4. HYDROLOGY

THE WATER CYCLE

bp-watercycle2In 1580, Bernard Palissy was the first person to describe the present day concept of ‘water cycle’. He described how water evaporates from the oceans and cools to form clouds. The clouds move inland where they rise, condense and fall as rain. This water gathers as lakes and streams and flows back to the ocean in a continuous cycle. In the 7th century B.C., Thales of Miletus believed that surface spray of the oceans was picked up by the wind and carried inland to fall as rain.

In earlier times people did not know the source of underground water. They thought the water of the oceans, under the effect of winds, was thrust towards the interior of the continents. They also believed that the water returned by a secret passage or the Great Abyss. This passage is connected to the oceans and has been called the ‘Tartarus’, since Plato’s time. Even Descartes, a great thinker of the eighteenth century, subscribed to this view. Till the nineteenth century, Aristotle’s theory was still prevalent. According to this theory, water was condensed in cool mountain caverns and formed underground lakes that fed springs. Today, we have come to know that the rainwater that seeps into the cracks of the ground is responsible for this.

This is described by the Qur’an in the following verses:

“Seest thou not that Allah sends down rain from the sky, and leads it through springs in the earth? then He causes to grow, therewith, produce of various colours.” [Al-Qur’an 39:21]

“He sends down rain from the sky and with it gives life to the earth after it is dead: Verily in that are Signs for those who are wise.” [Al-Qur’an 30:24]

“And We send down water from the sky according to (due) measure, and We cause it to soak in the soil; and We certainly are able to drain it off (with ease).” [Al-Qur’an 23:18]

No other text dating back 1400 years ago gives such an accurate description of the water cycle.

EVAPORATION

“By the Firmament which returns (in its round),” [Al-Qur’an 86:11]

WINDS IMPREGNATE CLOUDS

clouds3“And We send the fecundating winds, then cause the rain to descend from the sky, therewith providing you with water (in abundance).” [Al-Qur’an 15:22]

The Arabic word used here is lawaaqih which is the plural of laqih from laqaha, which means to impregnate or fecundate. In this context, impregnate means that the wind pushes the clouds together increasing the condensation that causes lightning and thus rain. A similar description is found in the following verses of the Qur’an:

“Seest thou not that Allah makes the clouds move gently, then joins them together, then makes them into a heap?—then wilt thou see rain issue forth from their midst. And He sends down from the sky mountain masses (of clouds) wherein is hail: He strikes therewith whom He pleases ( and He turns it away from whom He pleases. the vivid flash of His lightning well-nigh blinds the sight.” [Al-Qur’an 24:43]

“It is Allah Who sends the Winds, and they raise the Clouds: then does He spread them in the sky as He wills, and break them into fragments, until thou seest raindrops issue from the midst thereof: then when He has made them reach such of His servants as He wills, behold, they do rejoice!” [Al-Qur’an 30:48]

Modern data on Hydrology agrees perfectly with the Qur’anic description on the same subject.

The water cycle is described in several other verses of the Glorious Qur’an, including 7:57, 13:17, 25:48-49, 35:9, 36:34, 45:5, 50:9-11, 56:68-70 and 67:30.