A combination of short- and long-term measures that gives importance to both structural (traditional) means and non-structural techniques is required to solve the perennial flood problem in north Bihar.
BIHAR FLOODSnovember 15, 2008 EPW Economic & Political Weekly40case of earthquakes or hurricanes or torna-does or tsunamis. Does anyone say that they should be stopped or prevented from happening or controlled? What everyone would say is that they should be predicted, anticipated, and prepared for; that there should be timely information, a state of preparedness for disaster, the minimisation of damage and prompt and adequate response by way of rescue and relief when the disaster actually strikes. Exactly the same point applies to floods. In addition, we can also learn from well-established traditional coping practices evolved over centuries bycommunities accustomed to periodical floods. It may be added that whatever we do must be done in an open, consultative, participatory manner, fully involving the people concerned right from the beginning.That wisdom is for the future. What do we do about structures already built? If we repair the damage to the embankment in Nepal and try to put the Kosi back into its old course, we are (a) ignoring the plight of the people living between the embank-ments, and (b) running the risk of arecur-rence of a major disaster in the future. On the other hand, if we do not rebuild the structures but let the river find its natural course, we might be putting at risk a large number of people who are living and pur-suing their livelihoods in areasearlier “protected” by the embankments. That is indeed a difficult choice, but it is not really a dilemma, and the argument that we can-not put the clock back is not necessarily valid. Having realised the errors ofthe past, there is no escape from reversing them over a period of time very carefully, mini-mising the pain of readjustment to the ex-tent possible. That applies to global warm-ing and climate change, anditapplies equally to the fallacy of “flood-control”.PostscriptFollowing prime minister Prachanda’s visit to India in September, one hears once more references to a high dam on the Kosi and big hydroelectric projects. It appears that no lessons have been learnt from the past. In this ambience the unorthodox suggestions put forward in this article willprobably receive no attention at the official level in either country. However one hopes that there are people in both countries who will take note of what has been said here.Management of Floods in BiharC P SinhaA combination of short-and long-term measures that gives importance to both structural (traditional) means and non-structural techniques is required to solve the perennial flood problem in north Bihar.Bihar is the worst flood-affected state in India. Its geographical area and population are, respectively, 2.85% and about 8% of those of the country, but about 17% of the flood-prone areas and 36% of the flood-affected population of the country belong to this state. The state’s share in total average annual flood damage in the country is about 23%. Of all the river basins in the state, the ratio of flood-prone to catchment area within the state is maximum in the Kosi basin (89%). Floods have been a chronic and a serious problem forthe state, particularly for north Bihar. It hasforever remained in discussion, but this year’sbreach of the eastern afflux embank-ment of the Kosi at Kusaha (in Nepal) has caused unprecedented damage and attracted widespread attention and concern.Unique Case of North BiharThe flood problem in Bihar has unique characteristics. There is severe erosion, spilling and drainage congestion. Another peculiar feature of the rivers of north Bihar is that all of them (except the Burhi Gandak) originate in hills of Nepal and their catchment areas mostly lie in Nepal. This puts a big constraint on India so far as their comprehensiveandsustainable management is concerned.After the disastrous flood experience in the country in 1954, a National Pro-gramme of Flood Management was launched. In the subsequent five decades different long-term and short-term meas-ures for flood protection were adopted de-pending on the nature of the problem and local conditions. In Bihar flood manage-ment works implemented so far comprise construction of 3,455 kilometre of em-bankments, 365 kilometre of drainage channels and 47 town/village protection works. It is claimed that these measures have helped in affording reasonable pro-tection to 29.49 lakh hectares out of 68.8 lakh hectares flood-prone areas in the state. It is important to mention here that the Second Bihar State Irrigation Commis-sion (1994) analysed the flood damage data for the period 1968 to 1991 and on this basis observed, Although quite significant flood management works have been implemented in Bihar till March 1992, it is apparent from the reported figures of damages in all the 11 flood-prone basins that the damages have increased gradually and significantly in recent years.However, it is said that this increase in damage in the embanked area may be due to reasons like inflation, inflated reporting, increased productivity and enhanced value of property, increase in population due to encroachment, etc.C P Sinha (c-p_sinha@rediffmail.com) headed the Second Bihar State Irrigation Commission and was also associated with Indian Institute of Technology, Roorkee.
