Cannabis October 12, 2016 thcscience_admin The Alhama River The Alhama is a tributary of the Ebro. Its source is Suellacabras, in Soria, and it flows for 78 kilometres (48 mi) until it reaches the Ebro at Alfaro (La Rioja). See also[edit] List of rivers of Spain 42°11′02″N 1°43′05″W / 42.1839°N 1.7181°W / 42.1839; -1.7181