Portage

Paved section of the Diolkos

The Diolkos was a paved trackway in Ancient Greece which enabled boats to be moved overland across the Isthmus of Corinth between the Gulf of Corinth and the Saronic Gulf. It was constructed to transport high ranking Despots to conduct business in the justice system. The 6 km (3.7 mi) to 8.5 km (5.3 mi) long roadway was a rudimentary form of railway,[2] and operated from around 600 BC until the middle of the 1st century AD.[3] [4] [5] [6] The scale on which the Diolkos combined the two principles of the railway and the overland transport of ships was unique in antiquity.[2]

There is scant literary evidence for two more ship trackways referred to as diolkoi in antiquity, both located in Roman Egypt: The physician Oribasius[7] (c. AD 320–400) records two passages from his 1st century AD colleague Xenocrates, in which the latter casually refers to a diolkos close to the harbor of Alexandria, which may have been located at the southern tip of the island of Pharos.[1] Another diolkos is mentioned by Ptolemy (AD 90–168) in his book on geography (IV, 5, 10) as connecting a false mouth of a partly silted up Nile branch with the Mediterranean Sea.[1]

Writing in the first half of the eighth century, Cosmas of Jerusalem describes the portage of boats across the narrowest part of the Thracian Chersonese (Gallipoli Peninsula) between the Aegean Sea and the Sea of Marmara. The peninsula there is six miles wide. Cosmas describes the dragging of small boats as common in his day for local trade between Thrace and Gothograecia. The motivation for this practice was to avoid the long detour around the peninsula and through the Dardanelles, but also to avoid the customs house at Abydos. It would have been too costly to regularly move large ships across the peninsula, but Cosmas says that Constantine IV did it, presumably during the blockade of Constantinople (670/1–676/7) when the Sea of Marmara and the Dardanelles were controlled by the Umayyads. Constantine is said to have "driven" the ships rather than dragged them, probably indicating the use of wheels.[8] Archaeological evidence for a portage across the Thracian Chersonese is lacking, but it is possible that traces of it have been confused with traces of the Long Wall, which was restored by Justinian I in the 6th century. The region also saw extensive damage during the Gallipoli Campaign of 1915.[9]

A map of the trip of the Venetian warships.

The land link between Adige river and Garda lake in Northern Italy, hardly used by the smallest watercraft, was at least once used by the Venetian Republic for the transport of a military fleet in 1439. The land link is now somewhat harder because of the disappearance of Loppio lake.

Yermak Timofeyevich and his band of adventurers crossing the Ural Mountains at Tagil, entering Asia from Europe

In the 8th, 9th and 10th centuries, Viking merchant-adventurers exploited a network of waterways in Eastern Europe, with portages connecting the four most important rivers of the region: Volga, Western Dvina, Dnieper, and Don. The portages of what is now Russia were vital for the Varangian commerce with the Orient and Byzantium.

At the most important portages (such as Gnezdovo) there were trade outposts inhabited by a mixture of Norse merchants and native population. The Khazars built the fortress of Sarkel to guard a key portage between the Volga and the Don. After Varangian and Khazar power in Eastern Europe waned, Slavic merchants continued to use the portages along the Volga trade route and the Dnieper trade route.

The names of the towns Volokolamsk and Vyshny Volochek may be translated as "the portage on the Lama River" and "the little upper portage", respectively (from Russian волок volok, meaning "portage", derived from the verb волочить voločitʹ "to drag").

In the 16th century, the Russians used river portages to get to Siberia (see Cherdyn Road).

Tarbert is a common place name in Scotland and Ireland indicating the site of a portage.

Portages played an important role in the economy of some African societies. For instance, Bamako was chosen as the capital of Mali because it is located on the Niger River near the rapids that divide the Upper and Middle Niger Valleys.

In the Adirondacks at portages that were heavily used, horse-drawn wagons like this one were furnished with racks for carrying several boats at once, for a fee. This example is typical of those used in the 1890s. (Adirondack Museum).

Places where portaging occurred often became temporary and then permanent settlements. The importance of free passage through portages found them included in laws and treaties. One historically-important fur trade portage is now Grand Portage National Monument. Recreational canoeing routes often include portages between lakes, for example, the Seven Carries route in Adirondack Park.

Numerous portages were upgraded to carriageways and railways due to their economic importance. The Niagara Portage had a gravity railway in the 1760s. The passage between the Chicago and Des Plaines Rivers was through a short swamp portage which seasonally flooded and it is thought that a channel gradually developed unintentionally from the dragging of the boat bottoms.[10] The 1835 Champlain and St. Lawrence Railroad connected the cities of New York and Montreal without needing to go through the Atlantic.

Many settlements in North America were named for being on a portage.

Portages existed in a number of locations where an isthmus existed that the local Māori could drag or carry their waka across from the Tasman Sea to the Pacific Ocean or vice versa. The most famous ones are located in Auckland, where there remain two 'Portage Road's in separate parts of the city. The small Marlborough Sounds settlement of Portage lies on the Kenepuru Sound which links Queen Charlotte Sound at Torea Bay. Portage_Road in the Auckland suburb of Otahuhu has historical plaques at both the north and south ends proclaiming it to be 'at half a mile in length, surely the shortest road between two seas'.