Kosi on course

The sheer expanse of sand-covered ground at Kushaha,in Nepal,where there used to be green fields...

Written by Ravish Tiwari | Published:February 8, 2009 10:26 am

The sheer expanse of sand-covered ground at Kushaha,in Nepal,where there used to be green fields,bears testimony to the havoc wreaked by the breach in the Kosi embankment last year. It calls to mind Hindi novelist Phanishwar Nath Renu’s Parti Parikatha (story of the barren soil),which chronicled the misery of the people living under the shadow of the Kosi,a river in the habit of leaving miles and miles of land barren every time it charted a new course.

Just as the novel ends on a hopeful note,in real life,too,engineers succeeded in taming the river by building embankments that survived the landslide of 1979 and the earthquake of 1988.

The story,however,did not end there. The river charted a new course last year and the engineers who were the heroes of yesterday were suddenly the magnet of criticism,as everyone—including the three million who were affected—blamed them for the neglect of the embankment,which led to a breach at Kushaha on August 18,triggering the worst flood in Bihar in recent times.

A battery of about 80 engineers drawn from different divisions of the Irrigation Department of Bihar has moved the Kosi back to its course once again. Less than a week after the breach,the team swung into action to protect the breached eastern embankment from further erosion. On August 24,K.N. Singh,executive engineer with the Western Kosi Canal Division based in Khutahna,Madhubani,was roped in for the protection of the downstream nose of the breached site. J.N. Singh,executive engineer,Irrigation Division,based in Bathanaha (Araria),was in charge of protecting the upstream nose from further erosion.

Though the water discharge through the breached segment was well above 1.5 lakh cusecs for several weeks,the breach,which was about 1.2 km long to begin with,was finally held in check at a length of 1.8 km. About 500 trucks were hired to bring boulders and other materials from the Nepalese side to stop further erosion.

Meanwhile,the Bihar government constituted the Kosi Breach Closure Advisory Committee (KBCAC),with engineer N. Sanyal as its chairman. The KBCAC devised a workable solution to plug the breach before the next monsoon. Sanyal submitted his report in the first week of October last year,recommending the creation of a pilot channel to divert the river flow and reduce pressure at the breached segment without any delay. The pilot channel was to be 35 metres wide,3.5 metres deep and over eight kilometers long. Capable of handling at least 10,000 cusecs of water discharge,it would divert the water and reduce the flow at the breached segment.

Work on the channel began,with the services of about 20 excavators,500 tractors,over 4,000 labourers from Nepal and about 10 lakh sand bags. The Nepal Royal Army and its half-a-dozen elephants were soon patrolling the area. Engineers from the Hindustan Steel Corporation Ltd (HSCL) P. Sudhakar Reddy and Prithvi Raj,J.N. Singh,Shyam Yadav and Sanjay Kumar were involved in this mammoth task.

The engineers worked in a regimented fashion. Each executive engineer was assigned a specific task and given a makeshift office with a thatched roof on the sand-filled river bed. Ever since they started working on bridging the breach,all the engineers,technicians and labourers have been eating every meal together. Key people from the administration,too,visited the site regularly. Mukesh Kumar,from the Bihar administrative service,who is PA to the state’s water resources minister,has been camped here for over a month now. Irrigation commissioner from Patna,Ajay Naik,has been looking after the overall administrative affairs.

Given that even a 40-HP motor boat would take over an hour and a half to reach the breached segment against the rapid water flow,the odds were against the engineering. “Our excavators and heavy earth equipments had to reach the site by crossing the river downstream. On one instance,our excavator almost drowned and had to be rescued,” said Prithvi Raj.

The construction of the pilot channel was constrained for a brief period for want of a dredger to keep the mouth of the channel open. There was a delay of 40 days before a dredger from Vishakhapatnam was brought in for the job. Despite the constraints and the sheer enormity of the work,the channel was ready by December 8,and much to the satisfaction of the engineers,it could carry more water than they had expected—on Thursday,it was carrying 14,000 cusecs.

Meanwhile,engineers were also working on setting up disposable coffer dams—enclosures constructed to allow water to move into the pilot channel—upstream of the breached site to further cut the water discharge through the breach site. The work was assigned to Satish Kumar,the superintendent engineer of the eastern embankment. Work on the dams began on November 4,with Vashistha Construction Pvt Ltd as the contractor.

Coffer dam-1 was to be 160 metres wide and coffer dam-3 would be 400 metres wide. J.N. Singh,who worked on the latter,also successfully plugged two shallow channels upstream at Prakashpur. An expert in applying porcupine structures to induce siltation,he has been working overtime—he was brought to the site less than a week after the breach happened to hold on to its upper end and prevent further erosion,something he has done successfully.

