These changes may be exacerbated since the development of aquatic biota in the reservoirs often leads to introducing predatory fish to control mosquitoes. While the fish are ephemeral, they attract birds and thus generate instabilities in the bird populations and in their roles in ecosystem functioning.

Other effects of runoff on wadi beds and their surroundings depend on those features of the flow that vary spatially and temporally, from flash floods causing severe erosion and loss of organisms to moderate currents that leach salts and deposit nutrient-rich soil. Dams change the

3  

This river has been known as the Taninim River for approximately 60 years on international maps. However, it is also known as Wadi Zarka.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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BOX 4.1 The Azraq Oasis (Jordan)

The Azraq oasis or wetland is approximately 80 km east-southeast of Amman in the heart of the Azraq basin, which covers about 12,710 km2 and is located in southern Syria, eastern and central Jordan, and northern Saudi Arabia. The Azraq oasis is an outstanding example of an oasis wetland in an arid region. The oasis is fed by springs known locally as the Shishan and Drouz springs. The oasis is famous for its date palms and provides important habitat for migratory bird species as well as mammals such as the oryx.

Water was withdrawn from the oasis to serve the needs of Amman's growing population beginning about 1960, and the rate of withdrawal increased until about 1990 (Ramsar Convention Bureau, 1994). The current condition of the Azraq oasis is typical of arid region wetlands throughout the Middle East. Extensive pumping of the upper aquifer complex to provide water supplies for municipal, industrial, and agricultural uses has caused the springs that feed the wetland to dry up.

The characteristic land form within the basin is a rolling gentle plateau with minor relief in and around the central part of the basin. Elevations range from 1,576 m near Jebel El-Arab to 500 m at the Azraq depression. Many intermittently flowing wadis drain from all directions into the Azraq depression, forming ephemeral ponds that may remain for several months before being lost to evaporation. The basin overlies three aquifer complexes—upper, middle, and lower—with the waters in the upper aquifer complex being the most utilized. The basin is a major source of drinking water for Amman, Zarqa, and Irbid, three of Jordan's major cities.

The climate of the Azraq basin is characterized by hot dry summers and cool winters, during which most of the modest precipitation occurs. Mean annual rainfall ranges from 300 mm in the north to 150 mm in the west to less than 50 mm in the south and east. Precipitation comes from cyclones that arise in the west, cross the Mediterranean Sea, and bring cool air masses from Europe. The cyclones frequently spawn thunderstorms, producing rainfall that is irregular in intensity and duration. Convective or thunderstorm rainfall is oriented along the major axis of the eastern Mediterranean and extends eastward into Iraq. This type of rainfall contributes most of the precipitation in the Azraq Basin and occurs mainly during October, November, April, and May. More widespread, gentler rains (cyclonic rains) also reach the area, mainly in December, January, February, and March.

In 1987, at a meeting of the Conference of Contracting Parties in Regina, Canada, the parties concluded that the current rate of water withdrawal, 16 million m3/yr, was ''likely to provoke serious changes in the natural properties of the Azraq wetland and in particular [could] increase the salinity of the remaining water there." The conference called for a "proper assessment of the environmental impact of the pumping" and suggested that pumping be reduced by at least 50 percent, as recommended by Jordanian conservation organizations, at least until the environmental assessment was complete. It also urged that there be a long-term plan for water use that guaranteed the natural properties of this internationally important wetland (Ramsar Convention Bureau, 1994).

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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However, by 1990, the Jordanian Government established a "safe yield" of greater than the 1987 rate of pumping: this was 20 million m3/yr. The Jordanian Government invited the Ramsar Convention Bureau to apply its monitoring procedure at the site. This was done in March of 1990, and led to the conclusion that to restore the ecological character of the oasis, water withdrawals needed to be "reduced considerably." The convention made several other recommendations, including research recommendations.

After this procedure, the Jordanian Department of the Environment hired consultants to undertake studies of groundwater management, and the Global Environmental Fund (GEF) of the United Nations Development Program allocated $US3.3 million for five subprojects over a three-year period. They are intended to halt degradation of the Azraq wetlands and establish a management plan to allow the water resources of the Azraq basin to be used on a sustainable basis while preserving the unique biodiversity that characterizes the Azraq wetlands.

Although the project is in its early stages, an effort will be made to eliminate the overdraft from local aquifers and manage those aquifers so that water can be extracted from them to maintain the wetlands on a sustainable basis. A monitoring and assessment program has been included in the plans for restoration, to ensure that the restoration process achieves the goal of preserving the wetlands on a long-term basis. Should this restoration plan prove unsuccessful due to the difficulties of bringing ground-water extractions to an equilibrium (to make water available to support the wetlands), consideration will need to be given to developing imported supplies to support the wetlands. Imported supplies will be considerably more expensive than local ground-water supplies. Unfortunately, the ecological condition of the oasis continued to deteriorate for a while after 1990, and it is too early to determine the results of the GEF investments (Ramsar Convention Bureau, 1994).

