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There is a common myth that deserts are extremely sensitive to perturbation. While it is true that tracks made decades ago can still be seen in certain desert areas, there are also large regions of deserts that show little negative impact of heavy use by humans. This paradox can be explained by considering the interactions between the high spatial and temporal variability in rainfall, and patterns of human disturbance. Desertification is of great concern in many parts of the world, yet people struggle to define it. Losses of agricultural productivity are associated with the process of desertification, although these can have other causes such as declining returns from certain agricultural products. Indeed, it is the long-term declines in productivity and ecosystem function that are most closely tied to desertification. These are usually caused by direct human intervention.

This chapter examines how geology and climate create vastly different groundwater situations. Effective management of groundwater depends upon full consideration of these differences. The chapter begins with a distinction between confined and unconfined aquifers and a look at artesian wells, with a focus on Australia’s Great Artesian Basin. The characteristics of different rock types are illustrated by four basic aquifer rock types in sub-Saharan Africa. The chapter then turns to non-renewable aquifers in North Africa and Saudi Arabia. The fast-recharging Edwards Aquifer in Texas then provides a quite different story with its sensitivity to short-term climate variability and concerns about endangered species. The chapter concludes with a discussion of saltwater intrusion in coastal aquifers and the potential of brackish groundwater for water supply.

Ultramafic rocks come from deep within the earth. Most rocks on the surface of the earth are quite different from them. Unique rocks make unique soils and support special plants. Exploring the links and interactions among these unique rocks, soils, and vegetation is an interdisciplinary endeavor that has been accomplished by experts in three areas. It has helped elucidate serpentine rock–soil–plant relationships and provide a rationale for the unusual soil properties and vegetation associated with ultramafic rocks. Examples from arctic tundra to temperate rainforest and hot desert in western North America provide a framework for the investigation of serpentine geoecosystems around the world. The unusual character of most serpentine vegetation is readily apparent even to an untrained eye. Although a vast number of rock and soil types make up the earth’s surface, few have as dramatic and visible effects on ecosystems as do ultramafic, or serpentine materials. Most ultramafic rocks in western North America have been derived from the mantle of earth via ocean crust. Magnesium is highly concentrated in the mantle and calcium, potassium, and phosphorous are relatively low. Calcium and potassium are further depleted from peridotite in the partial melting of ultramafic rock at the base of the ocean crust. As oceanic plates drift from spreading centers, most of the ocean crust is subducted and returns to the mantle (chapter 2). Only relatively small fragments of ocean crust are added to the continents. Because eukaryotic organisms, from protozoa to plants and animals, have evolved on continental crust, they are adapted to soils with higher concentrations of calcium, potassium, and phosphorus (elements with higher concentrations in continental crust than in ultramafic rocks from the base of the ocean crust) and much lower concentrations of magnesium. Having evolved on continents, plants depend on relatively high ratios of calcium and potassium to magnesium, elements that they use for a wide range of physiological functions. Although there has been a long history of evolutionary adaptation to the chemistry of the continental crust, special adaptations have allowed some plants to colonize the atypical conditions of serpentine.

Water is continuously cycled from the atmosphere through geoecosystems to water bodies and, by evaporation and evapotranspiration, back to the atmosphere. Water is commonly transported long distances in the atmosphere. Eventually, it forms clouds that drop rain, snow, or dew on plants or the ground. The contributions of fog and dew to geoecosystems are generally minor, but they can be important factors along some coastlines. Water from most of the precipitation that falls to the ground infiltrates soils. Some is intercepted by plants and evaporates before it can reach soils, and some runs overland to streams without entering soils. Soils are important stores of water for plants. Excess water in soils and permeable substrata drains gradually. This gradual draining of infiltrated water diminishes flooding from storms and supplies water to streams between rainfall events, helping maintain more constant stream levels. The study of meteoric water, or water that is cycled through the atmosphere, is called “hydrology.” Watersheds are basic units of hydrological investigations. A watershed is a drainage basin—an area from which water drains to a common point. All water falling on a watershed (and not lost by evapotranspiration) leaves through a single, joint location that can be monitored with a stream gauge. There are exceptions, however, in which water drains from watersheds through permeable substrata, rather than at the lowest point in the ground surface topography. These “leaky” watersheds are common in basalt, poorly consolidated sandstone, and limestone terrains. We can examine some of the data from watersheds that are not known to be leaky to learn about the runoff characteristics of serpentine streams and their chemistry. Watersheds range in size from less than a hectare to large portions of continents (e.g., the Amazon River drains 6,475,000km2, about 35% of the South American continent). The smaller watersheds are drained by headwater streams with no tributaries, and the larger ones are drained by streams with many tributaries. Some of the most useful information can be gained from small watersheds because they have more uniform lithology, topography, soils, climate, and vegetation than larger ones.

