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Torrential watershed management actions should be integrated and their results designed to last for a long time. In Romania and in other countries, these actions cover the entire area of the watershed (slopes, banks, and riverbeds). They consist of complex sets of structural and non-structural measures and works designed to control runoffs and erosion, protect social-economic objectives and improve degraded lands. The most vulnerable structures are the hydrotechnical structures, which are placed on riverbeds in direct contact with torrential flows. Being limited by environmental factors (such as violent flash floods loaded with sediments and woody debris) and isolated conditions, these works should be monitored continuously and systematically. Research focusing on the deficiencies uncovered during torrent control structure servicing led to a substantiated monitoring system based on repeated inventories (once every 5-10 years). This paper presents the evolution of the physical states of 192 transverse structures between two successive inventories. It analyses the influence of some features (structure s age, initial condition rate, height, building materials) on a structure s condition rate variation. The results reveal the high influence of a structure s height on the annual decay of the structure. Due to the poor quality of building materials and improper technologies used after 2000, those structures have more damaged between inventories. The functionality of torrent control structures is affected by various factors that cause unembedding, undermining, cracks, breaks, and abrasions. In order to improve the maintenance of these structures, a substantiated monitoring system is required, as well as a well-trained staff (designers and builders).

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.

The present study evaluates the applicability performance of the Soil and Water Assessment Tool (SWAT) in small forested watersheds (less than 1000 km2). This open-source software is widely used in investigations focused on water availability and quality. Overall, SWAT model performance ranges between satisfactory to good. Normally, underestimates daily peak discharges. The limitations of the model are related to the accuracy of climate data used and to the time period used for validation. Watershed area, forest cover and streamflow spatial distribution have an important influence on modeling processes. Overall, from the analyzed studies, we observed for discharge a decreasing tendency, more pronounced towards the end of the 21st century (up to −54%). For surface runoff, was noticed the same decreasing tendency up to 41%. Regarding sediment yield, the results vary within very wide limits. These findings vary according to watershed location, scenarios adopted, and the eligible period of time.