The myth of flood control

The ‘trade-off’ between flood control, hydropower and irrigation

Where dams are used to ‘control’ floods, the problems of management are exacerbated by the desire of politicians to make the maximum use of the waters in the dam’s reservoir. For flood-control purposes, the water level in the reservoir must be kept as low as possible: for the purposes of generating hydro-electricity or of irrigation, the opposite is the case. There is, therefore, a trade-off between, on the one hand, the containment of floods and, on the other, the provision of electricity and irrigation water. More often than not, the latter uses have priority. As Widstrand puts it,

“the high short-term value of water for irrigation or hydropower would be too strong an argument not to sacrifice some flood-mitigation benefits in favour of increased supply benefits.” [24]

That trade-off frequently proves disastrous. Dr. A. L. Mukherjee describes how operations at a dam in West Bengal led directly to widespread flooding in 1978. [25] In their eagerness to generate the maximum amount of hydro-electricity, the dam’s authorities maintained the reservoir practically full even during the rains of May and June. Those rains were particularly heavy and, as a result, the flow of the river was greatly increased. With the reservoir full, the river’s floodwaters could not be contained behind the dam. Inevitably, vast areas of West Bengal were flooded.

More recently, we have the example of the 1983 floods which ravaged California. [26] Heavy snowfall – said to be three times the annual average – in the winter of 1983 resulted in greatly increased runoff from the Rocky Mountains during the following spring. The waters of the Colorado River swelled to almost unprecedented heights, quickly filling the reservoirs behind those dams which have been built along the river – and, incidentally, placing considerable stress on the dams themselves. Although it soon became clear that the water-level in the reservoirs would have to be lowered to avoid large-scale floods downstream, the decision to do so was put off time and again.

It is now clear that those delays were prompted by purely short-term political and economic motives. Worried about its massive budgetary deficit, the US government was anxious that government agencies throughout the state should increase their incomes as far as possible. Thus, Bob Gottlieb of the Metropolitan Water District (MWD) later revealed to William Scobie of The Observer that the MWD was under strong pressure from Washington “to squeeze every kilowatt from the river’s hydro-electric stations”.

So, too, says Gottlieb, there was pressure from California’s powerful farming lobby to keep the reservoirs as full as possible in order that the maximum amount of water could be provided for irrigation. Meanwhile, the tourist industry – which, in California, has an annual turnover of billions of dollars – was also lobbying to keep water levels high so that the reservoirs could still be used for recreation.

When, in the first week of July 1983, a decision was eventually taken to release water from the reservoirs, it was far too late. Officials openly admitted that they were unleashing “a controlled disaster” on the south-west. Fifty-five thousand acres of farmland were flooded: thousands of people made homeless; an estimated $100 million worth of property destroyed; and at least five people drowned.

Nonetheless, the US government refused to admit that the floods were man-made – or, more precisely, politician-made. For its part, the Bureau of Reclamation attributed the error to faulty computer models – its own and those of the national Weather Service. Local hydrologists, however, were less sanguine: they told Scobie, “the gates were opened ten weeks too late for basically politico-economic reasons”.

Dealing with floods: the ecological approach

Serious floods are not simply acts of God. As Arnold points out,

“Too often, flood policies and programmes are based on the assumption that flood disasters result from nature’s actions, not man’s, whereas in actual fact the misery and damage are mostly caused by human error – especially by poor land management and myopic flood-control strategies.” [27]

Those “myopic” flood-control strategies undoubtedly have their roots in the atmosphere of panic that reigns when a serious flood occurs. At such times, writes Arnold, “rationality is difficult to achieve”. He goes on to explain why:

“People in a trauma want immediate action which means dealing with the effects rather than the cause – in other words, building structural controls rather than adopting real long-term solutions.” [28]

How then should the problem be tackled? Quite obviously, our first task is to prevent any further deforestation in the catchment areas of the world’s greatest rivers. The importance of such an anti-deforestation programme is eloquently stated by B.B. Vohra, President of India’s Environment Planning Council, in a recent speech on the subject of land and water management.

“The only way to tackle the growing menace of floods, is to control deforestation, denudation and soil erosion in the watersheds of rivers.” [29]

Such a task

“must be undertaken on the most urgent basis, particularly in the case of the Himalayan rivers, if certain disaster is to be avoided. If this problem is not tackled in time, it is not difficult to imagine a situation in which, thanks to increasingly frequent and intense floods, and the consequent rise in the level of river beds, large portions of the rich flat lands of the Ganga basin may be turned into undrainable swamps. Perhaps it is already too late to save the situation because, while the denudation and erosion of the Himalayas is already far advanced and is growing rapidly, it will be years – even with the best will in the world – before we will be able to control it effectively.”

In India – as in many other countries – flood control is the responsibility of the Irrigation Department, whose officials are mostly engineers or people with an engineering mentality. Unfortunately, that Department is totally committed to building structural flood controls and is apparently unwilling even to entertain the notion that the solution to the problem of floods is of a non-technical character.

For that reason, Vohra very sensibly suggests that the responsibility for controlling floods should immediately be “handed over to organisations which can control soil erosion in the catchments”. The trouble, of course, is that such organisations do not exist: moreover, were they to be created, it is questionable whether they could survive for long in the present politico-economic climate.

Any long-term solution to the problem of floods must undoubtedly go further than simply halting deforestation. Indeed, deforestation is now so far advanced in many areas of the Third World that a massive and systematic programme of reafforestation is of the utmost urgency. That reafforestation is required – and for many reasons other than just flood control – is generally accepted by both governments and international agencies.

