The Importance of Hydrology While Planet Earth is endowed with abundant water.

Chapter 1 The Importance of Hydrology While Planet Earth is endowed with abundant water, the need for water at specific times and places often exceed the available supplies. Efforts to utilize this precious resource often result in adverse social and environmental impacts, causing disruption of water supplies to downstream users, and the loss of aquatic habitats. In addition to conflicts over water availability, the quality of water is often compromised by human activity. Use of water, as well as alteration of natural landscapes, can drastically affect the physical, chemical, and biological properties of water - what we call water quality. The materials in this book focus on understanding water from a quantity and quality perspective in the hope that we might better utilize this resource – thus preserving and protecting our planet for today’s occupants as well as tomorrow’s. 1.1 A Brief History Before we begin our study of water, let us reflect on how water has shaped our modern civilization – just what is it about water that makes it so important to human societies? Many of the earliest writings are of a religious nature. Early religious documents, such as the Bible (JudeoChristian), Talmud (Judaism), Koran (Islam), Code of Manu (Hindusim), I-Ching (Taosim), and the Analects (Confucianism), place great importance on water to society. Early human existence was a tug-of-war between feast and famine, and the weather was instrumental in affecting the availability of game, agricultural productivity, and catastrophic inundation. Accounts of floods and droughts have been handed down from the earliest prehistory: the flood of Noah which may be an account of the flooding associated with a breach between the Black and Mediterranean Seas; the seven plagues of Egypt, including floods and droughts, which prompted Moses to flee. While the earliest forms of agriculture probably relied directly on rainfall, the great societies of Egypt, Mesopotamia, the Indus, and China were linked to irrigation. The ebb and flow of rivers allowed the water to flood and fertilize the land during the wet season, and then supply supplemental water during the dry season. The need to allocate scarce water supplies during droughts provided an impetus for water resources administration - leading to the establishment of modern civilization. Knowledge of irrigation spread through the desert countries of North Africa and Southern Europe. The Romans built elaborate aqueducts to transport water over great distances. The elaborate irrigation and drainage systems of the Native Americans also developed hand-in-hand with an administration system that could resolve issues of communal work and rewards. Water has also been used as a means of transportation, both along rivers as well as in the seas and oceans. The accounts of Ulysses in the Odyssey tell the travails associated primitive travel by ship. Earlier travel in canoes and small sailing craft helped primitive peoples spread across the tropical Pacific, as far as Hawaii and Easter Island in the east Pacific. In the year 1086, twenty years after William the Conqueror had successfully invaded England, he authorized the inventory of all of his conquest. Included in this socalled Doomsday Book, or final accounting, are 6000 water mills that were used primarily for grinding wheat and other grains to make flour. By the seventeenth century, there were over 60,000 water mills in France producing the flour used to make their daily bread. Even in early American history, the importance of water mills on local commerce can not be underemphasized. Many cities in the eastern U.S. were located in proximity to sites where water power could be used for grinding corn and grains, or for powering industries. With the advent of the industrial age, reliance on hydropower as an abundant, cheap, and clean source of energy was widespread. First small, but then ever-larger, dams were built to harness the energy in water, culminating in the large dams of the twentieth century. As coal, and later nuclear energy, replaced hydropower, water was still needed to drive the steam turbines used to generate electricity. Water was also used to remove human wastes from cities by letting it flow through open sewers to the nearest stream channel. Industrial discharges of wastewater from mills and factories was as simple as constructing a ditchto the nearest river. Unfortunately, downstream water users were often left to bear the burden of pollution and sickness. As recreation and environmental concerns increased during the late-nineteenth and twentieth-centuries, greater efforts were placed on maintaining instream water quality. Restrictions on discharges, as well as an emphasis on wastewater treatment, led to major improvements in stream water quality. These improvements were only for point-sources of discharge, however, and not for stormwater discharged from nonpoint sources. American literature reflects the importance of water in American society. The writings of Mark Twain on the Mississippi River brought home the central role that water plays in commerce in nineteenth century America. The book Silent Spring, written by Rachael Carson in the 1950s, dramatized the plight