Empirical rainfall-based model for defining baseflow and dynamical water use rights

Author(s)

Gomez, Derly ^[1] ; Wendland, Edson ^[2] ; Diniz Melo, Davi de Carvalho ^[3]

Affiliation

^[1] Pontifical Bolivarian Univ, Dept Civil Engn, Monteria - Colombia

^[2] Univ Sao Paulo, Dept Hydraul & Sanit Engn, Sao Carlos, SP - Brazil

^[3] Univ Fed Paraiba, Dept Soils & Rural Engn, Areia - Brazil

• Document type: Journal article
• Source: RIVER RESEARCH AND APPLICATIONS; v. 36, n. 2 DEC 2019.
• Web of Science Citations: 0

Abstract

Water managers and stakeholders usually face uncertainty in water availability due to the challenge of incorporating the dynamic nature of precipitation into the water management system. Surface water rights are commonly related to the baseflow component, which is part of the precipitation incident on a watershed. This study proposes an empirical linear model to predict baseflow in perennial streams based on a moving average of antecedent rainfall data and the basin time response. The short-term responses of three nested basins were estimated using cross Fourier spectral analysis, and the proposed model was applied to two nested basin scales (1,867 and 3,519 km(2)), located in southeastern Brazil. Results indicate that the aquifer stores the rainfall water with regulation times of approximately 60days for the fast-subsurface flow and approximately 2-3years for the slow groundwater flow in both basins. Differences between our model results and monthly 95% exceedance discharge (Q(95)) were as high as 10 m(3) s(-1) between September and November in the largest basin, revealing how conservative Q(95) can be as a criterion for water allocation purposes. Despite the simplicity, our empirical rainfall-based model is structurally consistent and robust in representing the hydrological processes involving precipitation, groundwater storage and baseflow interactions at multiple scales by using few inputs and calibration parameters. Because it considers a range of rainfall periods, from past to present, our model contributes to a dynamic, predictive, and integrated water rights management. (AU)

• FAPESP's process: 15/03806-1 - Water availability and quality threats in a Guarani Aquifer System outcrop zone
• Grantee: Edson Cezar Wendland
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 16/23546-7 - Water availability under extreme events: droughts in the Paraná Basin region
• Grantee: Davi de Carvalho Diniz Melo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral