Floods of the last three decades in the Inner Pampa and their relationship with regional rainfall
Floods in the Pampean Region have a detrimental direct effect on plant production through crop flooding and soil salinization. Understanding the hydrological drivers of landscape flooding contributes to the implementation of more efficient mitigation actions. In this study, we determine the spatio-temporal dynamics of the surfaces water (SW) in the central portion of the Inner Pampean subregion and its relationship with regional rainfall records during the last 33 years (1987 to 2019). SW was estimated from spectral indices derived from satellite images (Landsat and MODIS) with a target temporal frequency of 6 months. The rainfall regime was characterized by monthly precipitation maps generated by interpolation of records from regional rain gauges. Two drainage basins were differentiated in the study region through a topographic analysis. They were designated as north basin (2.1 Mha), that includes the main channel of the Quinto River, and south basin (6.7 Mha). We found that flood periods (i.e., SW anomalies in the percentile range of percentiles [100:<90]) were short (~2 years) and recurrent. There were two flooding events in both basins (2001/02 and 2016/17) and an additional event in the south basin (1987/88). In both basins, the temporal dynamics of the SW was poorly associated with short (3 month) or long (3 years) term accumulated rainfall water. Although all flood events corresponded to positive rainfall anomalies, not all positive rainfall anomalies corresponded with large SW. The observed low predictive power of rainfall constitutes an indication that SW anomalies are also coupled to incoming regional surface and groundwater. Therefore, flood mitigation strategies should primarily aim at deepening groundwater levels by maintaining high evapotranspiration rates.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
2024
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/2374 |
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