River Hydromorphology Research Articles

Microplastic distribution and their abundance along rivers are determined by land uses and sediment granulometry

Microplastics in freshwater ecosystems have gained attention for their potential impact on biodiversity. Rivers are complex and dynamic ecosystems that transport particles and organic matter from the headwaters through watersheds to the ocean. Changes in land use and the presence of wastewater treatment plants (WWTPs) increase the risk of plastic contamination. Simultaneously, hydromorphological features of the watershed can influence the dispersion and retention of microplastics. This study assesses the impact of urban land uses and river hydromorphology on microplastic abundance and spatial distribution in two watersheds with contrasting land uses. Unexpectedly, our findings show that microplastics were widespread throughout watersheds both in water (3.5 ± 3.3 particles/L) and sediments (56.9 ± 39.9 particles/g). The concentration of microplastics in sediments significantly increased in granulometry ranging from 0.5 to 1 mm. Microplastics in running waters are significantly correlated with increasing urban land use coverage. However, the presence and distance of WWTPs did not affect microplastic distribution. In conclusion, contrasting patterns were observed for suspended and sedimented microplastic particles: suspended microplastics were associated with an anthropogenic effect, whereas the concentration of microplastics in sediments was determined by riverbed granulometry. Our results suggest that the interaction of anthropogenic and environmental factors shapes microplastic distribution along the rivers and their subsequent transport toward the coastal ocean. Finally, a review of the current literature reveals the absence of standardization in field and laboratory assessment techniques and measurement units, representing a challenge for intercomparisons of river microplastic studies.

Analysis of historical changes in planform geometry of a mountain river to inform design of erodible river corridor

The analysis of changes in planform geometry of the Biała River during the last 130 years is used to diagnose hydromorphological river degradation and thus to verify the need of river restoration through establishing an erodible river corridor. Outcomes from the analysis are then used for delimiting the erodible corridor and predicting the potential for future river widening in the corridor. The study analyses presentations of the active river zone and the structure of river geomorphic units on topographic maps from 1878, 1935 and 1962, aerial photos from 1967, 1977 and 1987, and orthophotos from 1998 and 2009. As a result of river channelization followed by channel incision, during the study period the width of the Biała was reduced to 16%–57% of its width in 1878. The river narrowing was associated with a reduction in the proportion of channel bars in the total river width and nearly complete elimination of islands. All these changes demonstrated the degradation of hydromorphological integrity of the river and the need for its restoration by allowing free channel development in an erodible corridor. The belt of the river migration during the last 130 years identified on the basis of overlays of the river position from all dates was ⁓5 times wider than the contemporary river. This justified delimiting the erodible river corridor on a substantially larger area of the valley floor than the area of the river in 2009. In 2009 the river was narrower than the largest river width recorded between 1878 and 1998 along nearly the whole length of the study river sections. This indicates that the concentration of flood flows in the narrow channel, increasing their unit stream power, is a factor increasing the potential for future bank retreat and channel widening in the erodible corridor of the river.

Reach hydromorphology: a crucial environmental variable for the occurrence of riverine macrophytes

Management measures targeting riverine macrophyte species often address dissolved nitrogen and phosphorus compounds. With recent reductions of nutrient pollution, effects of other variables have become more apparent. This study aims to shed light on the hierarchy of variables determining riverine macrophyte distribution, covering both surface water nutrients and a range of other variables, in a Central European landscape. We used a dataset of 1,371 monitoring samples to predict the presence and absence of 30 common macrophyte species with multiple random forest models. Besides surface water chemical variables (P-PO4, TN and pH), five reach hydromorphological variables (substrate, flow velocity, shading, width and depth) and a variable related to river size (distance from the river source) were use as predictors. The most important variables for the prediction of the species’ presence and absence were substrate, distance from the river source and flow velocity. Additionally, P-PO4 and shade were also important, whilst TN, pH, width and depth played only a minor role. River hydromorphology was more important than surface water chemistry for the occurrences of individual riverine macrophyte species, in particular under less extreme eutrophic conditions. Species occurrences were related to multiple interacting variables, amongst which hydromorphology often prevailed. Presence/absence of species and composition of assemblages cannot be attributed to surface water nutrients alone, even when considering river typologies. Therefore, the results support the conjecture that a broader approach considering a range of stressors is necessary to design restoration measures for management and enhancement of macrophyte diversity.

