Kosi flood again?

Embankment security still not sorted out BIHAR might see a repeat of last year's floods. The water level is rising in the Kusaha embankment; its breach killed more than 500 people in 2008. The chief engineer in charge of the embankment's maintenance fears that like last year repair work might suffer from criminal attacks. Assaults on engineers and labourers engaged in repair work were reported (see 'Let there be floods', Down To Earth, September 30, 2008).

A sustainable engineering disaster

Dinesh Kumar Mishra looks back at the history of floods in North Bihar and wonders what this year has in store

Dam's height restricted

Narmada authorities flouted environmental safeguards further increase in Sardar Sarovar Dam's height is not advisable, an expert committee of the Union environment ministry has said. The dam authorities want to raise the height of the dam from 122 metres now to 140 metres to increase the capacity of its reservoir. The expert committee advised the ministry against it saying the authorities did not comply with the prescribed environmental safeguards. The committee submitted its interim report on February 13, 2009.

Ifthen

Floods in India to be avoided using fuzzy logic IF A washing machine can figure out how dirty the laundry is, then it can calculate how long it should wash, how much detergent to add and how much water is needed. This is called the fuzzy logic technology and it works on a simple "if-then" principle. At present machines like air conditioners or microwave ovens have fuzzy logic technology operating them. Researchers from India have now suggested using fuzzy logic to improve dam operations.

Averse engineering

The right level

Orissa's floods made worse by full tank at Hirakud dam

Course correction

Can Bihar avert another Kosi disaster?

Spate of neglect

  Fluctuations in water level hampered rescue. At times it dropped too low for boats to ply, at times boats were trapped by submerged trees   The authorities knew of the impending disaster

Embankment indicted

Findings of the fact-finding team that studied floods in Bihar: Embanking the Kosi has prevented the Kosi's annual estimated silt load of 92.5 million cubic metres from spreading and improving soil fertility Deposition of silt has increased the riverbed by up to 4 m The raised bed of the river has obstructed the drainage from entering the river course, creating permanent waterlogging in 8,360 sq km

Kosi breaches

1963: At eastern embankment at Dalwa in Nepal 1968: At western embankment at Jamalpur 1971: Collapse of Bhatania Approach Bund in Supaul 1980: In the eastern embankment in Saharsa. 1984: In the eastern embankment at Navhatta in Saharsa 1987: In the western embankment at Samani and Ghonghepur in Saharsa 1991: In the western embankment at Joginia