Geography
Water Cycle
The water cycle is the continuous movement of water on, above, and below the surface of the Earth. It involves processes such as evaporation, condensation, precipitation, and runoff, which contribute to the circulation and distribution of water throughout the planet. This natural system plays a crucial role in regulating Earth's climate and supporting various ecosystems.
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11 Key excerpts on "Water Cycle"
- Karrie Lynn Pennington, Thomas V. Cech(Authors)
- 2021(Publication Date)
- Cambridge University Press(Publisher)
We saw for the first time a beautiful sphere of blue water, white clouds, and the browns and greens of our world floating in space. It was, and still is, a breath-taking image. We learned in elementary school that frozen and fluid water covers about 75 percent of the Earth’ s surface. That photograph from space made this simple fact come to life. The concepts regarding water’ s existence “all the time and everywhere” are explained by considering the three phases (stages) of water – liquid, solid, and gas, in the context of the hydrologic cycle. We’ re all familiar with this concept. 3.2 The Hydrologic Cycle The hydrologic cycle describes the continuous movement of water on the Earth’ s surface, through the Earth’ s soils and geologic materials, and into the atmosphere. It is the process of how water moves on, in, and above the Earth (see Figure 3.1). All water on Earth is constantly reused, recycled, and purified in this process. This dynamic water system is powered by energy from the Sun, which drives a continuous exchange of water molecules between the atmosphere, oceans, and the land. The major components of the hydrologic cycle are evaporation (vaporization), transpiration, condensa- tion, precipitation, runoff, infiltration, percolation, and storage [3]. Since the hydrologic cycle is circular, we can start our discussion anywhere – so we’ll start with the atmosphere. The most recognizable chemical formula is that of water, H 2 O, a strongly bonded combination of two atoms of hydrogen and one of oxygen. The cycling of water is linked with energy exchanges between the atmosphere, oceans, and land. The hydrologic cycle is important in determining both weather and weather variability. We know that water moves easily between its three phases and there are energy transfers during the phase changes (see Figure 3.2). Through a phase change, the energy input is used to overcome the intermolecular attraction (IMF) of the water molecules.
eBook - PDFHydrology and Hydroclimatology
Principles and Applications
- M. Karamouz, S. Nazif, M. Falahi(Authors)
- 2012(Publication Date)
- CRC Press(Publisher)
93 4 Hydrologic Cycle Analysis 4.1 INTRODUCTION Water exists on Earth in all its three states, liquid, solid, and gas, in various degrees of motion. Evaporation of water from water bodies such as oceans and lakes, formation and movement of clouds, rain and snowfall, streamflow, and groundwater movement are some examples of the dynamic aspects of water. The various aspects of water related to the Earth can be explained in terms of a cycle known as the hydrologic cycle. A brief system description of hydrologic cycle was presented in Chapter 2 (see Figure 4.1). The hydrologic cycle generally includes the water interac-tion between the atmosphere and the Earth, namely, precipitation, infiltration, evaporation, and evapotranspiration, as well as water movement and storage on and under the surface of the Earth, namely, surface runoff, subsurface flow, groundwater flow, and reservoirs and lakes. In this chapter, first, an estimation of precipitation, evaporation, evapotranspiration, and infiltra-tion and excess rainfall calculation are discussed. Analysis of surface runoff and subsurface flows is addressed in detail in Chapter 6, and details of groundwater flow are described in Chapter 7. Furthermore, in this chapter, water balance in the hydrologic cycle is described. Finally, kriging as a method of regionalizing sample data is discussed. 4.2 PRECIPITATION Precipitation is a major element of the hydrologic cycle. The measurement of precipitation is very important; there are essentially three different methods for precipitation measurements: Measurement by standard gauges: This is the traditional and long-established method. Time series are developed using this method, and if the sampling location is moved, the time series should be adjusted. This method provides point measurements; thus, it may not be representative even for a small area. There are sampling error and poor spatial averag-ing as well as recording and instrument errors.