of American birds due to the widespread application of pesticides, leading to strict controls on environmental toxins. Carson’s research relied upon electron capture detector, a technology developed by J.E. Lovelock, who later developed the Gaia hypothesis that Planet Earth is a selfregulating system with built-in checks and balances that controls the temperature and atmospheric gas composition. And finally, presidential candidate Al Gore’s book, Earth in the Balance, outlines the challenges facing modern civilizations when confronted with resource management decisions. Problems 1. Select a book to read on some aspect of water resources (suggestions provided at the end of this chapter). Describe the setting, characters, and plot. Indicate how important the book was in terms of changing the way we think of water. 2. Select a video to watch on some aspect of water resources. Describe the setting, characters, and plot. Indicate how important the book was in terms of changing the way we think of water. 3. Religious literature often provides the earliest accounts of the role of water in human society. Search for references to water in religious literature (such as the Jewish Talmud, Christian Bible, Islamic Koran, Hindi Code of Manu, Confucian Analects, or other source), using either published or internet sources. Note the importance or role of water in the reference. 4. Many ancient civilizations derived great pleasure exploring their environment. Select an ancient civilization and describe how they conceptualized the hydrologic cycle. 5. There are many water resources engineering marvels from the ancient past. Pick one and describe its purpose and relevance to the society of its time. 1.2 The Role of Science The early Greeks spent much time trying to understand the origin of rivers and streams. Thales (640-546 BCE) was an Ionian who popularized the belief that wind blew water into rocks along the coast, forcing water up through the rock under high pressure, where it eventually emerged in springs. Later, Plato (427-347 BCE), an Athenian, argued that water was contained in a single underground cavern, and was pushed up into springs by underground forces. Aristotle (384-322 BCE), also an Athenian, disagreed with Plato, arguing that water vapor from the atmosphere and interior of the earth condensed directly in the soil, making it moist. Seneca (4 BCE - 65 CE), a famous Roman senator, proved to the intellectuals of his day that precipitation that fell to the earth and infiltrated was not sufficient to supply all the water that was observed as streamflow. Even Kepler (1571-1630), a German scientist renowned for his contributions to astronomy, thought that the earth digested salt water and excreted fresh water as waste. It was not until Perrault (1608-1680), a French scientist, measured 520 mm of rainfall in the Seine River watershed during the period from 1668-1670 and showed that it was six times more than the river flow. This proved to a great many scientists that the source of water in rivers and streams is atmospheric precipitation falling on the soil. To this day, however, there is still great dispute over the source of water in streams. Many argue that stream- flow only results from overland flow during rainstorms. Others argue that while this may be true in urban areas where impervious surfaces dominate, the overland flow theory is not appropriate for forests and many agricultural areas. In these cases, streamflow results from infiltration, recharge, and subsequent exfiltration of water from ground water. How long have people been tracking precipitation? “In his book Meteorologica, Aristotle (340 BCE) mentioned topics such as clouds, mist, rain, snow, etc, but not the measurement of precipitation. Measuring rain and keeping records of it was apparently still far off in the future. “The earliest quantitative device for measuring rainfall seems to be credited to a king in Korea called King Sejong who lived from 1397 to 1450. One of his goals as king was to make his people literate, so not only did he invent a rain gauge, but more importantly, he invented a language and movable type for that language. “He decided that instead of digging into the soil to check for moisture, it would be better to have a standardized container about 30 cm in depth and 14 cm in diameter that stood on a pillar to measure the rainfall. These containers were to help villagers determine their potential harvest and to give King Sejong a better idea of how much the farmers should be taxed! So, these standard containers were distributed to each village. The rain gauge was invented in the fourth month of 1441, according to records.” CHAPTER 1. THE IMPORTANCE OF HYDROLOGY 3 “The tipping bucket rain gauge was invented by Christopher Wren in Europe around 1661 and used the standard of weight, or sometimes volume, of the liquid precipitation. This tipping bucket idea is still used in many of the automated electronic gauges today. “In 1887, Mr. Cleveland Abbe wrote a manual on Meteorological Apparatus and Methods for the U.S. Army Signal Corps (agency responsible for U.S. weather observations at the time). In this booklet, Mr. Abbe described the standards for the weather gauges to be used by the U.S. Army Signal Corps. This standard 8-inch diameter gauge is