I have heard of this before, and will most certainly up my intake of water, because I do experience dizziness;
"Drinking water is a simple, but effective, remedy for many cases of dizziness. Scientists have begun to study the impact of water on certain kinds of dizziness, such as dizziness caused by sudden changes of position.
Drink water to relieve dizziness
Method
To prevent dizziness that is caused by standing up suddenly, especially dizziness that happens when you first get up out of bed in the morning, drink two glasses of water before you get up.
To treat dizziness that occurs because you are fatigued and dehydrated from overexertion, sit down and sip water slowly. You may need some form of salt, even if it is just a bag of potato chips, to take with the water. Or you could try drinking a sports drink that includes electrolytes."
Source: Grannymed.com
http://www.grannymed.com/remedies/conditions/dizziness/water-for-dizziness