Editing Hydromanagement in Ancient India (section)

=== '''The Sringverapura Tank''' ===
The Sringverapura tank is one of the most spectacular instances of an ancient Indian water tank. It was discovered in Mathura, in the northern Indian state of Uttar Pradesh (formerly known as Uttar Pradesh), and was filled with water from the Ganges via a conduit. The Feeding Channel was formed by severing the nullah's banks and redirecting excess water into a specially dug channel. The feeding canal was roughly 11 meters wide at the top but just 3 meters wide at the bottom because of its landing sides. The water from the Feeding Channel entered a silting chamber, which was not in a direct line with the Feeding Channel but to its side, causing the water to lose some of its force before entering the chamber. In addition, the bottom of the silting chamber was approximately higher than the bottom of the feeding channel. This increase in the bottom level prevented a substantial amount of silt and other debris from entering the silting chamber. The water from the silting chamber entered the brick tank, whose several sections are labeled A, B, and C on the design. Before the Inlet Channel, there is a stepped ledge through which water goes from the silting chamber to Tank A. This stepped ledge was quite effective at halting the onslaught of the rushing water. The bottom of the inlet channel was similarly higher than the bottom of the silting chamber. This configuration prevented the silt in the bottom portion of the silting chamber's water column from entering Tank A and lowered the water thrust. Water cascaded down a series of steps, entering a larger area before reaching the ground. Such measures were taken so that the raging river water was calmed before it could even reach the floor of the first sector of the Brick Tank. A vertical wrapping approach with a set of three retaining walls sloping against the natural soil in Tank A This was done to prevent the walls from collapsing under the force of the incoming water. If there had been a single vertical wall as opposed to many sloping and terraced walls, the structure would have been more susceptible to the thrust. In addition, a horizontal wrapping technique was utilized, in which tank A gradually widened as it moved away from the inlet channel. This was done to permit the horizontal distribution of incoming water. Its base dips toward the south, which is opposite the Inlet Channel. The effect was that any remaining silt in the water was transported to the southern bank and permitted to settle there. In the south-east corner, a staircase was installed to periodically remove this silt. During the summer, when the water level would have been lower, it would have been most convenient to perform this task. To ensure that only pure water reached tank B, a linking tunnel was constructed higher than tank A. This portion of the tank complex served as the primary source of drinking water. Tank C, which will be discussed shortly, was smaller and appears to have been utilized for religious purposes as opposed to supplying water. Similar to the top of Tank A, a series of cascading steps, vertical and horizontal wrapping techniques, and a slightly elevated floor were utilized. Regarding the level of water kept in the tank complex, it was dependent on the base level of the Inlet channel, as any excess water over that level would have returned after the flood receded. All of this must have been sufficient for the time from September to June when there was no input. If this ran out, the water in Tank A, which was not as clean as that in Tanks B and C, would have also been used. In this context, it must be mentioned that the water from this tank complex was not intended for the entire town's inhabitants, but only for those who resided nearby. For others, particularly those who lived within a reasonable distance of the river, the river must have remained a convenient source of food. The hydraulic engineers also considered the possibility of evaporation, particularly in the post-winter months beginning in April. So as to overcome the probable scarcity, they devised an alternative device. In the tank's base, they dug wells that connected to the subsoil water. The pressure mechanism indicates that as the water table in the tank dropped, the subsoil-water wells must have become increasingly active. While the provision of sub-soil-water wells in the bed of the tank automatically guarded against water loss through downward seepage, the bricks of the retaining walls were extremely close together, leaving little passage for water, and the natural soil behind these walls was hard and compact, absorbing very little water. Since Tank B was the primary source of water, staircases were installed along its sides at regular intervals to allow people to access the water level and retrieve it. The water entering Tank B was extremely pure. Therefore, no stepping-up mechanism was deemed necessary in the canal connecting Tank B and Tank C. This waterway, unlike the Inlet Channel and Interconnecting Channel, was sufficiently wide and was definitely utilized for water retrieval and related activities, as evidenced by the staircases that fell into it. Tank C stands alone due to its circular design. An intriguing feature is the staircase that began at the then-ground level in the east, wound to the west and south, and fell all the way down with several landings in between. The presence of a considerable number of terracotta figures of gods and goddesses in Tank C, some in the lower deposits but the majority in the detritus, suggests that religious structures once stood nearby. Only parts of the clay statues were available. However, they can be identified as sections of the figures of Kubera, Shiva, and Parvati, among others. It is evident from this collection that Sringaverapura was a genuine religious center. Also, a well-thought-out waste weir was required to release excess water. Regarding the brick tank, Tank C was the final unit. Consequently, the surplus water had to be released via Tank C. Since the river is situated to its south, the river's outflow is organized through its southern portion. There was a set of six channels carved into the natural soil, as well as the remnants of a few bricks indicating their intentional use as overflow routes. It is evident from the preceding that the ancient hydraulic engineers who conceived and built the tank took every effort to assure its safety. This voluminous effort requires a substantial budget, a high level of technical expertise, and administrative oversight. It appears, by a process of elimination, that only a monarch with all his resources could have erected it. Circumstantial evidence suggests that the architect may have been King Dhanadeva of Ayodhya, whose territory included the location of Sringaverapura. Regardless of who constructed it, the Brick Tank unearthed in Sringaverapura is a testament to the expertise of Indian hydraulic engineers two thousand years ago (Lal, 1993)<sup>19</sup>.