## 4 Results and Discussions
This channel favours, in addition to the rapid transport of alluvium and the regressive evolution of the ravine in that sector due to the development of a steep slope through deep erosion, the generation of eddy currents that increase the flow rate and at the same time increase the erosion power in depth. Figure 14: Results of simulation 3. Additionally, due to the inclusion in the hydro-amelioration structure of the water intake pipe, the shear stress value is greatly diminished, which acts on the dam both upstream and at its downstream base, thus reducing the effects of erosion and at the same time contributing to its stability by creating favourable conditions for the deposits of sedimented alluvium with the action of the smaller volume of water discharged through the main spillway. It should be noted that the force vectors are oriented towards the upstream base of the dam, both in terms of lateral erosion and in terms of deep erosion, thus creating a favourable environment for the deposit of alluvial transported upstream, but also for production of eroded material by erosion of the banks in depth. Regarding the behaviour of the upstream and downstream dam sectors, they remain stable in terms of erosion and shear stress, compared to the values obtained in simulation 3. The major impact of the discharge pipe is highlighted only in the immediate vicinity of the dam, the rest of the torrential system not being majorly influenced by this new element included in the simulation. The behaviour of the entire torrential system analysed as a result of the implementation of hydro-improvement works can be analysed and highlighted best through the presentation and interpretation of the results obtained in terms of stream power in longitudinal profile (Figure 16). For the analysis and interpretation of erosion values, it was  
Figure 15: Results of simulation 4.  
decided to choose only Sectors II and III, because on the surface of these sectors the ravine has the highest potential from an erosional point of view due to the classic shape of the ravine and the large slope of the drainage channel. This leads to the likely potential for deep erosion and the identification of increased dynamics. The analysis of behaviour in the longitudinal profile of the erosion process highlights the very large decrease in erosion in hotspot 2 (HS2) by almost 100% compared to simulation 1, which had an exploratory purpose. There is a decrease in erosion power along the entire length of the longitudinal profile with an average of about 20%, being evident especially in simulation 3 and 4. In simulation 2, there is a decrease in erosion power downstream of the proposed hydro-amelioration work. The values are relatively small, approx. 10% (Figure 16). Figure 16: Comparative graphs of stream power value on longitudinal profiles. The effects of the implementation of the overflow dam as a solution to reduce lateral and deep erosion stand out with simulation 3, producing its effects in the downstream section where the erosion power is greatly reduced both along the entire longitudinal profile and in the hotspot area 2. This aspect highlights the beneficial influence of the proposed development measure on the whole downstream system. The same aspect can be observed in simulation 4, namely the accentuated reduction in the erosion power on the downstream sectors, with a small impact on hotspot 3. In that place, an average erosion power closer to the initial one was simulated, which is due to the low speed of movement of the volume of water, caused by the decrease in simulated volume at the tip of the hydrograph used in the modelling process. The results obtained in the implemented case study highlight the fact that such anti-erosion work is beneficial for the relative stabilization of the analysed ravine if the best decisions are made regarding the type and structure of the proposed arrangement. The erosion power decreases visibly within the analysed hotspot, changing its area effects from one simulation to another.