Chapter 1The Importance of HydrologyWhile Planet Earth is endowed with abundant water,the need for water at specific times and places often exceedthe available supplies. Efforts to utilize this precious re-source often result in adverse social and environmental im-pacts, causing disruption of water supplies to downstreamusers, and the loss of aq uatic habitats.In addition to conflicts over water availability, the qual-ity of water is often compromised by human activity. Useof water, as well as a lteration of natural landscapes, candrastically affect the physical, chemical, and biologicalproperties of water - what we call water quality.The materials in this book focus on understanding wa-ter from a quantity a nd quality perspective in the hopethat we might better utilize this resourc e – thus preserv-ing and protecting our planet for today’s oc c upants as wellas tomorrow’s.1.1 A Brief HistoryBefore we begin our study of water, let us reflect on howwater has shaped our modern civilization – just what isit about water that makes it so important to human soci-eties?Many of the earliest writings are of a religious na-ture. Early religious documents, such as the Bible (Judeo-Christian), Talmud (Judaism), Koran (Islam), Code ofManu (Hindusim), I-Ching (Taosim), and the Analects(Confucianism), place g reat imp ortance on water to s oci-ety.Early human e xistence was a tug-of-war between feastand famine, and the weather was instrumental in affect-ing the availability o f game, agricultural productivity, andcatastrophic inundation. Accounts of floods and droughtshave been handed down from the earliest prehistory: theflood of Noah which may be an account of the floodingassociated with a breach between the Black and Mediter-ranean Seas; the seven plagues of Egypt, including floodsand droughts, which prompted Moses to flee.While the earliest forms of agriculture probably relieddirectly on ra infall, the great societies of Egypt, Mesopo-tamia, the Indus, and China were linked to irrigation. Theebb and flow of rivers allowed the water to flood and fer-tilize the land during the wet season, and then supplysupplemental water during the dry season. The need toallocate scarce water supplies during droughts providedan impetus for water resources administration - leading tothe establishment of modern civilization.Knowledge of irrigation spread through the desert coun-tries of North Africa and Southern Europe. The Romansbuilt elabora te aqueducts to tra nsport water over greatdistances. The elaborate irrigation and drainage systemsof the Native Americans also developed hand-in-hand withan a dministration sys tem that c ould resolve issues of com-munal work and rewards.Water has also been used as a means of transportation,both along rivers as well as in the sea s and oceans. Theaccounts of Ulysses in the Odyssey tell the travails associ-ated primitive travel by ship. Earlier tr avel in canoes andsmall sailing craft helped primitive peoples spread acrossthe tropical Pacific, as far as Hawaii and Easter Island inthe east Pacific.In the year 1086, twenty years after William the Con-queror had successfully invaded England, he authorizedthe inventory of all of his conquest. Included in this so-called Doomsday Book, or final accounting, are 6000 wa-ter mills that were used primarily for grinding wheat andother grains to make flour. By the seventeenth century,there were over 60 ,000 water mills in France producingthe flour used to ma ke their daily bread. Even in earlyAmerican history, the importa nce of water mills on localcommerce can not be underemphasized. Many cities inthe eastern U.S. were located in proximity to sites wherewater power could be used for grinding corn and grains,or for powering industries.With the advent of the industria l age, reliance o n hy-dropower as an abundant, cheap, and clea n so urce of en-ergy was widespread. First small, but then ever-larger,dams were built to harness the e nergy in water, culminat-ing in the la rge dams of the twentieth century. As coal,and later nuclear energy, replaced hydropower, water wasstill needed to drive the steam turbines used to generateelectricity.Water was also use d to remove human wastes fro mcities by letting it flow through open sewers to the neareststream channel. Industrial discharges of wastewater frommills and factories was as simple as constructing a ditch1CHAPTER 1. THE IMPORTANCE OF HYDROLOGY 2to the nearest river. Unfortunately, downstream waterusers were often left to be ar the burden o f pollution andsickness.As recreation and environmental concer ns increasedduring the late-nineteenth and twentieth-centuries, greaterefforts were placed on maintaining instream water qual-ity. Restrictions on discharges, as well as an emphas ison wastewater treatment, led to major improvements instream water quality. These improvements were only forpoint-sources of discharge, however, and not for stormwa-ter discharged fr om nonpoint sources.American literature reflects the importance of waterin American society. The writings of Mark Twain onthe Mississippi River brought home the central role thatwater plays in commerce in nineteenth century America.The b ook Silent Spring, written by Rachael Carson in the1950s, dramatized the plight of American birds due to thewidespread application of pesticides, leading to strict con-trols on environmental toxins.Carson’s research relied upon electron capture detec-tor, a technology developed by J.E. Lovelock, who laterdeveloped the Gaia hypothesis that Planet Earth is a s e lf-regulating system with built-in checks and balances thatcontrols the temperature and atmospheric gas composi-tion. And finally, presidential candidate Al Gore’s book,Earth in the Balance, outlines the challenges facing mod-ern civilizations when confronted with resource manage-ment decisions.Problems1. Select a book to re ad on some aspect of water re-sources (suggestions provided at the end of this chap-ter). Describe the setting, characters, and plot. In-dicate how important the boo k was in terms of chang-ing the way we think of water.2. Select a video to watch on some aspect of water re-sources. Describe the setting, characters, and plo t.Indicate how important the book was in terms ofchanging the way we think of water.3. Religious litera tur e often provides the earliest ac-counts of the role of water in human society. Searchfor references to water in relig ious literature (such asthe Jewish Talmud, Christian Bible,