The Impact on Farm Household Welfare of Large Irrigation Dams and their Distribution

Hiroyuki Takeshima, Adetola Adeoti, and Oluwafemi Adebola Popoola. 2017. The Impact on Farm Household Welfare of Large Irrigation Dams and their Distribution across Hydrological Basins: Insights from Northern Nigeria. Feed the Future Innovation Lab for Food Security Policy Research Paper 55. East Lansing: Michigan State University

This Food Security Policy Research Paper has also been published as IFPRI Nigeria Strategic Support Program Working Paper No. 35 in September 2016.

ABSTRACT
Despite substantial past investment and continued interest in irrigation dam construction in Nigeria, evidence on the impact of such dams on household welfare is generally scarce. In particular, relatively few studies have been done on the geographical scope that their benefits may reach, despite growing evidence from elsewhere that the benefits of large irrigation dams can extend beyond the districts or hydrological basins that contain them, reaching particularly to hydrological basins located downstream. This study assesses the short-term effects of large irrigation dams on household consumption in the northern part of Nigeria. Using two rounds of the Nigeria LSMS survey, we apply multinomial logit inverse probability weighting (MIPW) methods to construct matching samples across three different types of hydrological basins – dam basins, which are basins that contain large irrigation dams and the area upstream of such dams; downstream basins, which are located downstream of large irrigation dams; and non-dam basins, which are not associated with large irrigation dams. Our analyses particularly focus on the benefits provided by such dams for mitigating the drought risks faced by farm households. Drought is an important factor that affects adversely the welfare of farm household in Nigeria. Supplemental irrigation is often used during drought to provide water to crops.

We find that in 2010 and 2012 farm households in downstream basins were relatively less affected by drought and enjoyed relatively stable between-season growth rates of real per capita income and food consumption compared to comparable households in dam basins or in non-dam basins. These findings are consistent with the hypothesis that such households are able to limit the damage drought might cause on their own food production. We link these findings to the following policy messages: (1) downstream hydrological basins are important geographical units to include in assessing the benefits from construction of large irrigation dams in Nigeria; and (2) decisions on where to construct new large irrigation dams or which existing dams to rehabilitate should be partly guided by information on the agricultural productivity and income levels of households in downstream hydrological basins relative to the basins within which construction or rehabilitation of such dams is planned.

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