Irrigation - Hydraulics
C. Karl Wittfogel
Karl Wittfogel first put forth the idea that Hydraulic Management caused internal pressures for a structured organization. People were forced to become unequal leaders in order to build and maintain irrigations system Wittfogel argued. In this model, leadership develops along with the use of 
irrigation system. As the systems grow, leadership is required to not only continue to construct new canals but to maintain old ones and, most importantly, ensure water is delivered to where it is needed.
Karl Wittfogel pointed out (as Steward did) that early civilizations appeared in regions where large-scale irrigation agriculture was practiced. He attempted to explain the major political systems of the world through control of irrigation agriculture in "Oriental Despotism" (1957)
Wittfogel saw societies that relied on large-scale irrigation as what he termed "hydraulic societies". He suggested that large-scale irrigation required centralized coordination and direction. Water was a natural resource, and became a crucial variable because it could be manipulated and agglomerated in bulk. Water management was especially important in places where rainfall was insufficient, but water was available nearby, such as in semiarid river valleys.
Wittfogel believed that irrigation itself had an organizing effect: scheduling of water use, maintenance of canals, and defense of canals from hostile neighbors all were forces at work within "hydraulic societies". Wittfogel thought that while irrigation can be carried out by small groups on an informal basis, it is more efficient and leads to greater growth if there is central management. In return, the person who manages the water has tremendous power over the farmers. If one source of power is so much more important than all others, a monopoly could develop within a society according to the way Wittfogel theorized. He believed that a single-centered government arose from "oriental despotism".
Wittfogel contrasted this kind of development with what happens in more temperate climates in which rainfall agriculture prevails. Alternate bases of power can arise to give a more balanced or multi-centered government in these region.
It is clear that Wittfogel's ideas don't work for all circumstances. There are, for example, several modern communities in Mesopotamia where small-scale cooperative irrigation works without centralized external control and work sufficiently for an adequate agricultural livelihood. As well, available archaeological and historical data imply that large-scale irrigation works were not prevalent in Mesopotamia until long after the rise of the state. The hydraulic society might be viewed as a result of state formation rather than as a cause based on what we now understand. It is unlikely that Wittfogel intended to imply that large-scale irrigation works necessarily preceded centralized government. The institutions of central government and large-scale irrigation would have grown side by side with expansion of irrigation systems and greater reliance upon these systems. Small-scale irrigation would have required a certain amount of administration, which would have expanded the irrigation system, which in turn would have required greater administration and so forth.
It was not irrigation itself, but the centralized coordination of irrigation activities that had important social consequences. It is possible that centralized administration and large-scale irrigation works were present at an early date, but because their growth was not incremental, they only became obvious in the archaeological and textual records after they had reached major proportions.
In another sense, the ancient Maya civilization arose in an area where irrigation was of marginal importance (though water control and management were important activities.) This along with central Mexican and Incan civilizations suggests that other forces may equally be important and that irrigation is not the sole reason for increased complexity.