SWAT Model Adaptability to a Small Mountainous Forested Watershed in Central Romania

Nicu Constantin Tudose,Serban Octavian Davidescu,Alin Lucian Mihalache,Sorin Cheval,Alin Lucian Mihalache,Oana Nicoleta Tudose,Cezar Ungurean,Mirabela Marin,Adriana Agafia Davidescu

doi:10.3390/f12070860

Abstract

This study aims to build and test the adaptability and reliability of the Soil and Water Assessment Tool hydrological model in a small mountain forested watershed. This ungauged watershed covers 184 km2 and supplies 90% of blue water for the Brașov metropolitan area, the second largest metropolitan area of Romania. After building a custom database at the forest management compartment level, the SWAT model was run. Further, using the SWAT-CUP software under the SUFI2 algorithm, we identified the most sensitive parameters required in the calibration and validation stage. Moreover, the sensitivity analysis revealed that the surface runoff is mainly influenced by soil, groundwater and vegetation condition parameters. The calibration was carried out for 2001–2010, while the 1996–1999 period was used for model validation. Both procedures have indicated satisfactory performance and a lower uncertainty of model results in replicating river discharge compared with observed discharge. This research demonstrates that the SWAT model can be applied in small ungauged watersheds after an appropriate parameterisation of its databases. Furthermore, this tool is appropriate to support decision-makers in conceiving sustainable watershed management. It also guides prioritising the most suitable measures to increase the river basin resilience and ensure the water demand under climate change.

Highlights

Watershed behaviour is influenced by multiple factors such as its geomorphologic characteristics and climate conditions [1]
This research is an effort that can be considered a novel step for future studies investigating the hydrological behaviour of small watersheds
We presented the methodology used for customising the SWAT model to the local specificity for testing its ability to simulate the hydrological processes within a small forested ungauged watershed located in a mountainous region

Summary

Introduction

Watershed behaviour is influenced by multiple factors such as its geomorphologic characteristics (e.g., slope, soil, land use) and climate conditions [1]. Flood events generated by faster snowmelt or compounded rain-snow events due to increased temperatures will be more frequent, in the mountainous regions [5,6,7]. Those changes will jeopardise the future sustainability of natural resources and, all activity sectors [8], water resources, through changes in flow regime [9,10]. As a climate change consequence, increments in water demand are forecasted [15]

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