BIHAR FLOODSEconomic & Political Weekly EPW november 15, 200841Planning for flood management does not involve absolute control of floods but im-plies management of flood in the most ben-eficial manner in the given circumstances. All the flood management measures fall broadly into two categories, (i) structural-involving construction of embankments, reservoirs, detention basins, interbasin transfer of water, raising of village, etc, and (ii) non-structural including flood plain zoning, watershed management, flood fore-casting, disaster mitigation and prepared-ness, etc. Both are complementary to each other and not mutually exclusive.EmbankmentsThe flood management works executed in Bihar so far mainly consist of embank-ments. They come under the category of short-term structural measures. They are very popular not becauseoftheirefficacy but due to being cheap and quicker to construct. However, they are criticised on the grounds of denial of fertilising silt to the flood plains, hamperinglandbuild-ing by rivers, rise in bed level of rivers particularly in aggrading ones, blocking natural drainage from the countryside and damages occurring despite their con-struction, etc. As such the wisdom of adopting embankments as measures of flood management is highly debatable.The Second Bihar State Irrigation Com-mission (1994) studied the nature of aggra-dation of the Kosi rivers bed. It found that during the period 1955-62 the cross sections of the river from Chatra to Supaul did not indicate any silting. Quite interestingly this reach of 102 kilometres was a degrad-ing reach, the average rate of degradation being between 165.6 and 3.8 millimetres per year in the different reaches during this period. The Indian Institute of Technology, Delhi, conducted cubature analysis in 1974 based on data from 1955 to 1974. The period 1955-62 approximately corresponds with the commencement and completion of the embankments. During the period 1963-74 the entire reach, except Bhimnagar-Dagmara (26 kilometre) was foundtobeaggrading, the rise of bed level peryearvaryingfrom 123.4 to 18.6 millimetres and the reach Bhimnagar to Dagmara degraded at a nominal rate of 8.3 millimetres per year. Another study conducted by University of Roorkee (now IIT Roorkee) concluded (1990) thattheaggradation of the order of 2.44 metres (with respect to the levels of 1984) might occur within the existing embank-mentsby 2005. A similar trend has been observed in case of the Gandak also. Dur-ing the past three decades approximately, the rise of bed level had been of the order of 1.8 metres. This type of aggradation neces-sitates perpetual raising and strengthening of the embankments.Comparison with Huang HoThe Kosi bears similarity with the Huang Ho river of China with respect to carrying highly sediment laden water. However, most of the silt carried by the Huang Ho is fine silt and the Kosi carries mostly fine to coarse silt. Both the rivers are embanked, though the history of embankment along the Huang Ho is probably the oldest. Its construction started during 500-600 BC and it was extended, heightened and strengthened in course of time as per need. The river bed has gradually risen higher and higher. The river bed in lower reaches was found to be rising by one to 10 centimetres per year in the middle of last century and at some places the bed was found even 10 metres higher than the sur-rounding country level. The mean level of water between embankments is now high-er than surrounding country and so the river is called “elevated river”. Records show that inundations and breaches have occurred on 1,500 or more occasions in lower reaches of the Huang Ho and there were 26 important changes of course, nine of them major. The Kosi bed has also been rising and the river has changed its course, even within the embankments, after having been embanked and its embankments breached eight times at different loca-tions. It can now be easily visualised as to what may ultimately happen as a result of construction of embankments along rivers of north Bihar. Does it mean that the project was wrongly conceived? No, I do not think so. What were lacking were necessary safeguards in its implementation.The important and crucial recommenda-tion of K L Rao and Kanwar Sain that coarse silt must be eliminated from the river flow was not suitably acted on. The embankment should have been used in combination with dam on the upstream, catchment area treatment, flood plain zoning, etc.Long-term SolutionsIt is well recognised that the long-term solution for the flood problem lies in creat-ing appropriate flood storage in reservoirs. The Damodar Valley Corporation is a very good example of reservoirs as effective measures for flood moderation. There is nodam either in Bihar or in Nepal on any of the tributaries of the Ganga which may provide flood moderation in north Bihar. The greatest difficulty in this respect is that there is no suitable site available in Bihar for dam building on any of