Ironically, while monsoon flooding creates its own set of problems of excess water, all our major cities are still coping with almost chronic shortages of drinking and other water supplies.

Water supply appears to be shrinking. It is not really so; it only appears so because ground water is being depleted rapidly as no provision is being made for its replenishment. On the contrary areas that earlier soaked up monsoon rain waters are now being plastered over for modern activities.  

The Caste Angle and Water Management

Modern dams tend to be built in hilly tracts, far from the irrigable areas, uprooting the already underprivileged to provide irrigation and other water facilities down lengthy canal systems to areas far downstream, which draw the economic benefit of the facility created with public funds.

Unlike modern day big dams which trap at best 10-20 percent of the precipitation, allowing the rest to flow away to save the massive dam structures, ancient reservoirs were designed to capture the flow from a designated catchment area. When full, the overflow was routed to similar reservoirs further downstream, all the way down until it reached the river or the sea, with enough stoppages of water on the way to allow sufficient percolation into the underground water table.
The virtually unending series of tanks and ponds dotting the countryside served not only for storage of water, but also reduced the damage from flash floods and from soil erosion, improved percolation and soil moisture, but also encouraged more greenery (and therefore more rains) and maintained the atmospheric humidity regime.

At one time, of the 43477 tanks in Karnataka, nearly 50% irrigated less than ten acres. The emphasis was 'small is beautiful' and self help. Large tanks were funded by philanthropy or kings.

Another specific example is the complex system of "overflow irrigation" which gave ancient Bengal its legendary prosperity; the destruction of which has bred nothing but malaria and poverty. Described in detail by Sir William Willcock, the system appears to have been constructed in the Ganga and Damodar valleys during the Chola regime 2000 years ago, inspired by Egyptian irrigation systems on the Nile.

Long, continuous, fairly parallel broad and shallow canals covered the region. At the head, they carried river water and at the tail rainwater drained from the fields. Irrigation was performed by breach in the banks of canals which were closed when the floods were over.

After heavy rainfall when the rivers received floodwater, the banks embanked with mud were breached at appropriate times and the flood waters were taken into the canals. If not diverted at the appropriate time, this could wreck havoc with inundation.

The heads of the canals were so located that the upper layer of muddy water from the floods, rich in fine clay and free from coarse sand would enter the canal. While the rains were sufficient to feed rice cultivation, the light silt soil was easily eroded and needed irrigation of clayey waters. The muddy and clayey early flood waters served the purpose of fertilization of the fields. Excess was then drained off by the field drains.

This engineering marvel served a distinct ecological purpose as well. While the overflow irrigation did its work, the damp bred mosquito larvae in millions. The muddy river waters brought in thousands of fish eggs, which traveled through the canals into the fields full of mosquito larvae, clearing the area of any threat of malaria. And the protein-rich fish ushered in general health throughout the region. 
The destruction of the system in the late nineteenth century converted the canals into stagnant pools breeding malaria and poverty.

Imagine the genius of Madhya Pradesh's tribals, who create intricate water systems over terrains, in channels with abysmal rises, to take water UPSTREAM, tens of kilometers around hills to water their fields on the plateaux. The work is extremely painstaking, in the channels, the land rise barely visible to the eye, except when one surveys the end result, actually seeing water travel upstream to heights of even over 100 ft.

Such communities bear great grudges against the modern espousal of tubewells and individual wells, as opposed to the earlier trends of communal assets. They claim that tubewells may bring prosperity to the person who puts down the well, but pumping out the water from deep underground acquifiers drains the wells of the surrounding fields, affecting the harvests of the neighboring farmers.

The Arthashastra recommends that the king shall construct reservoirs (setu ) filled with water either perennial or drawn from some other source. Alternatively he might provide sites, roads, timber and other necessary things to those who constructed reservoirs of their own accord or on a communal basis. Since the creation and upkeep of reservoirs was a communal effort, rather than an official governmental one, the reservoirs must, of needs, be of a manageable size.

Annual maintenance and repairs of the water systems was a communal voluntary effort, almost like a village festival; according to the Arthashastra, even compulsory for all, either in person, or by the sending of deputies.

Punishments are laid down for " defaulters "

'whoever stays away from any kind of cooperative construction (sambhuya setubandat ) should send his servants and bullocks to carry on his work, should have a share in the expenditure but should have no claim on the return. The natural overflow of water from higher tanks to tanks lower downstream shall not be stopped unless the lower tank has ceased to be useful for three consecutive years."

Severe punishment is prescribed for offenses, including emptying a tank of its water. Persons found letting water out of the tank or stopping the water from the fields of others during their time are to be fined.

After the arrival of the British and their known penchant for "divide and rule", the tensions generated between landowners and lower caste tenants undermined the voluntary system. Finally caste chickens came home to roost and the government of the day was forced to take over maintenance, which never happened. Today we have a legacy of big dams with non existent canals.

State and central governments routinely allocate funds for the construction of dams, sometimes for the canals also. Even in the case of the Narmada Main Canal, touted as the largest canal system in the world, ultimately, the Narmada Nigam has had to virtually steal the dam funds, possible only on account of the stay on the construction of the dam. Once the Supreme Court gave permission for the raising of the height of the dam, work on the canals has stalled and flash floods are the order of the monsoon day.

British India, with its rural vested interests such as zamindars, ryots and transferable village officials spelt the death of communal responsibilities and communal control over communal assets. This lasted for centuries until the creation of the modern panchayat system with its electoral conundrums.
It took the imposition of foreign systems in all administrative and other walks of life during the British era to subvert them, spelling doom to village democracies, and the systems dependent on them. This covered all facets of village life, from revenue and assessment to water courses and distribution, down to even a social structure like caste.