Canals are fundamental to the urban condition; arising with the first cities, canals were initially used for irrigation in agriculture, drainage, and waste disposal.  Their construction immediately enabled the generation of new forms of settlement, from metropolises in the Nile Valley to dispersed homes organized around cosmological geoglyphs in the highlands of Peru.  The first known canals appeared in Egypt around 4000 bce.

the agricultural areas enabled by irrigation canals can be seen to the north of the mountains; to the south, the geoglyphs that the nazca of peru are more famous for

Canals are slackwater channels- they are constructed water courses that allow for an optimal flow and water elevation to satisfy a given purpose.  And they are built for two main reasons:  water supply and navigation.  Within the typology of navigation canals there are three main categories:

defense (the Rideau Canal)- these canals were often large and long, forming a strategic, defensible line meant to connect points along its course.  This type of canal, as was the case with the intercoastal waterway and the Rideau Canal, was intended to add robustness to a society’s transit infrastructure in case of attack or seige by an enemy.

city network (Amsterdam or Xochimilco)- these canals were usually smaller and part of an interconnected system similar to a street grid.  They were intended for everyday traffic and accessible to most members of the mercantile and agrarian classes.

industrial (Mississippi River Gulf Outlet)- industrial canals are quite simply constructed according to a teleology:  the cheap and fast movement of massive quantities of bulk materials.  This is fundamental to the idea of the industrial changes happening in the 18th and 19th century in the Americas.

the James River in Richmond, Virginia; the Kanawha Canal is the slender channel to the north of the river at the edge of downtown; the Kanawha Canal was first surveyed and planned by George Washington; it was intended to connect trade in the Chesapeake Bay with the Mississippi River (by way of the Kanawha and Ohio Rivers), opening trade to the interior of the continent and enriching the ports of Virginia.

the Kanawha Canal in Richmond, Virginia, running by derelict grain mills

These are constructed using some combination three primary strategies:

canalization– regularization of an existing water course

channelization– creating a new channel for water to run through, often by excavation and construction of levees along the edges.

dredging– deepening, widening, and clearing of debris an existing water channel through means of underwater excavation

The focus of this project is industrial canals in urban areas where the real estate along the banks was often valuable and so called for an economy in construction of the edges.  An industrial canal boom occurred in the United States, and most other American countries, after independence was won.  As colonies, most had been maintained as landscapes of extraction and there was little need for industrial development.  With independence new emphasis was put on development of production capacity- factories- and this meant canals were needed.

The age of the industrial canal was defined by two things:  standardization and proliferation.Standardization in construction, including width and bulkhead technology, was necessary because the same ships were moving the same cargoes between different places.  Proliferation of canals occured because water-borne transportation of cargo was orders of magnitude cheaper than the overland transportation available at the time, such as the horse cart.  While some canals had been planned or even begun in the early 1800’s, it was the completion of the Eerie Canal in New York that ushered in an age of canals.  In 1784 there were no canals in the United States.  By 1850 there were over 4,500 miles of canals.  Almost all of these were approximately 40feet wide, enough to allow two barges to pass, and had a tow path along either side- sails were of no use and steamboats were practical only on larger waterways.

The introduction of the railroads three decades later meant that the early industrial canals were obsolete, being unable to compete with their economy of speed.  While canals such as the Eerie or Kanawha quickly fell in to disuse, many urban canals continued to operate; the built form that had accumulated around them lent a certain inertia to the way things were done.

Trucks and highways meant a new role for canals; canalization of rivers by the USACE had expanded the canal network to a continental scale; many war-time constructions such as the Houston Shipping Channel or Intracoastal Waterway were repurposed for super large ocean-going vessels; smaller canals that could not easily be expanded, such as those in urban areas whose expansion was limited by existing urban construction, were abandoned or turned over to sewage disposal.  This is the case with the object of our study:  The Riachuelo.


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