Dam-induced floods feared in Ahmedabad, Gandhinagar and Kheda districts
Even as 96 dams in Gujarat were put on high alert following heavy rainfall on the evening of September 11, many of them were full to their capacities, including the Sardar Sarovar Narmada Dam in Kevadia. At least 7,000 people were evacuated in August and September from different parts of the state, according to the latest reports and the Gujarat flood control department.
Experts say that in Gujarat, as in the rest of the country, there is lack of coordination between water management and disaster mitigation authorities, which often leads to dire situations wherein dams release unforeseen volumes of water, leading to floods.
Touch and go
Although the situation, according to the Gujarat revenue department’s flood control wing, is under control (as reported on Tuesday), officials in charge of Dharoi dam on the Sabarmati river in Mehsana district say 97,760 cusecs (27,373 cumecs) of water was released near Ahmedabad through 10 of the 12 gates to maintain the dam's water storage level on September 11. The inflow of water into the dam at present is 36,000 cusecs (10,080 cumecs) due to heavy rainfall in north Gujarat, a Dharoi dam official says. In Ahmedabad, waters on the Sabarmati river front almost touched the walkway, which is several feet above the danger mark. Water levels due to heavy rainfall on Sunday and Monday near Dharoi dam, which supplies drinking water to 300-odd villages besides six municipal towns of North Gujarat, rose to 188.89 metre. Dam officials say the danger mark is 188.90 metre.
Officials in charge of the dam say they have alerted the administration in Gandhinagar, Ahmedabad and Kheda districts. They have also alerted 19 villages in Prantij, Idar and Himmatnagar in Sabarkantha and 35 villages in Satalasana, Kheralu, Vadnagar, Vijapur and Unjha talukas of Mehsana district in Gujarat. Further, the collector of Ahmedabad district has issued flood warning on Monday evening to 21 villages of Dholka and Daskroi blocks after the reservoir water was released from Dharoi dam.
Meanwhile, Ahmedabad city received heavy rains between 6 pm and 8 pm on the evening of September 11. The city municipal corporation’s control room reported that western and northern parts of the Ahmedabad city received 12 mm rain in just two hours, leading to water logging near Army Cantonment and in Vejalpur and Naranpura localities, disrupting daily life. At 8 pm on Monday, water level at the Dharoi dam was 619.61 feet (188.85 metre), while its inflow and outflow was 4,366 cumecs and 15,411 cumecs respectively. Similarly, water level at Vasna barrage on the outskirts of Ahmedabad, was at 128.5 feet (39.1 metre) while its outflow in the Sabarmati was 13,522 cumecs. All the twenty-seven gates of Vasna Barrage, on the outskirts of Ahmedabad city, were kept open thus flooding low lying areas of Kheda districts.
'Decision support systems needed'
Experts feel that such situations, characterised by fear of floods, can be avoided through better coordination and efficient alarm facilities. “It is not just in Gujarat, but across the country, there needs to be better coordination between the water management authorities of the state as well as Centre and disaster management authorities. Previous experiences have shown that the upstream and downstream regions of a river do not coordinate with each other, often reducing time in which such warnings could be issued on time,” says Mihir Bhatt, honorary director of the non-profit, All India Disaster Mitigation Institute.
A 2006 paper published by Indian Institute of Management (Ahmedabad) professors, Dileep Mavlankar and Amit Kumar Srivastava, analysing the Surat floods of 2006, say the flood was caused by sudden release of water from Ukai dam on Tapi river. It states that many smaller dams in the country are still operating from rule books which date back to 1970s. The professors call for putting in place a decision support system, which takes several factors into account to predict floods, in the dams across the nation to avoid similar disasters.
Considering the latest trend of delayed monsoon experienced during late August or September across the country, Mavlankar and Srivastava state in their paper: “It is critical to maintain adequate flood cushion in the reservoir during August and September, as the major flood in Tapi usually occurs during these two months. However, it seems that the irrigation department’s main concern was to keep the dam reservoir as full as possible to make maximum water for irrigation in summer months.”
The R A Mehta committee, which looked into the causes of Surat floods of 2006, corroborated this. The committee report stated that there was a 42-hour delay in releasing water from the Ukai reservoir, causing unprecedented flooding in downstream villages and Surat.
Lives lost in Saurashtra
South Gujarat and Saurashtra experienced similar situations this year because of heavy rainfall experienced across the state. The India Meterological Department predicted very heavy to heavy rainfall towards the end of August and beginning of the month of September. Heavy rain in upper areas of Dang district and Kaprada and Dharampur in Valsad district and some parts of Dadra and Nagar Haveli led to heavy inflow of water in local rivers, causing floods in Valsad and Navsari districts in south Gujarat. According to the district collectorate of Navsari, as many as 5,000 persons had to be evacuated on September 10. These include people in 27 villages in Gandevi block, nine villages in Chikhli block of Navsari district while people were also evacuated from Bilimora and Gandevi towns.
In Saurashtra, about 45 million cubic metres of water was released from a dam on Saani River in Jamnagar district after one of the sluice gates in the dam broke, leading to flood-like situation in eight villages downstream. In total, 147 people have lost their lives due to the continuous rains and rain-related incidents in Gujarat experienced towards the end of August and beginning of September.
The state experienced a drought-like situation with only 318 mm of rainfall between June 15 and August 1. According to the data provided by Gujarat State Disaster Management Authority, the state average for total rainfall was at 465.28 mm on August 13, while on September 13 the total average rainfall experienced in the state was much higher at 817.14 mm. Thus the heavy rainfall towards the end of the month of August led the flood control room of the revenue department to issue alerts for 96 dams as many of them were already full. A Superintending Engineer from Panam Project Circle, Tushar Dholakia who has prepared a presentation on occurrence of flood in Gujarat considers heavy rainfall in the catchment area of a dam as one of the main reasons for occurrence of floods in the state.
On the other hand, Chief Engineer with Flood Control Unit of the Irrigation Department, M P Rawal says that dam waters are released as per the rule book of Central Design Organisation, a government body. However, he says the Gujarat Irrigation Dam has now launched pilots for five dams in the state, including Panam Dam in central Gujarat and Ukai dam in south Gujarat and three in Saurashtra for flood forecasting. “These are flood forecasting systems based on telematics which are now being used by the flood control unit of irrigation department in the state on a pilot basis. If these models work, they will be applied to all the 200 dams across the state,” says Dholakia.
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