Channel bar development, braiding and bankline migration of the Brahmaputra-Jamuna river, Bangladesh through RS and GIS techniques

ABSTRACT Erosion of banks and channel migrations are usually common phenomenon and recurring geo-hazardous problem in the Brahmaputra-Jamuna river system of Bangladesh. The present study intensively analysed multi-temporal Landsat satellite imageries (Landsat MSS, Landsat TM, Landsat ETM+, Landsat OLI TIRS), historical documents (Hunter maps), and literature information employing Remote Sensing and Geographic Information System techniques, and estimation of braiding and sinuosity indices especially emphasizing channel bar development, braiding, and bank-line migration of the river. The computed braiding indices of the river were 1.5, 10.3, 13.4, 11.0, 10.6 and 14.6 for the year of 1853–1857, 1977, 1989, 2000, 2014 and 2018, respectively (overall deciphering increasing trend). Similar to the braiding indices, the sinuosity indices (2.58, 7.02, 9.92, 8.31, 7.42 and 11.25 for the same selected years) of the river have also been changed over time. During 1853–1857 to 2018, 766.7 and 1624.2 km2 of lands extensively eroded on the east and west bank, respectively at a rate of 4.8 and 10.1 km2 yr−1. However, from 1977 to 2018, the erosion rates were 14.4 and 12.5 km2 yr−1, respectively. High discharges, sediment transport associated with random bars formation related braiding expansion, and weak bank materials are presumably the governing factors for causing such simultaneous severe bank erosion and remarkable bank-line migration phenomenon. Although, from 1853–1857 to 1977 the erosion of the river followed the river flow direction. It is expected that the outcomes of this research can contribute further research on morphodynamic characteristics of the braided river for better understanding the river characteristics, the river hydromorphology, water and sediment transport, its bank erosion, and formulating protective measurement plan for their sustainable current flow path maintenance.

A bankfull geometry dataset for major exorheic rivers on the Qinghai-Tibet Plateau

Bankfull river discharge shapes river morphology. The bankfull river surface planform and river width can be used to quantify river size. Regional studies of stream ecology, hydrologic modelling, river carbon emissions and geomorphology from the perspective of fluvial processes are hindered by the lack of a highly accurate spatially distributed river network that considers bankfull river geometry. Based on Sentinel-2 and Landsat 5/7/8 multispectral instrument imagery and in situ measured hydrological data, the river discharge and width of spatially distributed cross sections of six major exorheic rivers and their tributaries located on the Qinghai-Tibet Plateau (QTP) are calculated under bankfull conditions. Then, the bankfull river surface is extracted. Finally, a bankfull river width and surface area database is established. The provided planform river hydromorphology data can supplement global hydrography datasets and effectively represent the combined fluvial geomorphology and geological background in the study area.

Agroforestry Contributions to Urban River Rehabilitation

The context of urban rivers is one of pollution of their courses, the degradation of riparian habitats, the loss of biodiversity, and the marginalization of the human populations that live next to them. Due to urban growth, the hydrological dynamics in entire basins and the hydromorphology of rivers are changing. This situation increases flooding, decreases the availability of water for human use, and disconnects the rivers from the dynamics of the city. Agroforestry is the integration of cultural, wild, and domesticated diversity with use, conservation, and restoration objectives. These practices in cities can contribute to addressing the problems mentioned. We analyze agroforestry practices and the socio-ecological contributions to urban river rehabilitation. We review 37 experiences worldwide. Agroforestry practices included in the review are trees and hedgerows; wetland agroforestry; aquatic, botanical, edible, educational, and rain gardens; bioswales; green parking lots; food forestry; vegetation in alleys and streets; vertical terrace walls, among others. Agroforestry contributes to efforts to solve urban river problems, improve water quality and access, restore riparian habitats, enhance river hydromorphology, support local economies, and create a river culture. We emphasize promoting multi-relational people–river interactions based on theoretical and practical frameworks that integrate diverse disciplines, perspectives, and experiences.