Experience with the Azraq oasis shows how overexploitation of water resources in arid or water-scarce regions can threaten or destroy unique ecosystems. This experience has been repeated in many areas of the world, and as described here, in the Hula Wetlands of Israel. These ecosystems provide important services and habitat. Such unfortunate results are more likely when wetlands are treated as public goods with no one having an incentive to ensure that the services of the wetland are maintained and preserved. The case also illustrates that proactive investment and management strategies are required if unique environments such as the Azraq wetlands are to be protected and restored. Such strategies must provide for continuing management and monitoring to ensure that the wetlands resource is preserved and sustained.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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BOX 4.2 The Drainage of the Hula Valley (Israel)

Background

The Hula Valley is located in the north of the Jordan Valley rift valley, in the watershed basin of the Sea of Galilee (Lake Kinneret or Lake Tiberias). The valley outlet toward the lake was blocked by a volcanic eruption many years ago. Since then drainage out of the valley is limited, and conditions favoring flooding have prevailed. In the 1950s the center of the valley was covered by a lake (of about 10 km2), and a significant portion of the area, mostly north of the lake, was covered by marshes. An area totaling about 70 km2 was covered by water year-round and could not be used for agriculture. The marshes were breeding grounds of mosquitoes and the whole region was infested by malaria.

The lake and surrounding wetland were a unique ecosystem. The area was covered by a rare combination of plants representing cold and warm regions and was inhabited by numerous native animals as well as birds staying until their yearly migration. The lake and marshes were drained to help eradicate malaria and to expose the land to agricultural development.

The War Against the Swamp

Social Attitude

Israeli society in the 1940s and 1950s was a society of "pioneers," who were motivated by the desire to overcome the harsh natural obstacles of the country. Like most other Western civilizations, increased productivity has been a central societal value, and "emptiness" or undeveloped land was considered undesirable. A term describing this "emptiness,'' yeshimon in Hebrew, implies a destroyed, devastated environment. The positive activity of the pioneers was reported as "the struggle of man with the emptiness."

The Hula swamp represented the evils of nature. It was hardly penetrable, and disease-carrying mosquitoes inhabited it. Thus, the desire and ambition to win the battle against the swamp and to turn it into a site where people could live and prosper was deeply embedded in the Israeli social attitude at that time. Very few people had sentiments or consciousness toward the Hula as a natural resource. Nature and natural attractions were not considered at the time as an economic asset. Tourism hardly existed and the meager internal tourist business was centered on resorts where people came to rest from their work.

A few experts from Israel and abroad expressed some hesitation about the possible hydrogeochemical processes that might follow drainage of the Hula, such as land subsidence. These warnings were not taken seriously. A fraction of the area was not developed and was later reconstructed to function as a wetland nature reserve. This area was the least suitable for a natural reserve, at an elevation above the rest of the area, making it difficult to keep the land flooded. It was also close to a major drainage canal and therefore became polluted.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Environmental Changes (1955-1970)

Different types of organic soils, from muck to peat, have developed in the marsh area. Soil organic matter is highly unstable under the prevailing climatic conditions; it could be stable only under water. Once it was exposed, very quick decomposition processes took place. These processes, together with mechanical change in the structure of the organic colloids induced by desiccation, led to the subsidence of the organic soils. The area covered by organic soils subsided at an annual rate of 7 to 10 cm. This changed the drainage system continually, shifting the elevations of different zones in the valley, requiring a continual deepening of drainage canals.

The drained organic soils caught fire from external sources of ignition and through spontaneous combustion. When ground-water level is lowered, exothermal decomposition processes take place below the thermal insulation of the dry surface, leading to extensive heating and finally to combustion. The fires created immediate damage, causing air pollution and destroying farm land. Decomposition of the organic matter led to the release of several by-products, such as ammonium, and the subsequent accumulation of nitrates in the soil. Winter flooding of the area led to the washout of nitrates through the Jordan River to Lake Kinneret. The reclaimed marsh area was the major source of nitrates into the lake, apparently starting a sequence of processes leading to eutrophication of the lake. The nature reserve did not preserve the flora and fauna of the lake and the marshes. Many species disappeared, and an area once covered with a variety of plants and animals became a flat dusty region.

The Hula Valley Management Reconsidered: 1970-1977

Organizational Aspects

The collapse of the Hula hydrochemical system, as reflected in the increase in the flux of nitrates to Lake Kinneret/Lake Tiberias/Sea of Galilee and the early indications of eutrophication, led to a strong public response. The government decided to establish a watershed authority, the Lake Kinneret Authority, to coordinate all the efforts related to the management of the lake. Another coordinating body, the Hula Committee, was established to coordinate the work in the Hula Valley specifically. These organizations were the first environmental authorities in Israel and paved the way toward the development of other environmental authorities and finally to the establishment of the Ministry of the Environment.

A unique feature of the Lake Kinneret Authority is that it was made up of representatives of municipalities, farmers, water authorities, and industries in the watershed. The traditional conflict between business and production, on one hand, with environmental authorities on the other, was thus avoided.

The government regarded the maintenance of high water quality in the lake as a priority goal and allocated a relatively large budget for this purpose. The first act of the Hula Committee and the lake authority was to support and coordinate research aimed at the solution of the nitrates problem in the Hula Valley. A number of academic institutions were represented in a multidisciplinary research team. Frequent contacts and real-time feedback were maintained among scientists, managers, and engineers of the lake authority. As a result, the research was practical mission-oriented work, with many mid-course corrections and adaptation, and the implementation of the research findings was immediate.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Major Research Findings

A detailed study of the basin's hydrology was conducted. An artesian hydraulic gradient was found to induce a slow upward seepage of ground water, preventing any seepage of nitrate-rich water downward. Nitrate leaching occurred during the rainy season and during flash floods common in the Jordan River. During floods, when the water level in the river rises, water would flow into the low-lying peat area. A backflow of water following the flood carried large amounts of nitrate to the river and into the lake.

The microbial processes leading to the production and destruction of nitrates in the basin were studied. The effects of temperature, moisture contents, and oxygen on the production of nitrates was defined and quantified. The rate of nitrate accumulation was found to be high during the summer, if a deep soil profile was aerated and drained. The conditions to maximize denitrification, a process that lead to the conversion of nitrates to inert N2 gas were studied in detail.

This process occurred at a very fast rate when a dry soil was rewetted quickly. A burst of microbial activity was induced, due to the exposure of fresh surfaces of organic macromolecules disengaged when hydrogen bonding was reduced in the desiccated soil. It was found that properly timed sprinkle irrigation was an effective way to reduce the nitrate content of the soil. Intensively growing forage crops were found to take up high amounts of nitrogen and slowed nitrate accumulation.

Implementation

The research findings indicated that proper water management was the way to minimize nitrate production and leaching out. By deepening and widening the riverbed and constructing dams and banks, water entry during floods was minimized. Ground-water levels during the summer were maintained at a depth of 60 to 80 cm. Water level was reduced toward the winter, to about 120 cm, to make place for the rainwater. Water level was maintained using a series of dams on the main drainage canals, connected by a network of smaller canals.

The previously common subsurface irrigation system was replaced by a sprinkler system. The properly spaced and controlled irrigation-induced intensive denitrification reduced the nitrate storage in the soil profile by an order of magnitude. This operation can be considered the first field-scale biotechnological project. The above-mentioned steps were implemented within five years following the start of the work. The project led to a marked reduction in the leakage of nitrates from the region and in the influx of nitrates and total nitrogen into Lake Kinneret/Lake Tiberias/Sea of Galilee.

Environmental Changes (1977-1990)

The intensive environmental research conducted during the previous phase produced many by-products. One was a series of results that helped to improve the agricultural production in the valley, through improved irrigation methods, improved

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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fertilization, soil cultivation, and species selection. This success encouraged the agricultural use of the area. The land that belonged to a governmental holding company was divided into individual cooperative settlements. Another factor that affected the agricultural use of the area was the relatively high price of cotton and the profitability of cotton farming.

An additional change was the slow transfer of control of the area and the water system from the lake authority to the local water authority, dominated by the agricultural sector. The experts that acquired knowledge and understanding of the system were not involved in the control of the area. The previously recommended control of high ground-water level and the dense drainage-canal system needed for such control posed a difficulty for the farmers. Thus, there was pressure to destroy the canals to enable cultivation of large plots and to adjust the irrigation regime to the demands of cotton growing. Due to the absence of clear regulations or written guidelines and the disengagement of the system from environmental considerations, the "cash crop" pressures led to a slow destruction of water control in the area.

Drainage canals were filled in and the required high water ground-water level was not maintained. These changes led in the early 1980s to dramatic, possibly irreversible, damage to the peat area. Water level was lowered to a depth of a few meters, spontaneous fires spread, the dry soil became hydrophobic and did not hold water, and soil subsidence was accelerated. Soil fertility was reduced and parts of the area became desert.

Decision Process

The conventionally accepted response to land subsidence was to deepen the drainage canals to prevent the flooding of low-lying plots. The Hula Committee decided in 1982 not to continue this response but rather to reevaluate the situation. The committee decided to assess all possible alternatives for the management of this area. The first alternative to be considered was to continue the emphasis on the conventional farming system. This alternative would require the deepening of the drainage system together with an effort to solve the soil fertility problems. A second major alternative was to reflood part of the area, to solve environmental problems as well as to create sources of income from tourism and aquaculture. This option raised widespread objections from the agricultural lobby, mostly due to the fear that land rights would be taken if the area were reflooded.

The Hula Committee, together with the Lake Kinneret Authority, guided a prefeasibility study of the different options. One guiding principle was that the evaluation should be based, in the first phase, only on economic considerations. The finding of the prefeasibility study was clear: flooding and expansion of tourism in the area was not only an environmentally friendly option, but is the one that would generate more income. The recommendation of the Hula Committee to reflood part of the valley came at a time when the income from farming was risky and meager and when tourism was expanding. These trends encouraged the acceptance of the proposed project by the people in the region and by the different authorities. Presently, about 200 ha of previous peatlands are covered by water, forming an artificial lake surrounded by an area of wetlands. Water level in the area is maintained at a high level, and a number of projects are being planned.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Evaluation of the Decision Processes

The Decision to Drain: 1940-1950

Had the initial planning process for drainage of the lake included a serious environmental impact statement (EIS), it is quite probable that the decision would still have been to drain the lake. Most present-day institutions and experts would approve the project considering the information available and the external conditions at the time.* However, an EIS would have indicated the weak points of the project. It is possible that it would have directed the planners to better preserve the natural assets. Better ways might have been found to manage the area, especially in the management of ground-water levels to help minimize land subsidence and decomposition of the organic soils.

