Geography
Hydrological Processes
Hydrological processes refer to the movement, distribution, and quality of water on Earth. These processes include precipitation, evaporation, transpiration, infiltration, runoff, and groundwater flow. They play a crucial role in shaping landscapes, influencing ecosystems, and impacting human activities such as agriculture, industry, and urban development. Understanding hydrological processes is essential for managing water resources and addressing environmental challenges.
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11 Key excerpts on "Hydrological Processes"
eBook - PDF- Larry W. Mays(Author)
- 2019(Publication Date)
- Wiley(Publisher)
Chapter 7 Hydrologic Processes 7.1 INTRODUCTION TO HYDROLOGY 7.1.1 What Is Hydrology? The U.S. National Research Council (1991) presented the following definition of hydrology: Hydrology is the science that treats the waters of the Earth, their occurrence, circulation, and distribution, their chemical and physical properties, and their reaction with the environment, including the relation to living things. The domain of hydrology embraces the full life history of water on Earth. For purposes of this book we are interested in the engineering aspects of hydrology, or what we might call engineering hydrology. From this point of view we are mainly concerned with quantifying amounts of water at various locations (spatially) as a function of time (temporally) for surface water applications. In other words, we are concerned with solving engineering problems using hydrologic principles. This chapter is not concerned with the chemical properties of water and their relation to living things. Books on hydrology include Bedient and Huber (1992); Bras (1990); Chow (1964); Chow, Maidment, and Mays (1988); Gupta (1989); Maidment (1993); McCuen (1998); Ponce (1989); Singh (1992); Viessman and Lewis (1996); and Wanielista, Kersten, and Eaglin (1997). 7.1.2 The Hydrologic Cycle The central focus of hydrology is the hydrologic cycle, consisting of the continuous processes shown in Figure 7.1.1. Water evaporates from the oceans and land surfaces to become water vapor that is carried over the earth by atmospheric circulation. The water vapor condenses and precipitates on the land and oceans. The precipitated water may be intercepted by vegetation, become overland flow over the ground surface, infiltrate into the ground, flow through the soil as subsurface flow, and discharge as surface runoff. Evaporation from the land surface comprises evaporation directly from soil and vegetation surfaces and transpiration through plant leaves. Collectively these processes are called evapotranspiration.
eBook - PDF- Larry W. Mays(Author)
- 2011(Publication Date)
- Wiley(Publisher)
Chapter 7 Hydrologic Processes 7.1 INTRODUCTION TO SURFACE WATER HYDROLOGY 7.1.1 What is Surface Water Hydrology? For purposes of this book we are interested in the engineering aspects of surface water hydrology, or what we might call engineering hydrology. From this point of view we are mainly concerned with quantifying amounts of water at various locations (spatially) as a function of time (tempo- rally) for surface water applications. In other words, we are concerned with solving engineering problems using hydrologic principles. This chapter is not concerned with the chemical properties of water and their relation to living things. Books on surface water hydrology include: Bedient, Huber, and Vieux (2008); Bras (1990); Brutsaert (2005), Chow (1964); Chow, Maidment, and Mays (1988); Gupta (2007); Maidment (1993); McCuen (2004); Ponce (1989); Singh (1992); Viessman and Lewis (2002); and Wanie- lista, Kersten, and Eaglin (1997). 7.1.2 The Hydrologic Cycle The central focus of hydrology is the hydrologic cycle, consisting of the continuous processes shown in Figure 1.1.1. Water evaporates from the oceans and land surfaces to become water vapor that is carried over the earth by atmospheric circulation. The water vapor condenses and precipi- tates on the land and oceans. The precipitated water may be intercepted by vegetation, become overland flow over the ground surface, infiltrate into the ground, flow through the soil as sub- surface flow, and discharge as surface runoff. Evaporation from the land surface comprises evapo- ration directly from soil and vegetation surfaces, and transpiration through plant leaves. Collectively these processes are called evapotranspiration. Infiltrated water may percolate deeper to recharge groundwater and later become springflow or seepage into streams, also to become streamflow. The hydrologic cycle can be viewed on a global scale as shown in Figure 1.1.2.
