Riparian zones fulfill diverse ecological and economic functions. Sustainable management requires detailed spatial information about vegetation and hydromorphological properties. In this study, we propose a machine learning classification workflow to map classes of the thematic levels Basic surface types (BA), Vegetation units (VE), Dominant stands (DO) and Substrate types (SU) based on multispectral imagery from an unmanned aerial system (UAS). A case study was carried out in Emmericher Ward on the river Rhine, Germany. The results showed that: (I) In terms of overall accuracy, classification results decreased with increasing detail of classes from BA (88.9%) and VE (88.4%) to DO (74.8%) or SU (62%), respectively. (II) The use of Support Vector Machines and Extreme Gradient Boost algorithms did not increase classification performance in comparison to Random Forest. (III) Based on probability maps, classification performance was lower in areas of shaded vegetation and in the transition zones. (IV) In order to cover larger areas, a gyrocopter can be used applying the same workflow and achieving comparable results as by UAS for thematic levels BA, VE and homogeneous classes covering larger areas. The generated classification maps are a valuable tool for ecologically integrated water management.

Sustainable management of riparian zones requires detailed spatial information about vegetation and hydromorphological properties.Uncrewed aerial systems (UAS) or gyrocopters equipped with multispectral cameras yield imagery of small to intermediate scale areas.Machine learning classification workflows (object based, random forest) including additional geodata and trained with in-situ data allow to map classes of vegetation and hydromorphological substrate types with different level of detail.A case study was carried out in a floodplain area along the River Rhine, Germany, resulting in overall accuracies for UAS data of 89% for basic surface types, 88% for vegetation units, 75% for dominant stand, and 62% for substrate types.Classification probability maps helped to identify areas of lower classification performance, as e.g.vegetation within the transition zone, thus allowing for a subsequent, more focused and effective site inspection.In combination, this workflow provides a valuable tool for monitoring and ecologically integrated water management.

Up-to-date information about vegetation types and hydromorphological structures and features are essential for the management of waterways. They are e.g. used for the monitoring and reporting of riparian statuses and their changes e.g. after river restoration and consequently, numerous man-days are spent on field surveys. To allow for an effective survey of vegetation and hydromorphology in large or even inaccessible areas, a data acquisition and processing workflow is being developed complementing in-situ methods with remote sensing techniques. This is part of the joint research project “mDRONES4rivers” funded by the German Federal Ministry of Transport and Digital Infrastructure (19F2054A). Aerial surveys by unmanned aerial systems (UAS) and a gyrocopter are combined with ground measurements of hyperspectral reflectance signatures as well as with field mapping of vegetation types and hydromorphological structures and features. The remote sensing data is classified with an object based image analysis and classification algorithm. The mobile and (at selected sites) permanent measurements of hyperspectral field data and the typical field surveys provide data for calibration. Contrary to other approaches that focus on what can be detected and classified with certain sensor systems and datasets, the project addresses equally the user needs to obtain certain classes for monitoring and reporting. The intended results are (i) data acquisition, correction and classification workflow combining remote sensing and field data, identification and change detection (ii) of important vegetation and biotope types and (iii) of hydromorphological structures and substrate as well as indicators necessary for the evaluation of the hydromorphological quality. The preliminary results to be presented include datasets from UAS, gyrocopter, and field surveys, an outline of processing workflow and classification algorithm based on Python scripts and eCognition software and first vegetation and hydromorphological classification results from spring and summer datasets. In conclusion, procedures and algorithms are developed to use remote sensing in combination with and for the reduction of time-consuming traditional field surveys as a future operational tool for monitoring riparian vegetation and structures.

Depth erosion often occurs along rivers. Erosional tendencies are mainly caused by river training works, course shortenings, flood protection and reduced sediment supply due to dams and weirs. Balanced sedimentation, transport and erosion processes are of utmost importance for the connectivity of rivers and floodplains as well as for human water uses. In order to classify the level of bed incision, investigations were carried out for the case study area of the Lower Rhine in Germany, Europe?s most used waterway, using the hydromorphological classification tool Valmorph. It was developed to capture, quantify and evaluate hydromorphological conditions and changes. Comparative conditions for an evaluation have to be derived predominantly from type-specific historical quantitative data analyses. This paper analyses the Valmorph indicator ?mean bed level changes?. Data relating to the heights of the river bed levels between the years 1896?2010 were investigated. The classifications show an immense reduction from the previously extremely high erosion rates. Additionally, the monitoring identifies cause?effect relationships between incision rates and implemented sediment management measures. The findings are shown for various temporal and spatial resolutions, reflecting the development of the depth erosion. The knowledge obtained can be used for river basin management, for example for designing large-scale measures to restore river ecosystems with sediment deficits and for monitoring their success.

