According to the U.S. Census Bureau , the city has a total area of 20.4 square miles ( 53 km2 ) of which 20.3 square miles ( 53 km2 ) is land and 0.04 square miles ( 0.10 km2 ) ( 0.15 % ) is water .
20.3 square miles ( 53 km2 ) is land and 0.04 square miles ( 0.10 km2 ) ( 0.15 % ) is water .