Update on Orissa flood: IAG Orissa 11:30 Am 18th July'09

IAG Orissa Emergency Sitrep 7/2009
Time: 11.30 AM; Date: 18th July 2009

Orissa Flood Update

Situation Report

Met office waned for isolated heavy rain

On Saturday, the local met office waned for another spell of isolated heavy rainfall throughout the state in next 48 hours. Under the influence of Upper air Cyclonic circulation over North Orissa- Gangetic West Bengal and adjoining North West Bay of Bengal, a low pressure area has formed over North West Bay of Bengal off Orissa coast at 0830 hours IST of dated 18th July 2009.

Hirakud to open more 5 gates on Saturday

Hirakud dam authorities are all set to open 5 more gates of the reservoir to divert flood water. The incessant downpour in Chhatisgarh in last 48 hours raised the water level at 614.19 feet even after opening of 5 gates to release flood water on Friday afternoon as against its danger level of 630 feet. The inflow of water into the reservoir on Friday night was recorded 219831 cusec per second, while the outflow of water was recorded 183721 cusec per second.

Five sluice gates opened in Hirakud on Friday

Hirakud Dam project authorities have released water from the reservoir to river Mahanadi on Friday at 4.30 pm for the first time during this monsoon by opening 5 gates.

The Revenue Divisional Commissioner (RDC) of Northern Division Jamil Ahmed Khan opened the first gate after the rituals. IG of Police YB Khurania, Sambalpur Collector Pradipta Kumar Patnaik and Bargarh Collector SC Padhi were present on the occasion.
’As per the rule curve we have now more water in the reservoir. Mahanadi bed below is almost empty due to scanty rainfall in down-stream. This gives us the opportunity to release the extra water from the reservoir,’ said JB Mahapatra, the superintendent engineer (SE) of Hirakud dam project. ‘We will maintain the level at 600-605 feet up to the first week of August. And the present situation is no worrying for us even as the water level touched 613. 47 feet due to incessant rainfall in the upper catchments from 13th to 15th July,’ said Mohapatra.

The inflow of water into the reservoir was recorded 267940 cusec per second, while the outflow of water was recorded 35233 cusec per second.

Hirakud Dam

Hirakud Dam is built across the Mahanadi River, about 15 km from Sambalpur. Built in 1956, the dam is the world's largest earthen dam. Behind the dam extends a lake, 55 km long. Hirakud Dam is one of the longest dams in the world, about 16 miles (26 km) in length. It was the first major multipurpose river valley project started after India's independence.

Total length of Dam :15,748 Feet or 4800 Meter
Concrete Dam :3,937 Feet or 1200 Meter
Earth Dam :11,811 Feet or 3600 Meter
Left Dyke :32,274 Feet or 9837 Meter
Right Dyke :35,299 Feet or 10759 Meter
Maximumm Height of Massonary Dam :200 Feet or 61 Meter
Maximum Height of Earth Dam :195 Feet or 59.5 Meter
Sluice Gates Total :64 Nos.
Sluice Gates (Left) :40 Nos.
Sluice Gates (Right) :24 Nos.
Crest Gates :34 Nos.
Crest Gates (Left) :21 Nos.
Crest Gates (Right) :13 Nos.
Crest Gate Size :15.54 Meter * 16.1 Meter
Top Dam Level :RL 195.680 Meter (RL 642Feet)
Full Reservoir Level :Rl 192.024 Meter (RL 630 Feet)
Dead Storage Level :Rl 179.830 Meter (Rl 590 Feet)
Seal of Sluice Gate : 510 feet (160 m) RL
Gross Storage : 5,830,000 acre feet (7.19×109 m3)
Live Storage : 4,360,000 acre feet (5.38×109 m3)
Catchment Area : 83,400 km²
Total Power Capacity :275.5 MW

In the upper drainage basin of the Mahanadi River, centered on the Chattisgarh Plain, periodic droughts contrast with the situation in the lower delta region where floods may damage crops. The dam was constructed to help alleviate the problems by creating a reservoir and controlling river flow through the drainage system. The dam regulates the flow of the Mahanadi River and produces hydroelectricity through several hydroelectric plants. The dam helps control floods in the Mahanadi delta and irrigates 7,500,000 hectares of land. Hydroelectricity is also generated. The Hirakud Dam regulates 83,400 km² (32,200 mi²) of Mahanadi's drainage. The reservoir has a storage capacity of 5.818 km³ with gross of 8.136 km³.

The project provides 1,556 km² of kharif and 1,084 km² of rabi irrigation in industries of Sambalpur, Bargarh, Bolangir, and Subarnpur. The water released by the power plant irrigates another 4360 km² of CCA in Mahanadi delta. The dam can generate up to 307.5 MW of electrical power through its two power plants at Burla, on the dam's right bank and Chiplima, 22 km downstream from the dam. In addition, the project provides flood protection to 9500 km² of delta area in district of Cuttack and Puri.