While the engineers completed coffer dam-1 on December 10,the third dam was completed on January 16,after which the water started taking its course to the channel where coffer dam-2 was to be constructed. A team of engineers under executive engineer M.P. Thakur was brought in from Champaran Division. Thakur,who has experience working on the Gandak river bank,found that while coffer dam-3 provided him a second approach—in addition to the approach from the first dam—in constructing coffer dam-2,it also meant that a huge volume of water from the channels contained by the two dams was flowing through his channel.

The team managed to construct the final dam on January 26,2009. “The second channel,which was initially envisaged as a shallow,310-metre-wide channel,has deepened after a huge amount of water gushed through it. The two-sided assault from coffer dams-1 and 3 came in handy to complete the coffer dam on January 26,” Thakur said.

This marked a great achievement for the engineers who have been stationed there from August. Supaul’s district collector,N. Saravana Kumar,distributed sweets on the site after the completion of the last of the coffer dams. The process of building them had not been easy. At the site of coffer dam-3,dams were washed away twice,first on December 31 and then again on January 11,before the engineers managed to rein in the flow on January 16. The reason for the setbacks was the discharge of more water than calibrated readings pointed upstream,workers said. The engineers were also in for other surprises—J.N. Singh recalled that they had found a crocodile in September while working on the pilot channel.

After the dams were in place,the water had no other way but to flow from the pilot channel created earlier. In fact,the pilot channel has widened from its 35-metre width to over 100 metres in several stretches. “Most of this widening has come from erosion on the western bank of the pilot channel. This indicates that the Kosi is moving away from the eastern embankments and towards the western side trough. It is a good sign,” says J.N. Singh.

On January 31,when the breach was plugged completely,the entire team of engineers got Saravana Kumar to drive his car past the site. The work is far from over,though K.N. Singh,in charge of the downstream end of the breached site,is concentrating on plugging the final 600 metres of the breached segment. Although the plug has been completed,it needs to be raised to the level of 80-87.5 metres due to safety considerations.

Executive engineer Abdul Hamid,from the irrigation department’s Padrauna camp in Uttar Pradesh,who has been involved in the plugging work,told The Sunday Express over tea with his colleagues,“We have crossed the 82.5-metre level in the first phase,which can withstand over 60,000 cusecs of water—that kind of volume is only expected sometime in June. The work on the remaining section is on and it has crossed the 81-metre level.”

With water from three channels flowing through the new route,the chances of siltation blocking the mouth of the pilot channel and disrupting the plan had to be considered. Revati Raman Kumar—who had served as chief engineer of the Kosi river in 2002—and Indu Bhushan Kumar—who had served as executive engineer,head works division,Birpur,and had been in charge of the Kosi barrage between 2002 and 2005—suggested creating two more tributary pilot channels to keep things in control and J.N. Singh’s team went on to create these channels,which are now working according to the plan.

Indu Bhushan,deputy secretary in the Water Resources Department at Patna,was specially deputed to monitor the progress of the engineering works at Kushaha. He was the one who identified instances of seepage from the river bed near the coffer dams,which had created a shallow channel near the breached segment. He suggested building cross-bandhs as additional protection so water wouldn’t reach the breached segment. This suggestion,too,has since been successfully implemented.

Even as the irrigation department engineers are rejoicing over their success,some experts are keeping their fingers crossed. “The work,which initially appeared to be slow,has now picked up. But a lot remains to be done. The earth work needs to be supported by a strengthening of the newly constructed embankments using crated boulders. In addition,the compaction and moisture level of the constructions requires close monitoring and exact evaluation,” said a member of the high-level technical team constituted by the central government to suggest long-term measures for managing the river.

The men who made it possible
Satish Kumar

Superintendent engineer,Eastern Embankment Division,Saharsa,was in charge of constructing pilot channels and coffer dams.

J.N. Singh

Executive engineer from the irrigation division at Bathanaha,Bihar,he was among the first to camp at site after the breach in August last year. Was in charge of protecting the upstream end of the breached segment. Led the team that constructed the crucial pilot channel and coffer dam-3.

M.P. Thakur

Executive engineer from Champaran Division of the irrigation department at Motihari,constructed coffer dam-2.

K.N. Singh
Executive engineer on western embankment,was roped in to protect the downstream end of breached segment of eastern embankment in August. Is handling the construction of the last few metres of the breached embankment. Is also working on constructing spurs upstream of the breach for future protection.

Abdul Hamid
Executive engineer from the irrigation department in Padrauna,UP,he has been entrusted with the responsibility of the plugging work in the first 1,200-metre stretch of breached segment. Working under superintendent engineer Prakash Das,Hamid plugged the segment on January 31.

Revati Raman Kumar
Was chief enginer of Kosi in 2002,was brought in to improvise the pilot channel. Suggested additional channels near its mouth to reduce pressure and siltation.

Indu Bhushan Kumar
In charge of the Kosi barrage between 2002 and 2005,was deputed to monitor the engineering work. Suggested additional pilot channel to link water from dams to the main pilot channel,identified shallow channels forming due to seepage from river bed,recommended building cross bandhs.

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