Changes in the Ecological Status of Rivers Caused by the Functioning of Natural Barriers

Introducing the European beaver to the catchment area, which adjusts the habitat to its own needs (by building dams), may have a positive impact on the ecology, geology, and hydromorphology of rivers and intensify the water self-purification process. In this study, a comparative assessment of the ecological status was made between the areas where the species Castor fiber L. occurs (habitat type A) and the areas unaffected by the influence (habitat type B). For this purpose, the Macrophyte River Index (MIR) and the Hydromorphological River Index (HIR) were calculated, along with the floristic indicators of biodiversity: species richness and Margalef, Shannon–Wiener, and Simpson indices. Only 35% of the sites met the standard of good ecological status. The presence of hypertrophic species and anthropogenic modifications of the river bed had a negative impact. The spread of beavers has a significant positive effect on changes in hydromorphological conditions and water levels in the river. The water levels in habitat types A and B were 0.504 and 0.253 m, respectively. There were statistically significant differences in the HIR values between habitat types A and B, which were 0.585 and 0.535, respectively. In habitats of type A, the heterogeneity of the current and bed material as well as the diversity of elements accompanying the tree stands increased. Research has shown greater species richness and greater biodiversity of macrophytes in the habitats of beaver dams. The research confirmed the significant influence of the European beaver on changes in the environment. The activity of beavers intensifies the processes of introducing wetland and rush species to forest areas.

A Comparative Evaluation of Hydromorphological Assessment Methods Applied in Rivers of Greece

The ecological assessment of all surface water bodies in Europe according to the Water Framework Directive involves the monitoring of biological, physicochemical and hydromorphological quality elements. For the hydromorphological assessment in particular, there are numerous methods that have been developed and adopted by EU member countries. With this study, we compared three different methods (River Habitat Survey, Morphological Quality Index and River Hydromorphology Assessment Technique) applied in 122 river reaches that are part of the National Monitoring Network of Greece. The main objectives were (a) to identify whether different assessment systems provide similar classifications of hydromorphological status and (b) to distinguish strengths and weaknesses associated with the implementation of each method. Our results show that the River Hydromorphology Assessment Technique (RHAT) and the Morphological Quality Index (MQI) resulted in the same classification for 58% of the studied reaches, while 34% of the remaining cases differed by only one quality class. Correlations between the two indices per river type (ICT) showed that the two indices were strongly correlated for water courses located at low altitudes. Concerning the HMS index of the River Habitat Survey (RHS), which is an index that reflects the overall hydromorphological pressure, it showed larger differences with the other two indices, mainly because it classified more sites as “Poor” and “Bad” quality classes. Based on our results, we recommend that the two indices, RHAT and MQI, can be implemented complementary to the RHS for providing a rather easy and quick assessment of the overall hydromorphological status, at least until a national hydromorphological database is compiled that will allow for the proper adaptation of the Habitat Quality Assessment (HQA) index.

State Analysis of the Water Quality in Rivers in Consideration of Diffusion Phenomenon