We do not have the ability to predict environmental implications of human modifications of natural systems. One role of an EIS is to present a range of possible environmental implications. Such a list should direct a monitoring system aimed at getting an early warning of negative environmental developments. The Hula drainage project did not include any monitoring effort. Thus, changes in the environment were "discovered" only 15 to 20 years following the drainage when the changes were partially irreversible and almost catastrophic.

A clear response system should be ready in case negative environmental developments are detected. Such a system was not prepared and is often missing in environmental management processes worldwide. A project is approved by the environmental authorities following the development of a given set of predictions and expectations that show the effects of the project on the environment (the external effects) are acceptable. The ability to change the decision when the predictions and expectations are proved wrong is limited. By that time, investments have been made, and economical, political, and social interests are involved; and it is difficult to demand major modifications.

This is not the case when changes in conditions affect the internal functioning of a given project (e.g., the development of a better alternative product by a competing industry). Such a conditional approval system is needed to respond to unforeseen environmental effects of water resource development. An environmental approval should be reviewed periodically (e.g., once every 10 years), and the project owner must take some risk in case the project is found to cause negative environmental impacts. In the case of the Hula project, such conditional approval was not properly formulated and implemented.

*  

There was some opposition to the project by the "greens" of the time. They included persons from the region who enjoyed the area as it was and did not see it as a menace. Opposition to drainage was the driving force in establishing the first and strongest environmental nongovernmental organization in Israel, the Society for the Protection of Nature.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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features of the downstream flow incrementally and in various ways, so long-term studies are needed to evaluate dams' effects and to determine how much water should be released and how often, to reduce their damage to downstream biodiversity.

Indirect Effects of Water Use on Biodiversity, Ecosystem Services, and Water Quality

Water made unavailable to support biota at one site is usually transported to another site to support agricultural production or urban development. Year-round agriculture in the study area's drylands is totally dependent on irrigation, and neither agriculture nor urban areas can depend on local water resources. Water-resource development thus is a prerequisite for both agricultural and urban development. The dramatic increase in the extent of agricultural land and of urbanization in the study area, then, obviously reflects a significant increase in water use.

Although both agricultural and urban development require water-resource development, agriculture uses more land and has more effect on biodiversity than urban development. Agriculture, urban development, and the infrastructure connecting them (e.g., roads and pipelines) adversely affect biodiversity in two ways: through the loss of natural ecosystems by land transformation, and the loss of biodiversity in natural ecosystems resulting from their fragmentation, especially by infrastructure. Two other effects are restricted to agriculture: the damage to species in adjacent and nearby ecosystems caused by airborne pesticides, and the contamination of aquatic ecosystems and aquifers by pesticide and fertilizer runoff.

Loss of Natural Ecosystems and Biodiversity

The millions of dunams of agricultural land in the study area, much of it under intensive cultivation, means the loss of millions of dunams of natural ecosystems. The specific contribution of these lands to aquifer recharge and how it may have changed since their transformation to agricultural lands is not known. But it is likely that at least some damage has occurred. In fact, such indirect effects of water use on natural ecosystems may be the most undesirable effects on water supplies, more undesirable than the direct effects of water use on natural ecosystems. The dimensions of the loss of this service (recharge) depend on the geomorphological properties of the transformed watershed, its geographical placement with respect to regional aquifers, the diversity of ecosystem types in the landscape, and the type and structure of its natural vegetation. The degree

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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of loss also depends on the properties of the development, that is, on the agrotechnological practices and type of crops.

The allocation of land for agriculture and urban development has not taken such issues into account in the study area and most regions of the world. Evaluating the amount of water lost due to the appropriation of natural watersheds by agriculture and urban development in Israel, the West Bank and Gaza Strip, and Jordan is important. Such study may guide priorities for land uses within countries of the study area, keeping in mind that ecosystem services can be restored when agricultural land is abandoned and the natural ecosystem is rehabilitated.

The reduction of natural ecosystems also causes local extinction of populations and species, that is, reduction of biodiversity, regardless of the loss of ecosystem services. The persistence of a population is a function of its size, among other things. Population size is often a function of the area available for that population. The chances of extinction of a population dramatically increase when its available area, hence its size, is reduced below a species-specific threshold (NRC, 1995b). Similarly, in general, as the area of a natural ecosystem decreases below an ecosystem-specific threshold, the number of species inhabiting it decreases (Soulé, 1986); in general, species richness is positively correlated with habitat area (McArthur and Wilson, 1967). In this case too, it is not known how many species' populations have been lost in the study area through reduction in natural ecosystem size, by transforming these ecosystems via water resource developments.

