Jayanta Sharma
Artificial Flood" is a buzz words in all township of Assam. For the last few
decades all the gigantic departments failed to solve this problem. Many learned persons also wrote their views but failed.
Particularly, if we look at Guwahati City, there is no flood in British-developed areas like Uzan Bazar, Pan Bazar, Fancy Bazar or Paltan Bazar. We have not seen the waterlogging, but in newly developed areas the frequent flooding is seen. The logic is that, under British rule, they followed the gradient map of land, and now we follow the trend of water flow.
Simply, the British follow the gradient map of the land by using GTS contour mapping for installing drainage and sewage systems. Now, without considering the contour map, drains are developed, and for the wrong path determination to flow the excess water, it bunches back and creates artificial floods.
Every year during the monsoon, many parts of Guwahati go under water. Roads become rivers, homes are flooded, and daily life comes to a halt. While heavy rainfall is often blamed, experts say the real problem lies in how the city's drainage system has been planned-and how it can be improved.
A simple but powerful solution is now being discussed: use scientific contour mapping (GTS), improve drainage systems, and allow water to flow naturally instead of trapping it.
Why does Guwahati flood so easily?
Guwahati is surrounded by hills, and rainwater flows down quickly into the city. In the past, this water moved through natural channels, wetlands (beels), and streams into the Brahmaputra.
Many natural drains are blocked or encroached upon. Wetlands have been filled up. Drains are narrow, clogged, or poorly designed. Sewage and rainwater flow together in the same drains. As a result, even a few hours of heavy rain lead to waterlogging.
Now, let us discuss what GTS contour mapping is and why it matters.
More than 100 years ago, detailed land surveys were done across India, marking exact heights of land using what is called GTS (Great Trigonometrical Survey).
This map shows water can move quickly instead of getting stuck, which areas are high and low, and the natural direction water should flow. If Guwahati uses these contour maps properly, drains can be built along natural slopes. Flood-prone areas can be identified in advance. In simple terms: water will flow where it is supposed to flow.
Build Drains According to Land Slope: Many drains in the city are not aligned with natural slopes; for which, design drains based on contour maps.
Protect natural water bodies: Wetlands and beels act like natural sponges. These areas can store excess rainwater and reduce flooding. Stop filling wetlands and restore old channels and ponds.
Also read: Guwahati: Rainwater harvesting; violators to face GMC’s wrath