The San Marcos River rises from the San Marcos Springs, the location of Aquarena Springs, in San Marcos, Texas. The springs are home to several threatened or endangered species, including the Texas blind salamander, fountain darter, and Texas wild rice. The river is a popular recreational area, and is frequented for tubing, canoeing, swimming, and fishing. Course The river begins at San Marcos Springs, rising from the Edwards Aquifer into Spring Lake. Access to much of the headwaters is restricted because of the delicate ecosystem and numerous rare species. The upper river flows through San Marcos, and is a popular recreational area. It is joined by the Blanco River after four miles, and passes through Luling and Palmetto State Park. Near Gonzales, it flows into the Guadalupe River after a total of 75 miles (121 km). This course is the first section of the Texas Water Safari. History The history and naming of the river is somewhat unclear. It may have been discovered by Alonso de León's expedition in 1689, but some scholars believe they instead had found the Colorado or Navidad Rivers. The convention came to call the first sizable river beyond the Guadalupe, but at the time, the Comal River was often called the Guadalupe, and part of the Guadalupe often called San Ybón. In 1808, the Spanish established San Marcos de Neve, just south of present-day San Marcos. They had friendly relations with the Tonkawa Indians, but the hostile Comanche tribe forced them to leave in 1812. In 1998 and 2015, the river was affected by severe flooding. Events San Marcos hosts many events on the San Marcos River. The Texas Water Safari event has run every year since 1963; it uses canoes powered only by human muscle. This event uses the San Marcos River and the Guadalupe River, spanning from Aquarena Springs in San Marcos to Seadrift, Texas, a total of 260 miles. This event is actually composed of many parts, including an information seminar, the safari race, a preliminary race, and another short race. Racers must take enough food and provisions to last them the distance of the race. The Texas Water Safari is billed as the "World's Toughest Boat Race" and runs annually on the second Saturday of June. Another event is the San Marcos River annual San Marcos River Clean-Up, which is an organized spring clean-up of the whole river. Volunteers can either