Mayan Collapse

The Mayan civilization seem to fall apart around the ninth century. My theory for this collapse is that for a long period of time, a horrible drought swept over the Yucutan Peninsula. At first the Mayans didn't mind because of the underground canals of water that flowed throught their empire. But after so long, the canals started drying up. With no major lakes or rivers to get water from, the people couldn't drink or get water to grow their crops. Eventually their supplies ran out and the Mayan people couldn't survive any longer, so a major portion of the population died, therefore killing the great empire of the Maya.