the north Bihar rivers as they originate from Nepal. Of course, the Burhi Gandak is an exception but in this case also its main tributary, the Masan originates from Nepal. However, high dams on the Kosi, the Kamala, the Bagmati, the Gandak and the Burhi Gandak in Nepal are under consideration. They are not coming up because they require the ap-proval of the Nepal government which is not very easy to get. There seems to be a lack of political will and a sense of urgency on both the sides on this issue, the reasons for which may be many.The rational method of flood management in Bihar (north Bihar) should include a judi-cious mix of structural and non-structural measures. As regards structural measures it should have an appropriate combination of short-term measures like embankments and long-term sustainable measures like reservoirs with adequate provision of flood cushion. Natural detention basins may also be used for flood moderation and channel improvement may be tried if found techni-cally and economically feasible. Under non-structural measures flood plains zoning and management, flood proofing, flood fore-casting and warning, disaster preparedness and response planning, etc, may be tried.Catchment area treatment is very impor-tantfor soil conservation and reduction in sediment inflow to the rivers, but in this respect also the difficulty lies in the fact that about 85% of the area of the catch-ment lies outside Bihar and we cannotdo anything there out of our own. Flood plain zoning helps in reducing the flood damage and misery afflicted by flood on the people. It is necessary not only for mitigating the flood but also for reducing the damage
BIHAR FLOODSnovember 15, 2008 EPW Economic & Political Weekly42caused by drainage congestion. It recog-nises the basic fact that the flood plains are essentially the domain of the river and as such all developmental activities there must be compatible with the flood risk in-volved. However, due to inability of the governments to prevent or check the en-croachments of the flood plains, no begin-ning could be made so far in flood plain zoning. The government of India circulated a model bill on the flood plain zoning in 1974 among all the states of the country with the request to enact the same, but no state except Manipur could do so and this state also could not implement it. Flood proofing is essentially a combination of structural change and emergency action. Raising of some flood-prone villages above predetermined flood level and connecting them to nearby road or high land has been done, but the enthusiasm was lost very soon as the method did not provide any protec-tion to surrounding agricultural areas. The flood forecasting and warning system is already working in Bihar satisfactorily.The most common adjustment to the flood hazard in flood plains is simply to bear the loss and live with flood in areas where there is some serious constraint (as in north Bihar). Under the situation, floods become a matter of concern for all sections of society living in the affected areas and flood management needs active involve-ment and participation of all of the stake-holders to fulfil its objectives. The National Water Policy (2002) also advocates a parti-cipatory approach with the involvement of various governmental agencies, users and other stakeholders in an effective and de-cisive manner, in various aspects of plan-ning, design, development and manage-ment of water resources schemes.The problem of flood in Bihar is very com-plex and so is the task of its management. A strong political force is required for seeking and ensuring cooperation of Nepal without which sustainable long-term flood manage-ment in Bihar is not possible. Competent and capable engineers, well acquainted with the latest technology and enlightened and efficient bureaucracy should beentrusted with the job of policymaking and its imple-mentation. Their work should not be inter-fered with. Last but not the least,the involve-ment of the stakeholders in all stages of the process is a key factor for the success of the effort and optimisation of benefits.Kosi: Rising Waters, Dynamic Channels and Human DisastersRajiv SinhaThe recent Kosi floods have proved once again that inadequate control measures have been responsible for the recurring disasters. Typically flood control and riverinestudies focus on hydrologicalinformation, whereas a much more integrated approach that pays attentionto specificmorphological factors is required. Since Kosi is a dynamic river with auniquemorphology andbecause it is a river which has always carried high sediment loads, flood management strategies mustbeattuned to such specific parameters of the river, besides being much more than mere “river control” through embankments.Rivers play a critical role in human society and history as they are the major source of fresh water, trans-portation, and resources. However, this relationship is often “troubled” because changes in river discharge (floods or droughts) or position can play havoc with permanent settlements. Such changes can be caused by both natural forcing as well as human interventions or a combination of both. Natural processes may include short-term changes in sediment load, water volume or, long-term changes in relative sea level or climate change. Human interventions could impact in changes in sediment load or run-off through water resource management schemes such as dams, barrages and embankments. Human alterations of river systems can have many important consequences primarily because river systems are dynamic and highly integrated systems and any change in any part of the river can easily propagate and affect the whole system. The recent flood in the Kosi is certainly one of the biggest “human” disasters in recent years and it has sent out a strong signal that our flood management strategies are questionable and our preparedness to face such events is far too inadequate. Further, there has been a paradigm shift in flood management globally from “river control” primarily involving an engineering approach addressing the “effect” at a local scale to “river management” which empha-sises an integrated approach at a crossover of scales and addresses the cause rather than the effect. Even though India is a country drained by several large rivers, our river management strategies are rather rudi-mentary and our planners are yet to embrace modern approaches such as satellite-based monitoring and multi-criteria decision support system. This situation needs to be corrected to save a large population from repeated miseries of floods year after year.The Kosi: A Dynamic SystemThe Kosi river in north Bihar plains, eastern India is a major tributary to the Ganga river system and has long been considered as a problematic river due to recurrent and extensive flooding and frequent changes in its course. The gently sloping alluvial surface of the Kosi has been described as “inland delta”, “cone” and “megafan” by various researchers owing primarily to build-ing up of a very large positive topography caused by deposition of enormous quantity of sediments carried by the river which it is unable to transport. During the last two centuries, for which records are available, Rajiv Sinha (rsinha@iitk.ac.in) is with the Department of Civil Engineering, Indian Institute of Technology, Kanpur.
BIHAR FLOODSnovember 15, 2008 EPW Economic & Political Weekly40case of earthquakes or hurricanes or torna-does or tsunamis. Does anyone say that they should be stopped or prevented from happening or controlled? What everyone would say is that they should be predicted, anticipated, and prepared for; that there should be timely information, a state of preparedness for disaster, the minimisation of damage and prompt and adequate response by way of rescue and relief when the disaster actually strikes. Exactly the same point applies to floods. In addition, we can also learn from well-established traditional coping practices evolved over centuries bycommunities accustomed to periodical floods. It may be added that whatever we do must be done in an open, consultative, participatory manner, fully involving the people concerned right from the beginning.That wisdom is for the future. What do we do about structures already built? If we repair the damage to the embankment in Nepal and try to put the Kosi back into its old course, we are (a) ignoring the plight of the people living between the embank-ments, and (b) running the risk of arecur-rence of a major disaster in the future. On the other hand, if we do not rebuild the structures but let the river find its natural course, we might be putting at risk a large number of people who are living and pur-suing their livelihoods in areasearlier “protected” by the embankments. That is indeed a difficult choice, but it is not really a dilemma, and the argument that we can-not put the clock back is not necessarily valid. Having realised the errors ofthe past, there is no escape from reversing them over a period of time very carefully, mini-mising the pain of readjustment to the ex-tent possible. That applies to global warm-ing and climate change, anditapplies equally to the fallacy of “flood-control”.PostscriptFollowing prime minister Prachanda’s visit to India in September, one hears once more references to a high dam on the Kosi and big hydroelectric projects. It appears that no lessons have been learnt from the past. In this ambience the unorthodox suggestions put forward in this article willprobably receive no attention at the official level in either country. However one hopes that there are people in both countries who will take note of what has been said here.Management of Floods in BiharC P SinhaA combination of short-and long-term measures that gives importance to both structural (traditional) means and non-structural techniques is required to solve the perennial flood problem in north Bihar.Bihar is the worst flood-affected state in