Thousands of years ago, drawn by rich hunting grounds, prehistoric people settled by the banks of the Colorado River. These early campers left behind cooking and hunting tools, and over time, the implements and their users' bodies were buried by what are now the Highland Lakes.
Now, declining lake levels have left land exposed, leading to a rash of digs by amateur archaeologists — authorities refer to them less generously as looters — that have left the banks of Lake Travis gouged with holes.
Good long article on the problem in Texas.