eBook - PDF- W.J. Mitsch, M. Straškraba, S.E. Jorgensen(Authors)
- 2012(Publication Date)
- Elsevier Science(Publisher)
2/ HYDROLOGIC PROCESSES FOR MODELS OF FRESHWATER WETLANDS Michael J. Duever The processes of a conceptual hydrologic model of a freshwa-ter wetland are reviewed in detail. The unique hydrologic characteristic of wetlands is their narrow range of water table fluctuation above and below the ground surface which is depen-dent upon regional climatic and topographic characteristics and local site characteristics (microtopography, soil, vegetation) that create the necessary water depths and durations of inundation. The dominant processes controlling the distribution of water include atmospheric circulation, precipitation, evapotranspira-tion, and surface and groundwater flows. Surface and ground-water flows involve different portions of the same water mass. This water mass can be subdivided into surface water and three groundwater components: an unsaturated zone above the water table, an unconfined saturated zone below the water table, and a confined saturated zone below an impermeable aquiclude. One or another of these subdivisions may not exist at some sites or at different times at the same site. Most hydrologic differences among the various types of wetlands and shallow water bodies are of degree rather than of kind. Introduction At the most general level, the hydrologic cycle is the circulation of water from the earth's surface to the atmosphere and back again. While physical processes predominate, biological processes can also significantly influence the pathways involved and the rates at which water moves. Precipitation reach-ing the earth's surface can evaporate from land or water surfaces, run off to the oceans as surface water, seep into the earth, or return to the atmosphere via plant 9 10 I Hydrologic Processes transpiration. The economic importance of water has resulted in the development of a tremendous amount of information on the factors that control its distribution and movement.
eBook - ePubGlobal Hydrology
Processes, Resources and Environmental Management
- J. A. A. Jones(Author)
- 2014(Publication Date)
- Routledge(Publisher)
CHAPTER 3 Hydrological Processes within the river basinTopics covered3.1 Evaporation and transpiration losses 3.2 Infiltration and soil moisture 3.3 Runoff-generating processes 3.4 GroundwaterThe drainage basin provides the natural framework for the generation of riverflow. As such, it is widely recognized as the natural unit for water management and for the scientific study of hydrological response. In most cases, the topographic divide that forms the periphery of the basin acts as an impermeable boundary, dividing the land surface into discrete units for generating runoff. Within each unit, runoff response is controlled by the general water balance:where evaporation includes transpiration from plants and AStorage is the change in the amount of water stored in the rocks and soil. Each of the components of the water balance is affected by certain properties of the land surface, but those which are land based are affected most. As the residual product of the water balance, runoff integrates the effects of topography, vegetation, bedrock and surface materials on the other components, and so it tends to be the most sensitive and the most variable.The drainage basin has been recognized as the essential unit of study since the earliest field experiments. For practical reasons most basins selected for detailed process studies have been relatively small (e.g. 0.1–10.0 km2 ). These have provided a wealth of information on the processes of runoff generation and the effects of surface properties on ‘hillslope hydrology’, i.e. the pathways of water loss or drainage from the land. Over the last decade or so, they have begun to provide equally detailed information on water quality processes.There are still many problems in extrapolating and integrating the information gained from small basins into hydrological models for larger catchment areas (Chapter 6
eBook - PDF- Kenneth N. Brooks, Peter F. Ffolliott, Joseph A. Magner(Authors)
- 2012(Publication Date)
- Wiley-Blackwell(Publisher)
Over time, a stream forms its channel by performing work. The amount of work that a stream can perform on its channel is the stream’s power. These concepts provide the foundation for our discussions on the processes of water flow though soils and in stream channels and the relationships of sediment flow and channel forming processes later in this book. SUMMARY AND LEARNING POINTS The hydrologic cycle represents the circulation of water on earth and is driven ultimately by solar radiation. Hydrologic processes involved in the hydrologic cycle involve changes in state of water and flows of water that are a function of the properties of water and the allocation of energy. Water circulates continuously over time; thus, the molecules of water 48 Part 1 Watersheds, Hydrologic Processes, and Pathways that you drink today may have at one time been stored in a snowpack in the Himalayan Mountains, or fallen as rain on Inca civilizations in the Andes Mountains centuries ago. Understanding the hydrologic cycle and its linkages to energy provide the foundation for the study of hydrology. After reading this chapter, you should be able to 1. Define the key processes in the hydrologic cycle. 