Last week most of urban Maharashtra experienced heavy floods. More than 2 lakh people had to be evacuated as floods entered their houses.
Several people lost their lives. Most cities had heavy waterlogging. Roads were shut because they were flooded. The rivers flowed over many bridges. Communication channels broke down. Electricity failed. Sewage flowed into the rivers.
This is even though similar spells of rainfall have happened even last year. Last year 300 mm of rain had crashed down over 20 days from 30th June without similar disaster. This year, 300 mm of rain crashed down over 15 days from 20th July this year. That is just 5 days less or a 30% increase in the rate of precipitation. That is all it took to breakdown normalcy across the state. We have at least 29 percent more rainfall left this season to reach the normal rainfall for the season.
All floods are caused because the surface runoff caused by rainfall accumulates rapidly over the surface of the land because the natural buffers that absorb the runoff have either shrunk or disappeared.
Maharashtra flooded because its natural buffers to absorb the faster arrival of the same volume of rainfall were insufficient.
Figure 1 Source: http://maharain.gov.in/
What are these natural buffers?
Wetlands, or areas of marsh, or water, often seasonal, and often along streams and rivers, serve as natural buffers to excess rainwater.
Wetlands are recognised world over as the having an important role in providing resilience to our habitats from excessive rates of rainfall. Flood plains of rivers are part of this natural buffer that may be a wetland only for a few months of the year.
The sand in the streams and rivers absorbs water due to its porous structure. Streams and rivers with sand have higher percolation rates in comparison with those that are rid of their sand.
Green cover slows the rate of surface runoff as the leaf canopies of trees provides surface area where rain water lands, slowing its arrival on the surface while allowing some of it to evaporate. The roots of trees in the green cover also take up water and help create conditions in the soil that increase infiltration into the soil.
Over the last 50 years, at an increasingly accelerating pace, Maharashtra has treated wetlands as wasteland to be reclaimed for real estate and construction.
Particularly so in urban Maharashtra. As we have caused the base flows of rivers to dwindle by damming the rivers upstream, the flood plains and the land of the river itself has been enormously encroached. We’ve filled up river beds, built roads, metros and even buildings in the land of the river. This not only destroyed the buffer, it actually created habitat in the land that is periodically covered by water.
Over the last 10 years government projects under the JNNURM have destroyed the small natural streams of Maharashtra that drain fresh water from the hills and mountains to the rivers by channelizing the 40-60 meter wide streams into 1-5 meter cement channels.
In many cases they have even been reclaimed completely or have had their natural paths altered. This has destroyed the buffer they provided and their ability to absorb the excess rainfall and carry it the rivers. The smaller concrete channels are now unable to allow the water from the adjoining land to drain into what were once natural streams. This increases the surface runoff in the already concrete and non-absorbent adjoining land. Maharashtra has also been plagued with sand mining and the dredging that has degraded the ability of the streams and rivers to buffer excess precipitation.
Over the last 20 years the enormous loss of tree cover, especially in urban Maharashtra and along the inter-city expressways, despite the Maharashtra (Urban) Protection and Preservation of Trees Act, has destroyed its ability to buffer the excess precipitation even further.
Maharashtra has focused on the short term ignoring the Short Now, the lifetime of a child born today.
To prevent the floods in the future, the buffer zones must be restored.
As long as urbanization keeps the consequences of their action away from the perpetuators of the action, this may never happen. Urbanization is driven by revenues and profits. These revenues and profits do not pay the costs of the future or of the community.The land of the streams and rivers comes cheaper than other land. Those who reclaim the land of the rivers rarely face the consequence of their action because floods happen years after the encroacher has sold the property to innocent buyers.
If the cost of buying or owning the land of the stream or river, or that of its wetland or flood plains, were to require flood relief and drought relief taxes on the buyers that make such land several fold more expensive than the adjoining land, we may find a way to keep it free of encroachment.
If the use of sand for construction would cost more than substitutes for sand, the sand mafia may not find value in mining the rivers of sand. If the felling of a tree were to cost several times the revenue generated by removing a tree, the tree may be left alone.
Making the short term more expensive that the Short Now is just one way in which the Short Now may become a little more important than the short term.
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#All views expressed in this column are those of the author and Pune365 does not necessarily subscribe to them.
He can be reached @AnupamSaraph
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