Bhavani Shankar*
Department of Agricultural and Food Economics, University of Reading, P.O. Box 237, Reading, RG6 6AR, UK
Ashley Halls
Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London, SW7 2AZ, UK
Julian Barr
ITAD Ltd, Ditchling Common, Ditchling, Hassocks, West Sussex, BN6 8SG, UK
Bangladesh; Fisheries; Floodplains; Rice; Irrigation; Water.
Socio-economic and Policy
Surface water, Rice, Fish
Int. J. Water, Vol. 3, No. 1, 2005
Abstraction of surface water for irrigation poses a serious threat to the sustainability of floodplain fisheries in Bangladesh. Previous fisheries research has accorded a central role to dry-season water maintenance in maintaining the health of the fishery, and rice irrigation water abstraction desiccates waterbodies at a rapid rate due to the high water requirement for rice. Needless to say, this externality imposed on the fishery has important consequences for millions of poor who depend on fishing for their livelihoods. Several current trends indicate that this problem is going to worsen in the near future. Irrigated winter rice cultivation has spread over time to occupy cultivable land of all elevations. Smaller, cheaper and more mobile low lift pumps are now available. These, in contrast to the earlier generation of 2 cusec LLPs, do not need large command areas to be economically viable, and are also able to exploit smaller, shallower waterbodies. Increased attention is also now being focussed on surface water irrigation since groundwater sources may be reaching the limits of exploitation, and many are additionally feared to be contaminated by arsenic.
Although this issue crops up regularly in problem censuses and participatory research in Bangladeshi floodplains, it appears under-researched. Particularly, little quantified information is available to enable an appreciation of the seriousness of the problem. Using a dynamic pool fisheries model for the PIRDP area, we have estimated that every hectare of Boro rice irrigated by surface water means results in a reduction of 0.03 kg of fish per hectare. If the 6,773 hectare area that we model is visualised as a single ‘catchment’, this translates to 242 kg of fish for every irrigated hectare. Irrigating more than 500 hectares, i.e., only about one-thirteenth of the modelled area via surface water is enough to cause dramatic loss to the fishery. The problem is thus a very serious one. One route to mitigation is to reduce the amount of water commonly applied to the Boro crop. Although there are always avenues available to economise on water applied to individual plots, even the broad question of whether Boro production in Bangladesh is characterised by ‘excess’ irrigation applications is a debatable one. Indeed, it would appear that the problem lies in the extent of Boro cultivation itself rather than the amount of water applied to individual plots.
Crop diversification, particularly in the dry season, is being promoted across Bangladesh for a variety of reasons. Almost all alternative Rabi crops that compete with irrigated rice have lower water requirements and their promotion would provide a means to ameliorate the externality imposed by winter cultivation on the fishery and its dependent livelihoods. In the PIRDP region that we model, wheat and onions represent the most viable alternatives. Simulation of the effects of irrigation for wheat and onions reveals that the consequent impact on the fishery is much less compared to irrigation for Boro rice. Rabi diversification is thus one of the few mitigation routes that can be applied on a large scale (tailored to local conditions), with several other attendant advantages. The focus of diversification programmes has mostly concentrated on higher land elevations. This is natural, since the comparative disadvantage of rice compared to alternative crops increases with elevation. However, there is scope for successful diversification even in medium and medium–low elevation plots. This has already happened in some areas, with the DW-Aman crop, followed by Rabi crops such as wheat and onions replacing the previous Boro based systems. Our analysis of static profitability reveals that such Aman based systems can compete with Boro-based rotations, especially since the latter is often characterised by a single Boro crop in lower elevation plots. However, static profitability is but one aspect of the problem, and there is an urgent need for research into farm-level decision-making on rotation choice, and how changing livelihood circumstances are affecting decisions about the principal crop or season around which farm systems are constructed. Our analysis and discussion is also not meant to suggest wholesale diversification out of winter rice into alternate cereals or vegetables. For a variety or reasons, this would be neither achievable nor desirable. Rather, the suggestion is that the inclusion of even a limited programme of Rabi diversification, designed on a local basis, into the portfolios of floodplain action research projects could well prove beneficial to the fishery. This applies even to the several long-run management projects mostly focussed on floodplain fisheries that are underway or on the anvil in Bangladesh.
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