The socio-economic problems of irrigation, and the solutions

Overview

Single most effective way of preventing both salinisation and waterlogging and point of mulching in an irrigated dryland.

What you need to know

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Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What are the human costs of building the dam and reservoir that a large irrigation scheme depends on?

   Model answer

   The reservoir floods the valley floor, which is usually the most fertile and most densely settled land, so people are displaced, sometimes in very large numbers. Resettlement schemes often move communities onto poorer, drier land, break up kinship and support networks, and pay compensation that is late, inadequate or given only to those who can prove formal title, which excludes tenants and customary users. Villages, farmland, burial grounds, places of cultural or religious significance and archaeological sites are lost permanently. Those displaced rarely receive a fair share of the benefits, which flow to the irrigated area downstream.

2. 2

   Why do irrigation schemes so often widen inequality between farmers?

   Model answer

   Because the benefits depend on access to capital and on position in the system. Wealthier farmers can afford tube wells, pumps, fertiliser, high-yielding seed and drip equipment, so their yields and incomes rise fastest; poorer farmers cannot, and may go into debt trying. Land values on irrigated land rise, so landowners gain while tenants face higher rents and landless labourers gain only wages. In a canal system, farmers at the head of a distributary take water first and often take more than their share, leaving tail-end farmers with an unreliable supply. Over time the better land is consolidated into fewer, larger holdings and smallholders sell up.

3. 3

   What health problems are associated with irrigation schemes?

   Model answer

   Permanent slow-moving or standing water in canals, drains and paddy fields creates ideal breeding habitat for disease vectors that arid conditions previously suppressed. Mosquitoes breeding in still water spread malaria and dengue. Aquatic snails in canals host the parasite that causes schistosomiasis, or bilharzia, which infects people wading or washing in the water. Where drinking water and irrigation drainage mix, water-borne diseases such as cholera, typhoid and diarrhoeal illness spread. Pesticide handling without protective equipment causes poisoning, and in some regions naturally occurring arsenic or fluoride in deep groundwater has contaminated supplies drawn for irrigation and drinking.

4. 4

   How can irrigation create conflict over water?

   Model answer

   Because water taken by one user is not available to another. Upstream and downstream users of the same river compete, and where the river crosses an international boundary a dam or major abstraction becomes a diplomatic dispute, since downstream states lose flow they may depend on and there is often no binding agreement to allocate it. Within a scheme, head-end and tail-end farmers compete for canal water, and thousands of individual pumps compete for a shared aquifer that nobody owns. Irrigated arable farming also displaces pastoralists from dry-season grazing and from access to the river, and that clash between settled farmers and herders is a persistent source of violence on the desert margin.

5. 5

   What are the economic drawbacks of a large irrigation scheme for the country that builds it?

   Model answer

   Capital costs are enormous and are typically met by international loans, so the country carries debt and interest payments for decades, sometimes before the scheme delivers its promised returns. Maintenance is a permanent charge: canals silt up, structures decay, pumps need fuel and parts, and drainage systems need rebuilding, and where maintenance budgets are cut the asset deteriorates. Reservoirs silt up, reducing storage and shortening the working life of the dam. If the scheme is built around a single export crop, the economy becomes exposed to a fall in that crop's world price. And the sums invested are not available for alternatives such as small-scale water harvesting, health care or education, which may have delivered more benefit per pound spent.

6. 6

   Why can irrigation increase, rather than reduce, the vulnerability of farming communities?

   Model answer

   Because it replaces a low-yield but resilient system with a high-yield but dependent one. Farmers who abandon drought-tolerant traditional crops and rely on irrigated cash crops are exposed if the water supply is interrupted by drought, a broken pump, an unpaid electricity bill or an upstream abstraction. Reliance on purchased seed, fertiliser and fuel exposes them to price rises and to debt. Traditional coping strategies, such as mobility, mixed cropping and drought-resistant varieties, may be lost within a generation. When the system fails, it fails for everyone at once, whereas the older system failed patchily.

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