Alkaraji, un grand hydrologue iranien du IX e siècle

Transcription

1 Alkaraji, an Iranian Great Hydrologist in IXt h Century Alkaraji, un grand hydrologue iranien du IX e siècle Arash MALEKIAN Mohammad Javad POURAGHNIAEI Faculty of Natural Resources, University of Tehran PO Box , Karaj (Iran) arshmalek@yahoo.com m_pouraghniaei@yahoo.com Abstract The human civilization from beginning to this time include the name of great scientists that have had the major role in development and advancement of science, therefore our current knowledge is the collection of their efforts in different countries in centuries and years ago. Unfortunately some of these scientists that have had the advanced theories are unknown and their name aren t famous between current scientists. Iran, between the ancient civilized countries was the area of science exchange and dialogue of cultures. Iran was the origin of one of the oldest human cultures; because of it s major geopolitics conditions and it s location in the cross of east and west (in that time the most transport was by land travelling). Then Iranian and Muslims scientists have a great role in compliance of science, and in this paper we will introduce one of the greatest hydrologist in IX th century. Abol haseb-mohammad Alkaraji, the greatest Iranian Hydrologist, lived in IX th century. His advanced theories (which is valuable yet) are described in some books such as his ideas on hydrology and ground water in the book Exploitation of Hidden Waters but this scholar scientist isn t known in scientific communities of the world. He described most subjects related to hydrology and has some ideas on these matters. Most of his ideas are valid after hundred years. This paper describes Some of Alkaraji s ideas, including the reason of precipitation and closed cycle of water. Reason of water flow in the porosity media (hundred years before H. Darcy and Euler) on ground water and the genesis of springs and the effect of earth quick on its genesis, Geyser springs, different methods to finding aquifers and groundwater resources such as divining wells, study the vegetation cover, soil, geology and the study of physical and chemical properties of water, method of construction of Qanat, water refining and so on. 1

2 Alkaraji had had many trips to some of Islamic areas where were progressive in science on that time. His books are the collection and results of his experiences and enormous genius in many years ago. Note: Alkaraji s book isn t translated in English yet. The original book in Arabic language is in Paris museum. * * * 1. Introduction Iran, in its long history is the origin of many developed civilizations that have had deep effects on human and science history in the world. Because of considerable role and importance of Iran and Iranian scientists during history, it s impossible to ignore their efforts. One of the most important reasons for science development in ancient Iran was its special geographic and climatological condition. Mean rainfall in Iran is about on third of its average in the world and about two thirds of Iran has arid and semi-arid condition. There are some areas that don t receive a drop of rain in some years but a rainstorm cause suddenly big flood that destroys all things. These and other conditions such as hot days, cold nights, high evaporation and less biomass are the characteristics of most parts of Iran. For this reasons, water and its related science (hydrology) and study of the relationship between water and its environment and Iranian scientist has had major impression in development and evolution of hydrology, but many of these scientists and their theories are unknown up to this time. One of the greatest hydrologists is Abubakr-Mohammed-Ebn-Alhassan- Ashaseb-Alkaraji in IXt h Century. He borne in central part of Iran and traveled to many Islamic countries. He has written some books in natural sciences, but his the most famous book and also the emphasis of this paper is related to his book in hydrology entitled exploitation of hidden water. 2. Book Alkaraji, Iranian unknown genius scientist, as we know, has written twelve books in branches of science specially in math s and physics that some of them are as follow: Albadie fel Hesab (Introduction to Math), Alkafi fel Hesab (Compliance in Math) and Elal Hesab Eljabr (Reason of Algebra). Because of focus of the symposium Origin and History of Hydrology (OH 2 ), we will introduce his book in the field of hydrology and Ground water. In this book, Alkaraji has discussed and illustrated about some advanced theories in the 2