The waters of rivers are not only used for consumption, industry and agriculture but have also found their way into the transport and energy generation sectors. Many disturbances introduced into the aquatic environment are of the natural variety, which are the result of “admixtures” contained in water, e.g., through contact with soil, and of man-made types, which are directly related to humanities destructive influences. In the presented examinations, the most important processes affecting the spread and transport of these pollutants are taken into account, i.e., advection and diffusion. The authors present observations on the influence of the diffusion phenomenon on river flow modelling processes. Such an approach allows for the separation of the dynamics of water flow and the dynamics of transport of the dissolved substance mass. Specifically, phenomena occurring in relation to spatial coordinates, time and variable parameter values in the proposed mathematical model were analysed. Ultimately, this research will contribute to the correct design and implementation of a complementary diffusion module as an extension to an intelligent water quality control and monitoring system. The Intelligent Analytical Computing Control System architecture under development already includes other modules such as the Intelligent Filtration and Prediction Module and, complemented by the Intelligent Diffusion Module, provides a complementary tool for monitoring river hydromorphology. Implementation of the above solution will help to improve water quality, thus preventing and eliminating the appearance of undesirable pollutants in rivers, and increase the standard of living in the current threatened environmental world.

The role of topographic maps in river hydromorphology

The role of topographic maps in river hydromorphology

Non-Linear Visualization and Importance Ratio Analysis of Multivariate Polynomial Regression Ecological Models Based on River Hydromorphology and Water Quality

Multivariate polynomial regression (MPR) models were developed for five macrophyte indices. MPR models are able to capture complex interactions in the data while being tractable and transparent for further analysis. The performance of the MPR modeling approach was compared to previous work using artificial neural networks. The data were obtained from hydromorphologically modified Polish rivers with a widely varying water quality. The modeled indices were the Macrophyte Index for Rivers (MIR), the Macrophyte Biological Index for Rivers (IBMR), and the River Macrophyte Nutrient Index (RMNI). These indices measure the trophic and ecological status of the rivers. Additionally, two biological diversity indices, species richness (N) and the Simpson index (D), were modeled. The explanatory variables were physico-chemical properties depicting water quality and river hydromorphological status indices. In comparison to artificial neural networks, the MPR models performed similarly in terms of goodness of fit. However, the MPR models had advantages such as model simplicity and ability to be subject to effective visualization of complex nonlinear input–output relationships, as well as facilitating sensitivity analysis using importance ratios to identify effects of individual input variables.

Еstimating the Chézy roughness coefficient as a characteristic of hydraulic resistance to flow in river channels: a general overview, existing challenges, and ways of their overcoming

This paper deals with results of a systemized overview of the Chézy roughness coefficient calculation problem as one most frequently used empirical characteristics of hydraulic resistance. The overview is given in the context of the formation of reliable empirical data needed to support hydro-engineering calculations and mathematical modelling of open flows in river channels. The problem topicality is because of a large number of practical tasks which need such a pre-research. In many cases, the accuracy of determining empirical hydraulic resistance characteristics can largely affect the accuracy of solving tasks relating to designing hydraulic structures and water management regardless of chosen mathematical models and methods.Rivers are characterized by a significant variety of flow conditions; hydraulic resistance to flows in rivers can thus vary widely determining their flow capacity. Considering the variety of river hydro-morphology and hydrology, the Chézy roughness coefficient often appears to be the most complete characteristic of hydraulic resistance to open flows in river channels comparing with other integral empirical characteristics of hydraulic resistance.At present, there are a large number of empirical and semi-empirical formulas to calculate the Chézy roughness coefficient. The main aim of this study was to analyze and systematize them in the context of providing proper support to the open channel hydraulics tasks. To achieve the aim of the study, a literature review regarding the problem of determining the integral hydraulic resistance characteristics to open flow in river channels was performed, as well as formulas used to calculate the Chézy roughness coefficient in practice were explored and systemized. In total, 43 formulas to calculate the Chézy roughness coefficient, as well as 13 formulas that can be used to estimate the Manning roughness coefficient were analyzed and systematized. Based on all these formulas, about 250 empirical equations can be compiled to calculate the Chézy coefficient depending on hydro-morphological peculiarities of rivers and river channels, hydraulic conditions, formulas application limits, and so on.

