Title: Hydrological model performances in small and mid-size Brazilian semi-arid ungauged watersheds under agricultural use

Authors: Luan Carlos Andrade Santos; Genival Barros-Junior; Jose Adalberto Silva-Filho; Sergio M.S. Guerra; Fernando Cartaxo Rolim-Neto; Jose Ramon Barros Cantalice

Addresses: Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil ' Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil ' Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil ' Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil ' Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil ' Environmental Engineering Graduate Program, Rural Federal of Pernambuco University (UFRPE), Recife-PE, 52171-900, Brazil

Abstract: Hydrological applications in ungauged watersheds, typical in the Brazilian semiarid environment, require knowledge of hydrological response. To compute the runoff from these watersheds, conceptual models are often employed. This study evaluated the performance of four conceptual models, and the probability density functions (PDFs) that best fit the hydrometric data were determined. All semiarid watersheds under semiarid crops showed runoff coefficients from 0.49 to 0.56 for all return periods, implying that about 50% of rainfall became runoff, so the soil tillage used in these semiarid crops was inadequate and degraded the soil and the Brazilian semiarid. The Gamma and log-normal PDFs showed the best agreements with observed streamflow data from the Exu, Jacu, and Cachoeira watersheds. The efficiency indicators showed that the performance of hydrological models applied to these Brazilian semiarid ungauged watersheds was linked to the watershed size and the time of concentration.

Keywords: modified rational method; SCS curve number method; TR55 method; shrub; semiarid crops.

DOI: 10.1504/IJW.2023.136032

International Journal of Water, 2023 Vol.15 No.4, pp.301 - 324

Received: 19 Oct 2023
Accepted: 28 Oct 2023
Published online: 12 Jan 2024 *

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