The original published source of the claim and drawings is a defunct British newspaper that specialized in illustrated news from around the British Empire and the world. Then and now, British journalism has a highly inventive streak, with foreigners especially prone to finding themselves saddled with invented quotes and purely fictional claims. British libel law makes suit impractical and uneconomic.
The only individual named as a source is "Professor G A Reisner of Harvard University." This refers to George Andrew Reisner, a pioneering Egyptologist. He never published such findings or otherwise alerted his fellow Egyptologists about hidden rooms in the Sphinx in an era in which Britain ruled Egypt and US and British excavators had relatively easy access to the monuments at Giza.
In short, there is no evidence for hidden rooms inside or near the Sphinx. The only reasons to think so are the readings and predictions of a long dead psychic and the fabrications of an old British tabloid.
As for water being pumped from the ground near the Sphinx, it is likely part of an effort by the Egyptian authorities to preserve it and the pyramids. The growth of Cairo's suburbs and the year-round irrigation made possible by the Aswan Dam have raised the water table on the Giza plateau.
The result is that the pyramids and the Sphinx absorb water into their porous limestone, which causes salts to be deposited near their surfaces, resulting in the rock flaking away. The pyramids and the Sphinx are thus dissolving.
If the Sphinx is to survive, it must soon undergo renovations and repairs that include a detailed survey and study of the structure. Since Egypt will look to foreigners to pay for the work, the Sphinx will be examined carefully and the results published. Or, if the Egyptians to operate in their usual slipshod manner, the Sphinx will unveil its internal structure as it falls apart due to lack of adequate care.
Sounds like how the NEW YORK SUN newspaper got it’s start, publishing articles of a super telescope in South Africa that discovered bat men on the moon.
“This refers to George Andrew Reisner, a pioneering Egyptologist. He never published such findings or otherwise alerted his fellow Egyptologists about hidden rooms in the Sphinx in an era in which Britain ruled Egypt and US and British excavators had relatively easy access to the monuments at Giza.”
True, and he published an entire book about Giza, so he had every opportunity to do so.
The fact is, Reisner never even excavated the Sphinx. The only work he did at Giza was in the western funerary complex. Even the photos accompanying the article attest to this, since the photos dated 1925 (years after Reisner supposedly excavated the Sphinx) show it still buried in the sand. Clearing the sand away from it would be the very first step in any excavation, before you start prying up stones and digging through tunnels.