eBook - PDFPrinciples of Water Resources
History, Development, Management, and Policy
- Thomas V. Cech(Author)
- 2018(Publication Date)
- Wiley(Publisher)
The hydrologic cycle contains five key components: 1. Precipitation 2. Runoff 3. Surface and Groundwater Storage 4. Evaporation/Transpiration 5. Condensation PRECIPITATION Precipitation occurs when atmospheric moisture becomes too great to remain suspended in clouds. Under proper conditions, small, weakly linked mole- cules of water form droplets. These undergo a further process of coalescence, or joining together, and fall Herman Eisenbeiss/Science Source FIG. 2.3 Water striders are easy to identify by their long legs and lack of wings. They live and feed on the surfaces of ponds and other quiet water locations. A water strider relies on the surface tension of slow-moving or still water to move around and capture food. It can locate its prey by feeling vibrations on the water surface. Surface tension is also demonstrated on the International Space Station—http://apod.nasa.gov/apod/ ap130424.html. S I D E B A R Surface tension is essential for the transfer of energy from wind to water to create waves. Waves are necessary for rapid oxygen diffusion in lakes and seas. 3 For more information on surface tension and water (and why not to touch the surface of a rain- soaked tent), see http://water.usgs.gov/edu/surface- tension.html. THE HYDROLOGIC CYCLE 33 Precipitation Precipitation Groundwater Ocean Runoff Movement of moist air Condensation (cloud formation) Evaporation from ocean Transpiration from vegetation Evaporation from soil, streams, rivers, and lakes Percolation through soil and porous rock FIG. 2.4 This simplified diagram of the hydrologic cycle shows the pilgrimage of water as it makes its way from the Earth’s surface to the atmosphere, back to the land surface as precipitation, into rivers, lakes, soils or aquifers, or the ocean, and back to the atmosphere. All aspects of the cycle occur simultaneously, making it a remarkably simple yet complex subject of study.
eBook - PDFGroundwater Resources
Investigation and Development
- S Mandel(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
CHAPTE R 1 Overvie w of Term s and Concept s 1.1 GROUNDWATER AS PART OF THE HYDROLOGIC CYCLE Energy derived from the sun's radiation keeps the water on the earth's globe in a state of continual movement: from the oceans to the atmosphere by evaporation and vice versa by precipitation on oceanic surfaces; from the atmosphere to land and back by precipitation and evapotranspiration; and from land to the oceans by flowing surficial and underground waters. The term hydrologic cycle describes the sum of these global phenomena, although in reality only a small part of the global water traverses the full cycle from the ocean to atmosphere, to land, and back into the ocean. Figure 1.1a pictures the hydrologic cycle in the form of a system that is activated by an input, the sun's radiation, and produces an output, water flowing across the landmasses into the ocean. The global system thus defined can be applied only to the study of vast areas. In order to obtain detailed information of practical value, it is necessary to focus attention on a selected part of the hydrologic cycle. The part of the hydrologic cycle that transforms precipitation into flowing surficial and underground waters is shown in Fig. 1.1b. One part of the precipitation generates the surface runoff component of streamflow; another part percolates to the saturated portion of an aquifer and reappears on the surface in the form of springs and seepages, or drains underground directly into the ocean. Streams and aquifers are often interconnected by the seepage of water from the riverbed into the aquifer or vice versa. A third, é sola r radiatio n (input ) hea t heat , photosynthesi s Í evaporatio n precipitatio n wette d surfac e • evap o -transpiratio n runof f storag e in river s an d lake s infiltratio n storag e a s soi l moistur e seepag e fro m river s percolatio n stream f lo w storag e in saturate d aquife r Fig. 1.1 (a) The hydrologic cycle, (b) terrestrial part of the hydrologic cycle.
eBook - PDF- Peter Krenkel(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
6 The Dynamics of the Water Cycle THE HYDROLOGIC CYCLE The hydrologic cycle represents the basic source of water for all uses and is essential for maintaining life. Water is not only a building block for all living forms of life on earth, but it also supplies nutrients and accepts wastes. Undoubtedly, it is the most important component of the earth's ecological system. Most pollutants are transported to the place of their disposal via some phase of the hydrologic cycle. The hydrologic cycle can be visualized as a permanent routing of water from its largest pool—the oceans—to dry lands and back. It starts with water evaporating from the oceans, and then cloud formation and movement carry it to the land whence precipitation occurs and causes flow on and into the dry land surfaces (Fig. 6.1). During its travel, water accepts various contaminants and salts, a part of which are ultimately deposited back into the ocean. THE WATERSHED OR RIVER BASIN Water quality planning, research, and analysis of many environmental problems require a working unit which can be represented in system anal-156 The Watershed or River Basin 157 Fig. 6.1. The hydrologic cycle (Linsley et al., 1949). 158 6 The Dynamics of the Water Cycle ysis approach terms by a black box concept. The black box repre-sents a system for which the inputs and outputs are known or investigated and which can be described by a set of input-output relationships. This system should have a distinct boundary which would distinguish it from other surrounding systems. The best representation of such a system in hydrology and water quality management is a watershed or a drainage basin. A watershed has distinct advantages to other hydrologic and/or water quality system representations such as government territorial units. These usually have hydrologic and water quality inputs which may be dis-tributed to several output locations described by several system input-output relationships.