Although Israel has thus far (1998) lost only one mammal, one frog, and one fern from its aquatic and riparian biota, many more species are at high risk, especially amphibians (Yom-Tov and Mendelssohn, 1988). Moskin (1992) divided the 491 mammal, reptile, amphibian fish, fern, and monocotyledonous plants (excluding grass) species of Israel into two categories: aquatic or riparian versus nonaquatic. In each category, he compared the number of species at risk of extinction using the International Union for the Conservation of Nature (IUCN) categories of "extinct," "endangered," and "vulnerable" with those not at risk of extinction (using their categories "rare,'' "insufficiently known," and "out of danger").

Whereas only 14 percent of nonaquatic species were at risk, 35 percent of aquatic species were at risk, representing a statistically significant difference that was seen in each of the taxonomic groups. For fish (only aquatic, of course), the proportion of species at risk was similar to those in nonaquatic species in other groups. Nathan et al. (1996) showed that, although waterfowl and raptors consist of only one-third of the regularly breeding birds of Israel, all but one of the 14 extinct bird species of Israel were waterfowl (7 species) or raptors (6 species, 4 of which were mostly wetland or riparian). These data suggest that further reduction in the size

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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or water quality of aquatic ecosystems in the area could cause the extirpation of more than 35 percent of their vertebrate and plant species (and probably a high number of invertebrate species as well).

It is not known which regional ecosystems are more prone to species loss through reduction in size, nor what their thresholds are below which species are lost (see Appendix C). Thus, the fact that the number of extinctions in terrestrial ecosystems of the study area known so far is insignificant is not a cause for complacency. To conclude, the appropriation of land by agricultural and urban development impairs at least one water-related ecosystem service—recharge—and also jeopardizes regional biodiversity.

A troubling example of the loss of biodiversity is the loss of natural ecosystems in the Negev desert. In the 1950s, Israel promoted "greening the desert," resulting in a transformation of traditional rangeland to irrigated cropland, adversely affecting peripheral populations of plants and animals of rich within-species (genetic) diversity (Safriel et al., 1994). Increased urbanization, technological advances in wastewater treatment, recognition that agriculture in the central coastal plain endangers the coastal aquifer, and irrigation via the Israeli National Water Carrier all encourage this shift of Israeli agriculture from relatively wet, fertile regions to semiarid regions. But this shift accelerates the loss of biodiversity, and probably the provision of some ecosystem services. Thus, it is not sustainable over the long term. The loss of natural ecosystems and biodiversity occasioned through Israel's policy of greening the desert gives cause for concern about the potential adverse effects of Jordan's Badia Program to develop its eastern desert.

Effects of Fragmentation

An agricultural plot that dissects a natural ecosystem, or even a road cutting through that ecosystem, can split a large and hence safe ecosystem into two smaller, extinction-prone ones. Migration between two small ecosystems can offset the risk of species extinction in each, at least in any ecosystem that functions as a sink for migrants from another. But the development that caused the fragmentation often serves as a barrier for migration. Similarly, this barrier can erode within-species genetic variability, further contributing to risks of species extinction (Tilman et al., 1994). Statistics on road casualties of endangered species suggest that roads function as effective barriers between ecosystems. But the effects of fragmentation on the study area's biodiversity has not been studied.

Effects of Pesticides

Pesticides are applied rather generously in the study area; for example, 15,000 metric tons are applied every year in Israel. Especially when applied from the air, the effect of pesticides on

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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natural ecosystems adjacent to agricultural land is evident. Pesticides and herbicides are often concentrated at each link of food webs, sometimes at up to lethal concentrations in top trophic levels. Top-down effects on ecosystems may be highly significant, hence pesticides cause a great concern. Pesticides are also transported by runoff affecting aquatic ecosystems. The recent reductions in cotton production in Israel, for example, not only save water, but also reduce the pesticide damage to aquatic and other ecosystems.

Effects of Fertilizers

Fertilizers too are applied in large quantities in the study area, often in the irrigation water. Fertilizers reach aquatic ecosystems, where they can cause eutrophication, and they also contaminate ground water. Thus, water drawn from lakes, rivers, and aquifers for agriculture contaminates and alters ecosystem functioning. Again, such indirect effects of water use may be environmentally more significant than their direct effects. Because dryland ecosystems are limited not just by water but also by nutrients, the enrichment of fertilizers "escaping" from desert agriculture may dramatically change the functioning and structure of these ecosystems.

Effects of Trace Elements

Effects of trace elements have not received sufficient attention in the study area. However, the experience of irrigated agricultural development in the San Joaquin Valley in California (NRC, 1989) suggests that harmful trace elements, especially selenium, are abundant in agricultural drainage water, and these can be further concentrated in the food web, damaging wildlife and humans.

