The increasing demand for hydropower as a sustainable energy source in data‐scarce regions, such as Central Asia, highlights the need for easy‐to‐apply methods for the morphological evaluation of rivers, critical to assess and maintain river health. Remote sensing data then offers a valuable approach for detecting the morphological characteristics of rivers, their development and their underlying processes. Existing studies tend to focus on either large‐scale assessments, the use of single morphological metrics or the post‐assessment of already implemented anthropogenic changes. This study presents a novel framework for morphological river assessment using Sentinel‐2 imagery, integrating multiple metrics—channel count, river width, total wetted area, channel migration area and water occurrence frequency—to capture aspects of local braiding intensity and riverbed dynamics. We further developed suitable evaluation methods for these metrics that enable the interpretation and assessment of specific spatial and temporal aspects of morphological active river stretches. The assessment includes the seasonal and annual pattern of the morphological state, the overall bed form and dynamics and the extent of morphological uniform river sections. We applied this framework to a study site at At‐Bashy River in Kyrgyzstan and established such a morphological river state. This river state includes the definition of high dynamic seasons, distinguishes six morphological sections with different channel patterns and further allows a general assessment of factors influencing channel patterns and the impact of anthropogenic pressures in braiding systems. Defining a comprehensive morphological river state using remote sensing supports more informed and sustainable hydropower development and river management strategies in data‐scarce regions with the overall goal of protecting river stretches and counteracting anthropogenic alterations.

Establishing appropriate boundary conditions is essential for developing high-accuracy hydrodynamic models. However, this task is particularly challenging in topographically varying urban domains without monotonous slopes due to insufficient boundary information. This study investigates five different boundary conditions and establishes modeling practices of boundary conditions in pluvial urban flood modeling. A numerical test model within the city of Berlin is used, employing the 2D hydrodynamic finite element module of the open-source TELEMAC system. It performs unsteady simulations with nodal rainfall inputs for various precipitation scenarios, excluding infiltration. The results demonstrate that the suitability of boundary conditions is critically dependent on the surrounding topography. For boundary segments with a positive slope, a stage–discharge curve is found to outperform the other boundary conditions investigated in this study. Conversely, for segments with a negative slope, a closed wall boundary condition appears clearly preferable. Additionally, a drainage reservoir boundary condition performs effectively for more complex boundary segments but necessitates extensive preprocessing. Based on these insights, simulations were repeated with segment-tailored boundary conditions. The results indicate that this combined model outperforms the global application of each individual model.

Riparian and floodplain vegetation play a key role in controlling flow resistance, sediment transport, and channel morphology, shaping the dynamics of riverine ecosystems. Accurately representing these vegetation–flow–sediment interactions in numerical models is essential for predicting system responses and supporting sustainable river management. This study introduces an enhanced biomorphodynamic model in the open-source framework openTELEMAC, which combines multiple vegetation friction approaches with a method for predicting sediment transport in vegetated flows. The modular structure of the framework enables flexible configurations for different vegetation types (rigid or flexible) and flow conditions (emergent or submerged) by selecting suitable vegetation friction approaches, improving usability and extending model applicability. Model performance is evaluated using two laboratory experiments on bedload transport through emergent and submerged rigid vegetation. Simulations reproduce the measured bed and water surface profiles with high accuracy, yielding low goodness-of-fit errors (RMSE ≈ 0.5–1.8 cm, MAE ≈ 0.5–1.6 cm). The results highlight the sensitivity of predictions to vegetational input parameters such as the drag coefficient. Overall, the enhanced biomorphodynamic model advances the representation of vegetation–sediment interactions and provides an adaptable, open-source tool for eco-hydraulic and morphodynamic research.

The correct representation of the interaction between flow and vegetation in numerical hydrodynamic modeling has been of growing importance in recent years. As conventional roughness approaches like Manning-Strickler or Nikuradse fail to represent the hydraulic resistance of vegetation for various hydraulic conditions in depth-averaged models, vegetation approaches must be applied. These approaches calculate the time-variable hydraulic resistance of plants according to the plants' characteristics and the hydraulic conditions within the numerical hydrodynamic simulation. In the open-source numerical modeling software openTELEMAC-MASCARET, eight vegetation approaches are implemented. These approaches account for flexible and rigid plants in emergent and submerged conditions. In addition, a biomorphodynamic model was integrated into openTELEMAC-MASCARET. This biomorphodynamic model uses a drag force approach combined with Stone and Shen's (2002) approach to calculate the flow velocity in submerged flow conditions to account for the hydraulic resistance of plants. In this study, we compare the representation of vegetation in numerical modeling as a drag force according to the biomorphodynamic model with the implementation as a friction approach. This way of implementation also allows a comparison with the above-mentioned vegetation friction approaches. Additionally, Stone and Shen (2002) have developed an approach for calculating the hydraulic resistance, which we also implement to compare the performance of this approach. Therefore, we first convert the drag force approach of the biomorphodynamic model into a friction approach according to existing approaches. The resulting approach and the original hydraulic resistance approach of Stone and Shen (2002) are then implemented in openTELEMAC-MASCARET. In order to evaluate the performance of these two approaches, we compare the resulting Darcy-Weisbach friction factors to those of the existing approaches. Using a simplified test case within openTELEMAC-MASCARET, we calculate the bed shear stress in vegetated areas and compare it with the results of the biomorphodynamic model. The results indicate a good agreement between the newly implemented vegetation approaches and the existing ones and the biomorphodynamic model. This study thus lays the foundation for further numerical investigations using vegetation approaches, especially concerning the interaction between vegetation, sediment, and flow.

Hydropower development exerts strong pressure on river systems by fragmenting river basins, trapping sediments and creating downstream sediment starvation. These alterations severely degrade river ecosystems through losses in habitat abundance and deterioration of substrate composition. As hydropower continues to expand, there is an urgent need for informed sediment management to be included in hydropower planning. In Central Asia, where a high potential for hydropower development remains, hydromorphological data are limited, constraining the assessment of morphological processes. To address this data scarcity, this study creates for the first time a high-resolution dataset containing qualitative information on sediment transport and sediment connectivity in Central Asia. We modified a sediment connectivity model to work with openly available geospatial datasets and statistically variable input data. The simulation outputs were aggregated into spatially explicit probabilities of sediment transport, entrainment and deposition for five grain-size classes, along with connectivity indices. Comparisons with results from 2D numerical hydraulic modeling at four sites indicated an overall good agreement, although a consistent tendency toward overestimation. The resulting dataset facilitates the decision-making process in hydropower planning by informing three application domains: comparing hydropower sites, deciding on design and operational strategies, and evaluating ecological and morphological impacts. Although site-specific assessments and field data are crucial for individual hydropower projects, our dataset provides essential decision support for basin-wide hydropower development in Central Asia.