2. Understand the concept and application of a water budget for a watershed. 3. Define and explain the components of an energy budget. 4. Know how an energy budget can be used to solve for components of the water budget. 5. Understand the properties of cohesion, adhesion, and capillarity of water and describe how they influence water potential and soil water movement. 6. Understand and explain the energy conditions that affect the flow of excess water in a watershed and stream channel. REFERENCES Anderson, H.W., Hoover, M.D. & Reinhart, K.G. (1976) Forests and water: Effects of forest management on floods, sedimentation, and water supply. USDA For. Serv. Gen. Tech. Rep. PSW-18. Hanks, R.J. & Ashcroft, G.L. (1980) Applied soil physics. New York: Springer. Hanks, R.J., Gardner, H.R.
eBook - PDFArid Land Irrigation in Developing Countries
Environmental Problems and Effects
- E. Barton Worthington(Author)
- 2013(Publication Date)
- Pergamon(Publisher)
SECTION III Influence of Irrigation on Hydrological Processes: Quantity and Quality This page intentionally left blank CHANGES IN Hydrological Processes by G. KOVÄCS 11 Fo-utca 48-50, Budapest, Hungary The main objective of any human activity since the beginning of the long history of tool-making was to develop and control the environment. This objective will never change, because it is a basic demand of mankind to ensure better and more comfortable living conditions. In the past, when only a small part of the world was populated and the demands were considerably lower than now, the changes introduced caused only slight modifications to nature, change of land use and the building of habitations. The ever-growing popula-tion gradually increased the areas influenced, and isolated units coalesced to form areas where human activity dominated nature. The relatively slow increase of man's influence was accelerated by rapid population expansion and development of the technical civilization, which started in the last century and reached a state in recent decades when its quantitative increase turned into qualitative change. Two basic causes initiated the problems arising from this new feature of develop-ment: the demand to have a truly comfortable way of living (the consumptive society) and the power and technical knowledge to execute large-scale modifications of natural conditions. Although any direct human influence has a positive objective—to raise the living standard of a given group of human beings, the actions and interactions may have un-desirable side effects which cause unexpected changes in the environment. They may initiate irreversible processes causing deterioration of the desirable balances of nature and it is for this reason that protection of the natural environment became one of the most im-portant and urgent tasks in our time. However, the phrase protection of the environment is not absolutely correct.
eBook - PDF- Franklin W. Schwartz, Hubao Zhang(Authors)
- 2023(Publication Date)
- Wiley(Publisher)
2 Hydrologic Processes at the Earth’s Surface CHAPTER MENU 2.1 Basin-Scale Hydrologic Cycle, 12 2.2 Precipitation, 15 2.3 Evaporation, Evapotranspiration, and Potential Evapotranspiration, 20 2.4 Infiltration, Overland Flow, and Interflow, 23 2.5 Simple Approaches to Runoff Estimation, 25 2.6 Stream Flow and the Basin Hydrologic Cycle, 30 2.7 Flood Predictions, 37 Water circulates on earth from the oceans to the atmosphere to land and back to the oceans in what is known as the hydrologic cycle. The main pathways in the hydrologic cycle are shown schematically in Figure 2.1. Water evaporates from oceans, lakes, and rivers into the atmosphere. This water vapor is transported with the atmospheric circulation and eventually falls as rain or snow onto land, lakes, rivers, and oceans. Of the water falling on land, some proportion quickly evaporates, some flows to streams or lakes as overland flow, and some infiltrates the subsurface. Of the water entering the soil, some is transpired back into the atmosphere by plants. The remaining water (i.e., groundwater) follows a subsurface pathway back to surface (Figure 2.1). Non-potable ocean water stored within the hydrologic cycle constitutes approximately 96.9% of the water (~1.34 million × 10 3 km 3 ). Another 1.91% (26,350 × 10 3 km 3 ) is frozen in icecaps and glaciers (Trenberth et al., 2007). Most of the world’s available fresh drinking water is stored as groundwater (1.1%, or 15,300 × 10 3 km 3 ). Although the quantity of water stored in rivers is relatively small, ~0.0132% or (178 × 10 3 km 3 ), rivers are important because the flow is localized, and they deliver large quantities of water every day. 2.1 Basin-Scale Hydrologic Cycle Most hydrogeological investigations are conducted at smaller than global scales. A useful scale is that of a drainage basin or watershed, the fundamental hydrologic unit that organizes the investigation of surface waters.
