and is projected to bring in $42 million annually to the Columbus area. Demolishing an up-river dam allowed the project to construct the longest urban whitewater rafting course in the world. According to the Columbus Convention and Visitors Bureau, this initiative, in addition to other outdoor and indoor tourist attractions, led to around 1.8 million visitors coming to Columbus during the city's 2015 fiscal year. The city predicts that an additional 30,000 soldiers will be trained annually at Fort Benning in upcoming years due to base realignment and closure of other facilities. As a result, Columbus is expected to experience a major population increase. Geography Columbus is one of Georgia's three Fall Line Cities, along with Augusta and Macon. The Fall Line is where the hilly lands of the Piedmont plateau meet the flat terrain of the coastal plain. As such, Columbus has a varied landscape of rolling hills on the north side and flat plains on the south. The fall line causes rivers in the area to decline rapidly towards sea level. Textile mills were established here in the 19th and early 20th centuries to take advantage of the water power from the falls. Interstate 185 runs north-south through the middle of the city, with nine exits within Muscogee County. I-185 runs north about from its beginning to a junction with I-85 just east of LaGrange and about southwest of Atlanta. U.S. Route 27, U.S. Route 280, and Georgia State Route 520 (known as South Georgia Parkway) all meet in the interior of the city. U.S. Route 80 runs through the northern part of the city, locally known as J.R. Allen Parkway; Alternate U.S. Route 27 and Georgia State Route 85 run northeast from the city, locally known as Manchester Expressway. The city is located at . According to the US Census Bureau, the city has a total area of , of which are land and (2.14%) are covered by water. Climate Columbus has a humid subtropical climate (Köppen Cfa). Daytime summer temperatures often reach highs in the mid-90°Fs, and low temperatures in the winter average in the upper 30s. Columbus is often considered a dividing line or "natural snowline" of the southeastern United States with areas north of the city receiving snowfall annually, with areas to the south typically not receiving snowfall every year or at all. Columbus is within USDA hardiness zone 8b in the city center