Indians have a long history of storing water to tide through periods of deficient rainfall.
The country's oldest rainwater harvesting infrastructure dates from about 4,500 years ago when the Harappans in present-day Dholavira, Gujarat built reservoirs that occupied 10% of the city’s area.
In Karnataka, among the oldest water storage structures are those found at Iron Age sites like Hirebenakal in Koppal district which are approximately 2,500 to 3,000 years old. One of the first mentions of a tank in Karnataka comes from Banavasi where a beautiful 2nd century inscription records the construction of a tank by an official named Khadasati. From 6th century onwards, we have numerous epigraphs from around the state which mention the construction of tanks or reservoirs.
Across India, the provision of water was understood to be an important function of any good ruler. But this does not mean all reservoirs were built by rulers. In fact, most were built by ministers, merchants, chieftains or other elites for whom this was an act of both religious and political merit.
Essentially, such reservoirs consisted of a bund or small dam built across a valley so that water from small streams or run-off could collect behind it. The lakes that we see in cities like Bengaluru, Mysuru or Dharwad, for example, were all built this way. Many tanks were built in chains, with overflow from one flowing into the next one in the series.
Along with the tank would be constructed a sluice gate, which served to regulate water flow into irrigation channels. Essentially, it consisted of two stone pillars that supported two or three crossbars, each with a hole through its centre. The irrigation channel opened right under these pillars and went through or below the embankment to fields on the other side. The flow of water could be stopped with a piece of wood that blocked the channel’s opening. This wooden plug could be raised or lowered with a rope or pole that passed through the holes in the crossbars.
Like other forms of architecture, sluice designs were often characteristic of a particular period.
Hoysala sluices
Aravazhi Parthan, Assistant Archaeologist, Mysore Excavation Branch, Archaeological Survey of India, says, "The ornamentation, the carvings of animals, Gajalakshmi, or other motifs, are all very unique in Hoysala sluices."
Like their temples, sluices of the Hoysala period were usually built with schist. “The sluices would originally have been reached by boat, being some distance away from the bund," says Parthan.
He points out how Hoysala-period reservoirs usually have a single-roomed structure at the bund, at a point closest to the sluice. “These are often called shrines, but originally, they would have been for the use of the man who actually operated the sluice gates,” he speculates.
Vijayanagara sluices
Sluices of the Vijayanagara period are also distinctive and bear a strong resemblance to their temples, writes anthropology professor Kathleen Morrison, at the University of Pennsylvania. Vijayanagara period sluices were built of granite and had capitals, brackets and mouldings that were reminiscent of temple architecture. The lintels and pillars often had carvings of deities, and sometimes also ‘portraits’ of the donor.
Sluices with four pillars, which evoked temple gateways and mantapas even more strongly, were commonly built in this period. There are several sluices in this pattern around Hampi and Ballari, and also around Bengaluru and Mysuru.
While many of these centuries-old reservoirs are still in use, there are hundreds that have gone dry. And with that, the original purpose of the stranded sluice is quickly forgotten.
In Mysuru, for example, where the Doddakere is now a vast, dry bed, its sluice gate is mistakenly but commonly thought to be a watchtower. In some places, the sluices develop new cultural associations. A few have become shrines. Elsewhere, there is a tradition of offering baagina at sluices.
Even in reservoirs that are still functional, the old sluices have either disappeared or fallen into disrepair, thanks to shrinking water bodies, modern canals replacing the old irrigation channels, and buildings being erected on the old waterways.
Ten years ago, Bengaluru's vast Kudlu kere had a granite two-pillar sluice. Today, the lake has shrunk to a fraction of its former size and has gained a walkway but lost its historical sluice gate.
Unfortunately, there are also several old sluices that are almost abandoned in the dustbin of history. In the Kempambudhi Kere in Bengaluru, two possibly 16th century sluices were until recently marooned in islands of garbage. Though the garbage was recently cleared, the sluices are still inaccessible due to thickets of wild vegetation.
These relics should be restored to showcase our ingenious traditional water management systems.
(The author is the convenor of INTACH Bengaluru Chapter and the author of Discovering Bengaluru)