Mitigation

What is being done and what should be done to mitigate adverse effects on natural ecosystems and their biodiversity, as they are caused by current and future water-resource development in the study area? Mitigation activities are of four types: restoration of damaged aquatic ecosystems; securing allocation of water for aquatic ecosystems, thus guaranteeing their ecosystem services for the future; development and implementation of a system for environmental impact assessment of planned major water-management projects in the study area; and development of regional planning policies that integrate water-resource development, agricultural development, and the functioning of natural ecosystems, to promote overall sustainability.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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Wastewater for Restoration of Freshwater Ecosystems

Until 1991, the prevailing notion was that aquatic ecosystems should be rehabilitated by elimination of all effluents, ensuring flow of freshwater only. But the realities of water scarcity in the study area made it clear that rivers will dry up completely if the discharge of high-quality effluents back to them is not permitted when freshwater allocations are unavailable. For example, the Hula Nature Reserve in Israel has been found to function even when much of its water is effluent. The notion of using wastewater to help support biodiversity is based also on the belief that natural ecosystem can "serve themselves" by processing the wastewater. Many data have been accumulated, for example, along the course of the Yarkon River, to evaluate the treatment capacity of this river. For the month of June 1994, self-purification during the passage of water through measured sections of the river was evident in reductions of 0.1 to 0.5, 0.5 to 0.6 and 0.2 microgram/liter/second respectively in biological oxygen demand, chemical oxygen demand, and ammonium concentration—a high rate of self-purification, typical of an eastern Mediterranean climate (Rahamimov, 1996). Similar values have been measured in the plains section of the Soreq stream, and much higher values in the mountainous sections of this sewage stream. To increase the self-purification potential of the Yarkon, small dams have been constructed and the slowed-downstream above them is artificially oxygenated. An Israeli National River Administration was established in 1993 and charged with coordinating the restoration of river ecosystems, including the use of wastewater for this purpose. Though the main motivation for such action is recreation, the rehabilitated rivers promote biodiversity and provide ecosystem services. These restorations require water allocation of wastewater of specified quality, as well as freshwater allocation. This freshwater is not necessarily water lost to agriculture, because most of the allocation can be impounded at the lower reaches of the rivers, and the fraction lost by seepage recharges aquifers.

Balancing Water Resource Development with Biodiversity and Ecosystem Services

Regional Planning Using Advanced Technologies

Intensifying water-resource development puts the study area's biodiversity and ecosystem services at risk. It is therefore necessary to evaluate the benefits of the development against the lost biodiversity and services. The risk of loss can be reduced by striking an optimal balance between land allocation for development and for biodiversity. Remote-sensing

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
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and geographic information systems (GIS) technologies are now available to carry out this mission by means of the following steps.

  1. Taking stock of current land uses, classed by development (e.g., urban areas, industrial areas, rural settlements, agriculture, and infrastructure) and biodiversity (e.g., protected areas, open areas not legally protected, rangelands, and some types of extensive agriculture). Thus, the first GIS map layer can plot current development and existing biodiversity.
  2. Ranking the various types of existing biodiversity (e.g., an indigenous woodland of a given successional state or of a semiarid watershed) in terms of ecological value—i.e., provision of ecosystem goods and services and support of biodiversity—and the different sizes of each of these types.
  3. Assessing the relative value of existing biodiversity areas identified in step 1 using the rankings obtained in step 2. For highly developed sections of the study area, the biodiversity areas will be scattered patches of natural ecosystems within a matrix of development, with the size of each patch and its distance from adjacent patches contributing significantly to its relative value. In nondeveloped areas, patches of development will be interspersed within a matrix of natural ecosystems, and the relative value of each type of patch will be less affected by size and distances to similar patches. Relative values can be expressed as colors or color tones in a second GIS map layer.
  4. Estimating the dimensions and identifying the areas required for additional, forecasted water-driven development. The economic benefits of water-resource development of each of these areas can then be assessed and expressed in a third GIS layer.
  5. Overlaying the third map layer on the second layer is the first step in an iterative process leading to optimization. Given that biodiversity areas cannot be recreated, optimization will entail adjusting the development areas such that, for example, low-benefits development areas will not be overlain on high-value diversity areas. The optimization process, though, may be more complicated than just that.
  6. The major undertaking is step 2 above, namely the ranking of biodiversity and ecosystem services. This ranking has never been done in the study area in an objective, methodical manner, and ideally should be preceded by sufficient research. However, this fact should not discourage carrying out the exercise in current and future planning. Demand simply grows faster than the pace of the required research. It is therefore necessary to use existing knowledge, and improve the valuation as knowledge accumulates.

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×
Evaluation of Terrestrial Biodiversity and Ecosystem Services

The biota of an area can be evaluated by three criteria: its ability to provide ecosystem services; the number of species of realized and potential direct economic benefit that it includes; and its ability to absorb anthropogenic disturbances without loss in its ecosystem services or biodiversity (resistance), along with its potential for rehabilitation following disturbance (resilience; Safriel, 1987). Each of these criteria can be quantified by applying current knowledge, paradigms, or prevailing notions, as follows.

Provision of Ecosystem Services

Water-related ecosystem services depend on the property of the ecosystem and its placement within the watershed. Concerning properties, working hypotheses are that the larger the number of vegetation layers, the greater is the infiltration potential and the smaller the risk of soil erosion and intense surface runoff; and the larger the number of species, the greater the number of vegetation layers.