India. Its geographical area and population are, respectively, 2.85% and about 8% of those of the country, but about 17% of the flood-prone areas and 36% of the flood-affected population of the country belong to this state. The state’s share in total average annual flood damage in the country is about 23%. Of all the river basins in the state, the ratio of flood-prone to catchment area within the state is maximum in the Kosi basin (89%). Floods have been a chronic and a serious problem forthe state, particularly for north Bihar. It hasforever remained in discussion, but this year’sbreach of the eastern afflux embank-ment of the Kosi at Kusaha (in Nepal) has caused unprecedented damage and attracted widespread attention and concern.Unique Case of North BiharThe flood problem in Bihar has unique characteristics. There is severe erosion, spilling and drainage congestion. Another peculiar feature of the rivers of north Bihar is that all of them (except the Burhi Gandak) originate in hills of Nepal and their catchment areas mostly lie in Nepal. This puts a big constraint on India so far as their comprehensiveandsustainable management is concerned.After the disastrous flood experience in the country in 1954, a National Pro-gramme of Flood Management was launched. In the subsequent five decades different long-term and short-term meas-ures for flood protection were adopted de-pending on the nature of the problem and local conditions. In Bihar flood manage-ment works implemented so far comprise construction of 3,455 kilometre of em-bankments, 365 kilometre of drainage channels and 47 town/village protection works. It is claimed that these measures have helped in affording reasonable pro-tection to 29.49 lakh hectares out of 68.8 lakh hectares flood-prone areas in the state. It is important to mention here that the Second Bihar State Irrigation Commis-sion (1994) analysed the flood damage data for the period 1968 to 1991 and on this basis observed, Although quite significant flood management works have been implemented in Bihar till March 1992, it is apparent from the reported figures of damages in all the 11 flood-prone basins that the damages have increased gradually and significantly in recent years.However, it is said that this increase in damage in the embanked area may be due to reasons like inflation, inflated reporting, increased productivity and enhanced value of property, increase in population due to encroachment, etc.C P Sinha (c-p_sinha@rediffmail.com) headed the Second Bihar State Irrigation Commission and was also associated with Indian Institute of Technology, Roorkee.
BIHAR FLOODSEconomic & Political Weekly EPW november 15, 200841Planning for flood management does not involve absolute control of floods but im-plies management of flood in the most ben-eficial manner in the given circumstances. All the flood management measures fall broadly into two categories, (i) structural-involving construction of embankments, reservoirs, detention basins, interbasin transfer of water, raising of village, etc, and (ii) non-structural including flood plain zoning, watershed management, flood fore-casting, disaster mitigation and prepared-ness, etc. Both are complementary to each other and not mutually exclusive.EmbankmentsThe flood management works executed in Bihar so far mainly consist of embank-ments. They come under the category of short-term structural measures. They are very popular not becauseoftheirefficacy but due to being cheap and quicker to construct. However, they are criticised on the grounds of denial of fertilising silt to the flood plains, hamperinglandbuild-ing by rivers, rise in bed level of rivers particularly in aggrading ones, blocking natural drainage from the countryside and damages occurring despite their con-struction, etc. As such the wisdom of adopting embankments as measures of flood management is highly debatable.The Second Bihar State Irrigation Com-mission (1994) studied the nature of aggra-dation of the Kosi rivers bed. It found that during the period 1955-62 the cross sections of the river from Chatra to Supaul did not indicate any silting. Quite interestingly this reach of 102 kilometres was a degrad-ing reach, the average rate of degradation being between 165.6 and 3.8 millimetres per year in the different reaches during this period. The Indian Institute of Technology, Delhi, conducted cubature analysis in 1974 based on data from 1955 to 1974. The period 1955-62 approximately corresponds with the commencement and completion of the embankments. During the period 1963-74 the entire reach, except Bhimnagar-Dagmara (26 kilometre) was foundtobeaggrading, the rise of bed level peryearvaryingfrom 123.4 to 18.6 millimetres and the reach Bhimnagar to Dagmara degraded at a nominal rate of 8.3 millimetres per year. Another study conducted by University of Roorkee (now IIT Roorkee) concluded (1990) thattheaggradation of the order of 2.44 metres (with respect to the levels of 1984) might occur within