The natural geography of the 50 states varies tremendously, supporting an equally varied suite of wild species—from flocks of tropical birds in southern Florida to caribou migrations across the Alaskan tundra. The geography of risk, too, varies across the nation, reflecting the interaction between natural and human history. Similarly, present-day land and water uses will largely determine the future diversity and condition of the flora and fauna. We can learn much, though, from looking at the current condition of a state’s biota, since this both reflects the past and helps illuminate the future. A state’s ecological complexion and the evolutionary history of its biota are the primary determinants of its biological diversity. These environmental factors have encouraged spectacular diversification in many regions: for instance, the freshwater fish fauna in the Southeast, the magnificent conifers along the Pacific cordillera, and the small mammal assemblages of the arid Southwest. Conversely, geological events such as the expansion and contraction of the ice sheets have left other areas of the country with a more modest array of species. States, however, are artificial constructs laid out on the landscape’s natural ecological patterns. While some state lines follow natural boundaries, such as shorelines or major rivers, most cut across the land with no sensitivity to natural features or topography. Nonetheless, urban and rural dwellers alike identify with the major ecological regions within which they live, and this is often the source of considerable pride. Montana is “big sky country,” referring to the vast open plains that sweep up against the eastern phalanx of the Rocky Mountains. California’s moniker “the golden state” now refers more to its tawny hills of summer—unfortunately at present composed mostly of alien species—than to the nuggets first found at Sutter’s Creek. Maryland, home of the Chesapeake Bay, offers the tasty blue crab (Callinectes sapidus) as its unofficial invertebrate mascot. The list could go on, evidenced by the growing number of states that offer vanity license plates celebrating their natural environment. Natural features have always played a dominant role in determining patterns of settlement and land use.

Among shallow subterranean habitats, representative communities of hypotelminorheic (Lower Potomac seeps, Washington, DC), epikarst (Postojna–Planina Cave System, Slovenia), milieu souterrain superficiel (MSS) (central Pyrenees, France), soil (central Pyrenees, France), calcrete aquifers (Pilbara, Western Australia), lava tubes (Tenerife, Spain and Lava Beds National Monument, California), fluvial aquifers (Lobau wetlands, Austria), and iron-ore caves (Brazil) are described. Among non-cave deeper habitats, communities of phreatic aquifers (Edwards Aquifer, Texas), and deep phreatic aquifers (basalt aquifers, Washington) are described. Among cave habitats, representative tropical terrestrial (Gua Salukkan Kallang, Sulawesi, Indonesia), temperate terrestrial (Mammoth Cave, Kentucky), chemoautotrophic (Peştera Movile, Romania), hygropetric (Vjetrenica, Bosnia & Herzegovina), anchialine (Šipun, Croatia), cave streams (West Virginia and U.K.) and springs (Las Hountas, Baget basin, France) communities are discussed.

