Great Place for Water Tubing The Comal River may be the shortest river in the world, check it out in the Guinness Book of World Records. Just under 3 miles in length, the river begins and ends near downtown New Braunfels. The source of the Comal River begins from Comal Springs, which consists of many small springs located in and around Landa Park and Landa Lake. The springs form the Comal River, which eventually joins the Guadalupe River in the heart of downtown New Braunfels.