The Delhi Disaster Management Authority (DDMA) has managed to avert floods during monsoon by adopting the concept of ‘garbage in and garbage out.’ This concept means that the water is discharged from the capital at the same speed it is pushed into from the barrages of Hathnikund, Okhla and Wazirabad .
The Authority also monitored, for the first time, the hourly discharge of water from the Okhla barrage which was managed by the Uttar Pradesh flood and irrigation control department. Following this, the water level did not peak from 205.99 despite the discharge rate being 1.91lakh cusecs and 2.21 lakh cusecs on August 11, 2022. One cusec is equivalent to 28.32 liters per second.
The flood warning level of the Yamuna is 204.50 meters, while the danger level is 205.33 meters. The evacuation level for the people living in the low-lying area is 206 meters.
Sushil Singh, Special Chief Executive Officer (CEO) of the DDMA said that this year when the water was released by the Haryana from the Hathnikund barrage, the authority started the preparations to avert any flood situation in the capital.
“As the water reached Delhi, the water level at the old railway bridge started rising, I myself visited the Okhla barrage to ensure that the water is discharged from the same speed that is headed from the Hathnikund barrage,” Singh said.
“The water was discharged in a synchronized manner from the Wazirabad and Okhla barrage due to which this year the water level did not cross the 206-meter mark, following which there was no need to shift the people residing in the low lying areas,” Singh added.
During the monsoon, many parts of Delhi, including arterial roads, get waterlogged leading to traffic snarls even in an hour’s rainfall. The main reason is the problems related to the city’s storm water drains. The city works on a drainage master plan made in 1976 and one such plan prepared by IIT Delhi for the Delhi Government in 2018 is yet to be implemented.
According to officials, in Delhi’s case, flooding could be due to two reasons: floods in the Yamuna or local rainfall. In 1978, Delhi had witnessed a flood due to the rise in the Yamuna water level. But the annual urban flooding we see is due to local rainfall. The run-off water (water left after being absorbed by the earth) from the local rainfall is supposed to drain into the Yamuna through storm water drains. But due to a combination of reasons, including sewage flowing in storm water drains, it does not properly drain into the Yamuna and leads to urban flooding. The drains were made decades ago to handle a particular amount of run-off water. Over the years, the paved area has increased due to development.
While informing about the preparations made by the DDMA in case of the flood situation, a senior DDMA official said that the arrangements including boats have been deployed at various locations near the Yamuna River. 17 boats are placed at Boat Club under District Magistrate (East). In addition, 34 boats belonging to Irrigation and Flood Control Department are at their Timarpur shore. Out of these 51 boats, 29 are currently plying in the Yamuna River. Rest are kept on standby mode.
In 2021, the Yamuna river breached the danger mark on July 30 and the water level at the Old Railway Bridge had risen to 205.59 meters.
In 2019, the flow rate had peaked at 8.28 lakh cusec in August, and the water level of the Yamuna had hit the 206.60-meter mark, while in 1978, the river had swelled to an all-time record water level of 207.49 meters. In 2013, it had risen to 207.32 meters.
What creates a flood-like situation in the national Capital?
Normally, the flow rate of the water at the Hathnikund barrage is 352 cusecs, but the discharge increases after heavy rainfall in the catchment areas. The water discharged from the barrage normally takes two to three days to reach the national capital. Following this the water level also increases in Delhi, creating an alarming situation in the city.