eBook - PDFThe Blue Planet
An Introduction to Earth System Science
- Brian J. Skinner, Barbara W. Murck(Authors)
- 2011(Publication Date)
- Wiley(Publisher)
8 C H A P T E R O V E R V I E W In this chapter we: ■ Look at the reservoirs and pathways of the hydrologic cycle and how the hydrosphere interacts with other parts of the Earth system ■ Describe how water flows in channels and is stored on the surface ■ Examine flooding, its prediction, and its impacts on human interests ■ Describe the occurrence and movement of water under the ground ■ Consider society’s dependence on water as a resource The Hydrologic CYCLE Water on Earth’s surface The energy of flowing water is evident in this torrent pouring over the Atatürk Dam on the Euphrates River near Adiyaman, Turkey. 224 PART THREE • THE HYDROSPHERE: EARTH’S BLANKET OF WATER AND ICE The most familiar cycle of the Earth system is surely the hydrologic cycle, which describes the fluxes of water between the various reservoirs of the hydrosphere, the totality of Earth’s water on and just below the surface. We are familiar with these fluxes because we experience them as rain and snow or as a wet pavement drying by evapora- tion, and we see water moving and stored on the surface in streams, lakes, and wetlands. The movements of water through the hydrologic cycle and the important roles of water in the Earth system are the focus of this chapter. WATER AND THE HYDROLOGIC CYCLE Water in the atmosphere and large bodies of surface water play a central role in moderating temperature and control- ling climate. They are the source of much of the water vapor in the atmosphere, and they store heat energy, exchanging it with the atmosphere. Another important consequence of the hydrologic cycle is the great diversity of Earth’s landscapes. The erosional and depositional effects of streams, waves, and glaciers, coupled with tec- tonic movements, have produced landscapes that make Earth’s surface unlike that of any other planet in the solar system. Through its effects on erosion and sedimentation, the hydrologic cycle is intimately related to the rock cycle (FIG. 8.1).
eBook - PDFHydrology
A Science of Nature
- Andre Musy, Christophe Higy, Andre Musy, Christophe Higy(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
A fraction of this water may be in-tercepted before it reaches the ground either by evaporating again, or encountering an obstacle (plant, roof, etc) that slows its eventual return to the soil. The fraction of the precipitation that actually reaches the soil can, depending on actual physical and also thermodynamic conditions, either penetrate the soil (infiltration) or flow over the sur-face under the effect of gravity. The infiltrated water can either be stored temporarily in the soil or percolate deeper, helping to replenish underground aquifers. Finally, the water that flows on the surface becomes part of a river and eventually a body of water such as a lake or ocean, before evaporating again into the atmosphere. Meanwhile, the water that infiltrated the soil either returns to the surface via capillary rise, or is taken up by vegetation and released into the air through transpiration. Hydrology: A Science of Nature 37 Figure 2.10 is a diagram of this complete Water Cycle. We can see immediately that the Water Cycle can be divided into two main parts: the “terrestrial” cycle and the “oceanic” cycle. The oceanic cycle only includes the amount of flow that enters the ocean and does not describe the actual processes that occur in the ocean. As well, the oceans only supply water to the Water Cycle as a result of evaporation; no transpiration 2 or interception occurs. Before we discuss in detail the various elements of the hydrological cycle (in chapters 4, 5, 6, and 10), we will use the following section to define the principles of a quantitative description before describing flow and the different reservoirs in the Water Cycle. 2.3.4 General Principles of a Quantitative Description As we have mentioned, the Water Cycle can be divided into three essential phases: evaporation, precipitation, and surface and groundwater flow. These three phases include the phenomena of transport, temporary storage, and sometimes the change between phases.
eBook - PDF- Ian Clark(Author)
- 2015(Publication Date)
- CRC Press(Publisher)
121 5 Tracing the Water Cycle INTRODUCTION The hydrological cycle pumps over 1000 km 3 of freshwater each day to the conti-nents, the equivalent of 2000 Niagara Falls. Of this, over 90% is transpired back to the troposphere. Most of the balance runs off over the surface or infiltrates into soils and aquifers, ultimately discharging some 75 km 3 of freshwater to the oceans each day. Surface water discharge is extensively monitored for flood control, hydroelec-tric generation, and water resources management. Groundwater resources are also monitored with test wells installed in major aquifers to monitor water levels, rates of recharge, and water quality. These major components of the hydrological cycle are shown in Figure 5.1. In groundwater resource and contamination studies, questions of groundwater origin and subsurface history are important. Physical parameters such as ground-water level fluctuations when interpreted in together with rainfall and temperature data are fundamental to water resource evaluation. Isotopes provide a complemen-tary tool for distinguishing different water sources and recharge areas. The natural isotopes 18 O and D are an intrinsic component of the water molecule and so are ideal tracers. They are selectively partitioned at each step of the hydrological cycle, from primary evaporation over the oceans, through condensation and precipitation to groundwater recharge and runoff back to the seas. The principal hydrological processes that affect the distribution of isotopes through the hydrological cycle include the following: 1. Evaporation and formation of atmospheric vapor 2. Condensation and rainout with decreasing temperature 3. Reevaporation from soils and surface waters, which enriches the residual water in both isotopes 4.
