Influence of the rain gauge network on the performance of a hydrological lumped model applied at different basin scales

Influência da rede pluviométrica no desempenho de um modelo hidrológico concentrado aplicado em diferentes escalas de bacias

ABSTRACT

In this study was evaluated the influence of the rainfall monitoring network density and distribution on the result of rainfall-runoff daily simulations of a lumped model (IPH II) considering basins with different drainage scales: Turvo River (1,540 km²), Ijuí River (9,462 km²), Jacuí River (38,700 km²) and Upper Uruguay (61,900 km²). For this purpose, four rain gauge coverage scenarios were developed: (I) 100%; (II) 75%; (III) 50% and (IV) 25% of the rain gauges of the basin. Additionally, a scenario considering the absence of monitoring was evaluated, in which the rainfall used in the modeling was estimated based on the TRMM satellite. Was verified that, in some situations, the modeling produced better results for scenarios with a lower rain gauges density if the available gauges presented better spatial distribution. Comparatively to the simulations performed with the rainfall estimated by the TRMM, the results obtained using rain gauges’ data were better, even in scenarios with low rain gauges density. However, when the poor spatial distribution of the rain gauges was associated with low density, the satellite’s estimation provided better results. Thus, was conclude that spatial distribution of the rain gauge network is important in the rainfall representation and that estimates obtained by the TRMM can be presented as alternatives for basins with a deficient monitoring network.

Keywords:  Rainfall-runoff modeling; IPH II; Rain gauges scarcity; Product 3B42 version 7