The Lignon (French: "le Lignon" ) is a 20.7 km long river in the Ardèche "département", southern France.
 Its source is at La Souche, in the "Parc naturel régional des Monts d'Ardèche".
 It flows generally east-northeast.
 It is a right tributary of the Ardèche into which it flows between Meyras and Pont-de-Labeaume.
The Ardèche (Occitan: "Ardecha" ) is a 125 km long river in south-central France, a right-bank tributary of the River Rhône.
 Its source is in the Massif Central, near the village of Astet.
 It flows into the Rhône near Pont-Saint-Esprit, north-west of Orange.
 The river gives its name to the French department of Ardèche.
The Ahar River is a tributary of the Berach River (itself a tributary of Banas River, which in turn is a tributary of Chambal river, itself a tributary of Yamuna River, which in turn is the most important tributary of Ganges River).
 The river flows through the Udaipur city and is its larger drainage body.
 The spill water of the famous Lake Pichola and Fateh Sagar Lake of Udaipur district gets into the Ahar river.
 Though ironically, this historically important river is at present functioning as the drainage body of the Udaipur city filled with sewage and garbage.
 It is also the site of 3000 BCE to 1500BCE Chalcolithic archaeological culture Ahar-Banas culture.
The Saint Joe River (sometimes abbreviated St. Joe River) is a 140 mi long tributary of Coeur d'Alene Lake in northern Idaho.
 Beginning at an elevation of 6487 ft in the Northern Bitterroot Range of eastern Shoshone County, it flows generally west through the Saint Joe River Valley and the communities of Avery and Calder.
 Past Calder, it flows into Benewah County and through the town of St. Maries, where it receives its largest tributary, the Saint Maries River.
 It then turns northwest, passing through Heyburn State Park before reaching its mouth just north of the Kootenai County line.
 Much of the river's route through Heyburn State Park is partially flooded due to raised water levels from Post Falls Dam on the Spokane River below Coeur d'Alene Lake.
 With a mouth elevation of 2129 ft , it has been described as the highest navigable river in the world.
The Ibie is a 32.9 km long river in the Ardèche "département", southeastern France.
 Its source is at Saint-Jean-le-Centenier, 2 km south of the village.
 It flows generally south-southwest, through the northern part of the Côtes du Vivarais AOC.
 It is a left tributary of the Ardèche into which it flows at Vallon-Pont-d'Arc, 1.8 km southeast of the village.
Kem (Russian: Кемь ) is a river in Siberian in Russian Krasnoyarsk Krai.
 It is a left bank tributary of the Yenisei River.
 The name of the River Kem comes from the ancient word "kem" or "hem" that has a meaning of "great river".
 This toponymy is very popular and widespread from Siberia up to the Karelia and Finland.
 The river flows across the West Siberian Plain through the districts of Bolshemurtinsky, Kazachinsky, Pirovsky, and Yeniseysky District before discharging into the Yenisei River close to the town of Yeniseysk at 2045 kilometers before the mouth.
 The River Kem is 356 kilometres (221 miles) long.
 The Kem River basin covers a total area of 8,940 square kilometres (3,452 square miles).
 The most important tributaries of the River Kem are Tiya (Russian: Тыя ) at the 97 kilometer from the mouth and Belaya (Russian: Белая ) at the 115 kilometer from the mouth.
 Both major tributaries are on the left side.
 Source of the River Kem is located in Bolshemurtinsky District where it originate as a small creek in the East Siberian taiga.
 Due to the tributary rivers, towards the mouth river reaches 45 meters of width.
The Rhône ( ; French: "Le Rhône" ] ; German: "Rhone" ] ; Walliser German: "Rotten" ; Italian: "Rodano" ] ; Arpitan: "Rôno" ] ; Occitan: "Ròse" ] ) is one of the major rivers of Europe and has twice the average discharge of the Loire (which is the longest French river), rising in the Rhône Glacier in the Swiss Alps at the far eastern end of the Swiss canton of Valais, passing through Lake Geneva and running through southeastern France.
 At Arles, near its mouth on the Mediterranean Sea, the river divides into two branches, known as the Great Rhône (French: "Le Grand Rhône") and the Little Rhône ("Le Petit Rhône").
 The resulting delta constitutes the Camargue region.
The Ilek River ( "Elek", Russian: Илек ) is a steppe river at the southern end of the Ural Mountains.
 It is a tributary of the Ural River and lies in Orenburg Oblast in Russia and Republic of Kazakhstan.
 It rises just south of Orsk, flows south a short distance and then flows westward south of and parallel to the Ural River, with many meanders and oxbow lakes, and joins the Ural about 75 km west of Orenburg.
 Two main cities lie on the banks of the Ilek River: Sol-Iletsk and Aqtöbe (alternate spelling: Aktöbe, Aktyubinsk).
 The Ilek River remains the most polluted water body in the Ural-Caspian basin.
 The content of boron and chromium in the river is caused by the tailing ponds of former chemical plants via ground water.
 The quality class of water in the Ilek River changes from 4 – “polluted water” to 6 – “very polluted water”.
 A further tributary of the Ilek River is the Bolshaya Chobda.
 It is also of archeological significance since it has been discovered as the site of certain Kurgan (Indo-European) burials.
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The Chassezac (French: "le Chassezac" ) is an 84.6 km long river in the Lozère, Gard and Ardèche "départements", southern France, right tributary of the Ardèche.
 Its source is in the commune of Saint-Frézal-d'Albuges, 2.8 km northeast of Les Chazeaux, main hamlet in the commune.
 It flows generally southeast and flows into the Ardèche at Saint-Alban-Auriolles, 1.8 km east of the village itself.
The Krupa river is the Neretva left tributary and the main water current of Hutovo Blato, which leads the waters from Gornje Blato and Svitavsko lake into the Neretva river.
 The length of Krupa is 9 km with an average depth of 5 meters.
 Krupa does not have an actual source, but is actually an arm of Deransko lake.
 Also, the Krupa is a unique river in Europe, because the river flows both ways.
 It flows 'normally' from the 'source' to the mouth and from the mouth to the 'source'.
 This happens when, due to high water level and large quantity of water, river Neretva pushes the Krupa river in opposite direction.

Question: Ardèche is a tributary of the river that has a mouth at what body of water?
Answer: Mediterranean Sea