The relationships between groundwater and surface water, includes base flow needs for in stream flow, and subsurface water levels in wells.
History of hydrology
Hydrology has been a subject of investigation and engineering for millennia. For example, in about 4000 B.C. the Nile was dammed to improve agricultural productivity of previously barren lands. Mesopotamian towns were protected from flooding with high earthen walls. Aqueducts were built by the Greeks and Ancient Romans, while the History of China shows they built irrigation and flood control works. The ancient Sinhalese used hydrology to build complex irrigation Works in Sri Lanka, also known for invention of the Valve Pit which allowed construction of large reservoirs and canals which still function.
Marcus Vitruvius, in the first century B.C., described a philosophical theory of the hydrologic cycle, in which precipitation falling in the mountains infiltrated the earth’s surface and led to streams and springs in the lowlands. With adoption of a more scientific approach, Leonardo da Vinci and Bernard Palissy independently reached an accurate representation of the hydrologic cycle. It was not until the 17th century that hydrologic variables began to be quantified.
Pioneers of the modern science of hydrology include Pierre Perrault, Edme Mariotte and Edmund Halley. By measuring rainfall, runoff, and drainage area, Perrault showed that rainfall was sufficient to account for flow of the Seine. Marriotte combined velocity and river cross-section measurements to obtain discharge, again in the Seine. Halley showed that the evaporation from the Mediterranean Sea was sufficient to account for the outflow of rivers flowing into the sea.
Advances in the 18th century included the Bernoulli piezometer and Bernoulli’s equation, by Daniel Bernoulli, the Pitot tube. The 19th century saw development in groundwater hydrology, including Darcy’s law, the Dupuit-Thiem well formula, and Hagen-Poiseuille’s capillary flow equation.
Rational analyses began to replace empiricism in the 20th century, while governmental agencies began their own hydrological research programs. Of particular importance were Leroy Sherman’s unit hydrograph, the infiltration theory of Robert E. Horton, and C.V. Theis’s Aquifer test/equation describing well hydraulics.
Since the 1950’s, hydrology has been approached with a more theoretical basis than in the past, facilitated by advances in the physical understanding of hydrological processes and by the advent of computers and especially Geographic Information Systems (GIS).
III. Answer the questions:
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1. What is a subject of hydrology?
2. Name the scientists which work in this field of science?
3. What are domains of hydrology?
4. Is there any difference between hydrology and surface water hydrology?
5. What kind of surface water resources do you know?
6. Hydrology includes the field measurement of flow (discharge); the statistical variability at each setting; floods; drought susceptibility and the development of the levels of risk; and the fluid mechanics of surface waters, does not it?
7. What components of hydrologic cycle do you know?
8. What is an important aspect of water surface hydrology?
9. How did ancient people apply their hydrological knowledge?
10. What was the conception of ancient people about the hydrologic cycle?
11. Who were the pioneers of modern hydrology and why?
12. What other inventions in hydrology do you know?
IV. Do you agree or disagree with the following statements? Explain why.
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