Cheap meat, dairy, and eggs are an illusion—we pay for each with depleted forests, polluted freshwater, soil degradation, and climate change. Diet is the most critical decision we make with regard to our environmental footprint—and what we eat is a choice that most of us make every day, several times a day. Dietary choice contributes powerfully to greenhouse gas emissions (GHGE) and water pollution. Animal agriculture is responsible for an unnerving quantity of greenhouse gas emissions. Eating animal products—yogurt, ice cream, bacon, chicken salad, beef stroganoff, or cheese omelets—greatly increases an individual’s contribution to carbon dioxide, methane, and nitrous oxide emissions. Collectively, dietary choice contributes to a classic “tragedy of the commons.” Much of the atmosphere’s carbon dioxide (CO2) is absorbed by the earth’s oceans and plants, but a large proportion lingers in the atmosphere—unable to be absorbed by plants or oceans (“Effects”). Plants are not harmed by this process, but the current overabundance of carbon dioxide in the atmosphere causes acidification of the earth’s oceans. As a result of anthropogenic carbon dioxide emissions, the “acidity of the world’s ocean may increase by around 170% by the end of the century,” altering ocean ecosystems, and likely creating an ocean environment that is inhospitable for many life forms (“Expert Assessment”). Burning petroleum also leads to wars that devastate human communities and annihilate landscapes and wildlife—including endangered species and their vital habitats. Additionally, our consumption of petroleum is linked with oil spills that ravage landscapes, shorelines, and ocean habitat. Oil pipelines run through remote, fragile areas—every oil tanker represents not just the possibility but the probability of an oil spill. As reserves diminish, our quest for fossil fuels is increasingly environmentally devastating: Canada’s vast reserves of tar sands oil—though extracted, transported, and burned only with enormous costs to the environment—are next in line for extraction. Consuming animal products creates ten times more fossil fuel emission per calorie than does consuming plant foods directly (Oppenlander 18). (This is the most remarkable given that plant foods are not generally as calorically dense as animal foods.) Ranching is the greatest GHGE offender.

In May 1970, Look magazine ran an International Paper Company advertisement, “The Story of the Disposable Environment,” which envisioned a time when “the entire environment in which [we] live” would be discarded. “Colorful and sturdy” nursery furniture “will cost so little, you’ll throw it away when [your child] outgrows it,” the ad enthused, adding for the socially conscious, “experimental lowbudget housing developments of this kind are already being tested.” International Paper never addressed where the disposable housing, furniture, and hospital gowns, or the toxic chemicals used for processing raw materials and manufacturing products— or the fossil fuel emissions—would end up. More than 30 years later, we live with the consequences of that vision, which has transmuted the real environment that we depend on into a nightmarish one, dominated by colossal and increasingly hazardous wastes. For nearly all of human history and prehistory, people dropped their wastes where they lived, expecting the discards would largely disappear. When wastes were relatively minor and all natural materials, many of them did disappear through “natural attenuation”—the diluting or neutralizing effects of natural processes. But even after tens of thousands of years, many items in ancient garbage remain recognizable, and poking through prehistoric dumps can reveal significant details about long-gone people and their ways of life. History shows that soils and waters have limited capacities for processing even natural wastes. Garrett Hardin underscored these lessons in his 1968 essay “The Tragedy of the Commons.” From Roman urbs urbii (cities) to nineteenth-century industrial complexes, the refuse dumped in and around larger population centers issued foul odors and helped spread diseases. Public health concerns eventually forced towns and cities to provide sewers, “sanitary” dumps, water treatment, and more recently, sewage treatment. Nowadays, however, our sewers and dumps receive a sizable proportion of synthetic chemicals with unknown properties as well as millions of tons of toxic wastes, hazardous to humans and other living things.

