Examining Water Area Changes Accompanying Dam Construction in the Madeira River in the Brazilian Amazon

Abstract

<jats:p>Two recently constructed run-of-the-river dams (Santo Antônio and Jirau), along the Madeira River in Brazil, have been controversial due to their large unquantified impacts on (1) land use and land cover (LULC) and (2) on the area that would be flooded. Based on annual LULC data from 1985 to 2017, this study integrated intensity analysis and difference components methods to analyze the impacts of the two dams on the annual flooded area in upstream, midstream, and downstream regions of the Madeira River. The dam construction significantly influenced LULC change intensity in the upstream and midstream regions since 2011 and 2010, respectively. An increase of 18.5% of the newly flooded area (462.58 km2) in the post-dam construction period was observed. The water gross gain intensity was active during 2011–2017 and 2011–2014 in upstream and midstream, respectively. The dominant difference components of water change were exchanged in the pre-dam period and became quantity in the post-dam period for both upstream and midstream regions. Forest was the major land category replaced by water; however, the highest gain intensities occurred in other non-vegetated areas in upstream and midstream. This study provided a useful approach for characterizing impacts of dam construction on water area change.</jats:p>

Amazonian run‐of‐river dam reservoir impacts underestimated: Evidence from a before–after control–impact study of freshwater turtle nesting areas

“…The submersion of nesting areas agrees with previous studies that suggest that the impacts of run‐of‐river dam reservoirs are probably underestimated (Norris, Michalski & Gibbs, 2018a; Li et al, 2020). Run‐of‐river dams are known to alter flow rates upstream of the reservoir, reducing flow rates, which can lead to increasing upstream river levels and water residence times (Almeida et al, 2019a).…”

Amazonian run-of-river dam reservoir impacts underestimated: Evidence from a Before-After Control-Impact study of freshwater turtle nesting areas

“…The submersion of nesting areas agrees with previous studies that suggest the impacts of run-of-river dam reservoirs are likely underestimated (Li et al, 2020;Norris, Michalski, & Gibbs, 2018a). Run-of-river dams are known to alter flow rates upstream of the reservoir, reducing flow rates which can lead to increasing upstream river levels and water residence times (Almeida et al, 2019a).…”

Impacts of a large hydroelectric dam on the Madeira River (Brazil) on floodplain avifauna

“…Two large hydroelectric dams, Santo Antônio and Jirau, have been in operation on the Madeira River since 2012. These run-of-the-river dams employ a horizontal bulb turbine system that causes permanent flooding, mostly of previously seasonally flooded habitats along a large stretch of the river upstream of the dams but maintain water flow downstream (Li et al 2020). The Santo Antonio dam permanently inundated an area of 271 km2 in which most of the floodplain forest trees died (Fearnside 2015;Cochrane et al 2017;Li et al 2020).…”

“…These run-of-the-river dams employ a horizontal bulb turbine system that causes permanent flooding, mostly of previously seasonally flooded habitats along a large stretch of the river upstream of the dams but maintain water flow downstream (Li et al 2020). The Santo Antonio dam permanently inundated an area of 271 km2 in which most of the floodplain forest trees died (Fearnside 2015;Cochrane et al 2017;Li et al 2020). The newly flooded areas between the Santo Antonio and Jirau dams increased by 47.2% after dam construction (Li et al 2020).…”