Although the exact number of species in most of the study area's ecosystems is not known, these ecosystems can still be ranked in species richness. Woodlands and scrublands, for example, are richer than rangelands in the number of their perennial species (in dry subhumid areas), and stabilized sand dunes are richer than salt pans (in semiarid and arid areas). Vegetation maps that depict the major plant formations, such as those just mentioned, are available for most parts of the study area (Zohary, 1973), and the numbers of their species are also available in various sources. It is therefore possible to rank all of these major plant formations of the area by their number of plant species.

With respect to the placement of the ecosystem within the watershed, the higher the elevation of an ecosystem within the watershed, the greater the value of its services. For example, loss of woodland at the top of a watershed, where rainfall in the area is more abundant, will generate more destructive floods, with a greater loss to aquifers, than similar loss at the bottom of the watershed. Ecosystems can therefore also be scored according to their elevation above the bottom of the watershed.

Species of Potential Economic Value

An ecosystem with a large number of species is also likely to have a relatively large number of species of potential economic significance. An ecosystem can be ranked by its number of species not only to evaluate its biodiversity, but also to assess the potential economic value of its biodiversity. Sometimes, it is even possible to identify particular species whose potential is already realized. The following groups of species can be ranked by their realized or potential economic value, the top rank being most valuable: (1) progenitors of

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

cultivated species; (2) wild relatives of cultivated species; (3) noncultivated species currently collected for nutritional, medicinal, ornamental, aromatic, energy production, and industrial purposes; (4) high-quality forage species; (5) low-quality forage species; (6) species represented by peripheral populations; (7) species already identified by IUCN revised criteria under the categories of vulnerable and rare (including species whose economic significance is not yet known, but whose extinction would prevent the discovery of their significance); (8) species of inspirational and recreational value (which often translate to economic benefits); (9) species of scientific interest (which also have economic value, including through scientific discoveries); and (10) species that provide or manipulate habitats for other species, or are ecosystem engineers (Jones et al., 1994). An ecosystem can be scored by the number of its species in each of the above categories, multiplied by the rank of the category.

Resistance and Resilience

Resilience and resistance are positively (but not linearly) correlated with area. The risk of extinction is reduced with greater population size, population size increases with area, number of species increases with area, and the large perimeter-to-surface ratio of small areas makes their species highly vulnerable to surrounding development. However, it is difficult to prescribe the threshold size for an area to be nonresistant or nonresilient. Hence, in the study area, which as a whole is small, the larger the area allotted to natural ecosystems, the better.

Rehabilitation of biodiversity and ecosystem services following disturbance is faster when there are sources of immigrants. These sources are other natural ecosystems, so their significance increases as they are closer to the disturbed area. The penetrability of the surrounding areas for propagules interacts with their distance: the greater the penetrability of the areas, the farther the propagules can travel. For example, for many species, an extensive surrounding agricultural area is more penetrable than a surrounding urban region.

To conclude, the most valuable ecosystem is one with highest number of species, many of which are of potential economic significance; one that performs unusual or particularly valuable services; and a large ecosystem, especially if it is connected by a corridor to another similar natural ecosystem.

Evaluation of Aquatic Biodiversity

The study area is relatively poor in aquatic ecosystems. Therefore, in evaluating biodiversity, a higher score should be attributed to areas that contain aquatic ecosystems, or to each aspect of an aquatic ecosystem,

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

than to a terrestrial ecosystem otherwise having the same scores. Thus, the value of an aquatic ecosystem in the study area with a given number of species will be higher than that of a terrestrial ecosystem of the same number of species and the same size. The following identifies some guidelines for evaluating aquatic ecosystems.

In their provision of ecosystem services and number of species, aquatic ecosystems can be ranked as follows from greatest to less great: lakes, wetlands, ephemeral ponds, springs, perennial rivers, and streams. The higher the elevation of an aquatic ecosystem within a watershed, the greater the value of its services. Aquatic ecosystems also affect biodiversity of adjacent terrestrial ecosystems, by providing water for terrestrial vegetation, and water and food for terrestrial fauna.

With respect to species' economic value, the category of forage species in the previous list of terrestrial ecosystems should be replaced by species of fisheries significance. Special features of aquatic ecosystems that confer resistance and resilience, apart from features described for terrestrial ecosystems, are the distance of the ecosystem from polluting sources, which should be great, and the existence of corridors, such as streams, between isolated water bodies.

Using these sets of rules, it should be possible to evaluate regional biodiversity, and to use this evaluation as a tool to determine the extent of desirable water-resource development, such that this development is sustainable. Even if knowledge is incomplete, any serious attempt to rank areas in this fashion is likely to lead to better decisions.

