Temporal changes in land use and land cover due to retarding reservoir implementation

Abstract

This study examined the change in land use and land cover in the municipality of Mucugê, in the Brazilian state of Bahia, between 1993 and 2016, caused by the construction of the Apertado Dam, a retarding reservoir. For this purpose, satellite images were used to classify land use and cover and to map the areas. During this 23-years-period, Mucugê experienced significant changes. In 2016, compared to 1993, a reduction of 433.8 km2 (77%) of dense vegetation was observed. Of this reduction, 8 km2 was due to reservoir water level usage and 43.69 km2 to the introduction of irrigated agriculture. The latter has greatly expanded in the region, from 24.3 km2 in 1993 to 370.41 km2 in 2016. Such expansion primarily occurred on land previously occupied by pastures and anthropogenic areas in 1993. About 83.3% of the 370.41 km2 dedicated to irrigated agriculture in 2016 was occupied by pasture (91.6 km2) and anthropogenic land (216.86 km2) in 1993. Therefore, it is worth noting that agriculture expansion in Mucugê was not only based on the displacement of native vegetation. The establishment of a retarding reservoir inevitably presents both positive and negative effects on the surrounding area. Therefore, it is important to assess whether the positive impacts justify the investment and whether society is willing to bear the negative consequences. Our data show a positive impact of the Apertado Reservoir, whose implementation allowed the development of irrigated agriculture, predominantly on land previously used as pasture or other anthropogenic purposes.