Tropentag, September 10 - 12, 2025, Bonn "Reconciling land system changes with planetary health"

Assessing the invest^® seasonal water model in a Brazilian Cerrado agricultural watershed

Martin Luther University Halle-Wittenberg, Institute of Geosciences and Geography, Germany

Abstract

Modelling water-related ecosystem services (WES) in tropical, data-scarce landscapes remains a central challenge for sustainable land and water management. This study presents a critical assessment of the InVEST® Seasonal Water Yield (SWY) model, applied to the Alto Parnaíba Sub-basin, located in the MATOPIBA agricultural frontier of the Brazilian Cerrado. The objective was to evaluate the model’s ability to simulate dry-season baseflow under land-use and climate change scenarios.

In the SWY model, baseflow is calculated from a simplified water balance (precipitation minus actual evapotranspiration, P - AET). However, its spatial distribution results from a complex redistribution process shaped by parameters such as soil transmissivity, landscape connectivity, and subsurface flow direction—each simulating essential hydrological dynamics. The model does not explicitly represent groundwater recharge, root-zone water storage, or long-term vegetation-climate feedbacks, which limits its capacity to fully capture the behaviour of tropical hydrological systems.

Simulations for the period 2000–2023 indicate that dry-season baseflow more than doubled in key agricultural catchments—even under decreasing precipitation—primarily due to the widespread replacement of native vegetation with soybean monocultures. This reflects the model’s high sensitivity to evapotranspiration parameters: lower crop coefficients (Kc) reduce water loss and increase infiltration, generating an artificial surplus. While internally consistent, these results must be interpreted cautiously.

According to the literature, vegetation suppression and climate change may further disrupt regional moisture recycling, decrease rainfall, intensify surface runoff, and reduce deep aquifer recharge—undermining long-term water security. Thus, short-term increases in modeled water yield do not necessarily translate into hydrological resilience.

This study underscores the importance of critically interpreting InVEST model outputs in dynamic agricultural frontiers and highlights the need to complement them with local data and additional modelling tools. The findings offer valuable insights for evidence-based policy and integrated water resource planning in tropical regions under pressure.

Keywords: Agricultural frontier, baseflow, cerrado, evapotranspiration, inVEST model, land-use change, water security, water yield

Contact Address: Clara Müller Benarroz, Martin Luther University Halle-Wittenberg, Institute of Geosciences and Geography, Krausenstrasse23, 06112 Halle (Saale), Germany, e-mail: clara.geologiagmail.com