Basically, the water source is an underground aquifer that is refilled by the occasional heavy rains. Mecca lies in a 60km wide basin so water falling around runs down the gradient accumulates underground and feeds Zamzam.
The Saudi government has extensively mapped out the water sources that feed zamzam and careful urban planning ensures that construction work does not damage this underground natural reservoir.
In this way, the Saudi government ensures that human actions do not impede the flow of water to Zamzam.
Acts of God can still have an effect on Zamzam. During long periods without rain, the water level in the underground aquifer falls low and the Saudis limit the amount of water that is permitted to be extracted.
My link contains the statement that “except for a few periods when it became dry or was buried under sand, has been in use for around 4000 years” , but your first one says that it has never run dry.
Also, some of the other findings of the Zamzam Studies and Research Center , set up by the Saudi Geological Survey, run contrary to your first link.
The only explanation that i have been able to find when searching your linking is that the article in there was written several decades ago, and has been eclipsed by more recent scientific research by the Saudis.
writes Dr Mohar Ali (Professor of Islamic History, Islamic University, Madinah):
“At the time of their leaving Makka [in pre-Islamic Arabia], Banu Jurhum destroyed the Zamzam well by covering it with earth and burying on the spot some of their arms and armour and two golden gazelles. The well thus remained covered and unspotted for a long time.”
… he goes on to say:
“His [Abd al Muttalib’s] most outstanding achievement was the re-excavation and restoration of the Zamzam well. Since its destruction and burial by Banu Jurhum it had remained untapped and people had lost its trace.”
Sirat Al-Nabi and the Orientalists, Vol. 1A, pp. 37 & 40, 1st Edition 1997
it may have been buried on other occasions as well
As I mentioned, according to the article on the Islamic Cultural Centre (which is funded by government of 19 Muslim states including Saudi Arabia, Iran, the UAE, Syria, Pakistan, and Bangladesh amongst others), the well has, on a limited number of occasions over the past 4000 years, fallen into a state of disuse due to either running dry or being blocked with sand.
The article does not state the time periods when that happened, so the population was probably significantly less than it is today.
During those period, I would guess that the city, historically being quite wealthy, purchased water from trading caravans in the area.
Yet there is no other example of this phenomena anywhere...
MS: Never any arguments brother...Just two viewpoints being thrown on the table and being discussed on the scales of Truth...
A good debate or argument is like playing poker...The stakes are your beliefs and whoever has better sources, wins the hand...
That is why Islam is so engrossing...It's all about the knowledge you possess and the sources you cite...
You can imagine how good those players must be who spent their lifetime playing the game of Knowledge...I have lost many, many hands in my Sufistic days against the Wahabbis...That's why I myself am a Wahabbi now...:D
So, basically you had a better hand...I would have folded...:D