Reservoir yield intercomparison of large dams in Jaguaribe Basin-CE in climate change scenarios

Abstract

Climate changes can have different impacts on water resources. Strategies to adapt to climate changes depend on impact studies. In this context, this study aimed to estimate the impact that changes in precipitation, projected by Global Circulation Models (GCMs) in the fifth report by the Intergovernmental Panel on Climate Change (IPCC-AR5) may cause on reservoir yield (Q 90 ) of large reservoirs (Castanhão and Banabuiú), located in the Jaguaribe River Basin, Ceará. The rainfall data are from 20 GCMs using two greenhouse gas scenarios (RCP4.5 and RCP8.5). The precipitation projections were used as input data for the rainfall-runoff model (SMAP) and, after the reservoirs' inflow generation, the reservoir yields were simulated in the AcquaNet model, for the time periods of 2040-2069 and 2070-2099. The results were analyzed and presented a great divergence, in sign (increase or decrease) and in the magnitude of change of Q 90 . However, most Q90 projections indicated reduction in both reservoirs, for the two periods, especially at the end of the 21th century.Keywords: CMIP5; Reservoir yield; Coupling models. RESUMOAs mudanças climáticas devem causar diversos impactos nos recursos hídricos. As estratégias de adaptação às alterações previstas no clima dependem de estudos de impactos. Nesse contexto, esse trabalho tem como objetivo estimar os impactos que as alterações na precipitação, projetada pelos Modelos de Circulação Global (MCGs) do quinto relatório do Painel Intergovernamental de Mudanças Climáticas (IPCC-AR5), podem causar nas vazões regularizadas (Q 90 ) de dois grandes reservatórios (Castanhão e Banabuiú) localizados bacia do Rio Jaguaribe, Ceará. Os dados de precipitação são provenientes de 20 MCGs em dois cenários de emissão de gases de efeito estufa (RCP4.5 e RCP8.5). As projeções de precipitação alimentaram um modelo chuva-vazão (SMAP) e posteriormente, após a geração das séries de vazões afluentes aos reservatórios, foram simuladas as vazões regularizadas pelos reservatórios no modelo AcquaNet para os períodos de 2040-2069 e 2070-2099. Os resultados foram comparados entre si e indicaram grandes divergências tanto quanto ao sinal (acréscimo ou redução) como quanto à magnitude da mudança na vazão regularizada. Entretanto, a maioria das projeções indica redução da Q 90 nos reservatórios para os dois períodos, principalmente para o final do século.Palavras-chave: CMIP5; Vazão regularizada; Acoplamento de modelos.

Eutrophication risk assessment of a large reservoir in the Brazilian semiarid region under climate change scenarios

“…The divergences in the projections of the percent volume indicated the uncertainty propagation along the CGMs, SMAP and reservoir water balance. Similar results were found for the affluent flow in other studies for the Jaguaribe River basin (Fernades et al 2017, Gondim et al 2018. For example, (Estácio 2020) predicted relative changes varying from -50% to 300%, for the same reservoir of this study during the 2025-2055 period.…”

Limnology of the largest multi-use artificial reservoir in NE Brazil: The Castanhão Reservoir, Ceará State

“…Average annual rainfall varies from 400 to 1,000 mm and a historical annual mean of 756.5 mm during the past 80 years is recorded (FUNCEME 2016). The Middle Jaguaribe Basin, where the reservoir is located, is the driest subbasin of the river and shows a trend of decreasing annual precipitation in the past 90 years (Gondim et al 2012, Campos 2014, Fernandes et al 2017. Potential evaporation amounts for about 2,100 mm (SRH 2008).…”

“…During the driest years of these periods mean annual rainfall reached their minimum, significantly below the historical annual average: 302 mm (in 2012), 350 mm (in 1983), and 484 mm (1953), also suggesting strengthening of drought intensity in more recent years. Since these extended drought periods relate with strong El Niño events, whose tendency to increase due to global climate changes is expected, the Castanhão reservoir basin annual rainfall shows a forecast of at least 20% till during the next 40 years (Fernandes et al 2017). Since increasing water necessity from major human activities, in particular agriculture, is also expected, this scenario will worsen (Krol and Bronstert 2007, Marengo et al in press).…”

Projections of climate change in streamflow and affluent natural energy in the Brazilian hydroelectric sector of CORDEX models

“…This model has been successfully used in several studies that analyse the climatic and hydrological variables, mainly for corrections of modeled precipitation data, although, it can also be applied in the estimated ETP (Fernandes et al, 2017;Silveira et al, 2016Silveira et al, , 2019. In this study, two gamma CDF functions were necessarily used due to the elaboration of the probability mapping for the bias correction in the monthly time series of precipitation and ETP of the CORDEX RCM for the 24 basins representing the NIS; the first function was obtained through modeled data and the second through observed data.…”

“…Studies show how climate change may have major impacts that directly affect soil moisture, groundwater reserves and streamflow seasonality due to changes in spatial and temporal patterns of precipitation and evapotranspiration in the country (Guimarães et al, 2016;Silveira et al, 2016;Sales et al, 2015). Such aspects, associated with projections of increased demand for water and energy in the next decades, caused mainly by population and wealth growth, may exert great pressure on the Brazilian hydrosystems, affecting water and energy supply and consequently the entire national economy (Fernandes et al, 2017;Prado et al, 2016).…”