Fri Apr 10, F. Flechtner
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Besnier, Jessica, Getirana, Augusto, and Lakshmi, Venkataraman, 2026. Crossing the Threshold: Land Cover Change Triggers Hydrological Regime Shift in Brazil's Itaipu Hydropower Region. Remote Sensing, 18(6):848, doi:10.3390/rs18060848.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2026RemS...18..848B,
author = {{Besnier}, Jessica and {Getirana}, Augusto and {Lakshmi}, Venkataraman},
title = "{Crossing the Threshold: Land Cover Change Triggers Hydrological Regime Shift in Brazil's Itaipu Hydropower Region}",
journal = {Remote Sensing},
keywords = {earth observations, land cover change, Itaipu Dam, Upper Parana River Basin, hydrological changes, total water storage fluctuations},
year = 2026,
month = mar,
volume = {18},
number = {6},
eid = {848},
pages = {848},
abstract = "{What are the main findings? Land cover thresholds (32\% croplands, 27\%
savannas, 4\% wetlands) correlated with a hydrological regime
shift in August 2009, with terrestrial water storage increasing
by 151.6 cm at the Itaipu Reservoir Land cover change explains
73─88\% of post-2009 water storage variability, far exceeding
ENSO's influence (r = 0.42), demonstrating that cumulative
agricultural expansion now dominates over climate as the primary
driver Land cover thresholds (32\% croplands, 27\% savannas, 4\%
wetlands) correlated with a hydrological regime shift in August
2009, with terrestrial water storage increasing by 151.6 cm at
the Itaipu Reservoir Land cover change explains 73─88\% of
post-2009 water storage variability, far exceeding ENSO's
influence (r = 0.42), demonstrating that cumulative agricultural
expansion now dominates over climate as the primary driver What
are the implications of the main findings? Strategic land use
decisions{\textemdash}preserving wetlands, maintaining savannas,
regulating croplands expansion{\textemdash}now directly control
water storage resilience more than climatic factors in
reservoir-dominated agricultural frontiers The empirically
derived thresholds provide quantitative targets for adaptive
management and are transferable to other tropical hydropower-
agricultural systems through integration of GRACE, MODIS, and
other climate data Strategic land use
decisions{\textemdash}preserving wetlands, maintaining savannas,
regulating croplands expansion{\textemdash}now directly control
water storage resilience more than climatic factors in
reservoir-dominated agricultural frontiers The empirically
derived thresholds provide quantitative targets for adaptive
management and are transferable to other tropical hydropower-
agricultural systems through integration of GRACE, MODIS, and
other climate data Rapid agricultural expansion threatens water
security in one of the world's largest hydroelectric systems,
the Itaipu dam, located on the Brazil─Paraguay border. Yet
regional hydrological responses to land cover change and climate
variability remain insufficiently characterized at management-
relevant scales. The Upper Paran{\'a} River Basin (UPRB), which
sustains agriculture, hydropower, and municipal water supply
across both countries, exemplifies this challenge as
accelerating cropland conversion raises concerns about long-term
water availability. This study investigates hydrological
transitions and their statistical associations with land cover
changes in the Itaipu study region from 2002 to 2023. We
integrate GRACE/GRACE-FO (Gravity Recovery and Climate
Experiment Follow-On), Terrestrial Water Storage Anomalies
(TWSAs), MODIS (Moderate Resolution Imaging Spectroradiometer)
land cover, CHIRPS (Climate Hazards Group InfraRed Precipitation
with Station data) precipitation, and LandScan population
density using Pettitt's breakpoint test and Mann─Kendall trend
analysis to detect temporal breakpoints and quantify co-
variability between hydrology and land surface dynamics.
Together, these methods identify a significant basin-wide shift
in TWSAs in mid-2009, with storage increases of 151.6 cm at
Itaipu and 103.1 cm at Yguaz{\'u} Reservoir. Over the study
period, cropland expanded from 13.5\% to 37.9\% of total land
cover, while savanna declined from 28.1\% to 24.2\%. After 2009,
correlations between land cover and TWSAs strengthened
substantially, particularly for wetlands (r = 0.88), croplands
(r = 0.73), and savannas (r = {\ensuremath{-}}0.81; all p <
0.001), indicating strong coupling between landscape
transformation and basin-scale storage variability. Principal
Component Analysis shows land use change explains 39─41\% of
TWSA variance, exceeding hydroclimatic contributions. Granger
causality analysis reveals bidirectional coupling between
wetlands and water storage at Itaipu, while cropland and savanna
dynamics exert predictive influence on downstream hydrology in
the Yguaz{\'u} basin. Water balance decomposition further
indicates a post-2009 regime shift, with residual storage
transitioning from {\ensuremath{-}}10.6 to +4.7 and 78\% greater
runoff generation per unit precipitation, consistent with
reduced infiltration capacity. Together, these findings
underscore intensifying land─water feedback and the need for
adaptive watershed management under expanding agriculture and
climate variability.}",
doi = {10.3390/rs18060848},
adsurl = {https://ui.adsabs.harvard.edu/abs/2026RemS...18..848B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
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