Using MODIS-NDVI Time Series to Quantify the Vegetation Responses to River Hydro-Geomorphology in the Wandering River Floodplain in an Arid Region

Vegetation, hydrology and geomorphology are three major elements of the floodplain ecosystem on Earth. Although the normalized difference vegetation index (NDVI) has been used extensively to characterize floodplain vegetation growth, vigour and biomass, methods for quantifying the various distinct responses of floodplain vegetation to hydro-geomorphological changes in different lateral belts in arid regions are still needed. In this study, the Linhe reach was divided into four lateral belts based on their hydro-geomorphological characteristics, and the Moderate Resolution Imaging Spectroradiometer (MODIS)-NDVI time series statistical indicators were used to characterise the distinct changing the patterns of vegetation growth in different belts. The response of floodplain vegetation to river hydro-geomorphology in each belt was analysed. The result showed that the average maximum NDVI value in the regular inundation area was 0.23 and higher than that in the other lateral belts. The correlation between the water persistence time and peak NDVI value in the regular water inundation area was significant (ρ = 0.84), indicating that in contrast to highly frequent or extremely rare water inundation, regular water inundation provides significant benefits to floodplains. Continuous or highly frequent inundation may cause decreased vegetation productivity. Overall, our results suggest that the vegetation greenness response to the river hydro-geomorphology is different from the river to the edge of the floodplain. Thus, a better understanding of the interactions between the floodplain vegetation and river hydro-morphology and river water resource management in arid-region floodplains.

Assessment of river alteration using a new hydromorphological index.

Main river systems in large watersheds are mostly destroyed due to intense human activities. These rivers are modified by a number of water infrastructures such as dams, diversion weirs, flood control structures, and sediment traps. Such modifications alter the hydrology, continuity, and habitat quality of river waterbodies and degrade their overall ecological status. This study provides a systematic and quantitative assessment of river hydromorphology with a composite index based on four sets of criteria (i.e., hydrology, channel continuity, habitat quality, and bed modification) to assess the level of human intervention. The developed index is tested and implemented in Gediz River Basin in Western Anatolia (Turkey), which is one of the most important watersheds with regard to human settlements as well as agricultural and industrial production. The results of the developed index have revealed values between 42.36 and 88.14 on a 0-100 scale and a gradual decline in overall river hydromorphological quality along the flow path. The analysis has shown that barrier effects were found to be crucial in reduced river continuity and bed modification for flood control has resulted in degraded instream and riverbank habitat quality. The developed index methodology can serve as a systematic tool for assessing the hydromorphology and its associated influence in the ecological status of rivers. It can further assist the decision-makers in planning and prioritizing river restoration projects.

Impacts of Extreme Weather Events on Hydromorphology of UK Rivers

In this study, we assessed the effects of extreme weather events on Hydro-morphological Quality Elements in rivers of the United Kingdom alongside other pressures that will provide significant challenges for the implementation of the Water Framework Directive in the UK in terms of cost-effectiveness and sustainability. While observed meteorological data and river data sets were used for assessing changes in river systems and weather patterns, for future assessments, UK Climate Projections 2018 data was used. The studies in the literature have shown that during periods of extreme events, the river hydro-morphology is affected especially in terms of river flows, sediments and riparian zones such as draughts, and intense and heavy rainfall leading to reduced or exceptionally high flow respectively. Reduced flows can lead to the loss of habitat of aquatic organisms and an increase in fish deaths. Whilst increased river flows lead to changes of the hydro-morphology of rivers including changes to sediment dynamics and channels, rivers are also under negative effects of anthropogenic hydro-morphological pressures such as building dams and water abstractions. Furthermore, changes in river hydro-morphology can cause other problems such as increasing water temperature and decreasing dissolved oxygen, and thereby degrading Biological Quality Elements and Physico-Chemical Quality Elements. To deal with and mitigate these problems, a holistic view of water policy that considers climate change projections, reduces water demand, changes agricultural and urban land use practices, improves water availability and quality is required.