In recent years, we have become increasingly aware of the importance of water as a critical good, and questions of water supply, access, and management, both in quantitative and qualitative terms, have become key issues (Gleick 1993; Postel 1992; Stauffer 1998). The proliferating commodification and privatization of water management systems; the combination of Global Environmental Change with increased demands from cities, agriculture, and industry for reasonably clean water; the inadequate access of almost a billion people on the planet to clean water (over half of whom live in large urban centres); the proliferating geopolitical struggle over the control of river basins; the popular resistance against the construction of new megadams; the political struggles around water privatization projects; and many other issues; have brought water politics to the foreground of national and international agendas (Shiklomanov 1990; 1997; Herrington 1996; Roy 2001). In the twentieth century, water scarcity was seen as a problem primarily affecting developing societies (Anton 1993). However, at the turn of the new century, water problems are becoming increasingly globalized. In Europe, the area bordering the Mediterranean, notably Spain, southern Italy, and Greece, is arguably the location in which the water crisis has become most acute, both in quantitative and qualitative terms (Batisse and Gernon 1989; Margat 1992; Swyngedouw 1996a). However, northern European countries, such as the UK, Belgium, and France, have also seen increasing problems with water supply, water management, and water control (Haughton 1996), while transitional societies in eastern Europe are faced with mounting water supply problems (Thomas and Howlett 1993). The Yorkshire drought in England, for example, or the Walloon/Flemish dispute over water rights are illuminating examples of the intensifying conflict that surrounds water issues (Bakker 1999). Cities in the global South and the global North alike are suffering from a deterioration in their water supply infrastructure and in their environmental and social conditions in general (Lorrain 1995; Brockerhoff and Brennan 1998). Up to 50% of urban residents in the developing world’s megacities have no easy access to reasonably clean and affordable water. The myriad socioenvironmental problems associated with deficient water supply conditions threaten urban sustainability, social cohesion, and, most disturbingly, the livelihoods of millions of people (Niemczynowicz 1991).

This chapter describes the extent and formation of karst in Kentucky: how the dissolution of limestone by water shapes the underground and surface of over half of Kentucky; the ways that hydro geologists map karst aquifers, including illustrative examples. The beauty of caving in the Mammoth Cave area and throughout Kentucky karst is illustrated. The special challenges of construction and development on karst are discussed: karst flooding, cover-collapse sinkholes, maintaining water quality in karst.

Kentucky’s waterways carry a history of the landscape as well as life-sustaining water. Watersheds are any area of land draining water to a common water body, and the quality of the water body reflects human activity and natural processes. The Cane Run watershed is a polluted watershed in central Kentucky. A watershed-based plan was created by investigating the current status of the watershed and making plans to improve its conditions. Some progress has been made to improve the Cane Run watershed. Effective watershed-based plans require scientific inquiry as well as social considerations of the citizens in the watershed.

Much natural capital is common property – owned by no one. Important examples are water and fish. Such property is generally greatly overused – the lamentable histories of the American bison and the passenger pigeon illustrate the power of this tendency. Commercially valuable fish are today going through the same process. But there are ways of avoiding this, by establishing property rights or in other ways limiting access and usage. Such mechanisms have worked well for some fisheries and some aquifers, but fishing on the high seas is still out of control.

The chapter begins with looking at ways humans have dealt with drought—praying for rain, hiring a rainmaker, or hoping for the best. After World War II, the widespread availability of rural electrification, the deep turbine pump, and center pivot irrigation gave people the option of large-scale use of groundwater. This chapter provides an overview of how groundwater development has radically improved water and food security. The discussion then moves to the growing problems that have resulted from groundwater overuse in places such as the High Plains (Ogallala) Aquifer and the North China Plain. Recently, the GRACE (Gravity Recovery and Climate Experiment) satellites, which can provide precise estimates of changes in groundwater storage over very large areas, have helped draw attention to groundwater depletion around the world.

Managed aquifer recharge is a widespread and growing practice. In addition, using recycled water for groundwater recharge and water supply continues to grow as water resources are increasingly strained by population growth and climate change. Through a series of examples from around the world, the chapter illustrates the value as well as limitations of managed aquifer recharge and recycled water.

Virtually all chemicals that humans use can find their way into groundwater. The cost of aquifer protection through proper handling and disposal of hazardous chemicals is miniscule compared to the ongoing costs of trying to clean up a contaminated aquifer—if it’s even possible. This chapter provides historical background on major chemical pollutants and examines key difficulties surrounding chemical contamination and remediation of groundwater with examples from throughout North America.

The difficulties of determining who has the right to use groundwater and how much they can pump becomes even more complicated for aquifers that cross international boundaries. The chapter discusses the few countries that have made progress in addressing transboundary aquifer issues. The chapter also provides a brief history of the Transboundary Aquifer Assessment Program along the U.S.-Mexico border to illustrate key concepts and challenges.