still in use by many National Weather Service offices and cooperative weather observers across the United States and abroad.” [Source: www.cocorahs.org] History of flow measurement. “Hydraulic structures existed before recorded history. Archeologists have found irrigation systems in Mesopotamia and check and diversion dams on the Arabian Peninsula dating to about 5800 BCE. The first water level records on the Nile River appeared about 3050 BCE. The Romans, even though they did not fully comprehend hydraulic principles relating to discharge, devised a method based on pipe areas in order to charge for water supplied to baths and private residences. “Hero, a Greek of the first century AD, was the first to express the basis for flow measurement as we know it today. This important finding went unnoticed, however, for about 1500 years until Leonardo da Vinci extended the relationship to the continuity equation, but even da Vinci’s work went unknown until his manuscripts were found in 1690. “The German engineer, Reinhard Woltman, developed the spoke-vane current meter in 1790, a breakthrough for measuring velocities in rivers and canals. During the 18th and 19th centuries development and installation of weirs and flumes made flow measurements possible on irrigation canals, and gaging stations were constructed on many rivers to provide records of flows. New technology has provided various water measurement techniques, and stream flow data now can be accessed at over 4200 gaging stations in the United States.” [Source: James F. Ruff, www.informaworld.com/10.1081/EEWS2-120010345] Problems 1. Select a scientist from the past who had some in- fluence on changing how we think about water resources. Describe how they contributed to our modern understanding. 2. Describe how ancient cultures (e.g., Chinese, Egyptian, Persian, Babylonian, Mayan) described water resources. What was their hydrologic cycle? 3. Download maximum annual water levels from the so-called Nilometer. Summarize the source of the data and the types of behavior it displays. 1.3 Current Issues and Careers Water is usually managed for both quantity and quality. Too much water - too little water, are both issues of water quantity. Flood control and drought protection are opposite ends of the water quantity spectrum. Dams, bridges, canals, revetments, harbors, etc., are all structures used to protect people and property from natural variations in weather. Careers in water quantity have historically been left to the engineering profession, with some opportunities for economists. Design of so-called structural remedies, and the ability to pay for these structures, have preoccupied federal, state and local agencies since the beginning of the nation. In recent years, however, increasing attention is being placed on managing facilities, and providing initiatives for individuals to avoid building in flood-prone land, thus replacing structural with non-structural remedies to water resource problems. Little legislation exists to regulate water quantity on the national scale. Regional compacts are usually negotiated at the state or local level to find an acceptable allocation of water between jurisdictions, primarily for periods of drought. Little national legislation exists related to the regulation of flooding, other than requirements related to building in the flood plain. Unlike water quantity, the maintenance of water quality has a rigorous legal foundation, focusing on the protection of the quality of water supplies. We can divide modern water quality management into three categories; water supply, wastewater treatment, and the protection of aquatic habitats. Issues and career opportunities are often uniquely defined within each category due to its legislative history, listed in each section. The first water quality category, water supply protection and augmentation, relates to the need of society for abundant sources of inexpensive water of acceptable quality. Surface water quality issues related to drinking water fall under the Source Water Assessment and Protection (SWAP) program, which is a part of Safe Drinking Water Act. A similar program for ground-water quality is the Wellhead Protection Program (WPP), which also falls under the Safe Drinking Water Act. These programs are intended to preserve and protect drinking water supplies so that chronic and acute exposures to hazardous contaminants are minimized. In addition to water quality protection, new water supplies are routinely needed in growing communities for both municipal and industrial purposes. Reservoirs are one option for capturing excess streamflow during the winter months, and storing it for delivery during the drier summer months. Ground water is another resource that many communities are tapping whenever possible. Wastewater reuse is a potential source of new water for meeting the demands of growing communities. Efforts are also underway to recharge excess surface water in ground-water aquifers. The intent is to avoid the need to construct surface-water reservoirs, and to use the subsurface as an underground reservoir to store excess streamflow until it is needed. Important legislation related to water supply includes: CHAPTER 1. THE IMPORTANCE OF HYDROLOGY

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