Stable isotope analysis indicates positive effects of river restoration on aquatic-terrestrial linkages

Abstract Hydromorphological river restoration can significantly alter habitat configuration and modify invertebrate assemblages of rivers and floodplains. However, the consequences of these changes for ecosystem functioning and aquatic-terrestrial interactions are not known. As a restored shoreline has a more heterogeneous structure compared to a straightened river, restoration is likely to impact aquatic-terrestrial linkages in multiple ways, which might be captured based on biomarker indicators to characterize changes in food web functioning. We conducted a large scale comparative study targeting eleven river restoration projects in central and northern Europe to assess effects of river restoration on trophic patterns across the aquatic-terrestrial interface. We investigated the isotopic composition (δ13C, δ15N) of prey and of invertebrate consumers stratifying between the aquatic, riparian and terrestrial zones. The isotopic distance of riparian arthropods to instream macroinvertebrates and terrestrial arthropods was used as a measure of trophic linkage, and its variation with riparian habitat composition was quantified. Restoration enhanced aquatic-terrestrial linkages, indicated especially by differentiation in the δ15N isotopic signatures between aquatic, riparian and terrestrial consumers, rather than by δ13C signatures. The δ15N isotopic signatures of riparian arthropods revealed a higher relative trophic position in restored sections (δ15NRestored: 8.64‰, n = 11) as compared to non-restored sections (δ15NDegraded: 8.05‰, n = 11), lending support to the conjecture that restoration increased the proportion of more highly enriched aquatic prey (δ15NRestored: 10.01‰; δ15NDegraded: 10.38‰) while simultaneously reducing the share of lower enriched terrestrial prey (δ15NRestored: 4.88‰; δ15NDegraded: 5.53‰). Riparian habitat diversity and the share of exposed sand and gravel bars were positively related to the strength of aquatic-terrestrial linkages (R2 = 0.28 and R2 = 0.31, respectively), pointing to the importance of habitat diversification in the riparian zone in promoting trophic linkages between river and floodplain. These findings expand our understanding of the multifaceted outcomes of hydromorphological restoration, beyond biodiversity in the aquatic environment. It highlights the need to expand our current set of indicators in order to mechanistic understand restoration effects on ecological networks spanning across boundaries. This knowledge is highly relevant for the large restoration efforts driven by legislative frameworks such as the Water Framework Directive in Europe.

The role of spatial units in modelling freshwater fish distributions: Comparing a subcatchment and river network approach using MaxEnt

Species Distribution Models (SDM) are frequently used in ecological research, but the effects of model extent and granularity on model outcomes are rarely addressed. In freshwater SDMs, two different approaches are commonly used to define the granularity of the models, i.e. to subdivide entire river systems into appropriate spatial modelling units: river reaches on the actual river network or subcatchments. We built maximum entropy (MaxEnt) SDMs for barbel (Barbus barbus) and grayling (Thymallus thymallus) in the River Ruhr catchment in Germany with identical environmental predictor data and analysed the difference between these two approaches. All models performed well (AUC > 0.9) and geographic predictors (e.g. distance to the river source) dominated over hydromorphological predictors in explaining species distributions. There was high agreement between the two model setups in river parts of low and high habitat suitability but considerably lower agreement in river parts of medium habitat suitability. In these medium suitable river parts, model results were spatially very heterogeneous and alternated at fine spatial scales especially in models based on river reaches. Increasing model regularization, a setting to control overfitting, had a smoothing effect on the environmental variables in the river reach models similar to the coarser subcatchment granularity. A restriction of the spatial extent led to a shift in predictor contributions to the model and an increase of the importance of hydromorphologic predictors by ca. 45 %. Restricting the model extend to the natural core distributional area of a given fish species might therefore be considered beneficial for the application of SDMs in a management context. By decreasing the weight of fixed geographic predictors in the model, predictors relating to hydromorphological river structures (i.e. which are accessible for restoration projects) gain importance. We conclude that SDM setups based on river reaches and subcatchments can both give valuable complementary information about the distribution of species. The high-resolution model based on river reaches might better discover individual local habitat features, whereas the subcatchment model might better account for the minimum spatial requirements of a fish population.

