The economics of water supplies to cities and towns..
Water stress in summers...some back of envelop calculations...
Is it necessary that urban areas have to face water stress in summers. India is blessed with so much precipitation, that water should be the least of anyone's worries...but reality is just the opposite.
Take a typical city in India...the overall urban density of population is about 3000 persons per sq Km... the annual precipitation is 800 mm...so one sq.Km gets about 800,000 cu meters of water from God every year....that is 800 million liters of water.
One person can comfortably survive with about 100 liters of water per day...that is less than 40,000 liters per year....for 1,000 persons, 40 million liters would be required...so each sq Km with 800 million liters supply from God, 20,000 persons could be easily supported...
The density of population of Class 1 cities is only 7,000 per sq. Km...the density of Class 2 cities is 3,000...and smaller towns it is much less...
Thus even the most heavily populated cities in India need not look for external sources of fresh water supply...
But India does not believe in doing things in a straight forward and simple manner...
The government drives away poor farmers in remote areas to build huge dams which submerge productive farmlands and deprive millions of their livelihoods...then it drives away many more to build canals to transport the water to cities and towns...
The government of India is basically acting as an invasion force...it uses the might of the state to transfer wealth from the poor to itself and its employees...it drives away poor farmers and tribals from their lands, it invests in huge projects like dams and canals for bribes and kickbacks...no wonder we have naxalites and separatists spawning all over the country...
The right model for water management is the one implemented by Anna in Ralegan and Rajendra Singh in Alwar...India gets most of its rain in the monsoon season and any specific area actually gets its quota of rain in a dozen sharp showers...so it is very important to harvest this water into underground aquifers before it evaporates in the strong summer sun or joins larger rivers to eventually flow into the sea...
So instead of building mega dams on large rivers, it is best to build numerous small watershed bunds on small seasonal streams...the water collected after each shower quickly percolates underground and recharges all aquifers in the vicinity...
The rising water table lowers the cost of pumping out water for irrigation and makes water accessible for small farmers who cannot afford expensive submersible pumps which are the only way to pump out water from great depths when the water table is too low...
Another coincidental advantage is that the underground water is evaporation proof and the overflow from the aquifers feeds the larger rivers downstream throughout the year maintaining even flow in them while preventing catastrophic flooding during monsoons...
So why do governments do not follow this sensible policy and instead go about displacing people who have no voice...the answer lies in human greed...large projects generate large opportunities for graft, kickbacks and extortions....and money is the mother's milk for all political activity in this country...so these hoodlums will keep brainwashing all citizens that dams are good for the country and stuffing their pockets with the moolah in undisguised glee...
Just how much energy and expense is required to lift water from underground water tables or aquifers...
10 Joules are required to lift one liters of water one meter.
One unit of energy i.e. one KWH has 36,00,000 Joules.
One family of 5 persons needs 200,000 liters of water per year.
If with good water harvesting, the water table is at 20 meters depth, then the energy required for lifting 200,000 liters of water up by 20 meters is 40 million joules.
This is a little less than 10 units of electricity...or about Rs.50 expense per year...
Even if the water table is at 60 meters depth, the expense for lifting the water is only Rs. 150 per year per family of 5 members...
So it makes a lot of economic sense for the government to focus entirely on making underground water available to all citizens. This can only be done by strategically recharging underground aquifers by following the lead given by visionaries like Anna and Rajendra Singh...Anna is not even a high school graduate...so he would not even understand all these calculations...but all geniuses have an intuitive understanding of the optimal path to a solution...
Compare this with the expense of driving out farmers from their land, hearth and homes to build mega dams on rivers hundreds of miles away from cities, building expensive canals to transport the water and then running an inefficient and corrupt municipal water supplies department which runs the constantly corroding infrastructure...
Why don't governments follow this sensible approach to water management...because building water infrastructure creates opportunities for graft, kickbacks and extortion in addition to the creation and growth of vast patronage networks that ability to provide government employment on the basis of caste, region, religion and other identity politics brings...