## 2 Materials and Methods
### Case Study  
A synthesized example of results obtained in a real case study demonstrates the feasibility of the hypothesis established in this review work. A crucial hydrographic basin in the central region of Cuba was examined to demonstrate the implementation of an integration methodology combining isotopic and nuclear techniques (FRN, FP, and IH) to evaluate the degradation of land and water resources. In the province of Cienfuegos, within the Hanabanilla hydrographic sub-basin (176.47 km\({}^{2}\)), two sub-basin sectors were selected for the application of isotopic and nuclear techniques: the \"River Hanabanilla\" sector (66.11 km\({}^{2}\)) and the \"River Charco Azul\" sector (47.67 km\({}^{2}\)). The region is distinguished by the presence of the Hanabanilla reservoir, which is home to a hydroelectric generation plant. The area comprises sectors with topography characteristics of mountainous regions, featuring elevated slopes, considerable runoff, and water erosion. The study area's predominant land uses are forestry, protected areas, coffee crops, temporary crops, livestock, and human settlements (Figure 2). The proposed working hypothesis is that the integration of isotopic and nuclear techniques facilitates the design and implementation of a sampling strategy (in terms of sediment sources and mixtures), supports the interpretation of results, and allows for the quantification of degradation, the identification of causes and sources of degradation, and the assessment of water resource dynamics. These outcomes are supported by the results obtained from techniques applied in previous stages. Figure 2: Hanabanilla sub-basin and selected sectors in the case study. A range of isotopic and nuclear techniques were employed, including FRN (\({}^{137}\)Cs), FP (CSSI), IH (\({}^{18}\)O and \({}^{2}\)H), and geochemistry of water. Fifty-six samples were analyzed for FRN, twenty-five for FP, and fourteen points for periodic IH sampling, including four sediment cores at the Hanabanilla reservoir's bottom (points I, II, III, and IV). The initial FRN technique was implemented in both sectors to evaluate soil redistribution. The results obtained from this technique were then considered during the sampling design and the selection of source and mixture points in the landscape. Sequentially, the quantification of the final contributions of the sediments was obtained using FP. Finally, the third technique, IH, was employed with FP to assess the impact of water dynamics (underground, superficial, and reservoir) on the existing sedimentation zones in the Hanabanilla River sector and the sub-basins. The FP technique was applied differently in the two selected sectors to test the proposed hypothesis. Initially, the FP results were obtained without considering the results of the FRN technique. Subsequently, the FP results were obtained using the FRN soil redistribution data to reinforce the selection of source soil and mixture sediment zones, representing a fundamental stage of the FP technique. The results were evaluated using a range of statistical methods, including the range test, principal component analysis (PCA), goodness of fit of the solution, source contribution graphs, and others, to estimate the relevance of the two application variants with or without integration of FRN data. In the case of the River Hanabanilla sector, three sources were considered in developing the FP technique: forestry, temporary crops, and coffee crops. Additionally, one mixing zone was identified. The tracer was CSSI (carbon chain \({}^{14}\)C to \({}^{34}\)C), and the FingerPro model [84] was employed to estimate sediment contributions. The results obtained are shown in Table 2.  
In the case of the River Charco Azul sector, three sources were considered during the application of the FP technique: forestry, coffee crops, and fruit trees. Additionally, one mixing area was incorporated into the analysis.