eBook - PDFHydrology
A Science of Nature
- Andre Musy, Christophe Higy, Andre Musy, Christophe Higy(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
The objective of this chapter is to present both the traditional and modern theories related to the mechanisms of flow generation, starting with Horton's ideas - truly innovative at the time - to the current concepts based on the idea of preferential flows. However, it is important to remember that research is incomplete; despite the many scientific contributions of the past few decades, hydrological behaviour remains poorly understood. In fact, the development of new theories gave rise to a whole new set of issues and questions. As the principal objective of this chapter is to provide descriptions of the main processes of flow generation, we will not go into detail on the experimental protocols used to identify them, except for a brief overview of environmental tracers. T Hydrological Processes and Responses 276 11.2 GENERAL INFORMATION Because the study of processes is relatively recent, there is still a certain amount of confusion about the terminology used to name them. So in this chapter, whenever we discuss a process, we will mention the various terms by which it is known. In general, the processes governing flow are poorly understood. This is due in part to the fact that there are many different answers to the main two questions in hydrology. Therefore, this chapter will try to answer – at least in part – these two questions: “What is the future of rainfall water?” (Penmann, 1963) and “What is the source of the water in rivers?” (Hewlett, 1961), by identifying the four main paths that water travels into the rivers as proposed by Ward and Robinson (1990), and illustrated in Figure 11.1: 1. Direct precipitation P d on the surface of a waterbody. 2. Overland flow or surface runoff. The concept of “runoff” is actually a poor representation of the physical processes involved in flow generation, and is increasingly abandoned in favour of the concept of “flow.” 3. Subsurface flow (throughflow, interflow) R S which can be defined as “fast internal flow.” 4.
eBook - PDF- Xixi Wang(Author)
- 2021(Publication Date)
- Cambridge University Press(Publisher)
70 3 Watershed and Hydrologic Processes (a) (b) Figure 3.8 Screenshots of Excel Solver for Example 3.7. The spreadsheet and dialog box for: (a) setup; and (b) solution. 3.2 Basic Hydrologic Processes 71 In Excel Solver, specify the objective function cell in the Set Objective box, check the Max radio button specify the cells of the decision variables in the By Changing Variable Cells box, and add constraints in the Subject to the Constraints box of (Figure 3.8a). Specify initial values of the decision variables that satisfy the constraints (i.e., in the feasible region), such as x A = 70 ha and x B = 130 ha. Click the Solve button to get the optimal solution: x A = 140 ha, x B = 60 ha, and z = $2,437,500 (Figure 3.8b). When the five constraints are plotted in the x A ∼ x B coordinate system, the feasible region can be defined and is shown as the red line in Figure 3.9. Graphically, the initial values of the decision variables (x A = 70 ha, x B = 130 ha) are one point on the line, and the optimal solution (x A = 140 ha, x B = 60 ha) is the lower end of the line. It can be shown that the objective function has a value at any other points on the line smaller than that at the lower end. initial values 0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160 x B (ha) x A (ha) xB ≤ 140 xB ≥ 60 x A ≥ 60 x A ≤ 140 x A + x B = 200 optimal solution feasible region Figure 3.9 Graphical solution of Example 3.7. 3.2 Basic Hydrologic Processes This section introduces the hydrologic cycle and its physical processes and presents the widely used methods for quantifying the processes. 72 3 Watershed and Hydrologic Processes 3.2.1 Precipitation As illustrated in Figure 3.6, precipitation is the primary water source of a hydrologic system. Pre- cipitation occurs when water vapor in air reaches its saturation pressure.
