Question: Siglistorf is a municipality in the Swiss canton that is situated by the lower course of what river?
Context: Prądnik (also called Białucha in its lower course) is a river in Poland, running through the Kraków-Częstochowa Upland in Poland's Lesser Poland voivodeship.  The river is a left tributary of Vistula.  The source of the river lies in the village of Sułoszowa in the Olkulsz Uplands.  It flows in a deep gully through the Ojców National Park.  The lower run in Kraków has been designated an ecological reserve on 17 December 2008.  Until 1655, when Vistula changed its course in the vicinity of , Prądnik joined Vistula's old riverbed near what is now Blich Street.  However, in modern times the lower run of the river is regulated and empties itself into the Vistula in the Kraków's borough of Dąbie. The Vipava (in Slovene) or Vipacco (in Italian) or "Wipbach" / "Wippach" (in German) is a river that flows through western Slovenia and northeast Italy.  The river is 49 km in length.  After entering Italy it joins the Isonzo/Soča in the Municipality of Savogna d'Isonzo.  This is a rare river with a delta source, formed by nine main springs.  The Battle of the Frigidus was fought near the river, which was named "Frigidus" ('cold') by the Romans.  It has the pluvial-nival regime in its upper course and the pluvial regime in its lower course. Arachthos (Greek: Άραχθος ) is a former municipality in the Arta regional unit, Epirus, Greece.  Since the 2011 local government reform it is part of the municipality Nikolaos Skoufas, of which it is a municipal unit.  The municipal unit has an area of 73.431 km.  It is situated along the lower course of the river Arachthos, south of Arta. Dadan River (达旦河 , "Dádàn Hé") is a right tributary of the Jinsha River in Yunnan Province, southwestern China.  It rises in the western Binchuan County, the upper course is called Waxi River (瓦溪河 , "Wǎxī Hé") or Binju River (宾居河 , "Bīnjū Hé").  The middle course of it is called Sangyuan River (桑园河 , "Sāngyuán Hé") or Naxi River (纳溪河 , "Nàxī Hé") and flows through the Binchuan County from south to north.  The lower course of it is located in southern Yongsheng County.  The river has a length of 102.4 km and drains an area of 1,888 square km. Kaiseraugst (Swiss German: "Chäiseraugscht") is a municipality in the district of Rheinfelden in the canton of Aargau in Switzerland.  It is named for the Ancient Roman city of Augusta Raurica whose ruins are situated nearby.  The prefix "Kaiser-" ("imperial") refers to the fact that this town was part of Further Austria, as opposed to neighbouring Augst, which was in the Swiss canton of Basel. Aarau (] , locally [ˈɑːræʊ]) is a town, a municipality, and the capital of the northern Swiss canton of Aargau.  The town is also the capital of the district of Aarau.  It is German-speaking and predominantly Protestant.  Aarau is situated on the Swiss plateau, in the valley of the Aare, on the river's right bank, and at the southern foot of the Jura Mountains, and is west of Zürich, and 65 km northeast of Bern.  The municipality borders directly on the canton of Solothurn to the west.  It is the second-largest town in Aargau after Wettingen.  At the beginning of 2010 Rohr became a suburb of Aarau. Rhein-Mosel is a "Verbandsgemeinde" ("collective municipality") in the district Mayen-Koblenz, in Rhineland-Palatinate, Germany.  It is situated along the lower course of the river Moselle, south-west of Koblenz.  The seat of the municipality is in Kobern-Gondorf.  It was formed on 1 July 2014 by the merger of the former "Verbandsgemeinden" Untermosel and Rhens. Tarasp is a former municipality in the district of Inn in the Swiss canton of Graubünden.  Its eleven settlements are situated within the Lower Engadin valley along the Inn River, at the foot of the Sesvenna Range.  On 1 January 2015 the former municipalities of Ardez, Guarda, Tarasp, Ftan and Sent merged into the municipality of Scuol. The canton of Aargau (German "Kanton"    ; sometimes anglicized Argovia; see also other names) is one of the more northerly cantons of Switzerland.  It is situated by the lower course of the Aare, which is why the canton is called Aar-gau (meaning "Aare province").  It is one of the most densely populated regions of Switzerland. Siglistorf is a municipality in the district of Zurzach in the canton of Aargau in Switzerland.
Answer: Aare