There is no dearth of literary references pertaining to irrigation in the Mauryan period. Archaeological excavations attest the presence of several terracotta ring wells at Hastinapur, New Delhi, Ropar, Ujjain and Nasik. These have also been reported in Eastern UP and Bihar.
Although not all of them were used for irrigation purposes, there is evidence that the water from brick well at Ujjain irrigated the fields. Many tanks (including the votive ones) have been discovered at Taxila, Hastinapur, Udaipur, Ahicchatra (in Bareilly), Kausambi and Bhita. A number of tanks found at Mathura were also being used for irrigation.
What is noteworthy about these tanks and wells is that these were mostly located in areas where irrigation was necessary. In comparison, there was a relative paucity of wells, tanks and canals in the central Gangetic plains. There was general increase in the number of wells in the post-Mauryan period notwithstanding the decline in the number of ring wells.
The significance attached to artificial irrigation underwent a change during state- formation. Here, the reasons more than cause of subsistence were economic and political. Greater attention was paid to agriculture for it was the primary source of revenue. In the Swat region a tank was developed in 29 AD under the instructions of Theodorus, the Datiaputra.
The region of Saurashtra bears testimony to the history of Sudarshan Lake. Later the dam of the lake was badly damaged because of heavy flooding. In the second century AD this lake was renovated under Saka ruler Rudraman. Similarly, king Kharvela extended an old canal in Kalinga.
At Besnagar in Madhya Pradesh is found an old canal. The Bes River was located about two furlongs from this canal. It has been suggested that this canal was perhaps an inundation canal because rivers in this part of the country overflow in the rainy season and remain dried up in the summer.
As far as the role of state is concerned, some of the irrigation sources necessitated state’s initiatives. The initial outlay of the canal required huge expenses and hence was beyond the means of individuals and communities. They could build relatively less expensive tanks but these tanks could not irrigate large areas.
It was only with the publication of Karl A. Wittfogel’s work on “Oriental Despotism” that the studies on water resources and it’s relation with the state gained impetus. Wittfogel proposed that the requirement of large-scale irrigation in arid or semiarid region led to an enormous hydraulic organisation, which in course of time became the source of agro-hydraulic despotism. Organisational forms developed inevitably because water’s specific properties needed task management.
Wittfogel’s contention is that the hydraulic route was a deliberate choice for it provided productive benefits. In such a system the state became all powerful and acquired matchless military power with even the dominant religion fused within the structure.
Wittfogel classified the Mauryan Empire as a grandiose hydraulic economy. No legal and social pluralism was allowed to exist in a hydraulic state and its absolutist nature remained undisturbed. To enhance the plausibility of his theory, Wittfogel applied to it all the central elements of ‘totalitarianism’. He devised the theory of ‘diffusion and generalisation’ in order to Explain variations from his ideal model. Variation, according to him occurred due to the coreness of the area and its relation to marginal and sub-marginal regions.
Property rights, which were weak in a hydraulic state, also formed the basis of variation, viz. (a) simple, (b) semi-complex and (c) complex. Indian case ‘was picked up as a semi-complex model. The relation with the state determined class position in such a society. The ruled did not participate in the state process.