The World Bank in particular has, on occasions, made the reafforestation of watersheds a condition for the financing of water-development schemes. But reafforestation for the World Bank (and most other aid agencies) still means the planting of row upon row of fast-growing pines or other exotic trees which often have a very shallow root system and, therefore, a minimal capacity either to retain water or to bind soils within their roots.

If, moreover, those trees have been chosen for planting, it is largely because there is a ready market for their timber: it is thus taken for granted that, one day, they will be cut down. Such trees are, therefore, of little use in combating erosion or run-off. If those functions are to be fulfilled, then it is of vital importance that reafforestation programmes ensure that a mix of native trees be planted so that the new forests resemble as closely as possible those that previously grew in the area. Only then can we be confident that the trees will be adapted to local geological, biotic and climatic conditions.

Finally, it is essential to prevent the further development of the flood plains of the great rivers. Again this is not only necessary for flood-control purposes. Flood plains, as Arnold points out,

“provide key links in many food chains. They are the habitat of numerous birds and other wildlife. They support a vast diversity of plant-life, they also provide some of the most fertile land and best-watered land for growing crops for a society that has mastered the technique of doing so.” [30]

The last thing one should do with such land is cover it with housing estates and factories.

In a country like Bangladesh, where flood plains make up 66 percent of the land area, it will of course not be possible to prevent all building on the flood plains. But, where floods are of a common occurrence, people eventually learn to live with them. Among other things, houses can be designed and built that are able to withstand flooding or that can easily be rebuilt after inundation.

Above all, what is required is a completely new attitude towards the problem of flood control. We must abandon the illusion that floods can actually be eliminated. Regardless of the brilliance of our scientists, the ingenuity of our engineers and the generosity of the World Bank, floods will continue to occur. But they need not necessarily cause disasters. On the contrary, throughout history, floods have been made use of by populations inhabiting river basins to irrigate and fertilise their fields in a perfectly sustainable manner. If floods could be brought once more under the joint control of the forests and the flood plains, we too might learn to live with floods and derive from them still more sophisticated benefits.

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References

1.	Carl Widstrand, “Manageability and Unmanageability of Water” in Carl Widstrand (ed) Water Conflicts and research Priorities. Pergamon, Oxford 1980; p.93.
2.	Peter Freeman, Environmental Considerations in the Management of International Rivers: A Review, (Working Draft), Threshold, International Center for Environmental Renewal, Washington DC March 1978.
3.	Li Jinchang, “Lessons learned from Heavy Floods”. Mazingira Vol. 6 No. 2, 1982; p.58.
4.	Department of Irrigation, Report of the National Commission on Floods, Vol 1. New Delhi, 1980. Cited by Centre for Science and the Environment, The State of India’s Environment, 1982. New Delhi 1982; p.62.
5.	Maurice Arnold, “Floods as Man-made disasters”. The Ecologist Vol. 6 No. 5, June 1976; p.172.
6.	Stanley A. Changnon, Jnr., Flood Mitigation: Policy Failure? A Research Agenda to address the issue. Paper presented to the AAAS Annual Meeting, 26-31 May 1983, p.1.
7.	B. B. Vohra, “Managing Land and Water Resources”. The Indian Express, Madras, 13 September 1978. Quoted by Carl Widstrand, op.cit., 1980, p.94.
8.	Maurice Arnold, op.cit. 1976, p.171. See also: Stanley A. Changnon, op.cit. 1983, p.1.
9.	Maurice Arnold, op.cit. 1976; p.172.
10.	Ibid, p.171.
11.	Arthur E. Morgan, 1971, Dams and other Disasters. Porter Sargent, Boston, Mass, p.422. Quoted by Arnold, op.cit. 1976, p.170.
12.	Charles B. Bet, Jr. The 1973 Flood and the Effects of Man on Stages of the Mississippi, near St. Louis. Paper presented at the annual conference of the Geological Society of America, St. Louis, Missouri, 1973. Quoted by Maurice Arnold, op.cit. 1976; p.170.
13.	Maurice Arnold, op.cit. 1976, p.169.
14.	Alan Grainger, “The State of the World’s Tropical Forests”. The Ecologist Vol. 10 No. 1; p.45.
15.	“Savage Waters that will not be Tamed”. The Economist, 9 September 1978; p.59.
16.	Li Jinchang, op.cit. 1982; p.58.
17.	Ibid, pp.58-59.
18.	Maurice Arnold, op.cit. 1976; p.169.
19.	D. R. Sikka, “Integrated Hydrologic and Societal Interactions of Floods and Droughts in India”. In E. F. Schulz et.al. (eds), Floods and Droughts: Proceedings of the Second International Symposium in Hydrology. Water Resources Publications, Fort Collins, Colorado; pp.237-245. Quoted by Maurice Arnold, op.cit. 1976; p.171.
20.	The Economist, op.cit, 1978; p.59.
21.	The Statesman, New Delhi, 19 August 1978. Quoted by Carl Widstrand, op.cit. 1980; p.94.
22.	Carl Widstrand, op.cit. 1980; p.95.
23.	The Indian Express, 1978. Quoted by Carl Widstrand, op.cit. 1980; p.95.
24.	Carl Widstrand, op.cit. 1980; p.94.
25.	A.L. Mukherjee, The Sunday Statesman, Calcutta, 10 September 1978. Quoted by Carl Widstrand, op.cit. 1980; p.94.
26.	William Scobie, The Observer, 10 July 1983; p.10.
27.	Maurice Arnold, op.cit. 1976; p.172.
28.	Ibid, p.171.
29.	B. B. Vohra, A Policy for Land and Water. Sardar Patel Memorial Lecture 1980, Government of India (Department of Environment), New Delhi 1980; p.12.
30.	Maurice Arnold, op.cit. 1976; p.172.