Joint Determination of Perceived Favorable and Adverse Environmental Impacts of Mega-Dam by Residents: The Case of Merowe Dam, Sudan

Background: Although mega-dams play a significant role in development, providing electricity, irrigation, and flood control, perceptions of their contribution remain mixed, particularly regarding the environmental impacts. Methods: This study jointly determines perceived favorable and adverse environmental impacts of mega-dams by affected residents using a bivariate Tobit model on a clustered random sample of 300 households surveyed from (a) upstream, (b) upstream-relocated, and (c) downstream communities of the Merowe Dam in Sudan. Model diagnostic reveals that the perception of favorable and adverse environmental impacts is significantly and positively correlated, implying that univariate analyses of such perceptions are biased, thereby justifying the use of a bivariate approach. Such joint perception analysis using a bivariate Tobit model confirms that affected residents are well aware of both the positive and negative impacts of the dam, not commonly seen in the literature. Results: Results reveal significant differences in perception among communities on individual indicators of favorable and adverse environmental impacts of the dam. Education, income from farming, and relocation significantly decrease the likelihood of perceiving adverse environmental impacts whereas farmers of all farm types increase it. Selected farming categories and gain in land size after dam’s construction significantly increases the likelihood of scoring high on favorable environmental impacts whereas income from fishing significantly reduces it. Conclusions: Perception towards the favorable and adverse environmental impacts are not independent, rather significantly and positively correlated, confirming that affected residents are aware of both types of impacts of the Merowe Dam. Upstream-relocated residents are less likely to report the significant adverse environmental impacts of the dam, whereas both upstream and upstream-relocated residents are less likely to report significant favorable impacts of the dam. Policy implications: Include establishing educational institutions, allocation of agricultural land, and mitigating adverse environmental impacts by setting up community environmental monitoring programs in affected areas to boost community perception of the favorable environmental impacts of mega-dams.