Question: Which river crossed the city which was at 40 km southwest from Fabro?

full_context: Document 1: Foligno railway station: Foligno railway station (Italian: "Stazione di Foligno" ) serves the town and "comune" of Foligno, in the region of Umbria, central Italy. It is also the most important railway junction in Umbria. Opened in 1866, it forms part of the Ancona–Orte railway, and is the southeastern terminus of the Foligno–Terontola railway, which links Florence with Rome.
Document 2: Province of Perugia: The Province of Perugia (Italian: "Provincia di Perugia" ) is the larger of the two provinces in the Umbria region of Italy, comprising two-thirds of both the area and population of the region. Its capital is the city of Perugia. The province covered all of Umbria until 1927, when the province of Terni was carved out of its southern third. The province of Perugia has an area of 6,334 km² covering two-thirds of Umbria, and a total population of about 660,000. There are 59 comunes (Italian: "comuni" ) in the province. The province has numerous tourist attractions, especially artistic and historical ones, and is home to the Lake Trasimeno, the largest lake of Central Italy. It historically the ancestral origin of the Umbri, while later it was a Roman province and then part of the Papal States until the late 19th century.
Document 3: Province of Pesaro and Urbino: The Province of Pesaro and Urbino (Italian: "Provincia di Pesaro e Urbino" , ] ) is a province in the Marche region of Italy. Its capital is the city of Pesaro. It also borders the state of San Marino. The province is surrounded by San Marino and Emilia Romagna in the north, Umbria and Tuscany in the west, Ancona in the south and the Adriatic Sea on the east. The province has an enclave of the umbrian common of Citta' di Castello named Monte Ruperto.The province is also known as "Riviera of Hills". It is mostly covered by hills and is popular for its beaches. The Ceramics museum and the Biblioteca Oliveriana are located in the capital city. The County Council is based in Pesaro while the headquarters of the provincial administration are in Urbino. The coat of arms of the province consists of a shield divided into two parts, each part is given the coat of arms of the two capitals. It has a robust economy with low unemployment, based on craft and small and medium industries, agriculture, tourism, resorts and cultural center. It has a very low per capita energy consumption. The art and craft industry contributes to 22% of the province's GDP. Tourism in the province plays a primary role in the local economy, the main attractions are the sea and the Apennines. The beaches of Gabicce Mare, Pesaro, Fano and Marotta are the most famous ones.
Document 4: Turin: Turin ( ; Italian: "Torino" , pronounced ] ; Piedmontese: "Turin", pronounced ] ) is a city and an important business and cultural centre in northern Italy. It is the capital city of the Metropolitan City of Turin (an administrative division of Italy) and of the Piedmont region, and was the first capital city of Italy from 1861 to 1865. The city is located mainly on the western bank of the Po River, in front of Susa Valley, and is surrounded by the western Alpine arch and Superga Hill. The population of the city proper is 886,837 (31 December 2016) while the population of the urban area is estimated by Eurostat to be 1.7 million inhabitants. The Turin metropolitan area is estimated by the OECD to have a population of 2.2 million.
Document 5: Amaro, Friuli: Amaro (Friulian: "Damâr" , Slovene: "Amar" ) is a "comune" (municipality) in the Province of Udine in the Italian region Friuli-Venezia Giulia, located about 100 km northwest of Trieste and about 35 km northwest of Udine.
Document 6: Perugia railway station: Perugia railway station, also known as Perugia Fontivegge railway station (Italian: "Stazione di Perugia; Stazione di Perugia Fontivegge" ) is the main station serving the city and "comune" of Perugia, in the region of Umbria, central Italy. Opened in 1866, it forms part of the Foligno–Terontola railway, which also links Florence with Rome.
Document 7: Fabro: Fabro is a "comune" (municipality) in the Province of Terni in the Italian region Umbria, located about 40 km southwest of Perugia and about 60 km northwest of Terni.
Document 8: Città di Castello: Città di Castello (] ) is a city and "comune" in the province of Perugia, in the northern part of the Umbria region of Italy. It is situated on a slope of the Apennines, on the flood plain of the river Tiber. The city is 56 km north of Perugia and 104 km south of Cesena on the SS 3 bis. It is connected to the A1 highway by the SS 73 from Arezzo (17 mi). Città di Castello has an exclave named Monte Ruperto within Marche.
Document 9: Terenzo: Terenzo is a "comune" (municipality) in the Province of Parma in the Italian region Emilia-Romagna, located about 100 km west of Bologna and about 30 km southwest of Parma. As of 31 December 2004, it had a population of 1,250 and an area of 72.4 km2 .
Document 10: Deruta: Deruta is a hill town and "comune" in the Province of Perugia in the Umbria region of central Italy. Long known as a center of refined maiolica manufacture, Deruta remains known for its ceramics, which are exported worldwide.
Document 11: Riolo Terme: Riolo Terme is a "comune" (municipality) in the Province of Ravenna in the Italian region Emilia-Romagna, located about 40 km southeast of Bologna and about 40 km southwest of Ravenna. The main attraction of the town are the termal baths.
Document 12: Assisi: Assisi (] , from the Latin: "Asisium" ) is a town and "comune" of Italy in the Province of Perugia in the Umbria region, on the western flank of Monte Subasio.
Document 13: Fanna: Fanna is a "comune" (municipality) in the Province of Pordenone in the Italian region Friuli-Venezia Giulia, located about 100 km northwest of Trieste and about 25 km northeast of Pordenone.
Document 14: Perugia: Perugia (] ; ) is the capital city of both the region of Umbria in central Italy, crossed by the river Tiber, and of the province of Perugia.
Document 15: Mount Fumaiolo: Mount Fumaiolo (Italian Monte Fumaiolo) is a mountain of the northern Apennines range of Italy located in the southern-most corner of the Emilia-Romagna region, c. 70 km from the town of Cesena. It is at the border Emilia-Romagna and Tuscany. With an elevation of 1407 m , Mount Fumaiolo overlooks the villages of Balze di Verghereto, Bagno di Romagna and Verghereto, in Romagna, and thanks to its extensive fir and beech forests, it is a well-appreciated tourist area of natural interest. It is most famous for being the source of the Tiber, as well as the river Savio.
ground_truth: Tiber