After devastating floods in mid-August made global headlines when entire swaths of Kerala was inundated for several days, the regions that saw the worst flooding are now reeling under acute water scarcity. Not only rivers, distributaries, and local streams but wells in some areas have also gone bone-dry, leaving locals struggling to find even drinking water.
Now, leading water resources engineer Dr Madhusudan CG (a doctorate in Hydrology and Climate change from IIT Bombay), who is himself facing the brunt of this scarcity, has raised an alarm over Kerala's water shortage.
“On the face of it, hydrologically speaking this is good for the soil as it will make the ground better prepared for the next monsoon, but the drought situation will be a challenge over this year. Apart from trying to conserve the North Eastern rains from October or providing tankers nothing else can be done,” he said.
Dr Madhusudan explained how the hydrology of the west coast of India, and the Western Ghats in particular, is significantly different from other parts of the country.
“This region receives a huge amount of rainfall, thrice the national average, mostly (75-85%) during the southwest monsoons (June-September). There will be active and break rainfall spells during this period. This year, apart from the early onset, it was super active during the initial phase, contrary to the normal behaviour. By the end of the second week of July, all streams were flowing bank full, almost all the reservoirs were at their full storage capacity and well water levels were almost at the soil surface,” said the scientist who himself hails from Thaikkattussery near Ollur in Trichur district.
He pointed out how rainfall received in the forested hills and slopes of the Western Ghats flows through the soils and not as overland flows above the ground surface like in the Indo-Gangetic plain.
“Due to the high porosity of the soil, water infiltrates vertically through the soil column and recharges the groundwater. Once the groundwater levels are above a certain threshold (i.e. near the surface) water will be released through numerous natural micro/macro tube like holes inside the soil (called ‘soil pipes’) which is present near the surface. Water can move laterally through these holes much faster than through the soil matrix. Water can be drained safely through the hill slopes towards the stream banks through these natural soil pipes.
"By July end, the soil in the hills and slopes of the Western Ghats and plains were supersaturated. The heavy spell of rain in August's second week, after a short break in the preceding weeks, put more pressure on these soil pipes which lead to swelling in its size and water carrying capacity. The increased size of these soil pipes provided safer passages to the flood waters, thus preventing the total collapse of these fragile hill slopes across the Ghats,” he said, emphasising how sites of occurrence of landslides were mostly in places of human intervention where these natural soil pipes are obstructed.
According to him, “The increased size of the soil pipes drained out water much faster than normal and it led to the lowering of river water level in the wells and streams across the state. Since the pipes are still engorged even if we receive good northeast monsoon, water will drain faster and we are going to face an extreme drought condition. The severity of the drought will vary from place to place depending upon the hydro-geology.” Incidentally, the well in his own home is dry.
The Kerala government, meanwhile, is choosing to downplay the whole issue. “The government has ordered a study into the phenomenon. Meanwhile, we are telling people not to panic,” the Water Resources Minister said.
He insisted that the wells have dried up due to their being emptied out by people trying to clean them after they were submerged. “In a few days, the water will gather in the wells again.”
Others like Himanshu Thakkar of the South Asia Network for Dams, Rivers and People pointed out how this was a man-made disaster. “Poor management of dam water is responsible for the floods has been established clearly. And the sheer current and flow took all the top soil away, destroying the groundwater system. While finding a solution to the water scarcity Kerala is staring at is important, we'll have to look at what steps are put in place to avoid this happening anywhere else.”