the existing embank-mentsby 2005. A similar trend has been observed in case of the Gandak also. Dur-ing the past three decades approximately, the rise of bed level had been of the order of 1.8 metres. This type of aggradation neces-sitates perpetual raising and strengthening of the embankments.Comparison with Huang HoThe Kosi bears similarity with the Huang Ho river of China with respect to carrying highly sediment laden water. However, most of the silt carried by the Huang Ho is fine silt and the Kosi carries mostly fine to coarse silt. Both the rivers are embanked, though the history of embankment along the Huang Ho is probably the oldest. Its construction started during 500-600 BC and it was extended, heightened and strengthened in course of time as per need. The river bed has gradually risen higher and higher. The river bed in lower reaches was found to be rising by one to 10 centimetres per year in the middle of last century and at some places the bed was found even 10 metres higher than the sur-rounding country level. The mean level of water between embankments is now high-er than surrounding country and so the river is called “elevated river”. Records show that inundations and breaches have occurred on 1,500 or more occasions in lower reaches of the Huang Ho and there were 26 important changes of course, nine of them major. The Kosi bed has also been rising and the river has changed its course, even within the embankments, after having been embanked and its embankments breached eight times at different loca-tions. It can now be easily visualised as to what may ultimately happen as a result of construction of embankments along rivers of north Bihar. Does it mean that the project was wrongly conceived? No, I do not think so. What were lacking were necessary safeguards in its implementation.The important and crucial recommenda-tion of K L Rao and Kanwar Sain that coarse silt must be eliminated from the river flow was not suitably acted on. The embankment should have been used in combination with dam on the upstream, catchment area treatment, flood plain zoning, etc.Long-term SolutionsIt is well recognised that the long-term solution for the flood problem lies in creat-ing appropriate flood storage in reservoirs. The Damodar Valley Corporation is a very good example of reservoirs as effective measures for flood moderation. There is nodam either in Bihar or in Nepal on any of the tributaries of the Ganga which may provide flood moderation in north Bihar. The greatest difficulty in this respect is that there is no suitable site available in Bihar for dam building on any of the north Bihar rivers as they originate from Nepal. Of course, the Burhi Gandak is an exception but in this case also its main tributary, the Masan originates from Nepal. However, high dams on the Kosi, the Kamala, the Bagmati, the Gandak and the Burhi Gandak in Nepal are under consideration. They are not coming up because they require the ap-proval of the Nepal government which is not very easy to get. There seems to be a lack of political will and a sense of urgency on both the sides on this issue, the reasons for which may be many.The rational method of flood management in Bihar (north Bihar) should include a judi-cious mix of structural and non-structural measures. As regards structural measures it should have an appropriate combination of short-term measures like embankments and long-term sustainable measures like reservoirs with adequate provision of flood cushion. Natural detention basins may also be used for flood moderation and channel improvement may be tried if found techni-cally and economically feasible. Under non-structural measures flood plains zoning and management, flood proofing, flood fore-casting and warning, disaster preparedness and response planning, etc, may be tried.Catchment area treatment is very impor-tantfor soil conservation and reduction in sediment inflow to the rivers, but in this respect also the difficulty lies in the fact that about 85% of the area of the catch-ment lies outside Bihar and we cannotdo anything there out of our own. Flood plain zoning helps in reducing the flood damage and misery afflicted by flood on the people. It is necessary not only for mitigating the flood but also for reducing the damage 
