(Summary of "Ingenieria prehispanica americana y sus lecciones para hoy", presented at 49th Congress of Americanists,
Quito, Ecuador, July 1997)

Prehispanic civil engineering works of the American continent have yet to receive the attention and the respect they deserve. Since the Conquest, not only the western intellectuals and builders, but also the continent’s own population ignored them. The westerners, because they aimed at firstly in looting the continent’s immense mineral wealth and secondly at transplanting a political scheme, dependent totally on western economic power centers, assuring a continuous flow of wealth in their direction. The American population, the majority mestizos, who received the politico-economic reins from the colonial administrations glorifying the western "civilization", not only ignored their own past beyond the Conquest but also destroyed it, at times intentionally. Only recently, specifically during the last mid-century, has surged among the American populations an interest in seeking an own identity based on prehispanic cultures. Hence, the need to rediscover and reevaluate the ancient systems of political and economic development.

However, the majority of the investigations about ancient engineering works deal with their anthropological or archaeological aspects. Hardly any had focused the attention on analyzing the technological know-how possessed by the ancient cultures for the benefit of modern engineers and political decision-makers.

The donors' skewed "aid" schemes convert poor countries into museums of white elephants.

The planning and design of public infrastructure works should agree with the political and economic structure of the host country, because they form the backbone of its economic development. The geography and the climate of a region also bear strongly on the feasibility and the effectiveness of a development project. However, powerful donors usually force upon the impoverished countries of the American continent engineering plans and designs prepared for Europe and the United States, whose socioeconomic, political, geographic and environmental conditions are starkly different. The imported "experts," inherently tied to financial aid, insist on transplanting familiar schemes that, in the end, convert the donor the net beneficiary, in terms of the flow of sales and wages. Such "aids" have transformed these poor countries into museums of white elephants, and as a consequence, into eternal debtors.

The teaching and the practice of civil engineering throughout the American continent also imitate to the letter the technology evolved in the last couple of centuries in Europe and in the US. The local engineers, indoctrinated through imported textbooks, feel more at ease with imported "solutions" in resolving problems than adapting their knowledge to local conditions.

This article reevaluates the current practice of American civil engineering in order to improve it incorporating the local technology of the past. An analysis of the basic principles of prehispanic engineering practice, that considers ancient public works in general, sets the background. In the complete document, we will next examine the design and construction techniques of specific prehispanic civil engineering projects. We will also analyze alongside some large recent civil works, mainly to point out the incompatibilities with local conditions of their design criteria or construction techniques.

Basic engineering concepts
Two important principles: the efficient use of the resources available and the effectiveness of a project design, set the foundation of modern engineering.

A deep analysis of prehispanic engineering works shows us that those engineers also had adhered strictly to above concepts. Of the resources available then, the tools were quite rudimentary: none of iron, some of copper and other metals, but mostly of wood and stone. Nor they had sophisticated means of transportation, only animals for carrying cargo and even that only in certain regions. The manual labor, abundant when mobilized by a strong socio-political organization, produced the bulk of the work. Another abundant resource then, compared to now, was time: the construction of many ancient works seems to have prolonged for decades, if not centuries.

Engineers of the past used manual labor & time efficiently to build structures that remained effective over long periods.

