Tresa
Lake Maggiore
['Ussuri River', 'Chesapeake Bay', 'Ganges River', 'Great Stour river', 'Chilkat River', 'Humber Estuary', 'Ob River', 'Indus River', 'river Weser', 'Aveyron River', 'Altamaha River', 'Caspian Sea', 'Cumberland River', 'Tampa Bay', 'Newark Bay', 'Squamish River', 'Guyandotte River', 'Skagit River', 'Segre', 'Wissahickon Creek', 'River Danube', 'Lake Onega', 'Oostanaula River', 'River Rhine', 'Santiam River', 'Sacramento', 'Wabash River', 'Canadian River', 'Lena', 'Clutha', 'Illinois', 'Xi River', 'Des Moines River', 'Cooks River', 'Monongahela River', 'Colorado River', 'Aras River', 'Mackenzie River', 'Tanana River', 'River Severn', 'Limpopo River', 'Yellow River', 'Roanoke River', 'Lake Ladoga', 'Lake Memphremagog', 'River Eden', 'River Spree', 'Chenango River', 'Klamath River', 'Connecticut River', 'Harrison Lake', 'Sava', 'Mediterranean Sea', 'Chesapeake Bay watershed', 'Platte River', 'Little Kanawha River', 'Hudson Bay', 'Kolyma River', 'Walhonding River', 'Agano River', 'Moose River', 'Susquehanna River', 'Sava River', 'Heilong River', 'Awash', 'Essequibo River', 'Amu Darya', 'Karun River', 'Pranahita River', 'Northern Dvina River', 'Millstone River', 'Rhine', 'River Trent', 'Roaring Fork River', 'Long Island Sound', 'Nan River', 'Wallkill', 'Kama', 'Murrumbidgee River', 'Illinois River', 'Copper River', 'Snake River', 'Yakima River', 'Moselle', 'North Platte', 'Columbia River', 'Brahmaputra River', 'Bighorn River', 'Saint Lawrence', 'Don River', 'Rio Negro', 'Narew river', 'River Elbe', 'Liard River', 'Kiskiminetas River', 'Colorado', 'Conestoga River', 'Kootenai River', 'Dnister']
Margorabbia
The Margorabbia is a ‘torrent’—or intermittent stream—of the province of Varese in north Italy’s Lombardy, a tributary of the Tresa which it joins a few hundred metres upstream of Lake Maggiore. The source is near Valganna. After forming a number of small lakes, including Lago di Ganna and Lago di Ghirla, its course continues through the Prealps of Varese until near Cunardo it is swallowed up by a system of caves: Pont Niv, Antro dei Morti, Grotte di Villa Radaelli and Grotte del Traforo. It emerges from underground near Ferrera di Varese and runs through the Valtravaglia crossing the valley’s communes of Grantola, Mesenzana and Germignaga. A cycle path has recently been constructed along this part of the river. The torrent has many affluents. The most important left side tributaries are the Rancina, the Boesio and the Gesone; from the right it receives the waters of the Boggione, the Lisascora and the Grantorella. Thanks to the wet and karstic areas it traverses, the Margorabbia has a generally high discharge and dries up far less frequently than many torrents. These feature made it a useful source of power for the mills and factories which grew up along its banks. The power hammers of Ghirla in the commune of Valganna are particularly well known. The river is subject to sudden and dramatic increases in its flow, becoming truly ‘torrential’. Very often bridges have been destroyed, or it has broken its banks and caused severe flooding in the Valtraviglia. Today many artificial embankments have been constructed along the Margorabbia for the purposes of flood protection.