- Claude G Manoli, Richard C Ragaini(Authors)
- 2005(Publication Date)
- World Scientific(Publisher)
8. WATER AND POLLUTION This page intentionally left blank This page intentionally left blank OVERVIEW OF THE HYDROLOGIC CYCLE AND ITS CONNECTION TO CLIMATE: DROUGHTS AND FLOODS BISHER IMAM, SOROOSH SOROOSHIAN Center for Hydrometeorology and Remote Sensing University of California, Irvine, USA INTRODUCTION Water is both ubiquitous and important to life on Earth. Through the hydrologic cycle, the occurrence, circulation, and distribution of water in various compartments of the Earth's system, affect the life of the world's increasing population. While oceans hold more than 96.5% of the global water (Shiklomanov and Rodda, 2003), fresh water, which represents a minor fraction (2.53%), is distributed among various reservoirs (Figure 1). The interplay between gravity and solar energy are the primary mechanisms forcing the lateral and vertical movement of waters between these reservoirs and across their interfaces. From the hydrologic point of view, precipitation is the key hydrologic variable linking the atmosphere with land surface processes, and plays a dominant role in both weather and climate. Three fourths of the heat in the atmosphere is contributed by the global release of latent heat (Kummerow et. al., 1998, 2000), while the distribution of water vapor and clouds control the radiation balance. Regional precipitation plays a major role in weather patterns and is, of course, the major renewable source of fresh water (both liquid and frozen). Too much precipitation, or too little, can cause significant damage to life and property through floods and droughts. These two extremes, caused by climatic fluctuations, have been constant concerns to societies since the dawn of humanity. Such concern is exemplified in the Pliny the Elder (23-79 AD) words describing the role of the River Nile in regulating the livelihood of ancient Egyptians: The country has reason to make careful note of either extreme.
eBook - ePubGlobal Hydrology
Processes, Resources and Environmental Management
- J. A. A. Jones(Author)
- 2014(Publication Date)
- Routledge(Publisher)
Atmosphere, weather and climate. London, Routledge: 392pp.Mason B J 1962 Clouds, rain and rainmaking. Cambridge, Cambridge University Press. A classic and readable introduction.Present and past states of the hydrological cycle are discussed in:Street-Perrott A, M Beran and R Radcliffe (eds) 1983 Variations in the global water budget. Dordrecht, Reidel: 518pp.Solomon S J, M Beran and W Hogg (eds) 1987 The influence of climate change and climatic variability on the hydrologic regime and water resources. Wallingford, International Association of Hydrological Sciences Pub. No. 168: 640pp.UNESCO 1978 World water balance and water resources of the Earth. Paris, UNESCO: 663pp. World maps and detailed explanatory book.Discussion topics 1. Outline the main factors that control the intensity and spatial distribution of any one hydrological component. 2. Consider the differences in the fluxes and geography of the hydrological cycle between an ice age climate and the present day. 3. Discuss the importance of accurate assessments of hydrological fluxes and an adequate understanding of exchange processes for the sound exploitation of water resources.
- Bradley Striebig, Adebayo Ogundipe, Maria Papadakis, , Bradley Striebig, Adebayo Ogundipe, Maria Papadakis, , Bradley Striebig, Adebayo Ogundipe, Maria Papadakis(Authors)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 138 C H A P T E R 3 Biogeochemical Cycles F I G U R E 3 . 1 6 Estimated effective rainfall in June in the United States. Source: Based on NOAA Normal P minus June 2012 PE (inches) 2 7.79 to 2 5.00 2 4.99 to 2 4.00 2 3.99 to 2 3.00 2 2.99 to 2 2.00 2 1.99 to 2 1.00 2 0.99 to 0.00 0.01 to 1.00 1.01 to 2.09 composed of very fine, lightweight water droplets. These droplets may collide and combine to form larger droplets that may eventually grow large enough to produce precipitation. 3.6 Precipitation Water moves from the atmosphere to the surface of the planet through precipitation. Precipitation may occur when the atmosphere becomes completely saturated with water (100% humidity) and the droplets have enough mass to fall from the atmo-sphere. Evaporation from the oceans and eventual cooling of the water vapor from the oceans account for approximately 90% of the Earth’s precipitation. Locations near the oceans generally receive greater rainfall than those in the interior of the continents as illustrated in Table 3.4. Variation in precipitation patterns is shown in Figures 3.17 to 3.21. However, some areas, such as the desert highland of Chile, are the most arid in the world, even though they are not far removed from the Pacific Ocean. Ocean currents, weather patterns, latitude, and geography are important influences on precipitation patterns. Some fraction of precipitation seeps into the ground through a process called infiltration . Groundwater tables are replenished and sustainable when the rate of infiltration is equal to or greater than the rate of withdrawal from the groundwater table.
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