In the past the engineers must have efficiently managed these two resources, time and manual labor, because imitating their monumental works poses quite a challenge even today, despite the availability of sophisticated machinery. Unconstrained by time, they would design a project allowing a series of construction stages, each stage furnishing a stand-alone, full-fledged public use structure. Whenever the rulers decide on extending, enlarging or enhancing the structure, they could build the next stage without destroying any part of the preceding.
Huaca del Sol
of millions of bricks laid in segments
Managing the labor force presented a problem of another dimension: agglutinating around a grand task the massive army of workers, composed of many small groups proceeding from distinct villages. Primarily because they contributed labor not for money, but to fulfill collective tributary obligations. Thus, each group would respond only to the orders of its own leader. In addition, each group probably substituted its workers rotationally, from others originating from the same village. To solve such a complex labor management problem, the past engineers divided the work, at least in certain projects, into segments or tasks, each more or less independent, relatively small and simple in carrying out. To accelerate the construction, they probably competitively organized these tasks, now assigned to individual groups. Obviously, they had to employ specialized groups for unifying the segments and for final touch-ups. Such segmentation could have forced the designers to sacrifice a project’s structural complexity. However, as Uceda and others (1994) witnessed in the pyramid Huaca de la Luna in Peru, the designers had creatively used certain architectural elements of one stage for different purposes in the next, preserving the utility and the complexity of the structure.
The effectiveness of a project design depends on its capability to solve the initial problem in the long run. In evaluating the efficacy of a structure, we need to consider the realities of the ancient societies as well as their aspirations. The Inca Kingdom conceived its monumental highway system, which extends for more than 23,000 kilometers, to satisfy the need to maintain a rapid communication system between the capital city and the remote corners of its immense empire. The well-designed road system, supported by numerous tambos (rest houses), could sustain an agile mail transfer system through the chasquis (runners). They could, for example, communicate between Quito and Cuzco (the Inca capital) in less than 5 days: only several centuries later would the western societies match such a speed (von Hagen 1977).
The Inca road system
Artificial canals of Momposina swamp
The vast plains around the lake Titicaca, at the frontier between Bolivia and Peru, once covered almost entirely by camellones (artificial ridged fields), lie abandoned today due to water logging and frost. Experimental fields built imitating the ancient system of ridged fields demonstrated that the technique not only prevents frost damage, but also yields harvests greater than what the modern technology could achieve there (Kolata 1991). In Colombia, the vast Momposina swamp today cannot sustain more than 1 person per sq. km because of prolonged inundations. Yet, the archaeological evidence indicates that, 2000 years ago, during the golden era of the Zenu society, an extended system of canals and elevated fields supported a population of about 170 persons per sq. km (Plazas & Falchetti 1986).
Certain prehispanic works, especially some agricultural development projects, continue to function even today. (Obviously, here we speak of a selected group of works that survived the ordeal of the Conquest and hence cannot generalize this analysis to all the ancient works, but it does not prevent us from examining the reasons behind their extraordinary effectiveness.) In the Peruvian coast, for many centuries, local farmers have used irrigation canals and ground water recollection systems for cultivation. Their effectiveness and continuity depend on:
1) farmers understanding the technology involved,
2) the continuing need of such systems for villagers’ survival and
3) the farmers’ ability to operate and maintain the system by themselves.
Though the colonial rulers dismantled the traditional socioeconomic structure, the agricultural communities could preserve these projects because the effort involved lied within their technical and organizational capacity. In other words, these projects could be sustained using locally available resources, a concept frequently heard in relation to modern development projects as well, but limited mostly to paper.
In modern times, when a project fails, we blame the nature first. Paradoxically, mostly all modern development projects profess to fight against the nature or conquer it. Even after many costly failures, we have not yet learned that "conquering the nature" is only an illusion, sold by the manufacturers of expensive machines and materials. In tackling the nature, prehispanic engineers seemed to have used a nonconfronting, nonconquering philosophy –one of conviviality. For example, the ancient system of flood control in the lower Guayas river basin in Ecuadorian coast, which had modified more than 50,000 hectares of swamp land with canals and ridged fields, never contemplated blocking off those high flowing rivers in the catchment. Instead, that system allowed the peak floods to enter wide, artificial canals either side of the river, and thus lowered the flood water level keeping the farmlands and residential areas safe and dry. We cannot say that the ancient systems never suffered damages from the fury of the nature, yet they apparently tried to understand the nature and learn from their failures.

A delusive attempt at "conquering the nature"
Bajo Guayas, Ecuador

The prehispanic civil engineering works deserve recognition not only for their historical value, but also for what they can contribute to improve modern engineering: specifically, their emphasis on
1. long-term planning
2. efficient use of local resources
3. the philosophy of living in harmony with the nature
4. the willingness to learn from the errors and
5. the true sustainability of the projects.
In future investigations of prehispanic works, engineers should play an active role, in directing them towards obtaining greater information on design concepts and construction techniques.
Unfortunately, very few engineering projects, like the recovery of the techniques of terracing (Valerza 1993) and of chinampas (Gómez-Pampa et al. 1982), use this age-old wisdom today. We can best promote an interest on prehispanic engineering experiences among modern engineers through academic institutions, by including such themes in academic curriculum, so that we can change the current attitudes of disrespect towards local techniques and knowledge. Hopefully then, the engineers would contemplate before making crucial technical decisions, how their ancestors acted in resolving problems, and not simply promote "imported solutions" as the only way to progress.

Gómez-Pampa, Arturo, Hector Luis Morales, Epifanio y Julio Jiménez Avia
1982 Experiences in traditional hydraulic agriculture. En Maya subsistence, edit: Kent V. Flannery, Academic Press. p. 327-342.

Kolata, Alan L.
1991 The Technology and organization of agricultural production in the Tiwanaku state. Latin American Antiquity 2(2): 99-125.

Plazas, Clemencia y Ana María Falchetti
1986 La cultura del oro y el agua, un proyecto de reconstrucción. Boletin Cultural y Bibliografico, Banco de la República, Bogotá, vol. 23(6): 57-72.

Uceda C., Santiago, Ricardo Morales G., José Canziani A. y María Montoya Vera
1994 Investigaciones sobre la arquitectura y relieves polícromos en la Huaca de la Luna, Valle de Moche. En Moche: propuestas y perspectivas, edit: Santiago Uceda C. y Elías Mujica, Universidad Nacional de la Libertad - Trujillo, Perú, p. 251-303.

Valerza, Galo Ramón
1993 Tierras y manos indias. COMUNIDEC, Quito.

von Hagen, Victor W.
1977 La Carretera del Sol. Editorial Diana, México.

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