In Europe, the so-called Water Framework Directive was established to achieve a good ecological status of natural water bodies by 2015. In the case of heavily modified and artificial water bodies, the principle of a good ecological potential (GEP) applies. Methods have been developed for the evaluation of natural water bodies. However, these methods do not take the uniqueness of the assessment of heavily modified and artificial water bodies into consideration. On behalf of a working group on water issues of the federal states and the federal government (called LAWA), a nationwide assessment method of the GEP has been developed and its application has been verified within the framework of a practical project. Federal Waterways were not sufficiently considered. Hence we have been prompted to develop an assessment method for heavily modified and artificial water bodies, especially for federal waterways. Nearly 80% of the German federal water bodies are designated as heavily modified and artificial. The inclusion of federal waterways allows the unique characteristics of large rivers to be integrated in the methodological framework. Hereinafter, the results of the first working steps of the investigation as well as the methodological framework will be presented.

The Sediment Management Plan for the Elbe River of the RBC Elbe and ICPER combines the issues of sediment quantity, hydromorphology, sediment quality as well as use-oriented sediment aspects. Indicators for the assessment of the sediment status under the aspect of hydromorphology were selected relating to sediment management and the European Water Framework Directive, EC-WFD. Objectives were to investigate and evaluate the sediment budget as a part of the hydromorphological status of the river and to derive recommendations for actions to improve the conditions. Parameters like sediment continuity, depth variation, substrate of the river bed and others were analysed as representative indicators. The hydromorphological results were compared with evaluations of the biological quality (macrophytes/phytobenthos, fishes, macroinvertebrates and phytoplankton) by choosing different methods for aggregation on both examined subjects. The findings for biology were achieved in the context of the implementation of the EC-WFD by the German federal states. Hydromorphological and biological quality components are closely linked. The intention of this study was to identify conformity between hydromorphological and biological statuses based on their proportional size in the same assessment of results. This applies to 5 km long aggregate river stretches up to the water bodies of the inland Elbe River. The interactions were investigated for 586 km in total, the German federal waterway inland Elbe River extends from the German-Czech border to the Geesthacht weir. In summary, the obtained results of the comparison provide various conclusions and may be suitable e.g. for integral sediment management, rehabilitation aspects and an optimised river maintenance and river basin management.

Introduction: River continuity (for sediments and organisms) is one of the hydromorphological quality elements of the Water Framework Directive (WFD) of the European Commission. The Directive was established in order to protect and improve the waters throughout the EU. The hydromorphological quality elements provide a variety of habitats in river ecosystems, if the hydromorphological conditions are near those that would naturally occur. Sediment continuity is basically ruled by the presence or absence of cross structures in the river. Their barrier effect for sediment transport results often in upstream backwater effects with sediment accumulation and downstream erosion of the riverbed. The sediment budget of a river is closely connected with its hydromorphology. Insufficiently developed hydromorphological features are indicators of a disturbed sediment budget. Vice‐versa, the hydromorphological characteristics of the river have influence on the prevailing sediment conditions [1, 2].

The investigation of spatial and temporal changes of river width and width variability is a suitable tool for analysing morphological changes and estimating the ecological quality of a river, e.g. for the European Water Framework Directive. However, width and width variance interact closely with the varying hydraulic and sedinnentological conditions in the river. In general, a high width variance is often accompanied by a high depth, flow and sediment diversity which in turn is an indicator for the existence of different micro- (river bed) and mesohabitats (e.g. riffles and pools). The width variance provides information on the morphodynannics and resilience of a river. It also gives some indication of the length of the river banks and the number of diverse and ecologically vital habitats in the river bed, along the riparian zone and in the floodplain. This study examines changes of the channel width and width variation of the river Elbe and compares different methods while quantitatively assessing these hydronnorphological parameters. Dependent on the discharge, width and width variation for different spatial situations (e.g. river bed, floodplain) are determined for a historical (1830-1850) and a current condition. These data are statistically analysed and compared to obtain a five-point scale evaluation. Based on the results, this study should give recommendations as to which method is best suited in terms of various aspects. Special consideration will be given to different ecological issues.