BIHAR FLOODSnovember 15, 2008 EPW Economic & Political Weekly42caused by drainage congestion. It recog-nises the basic fact that the flood plains are essentially the domain of the river and as such all developmental activities there must be compatible with the flood risk in-volved. However, due to inability of the governments to prevent or check the en-croachments of the flood plains, no begin-ning could be made so far in flood plain zoning. The government of India circulated a model bill on the flood plain zoning in 1974 among all the states of the country with the request to enact the same, but no state except Manipur could do so and this state also could not implement it. Flood proofing is essentially a combination of structural change and emergency action. Raising of some flood-prone villages above predetermined flood level and connecting them to nearby road or high land has been done, but the enthusiasm was lost very soon as the method did not provide any protec-tion to surrounding agricultural areas. The flood forecasting and warning system is already working in Bihar satisfactorily.The most common adjustment to the flood hazard in flood plains is simply to bear the loss and live with flood in areas where there is some serious constraint (as in north Bihar). Under the situation, floods become a matter of concern for all sections of society living in the affected areas and flood management needs active involve-ment and participation of all of the stake-holders to fulfil its objectives. The National Water Policy (2002) also advocates a parti-cipatory approach with the involvement of various governmental agencies, users and other stakeholders in an effective and de-cisive manner, in various aspects of plan-ning, design, development and manage-ment of water resources schemes.The problem of flood in Bihar is very com-plex and so is the task of its management. A strong political force is required for seeking and ensuring cooperation of Nepal without which sustainable long-term flood manage-ment in Bihar is not possible. Competent and capable engineers, well acquainted with the latest technology and enlightened and efficient bureaucracy should beentrusted with the job of policymaking and its imple-mentation. Their work should not be inter-fered with. Last but not the least,the involve-ment of the stakeholders in all stages of the process is a key factor for the success of the effort and optimisation of benefits.Kosi: Rising Waters, Dynamic Channels and Human DisastersRajiv SinhaThe recent Kosi floods have proved once again that inadequate control measures have been responsible for the recurring disasters. Typically flood control and riverinestudies focus on hydrologicalinformation, whereas a much more integrated approach that pays attentionto specificmorphological factors is required. Since Kosi is a dynamic river with auniquemorphology andbecause it is a river which has always carried high sediment loads, flood management strategies mustbeattuned to such specific parameters of the river, besides being much more than mere “river control” through embankments.Rivers play a critical role in human society and history as they are the major source of fresh water, trans-portation, and resources. However, this relationship is often “troubled” because changes in river discharge (floods or droughts) or position can play havoc with permanent settlements. Such changes can be caused by both natural forcing as well as human interventions or a combination of both. Natural processes may include short-term changes in sediment load, water volume or, long-term changes in relative sea level or climate change. Human interventions could impact in changes in sediment load or run-off through water resource management schemes such as dams, barrages and embankments. Human alterations of river systems can have many important consequences primarily because river systems are dynamic and highly integrated systems and any change in any part of the river can easily propagate and affect the whole system. The recent flood in the Kosi is certainly one of the biggest “human” disasters in recent years and it has sent out a strong signal that our flood management strategies are questionable and our preparedness to face such events is far too inadequate. Further, there has been a paradigm shift in flood management globally from “river control” primarily involving an engineering approach addressing the “effect” at a local scale to “river management” which empha-sises an integrated approach at a crossover of scales and addresses the cause rather than the effect. Even though India is a country drained by several large rivers, our river management strategies are rather rudi-mentary and our planners are yet to embrace modern approaches such as satellite-based monitoring and multi-criteria decision support system. This situation needs to be corrected to save a large population from repeated miseries of floods year after year.The Kosi: A Dynamic SystemThe Kosi river in north Bihar plains, eastern India is a major tributary to the Ganga river system and has long been considered as a problematic river due to recurrent and extensive flooding and frequent changes in its course. The gently sloping alluvial surface of the Kosi has been described as “inland delta”, “cone” and “megafan” by various researchers owing primarily to build-ing up of a very large positive topography caused by deposition of enormous quantity of sediments carried by the river which it is unable to transport. During the last two centuries, for which records are available, Rajiv Sinha (rsinha@iitk.ac.in) is with the Department of Civil Engineering, Indian Institute of Technology, Kanpur.