3 field of Water, Geology and vegetation cover study related to different parts of Hydrology in IXt h Century. 3. Alkaraji s theories 3.1. Gravity Force and spherical form of Earth Alkaraji before other scientists discussed about spherical form of Earth and he supposed the reason of water flows for this form of Earth. Also he defined the form of Earth as: Earth with it s mountains, plains, valleys and seas is spherical and all materials (solid, liquid) tend to center of Earth (Gravity force). Gravity force theory is related to Newton in 1727 but scientists and also Newton didn t know that Iranian scientist on thousand year before him discussed this theory clarify; any parts of things are polled to center of Earth. In other parts of his book wrote: The reason of destroying and damaging of building is their tendency to the center of Earth. We know exploration of gravity force is one of the important bases of the development of science. Karaji using this theory discussed and based to other theories and Newton using physical and math s proved it Equilibrium of forces in the Earth Alkaraji has written that because of mountain, valley and sea, the form of Earth is not absolute spheroid, because, if it was spherical, water covered all parts and there wasn t anywhere for living of people and animal. With tendency to center and Semi-spheroid theories he proved another theory named Equilibrium of Force and said: All forces that act on n material in Earth must be equilibrated in center of Earth Close cycle of Water and Environment and reason of precipitation Alkaraji has written: Sun absorbs the sweetest and lees denser parts of water and transforms it into air. Also : Transformation of air (vapor) to water in cold days and regions and retransformation of water to air (vapor) in warm days and regions cause a flow and is important in reclamation of lands, agriculture and irrigation. In the subject of precipitation he wrote: Water after saturation in land, comes to sea and origin of most water is from snow, rainfall and reaction of air (vapor) and water. 3

4 3.4. The reason of water flow He related this reason with gravity forces and surface differences and discussed its differences absolutely form center of Earth. But today, we suppose surface differences between two locations. H. Darcy in 1857 found the friction coefficient between liquid and bed of stream and discussed on water flows using physical and mathematical theories. Alkaraji, in IX th Century wrote: Water, as other materials tend to flow to the center of Earth form high to low elevation according to gravity force Generation of Ground Water Penetrated water Alkaraji wrote: There are reservoirs in Earth that water stores there and some parts of it comes up in the form of spring and water when reaches to an impervious layer and stops there. By using wells, it comes up according to its power and aquifer pressure Penetration of air into ground Humid vapor penetrates to the pores and transform to water after distillation. This theory named Distillation theory Updrawing of deep water In this theory, apart of precipitation infiltrate to the earth via pores and fill water resources in Earth. Acceptance of this theory is clear after precipitation with increasing of spring yield; Qanats and decreasing of water yield in drought periods Water finding By experimental Method In this case Alkaraji has been said: If an area has humidity, it has water in inner parts. He suggested an experiment in this subject. Also he said: In the morning if we see vapor or fog near Earth, that ground has water By divining Method Ancient Iranians are inventors of Qanat construction and using dowsing and measurement of water, they were able to find the amount and place of groundwater. They dug some wells in aquifer area and with harvesting samples, they estimated water yield. This method is one of the best methods for finding ground water By studying of vegetation cover In this case, Karaji explained some plants that are reasons of water presence in an area such as Sorrel, Celery, Nightshade, and PennyRoyal. 4

5 Today, the easiest method to finding ground water is the study of vegetation cover in area By study the soil and ground types Karaji s theories in the case of Hydrogeology are similar and up-to-date theories. He illustrates his idea on area of watershed, amount of snowy area, existence of pores and their role in infiltration. References 1. Behnia A.K. (1989): Make and Manage of Qanat Book. pp Bybordi M. (1974): Ghanat of Iran (drainage of Sloping Aquifer). J. of Irrigation and Drainage, 10785, pp Lightfoot (1996): Syrian Qanat Romani. J. of Arid Environment. 4. Kuros Gh. (1975): Water and Irrigation culture in ancient Iran. Ministry of Energy. 5. Pouraghniaei M.J. and al. (2000): Qanat as an ancient Iranian method for using groundwater. Int. Conference on groundwater, May 2000, Saitama, Japan. 5