Recommendations

This chapter has shown that maintaining and enhancing ecosystem goods and services will help—not hinder—most aspects of economic development and welfare in the study area. These goods and services enhance the quality of life of the study area's inhabitants; and they are required to maintain environmental quality, including water quality. The chapter has shown that biological diversity is important as well, and protecting it is likely to protect the structure and functioning of ecosystems to achieve those benefits; maintaining ecosystem goods and services will also protect biodiversity. The two points above require that, in plans for providing and allocating water resources among various uses in the study area, a balance is needed among environmental, economic, and other objectives when they do not lead to the same priorities for water use.

Two types of recommendations follow. The first outlines the scientific information needed to better understand the relationships among ecosystem goods and services, ecosystem structure and functioning, and biodiversity, and also the information needed to assess the balances and

Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×

tradeoffs among various objectives. The second set of recommendations outlines ecologically based methods for improving the sustainability of water supplies, based on scientific information already in hand.

Research Recommendations

  1. Identify and quantify the services provided by each of the study area's ecosystem types, distinguishing between water-related services, and other services. Study and quantify the optimal and minimal water allocations (quantity and quality, in time and space) for each of these ecosystems to sustain the provision of each of their services.
  2. Determine which of the ecosystem types within the study area's landscapes play landscape-relevant keystone roles and investigate ways to maintain natural processes, and hence diversity at the landscape and region scale, while meeting the human demands of these landscapes.
  3. Identify species of the study area that are endangered or at risk of becoming endangered, assess the contribution of each to water-related ecosystem services, identify the causes for the endangerment of these species, and explore means to reduce the risks.
  4. Compare local water losses from evapotranspiration of natural and moderately managed major ecosystems of the study area to regional water gains from each of the ecosystem services, including increasing infiltration and reducing surface runoff and its associated topsoil erosion.
  5. Assess the study area's biodiversity components (species, ecotypes, and populations) of current and potential economic significance, especially in aquatic habitats and climatic transition zones inhabited by peripheral populations, and determine the water allocation and the land area and configuration required for their conservation.
  6. Assess the economic and biodiversity significance of the study area's indigenous dryland trees, especially the desert acacia, and the effects of current and potential relevant development projects (wells, dams, and roads) on the sustainability of the trees.
  7. Conduct long-term studies to evaluate the effects of damming stormwater on biodiversity at the lower reaches of watersheds, especially in hyperarid and arid regions, and use the results to prescribe amounts of water that must be released to reduce damages to downstream biodiversity.
  8. Evaluate the amount of water lost through regional appropriation of natural watersheds by agriculture and urban development, to generate guidelines for land use allocation in areas still not developed and for changes in current land use.
  9. Study the rate of extinctions of species populations in the study area resulting from fragmentation, transformation, and reductions in size
Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
×
    1. of natural ecosystems, and use the results to provide guidelines for water management and related development projects.
    2. Evaluate the amounts of water allocated to nature reserves and other ways of protecting biodiversity that go to recharging aquifers after these uses.
    3. Study the role of the area's natural ecosystems in treating wastewater of various quality, the degree to which freshwater allocated to natural ecosystems can be replaced by treated wastewater, and the technologies appropriate for this substitution.
    4. Conduct the research required to define improved criteria for evaluating the significance of the area's biodiversity in providing ecosystem goods and services.
    5. Operational Recommendations

      1. The sustainability of water supplies requires that the area's natural ecosystems be treated as one of the legitimate users of the study area's water resources.
      2. Because water-resource development and the further development it promotes can damage biodiversity and therefore impair the provision of ecosystem services, development in the study area should be carried out so that the gains of water-resource development clearly outweigh lost ecosystem services and reduced biodiversity.
      3. Precise objectives should be set for all aquatic, riparian, and other water-dependent sites in the study area, specifying the type of biodiversity to be maintained and the type of ecosystem service the site can provide and whose continuance should be ensured. These objectives should be used to determine the minimal required allocation of water quantity and quality. Indicators, benchmarks, and monitoring programs for each water-allocation site should be developed to review and update the allocations.
      4. In future land-use planning, as in water-resource planning, the benefits of proposed developments should be evaluated against the cost of lost biodiversity and reduction of ecosystem services.
      5. When the study area's climatic transition areas (rich in within-species or genetic diversity), as well as other areas rich in progenitors and relatives of domestic crops, are targeted for water-driven development, it would be prudent to consider setting aside within them protected areas sufficiently large to serve as repositories of genetic resources.
      6. The costs and benefits of avoiding, reducing, or mitigating the effects of fragmentation of natural ecosystems should be considered when planning water development and allocation and the additional development they promote.
    Suggested Citation:"4 Water and the Environment." National Academy of Sciences. 1999. Water for the Future: The West Bank and Gaza Strip, Israel, and Jordan. Washington, DC: The National Academies Press. doi: 10.17226/6031.
    ×

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    This book is the result of a joint research effort led by the U.S. National Academy of Sciences and involving the Royal Scientific Society of Jordan, the Israel Academy of Sciences and Humanities, and the Palestine Health Council. It discusses opportunities for enhancement of water supplies and avoidance of overexploitation of water resources in the Middle East. Based on the concept that ecosystem goods and services are essential to maintaining water quality and quantity, the book emphasizes conservation, improved use of current technologies, and water management approaches that are compatible with environmental quality.

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