The Comal River is the shortest navigable river in the state ofTexas and in the United States. Proclaimed the "longest shortest river in the world" by locals, it runs entirely within the city limits of New Braunfels in southeast Comal County. It is a tributary of the Guadalupe River. The Comal begins at Comal Springs in Landa Park and flows 2.5 miles until its junction with the Guadalupe. The Comal was originally called the Little Guadalupe in early Spanish accounts. After Spaniard Pedro de Rivera y Villalón identified the longer river as the Guadalupe in 1727, the Comal was given its current name. The name means basin or flat dish in Spanish. The river is also one of only two rivers to host the fountain darter, a fish now in danger of extinction. The only other river inhabited by the darter is the nearby San Marcos River.
~above taken from www.wikipedia.com~