Habitat Enhancement Solutions for Iberian Cyprinids Affected by Hydropeaking: Insights from Flume Research

Due to peak electricity demand, hydropeaking introduces rapid and artificial flow fluctuations in the receiving river, which alters the river hydromorphology, while affecting the downstream ecological integrity. The impacts of hydropeaking have been addressed in flumes and in rivers. However, few studies propose mitigation solutions based on fish responses. The objective of this communication was to assemble the methods and outputs of flume research focused on Iberian cyprinids and to present recommendations to be used by freshwater scientists and hydropower producers. Emphasis was given to the critical role of integrating ecology and hydraulics to find the causal pathway between a flow change and a measurable fish response. The use of diverse behaviour quantification methods, flow sensing technologies, and statistical tools were decisive to strengthen the validity of the findings and to identify fish-fluid relationships, according to flow events. This communication encourages further research to identify flow thresholds for key life-cycle stages and complementary river studies to design and assess mitigation solutions for hydropeaking. Although the research focused on an Iberian cyprinid, the methods suggested have the potential to be extended to other fish species affected by hydropeaking.

A Combined Field and Remote-Sensing Based Methodology to Assess the Ecosystem Service Potential of Urban Rivers in Developing Countries

Natural rivers in urban areas bear significant potential to provide ecosystem services for the surrounding inhabitants. However, surface sealing by houses and street networks, urban drainage, disposal of waste and wastewater resulting from advancing urbanization usually lead to the deterioration of urban rivers and their riparian areas. This ultimately damages their ability to provide ecosystem services. This paper presents an innovative methodology for a rapid and low-cost assessment of the ecological status of urban rivers and riparian areas in developing countries under data scarce conditions. The methodology uses a combination of field data and freely available high-resolution satellite images to assess three ecological status categories: river hydromorphology, water quality, and riparian land cover. The focus here is on the assessment of proxies for biophysical structures and processes representing ecological functioning that enable urban rivers and riparian areas to provide ecosystem services. These proxies represent a combination of remote sensing land cover- and field-based indicators. Finally, the three ecological status categories are combined to quantify the potential of different river sections to provide regulating ecosystem services. The development and application of the methodology is demonstrated and visualized for each 100 m section of the Pochote River in the City of León, Nicaragua. This spatially distributed information of the ecosystem service potential of individual sections of the urban river and riparian areas can serve as important information for decision making regarding the protection, future use, and city development of these areas, as well as the targeted and tailor-made development of nature-based solutions such as green infrastructure.

Diverging response patterns of terrestrial and aquatic species to hydromorphological restoration.

Although experiences with ecological restoration continue to accumulate, the effectiveness of restoration for biota remains debated. We complemented a traditional taxonomic analysis approach with information on 56 species traits to uncover the responses of 3 aquatic (fish, macroinvertebrates, macrophytes) and 2 terrestrial (carabid beetles, floodplain vegetation) biotic groups to 43 hydromorphological river restoration projects in Germany. All taxonomic groups responded positively to restoration, as shown by increased taxonomic richness (10-164%) and trait diversity (habitat, dispersal and mobility, size, form, life history, and feeding groups) (15-120%). Responses, however, were stronger for terrestrial than aquatic biota, and, contrary to our expectation, taxonomic responses were stronger than those of traits. Nevertheless, trait analysis provided mechanistic insights into the drivers of community change following restoration. Trait analysis for terrestrial biota indicated restoration success was likely enhanced by lateral connectivity and reestablishment of dynamic processes in the floodplain. The weaker response of aquatic biota suggests recovery was hindered by the persistence of stressors in the aquatic environment, such as degraded water quality, dispersal constraints, and insufficient hydromorphological change. Therefore, river restoration requires combined local- and regional-scale approaches to maximize the response of both aquatic and terrestrial organisms. Due to the contrasting responses of aquatic and terrestrial biota, the planning and assessment of river restoration outcomes should consider effects on both components of riverine landscapes.