eBook - PDFFlooding and Management of Large Fluvial Lowlands
A Global Environmental Perspective
- Paul F. Hudson(Author)
- 2021(Publication Date)
- Cambridge University Press(Publisher)
3 Hydrologic and Geomorphic Processes in Fluvial Lowlands and Deltas [D]ata from eastern and western United States and the examples from India indicate a remarkable uniformity in the recurrence interval of overbank flooding. —Wolman and Leopold (1957) 3.1 CONTEXT OF LARGE RIVERS Each lowland river is unique, having a distinctive combination of geomorphic, human, and environmental features and processes that require tailor-made approaches for sustainable river man- agement. This chapter examines flooding and geomorphic pro- cesses across larger lowland rivers and deltas. This is approached primarily from a “natural” perspective, and with attention to those processes and features that relate to human activities and lowland hydraulic engineering examined in subsequent chapters. Specifically, this includes a review of hydroclimatology, river bank erosion, flooding and overbank sedimentary processes, and deltaic geomorphic processes. By virtue of being coastal draining rivers that support large populations and economic activities, most of the lowland rivers examined in this treatise are larger rivers. While there are mul- tiple definitions for large rivers, some of the criteria utilized include geology, hydroclimatology, morphology, and discharge and sediment flux (i.e., Potter, 1978; Schumm and Winkley, 1994; Gupta, 2007; Latrubesse, 2008). Geologically, large rivers usually have drainage basins that link two or more physiographic provinces (Potter, 1978; Dunne and Aalto, 2013). This often includes headwaters in orogenic belts or cratons that drain to axial trunk valleys controlled by regional-scale structural lows with a seaward extension. And large river valleys and deltas require large amounts of sediment (Figure 3.1).
eBook - PDF- Chenghai Wang(Author)
- 2023(Publication Date)
- Wiley-Blackwell(Publisher)
PSs and SFSs exhibit distinct thermal and hydrological features that are different from each other. PSs display a narrower time span of active Hydrological Processes (i.e. May–September) than SFSs (i.e. April–October). Both precipita- tion and liquid soil moisture display positive correlations with evapotranspiration (ET), and runoff during the warm months across the stations. Base flow generation is dominated by deep ground- water. ET changes are primarily associated with precipitation changes. The slight enhancement of the surface Hydrological Processes is indicated primarily by the statistically nonsignificant changes Hydrological Processes in Cold Regions 120 in evapotranspiration and runoff in most months at the study sites, and the enhancement is due mainly to the effects of precipitation changes, and subsequently to frozen soil degradation. It is expected that, besides precipitation changes, changes in liquid soil moisture also have implications for surface Hydrological Processes, though varying degrees. Under current conditions, permafrost soil plays a limited role in surface Hydrological Processes compared to seasonally frozen soil. However, as global warming continues and permafrost degrades to seasonally frozen soil, more active surface Hydrological Processes could be expected in the warm months in the region. In general, surface Hydrological Processes were enhanced, though not in a statistically signifi- cant way. The enhancement was due mainly to increasing precipitation, with frozen soil degrada- tion also playing some role through its effects on evapotranspiration, runoff, and base flow in cold regions. 6.4 River Ice and Lake-Ice Hydrology River ice, lake ice, and sea ice are important components of the cryosphere, its development not only directly reflects climate change, but also has a far-reaching influence on the global water cycle. The river ice formed in the inland open water and lake ice is different.
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