Lake Tuscaloosa was built because because more people were living in Tuscaloosa. The reservoirs already there, Harris Lake and Lake Nicol, didn't provide enough water. A dam was built on North River. When that dam filled, the water behind it became Lake Tuscaloosa. Lake Tuscaloosa provides more water than either of the other two reservoirs. Lake Tuscaloosa's water is treated to make it safe for people to drink. It also provides untreated water for industrial use.