High Mountain Rivers Research Articles

Quantifying future water resource vulnerability in a high-mountain third pole river basin under climate change

Understanding the water resource vulnerability (WRV) in global mountain regions under climate change is crucial for water resources management and socio-economic development. However, the WRV in the high-mountain Third Pole region (with quite a few transboundary river basins) remains largely unclear. Here, we have applied a comprehensive assessment framework of WRV to a Third Pole high-mountain river basin (Nujiang-Salween River, NSR) and its dependent downstream. The framework consisted of sensitivity, exposure, adaptability, hazard, and water stress indices, considering climate change, socio-economics, government effectiveness, natural disasters, and water supply capacity of the target river basin. Our results indicate that the downstream area (with intensive human activities) often exhibited significantly higher WRV than the mountain region; while the WRV shows an M-shaped change with increasing elevation, with the highest vulnerability occurring in a relatively low elevation range (e.g., 500–1500 m for the NSR basin). In the near future, we find that the spatial pattern of WRV in the basin is alternately influenced by adaptation, water scarcity, and exposure; whereas climate change serves as the main driver affecting the WRV in the far future. These findings enhance our understanding of the WRV in high-mountain transboundary basins of the Third Pole under global change.

Isotopic and chemical signatures of high mountain rivers in catchments with contrasting glacier and rock glacier cover

Glaciers and rock glaciers are key elements of mountain hydrological systems, but their relative influence on the chemical and isotopic conditions of streams within the river continuum is still overlooked. During three consecutive years (2019–2021), we studied 24 stream sections in two catchments (Plima and Schnals, Eastern Italian Alps) with varying cover of glaciers and rock glaciers. End-member mixing models based on δ2H and d-excess revealed a large spatial and temporal variability in the contribution of different water sources to stream runoff. Overall, snowmelt (77 ± 17 %) and rainwater (5 ± 5 %) were the largest and the smallest runoff components, respectively. The ice melt contribution was high in streams fed by glaciers (23 ± 15 %) and rock glaciers (16 ± 16 %). In the highly-glacierised Plima basin, the tracer-based estimation of annual ice melt fraction matched reasonably well (90–167%) the mean annual glacial ice loss estimated by geodetic mass balance. In contrast, we found a large overestimation of the ice melt component derived from mixing models in the poorly glacierised (but rock glacier-rich) Schnals catchment. In streams influenced by rock glaciers, at both catchments the particular temporal patterns of electrical conductivity resulted in unreliable estimates of the meltwater/groundwater fractions of runoff. Depending on the local lithology, concentrations of trace elements (Sr, Ni, Ba, Mn, Zn, Al) were high in streams fed by rock glaciers and glaciers, and close/below the limits of quantification in non-glacial streams. In alpine areas, the abundance of rock glaciers can confound the isotopic and chemical signature imparted by glaciers, thus hindering the use of tracer-based methods for hydrograph separation. Under the combined influence from glaciers and rock glaciers, concentrations of trace elements can surpass the limits for drinking water quality even in downstream areas, as we observed at the Schnals catchment for nickel.

Seasonal catchment memory of high mountain rivers in the Tibetan Plateau

Rivers originating in the Tibetan Plateau are crucial to the population in Asia. However, research about quantifying seasonal catchment memory of these rivers is still limited. Here, we propose a model able to accurately estimate terrestrial water storage change (TWSC), and characterize catchment memory processes and durations using the memory curve and the influence/domination time, respectively. By investigating eight representative basins of the region, we find that the seasonal catchment memory in precipitation-dominated basins is mainly controlled by precipitation, and that in non-precipitation-dominated basins is strongly influenced by temperature. We further uncover that in precipitation-dominated basins, longer influence time corresponds to longer domination time, with the influence/domination time of approximately six/four months during monsoon season. In addition, the long-term catchment memory is observed in non-precipitation-dominated basins. Quantifying catchment memory can identify efficient lead times for seasonal streamflow forecasts and water resource management.

On the Performance of Sentinel-3 Altimetry over High Mountain and Cascade Reservoirs Basins: Case of the Lancang and Nu River Basins

Satellite radar altimetry has been widely utilized in hydrological research, particularly with the advent of Sentinel-3, a Synthetic Aperture Radar (SAR) altimeter operating globally and equipped with an innovative onboard tracking system referred to as the open-loop tracking command (OLTC). Utilizing a pseudo-DEM (Digital Elevation Model), controlled through the OLTC, holds significant promise for the reliable observation of inland water bodies. Nevertheless, the complex geographical conditions in high mountain and reservoir river basins pose challenges in defining an appropriate pseudo-DEM for hydrological targets, potentially leading to reduced performance of Sentinel-3. This study aims to comprehensively evaluate the performance of Sentinel-3 by selecting the Lancang and Nu River basins in southwest China as a case study. These two rivers have a similar natural environment, but cascade reservoirs distinguish the Lancang River basin. By analyzing waveform energy from echoes of virtual stations (VSs) in both river basins (27 VSs in the Lancang River basin and 39 VSs in the Nu River basin), the performance of Sentinel-3 in different tracking modes and OLTC versions were compared. The results indicated that the detection rate of Sentinel-3A increased when transitioning from the closed-loop mode to the open-loop mode and with the implementation of newer OLTC versions (36.8% increased to 47.4%, 60.5%, and 63.2% in OLTC V5.0, V6.0, and V6.1, respectively). Similarly, the detection rate of Sentinel-3B rose from 64.3% (OLTC V2.0) to 71.4% and 75.0% in OLTC V3.0 and V3.1, respectively. Additionally, the cascade reservoir causing river channel expansion results in a better performance of Sentinel-3A in the Lancang River compared to the Nu River in the closed-loop mode (13.0% and 35.7%, respectively). Nevertheless, the considerable fluctuations in water surface caused by reservoir impoundment led to a wrong pseudo-DEM, resulting in poor performance of Sentinel-3 in reservoir regions before OLTC V6.0 was updated. The detection rate of low altitude, broad water surfaces (>500 m) decreased from 100% in a closed-loop mode to 0% in an open-loop mode, but increased to 100% in OLTC V6.0 and V6.1, respectively. The detection rate of high altitude, narrow water surfaces (<500 m) increased from 0% in a closed-loop mode to 40.9% in OLTC V6.1. Although the detection ability of Sentinel-3 is improving with the implementation of newer OLTC versions, the seasonal variations (usually more than 60 m) of water levels in reservoirs exceeded the size of the range window (60 m), rendering a complete measurement impossible.

Spatial-temporal distribution of birds in the northern macroslope of the Kyrgyz mountain ridge (Tien Shan)

Based on the results of our analysis, a classification of bird species of the Kyrgyz mountain ridge (Northern Tien Shan) was compiled according to their preference for habitats and occurrence throughout the year. The program of factorial classification used for this unites species according to the maximum similarity in their distribution and stay in an unspecified number of clusters. In total, 4 supertypes and 12 types of preferences have been identified along the Kyrgyz ridge. In the supertype of birds that prefer undeveloped areas, 6 types were distinguished, namely, the species choosing: 1 – high mountains, 2 – high and medium mountains, 3 – medium mountains, 4 – medium mountains and foothills, 5 – foothills, and 6 – found at all heights. The supertype of birds preferring built-up areas is represented by one type only: the species preferring foothill sheaths and villages, and the supertype of birds preferring rivers and their banks is represented by four types, namely, the species preferring: high-mountain rivers in the summer and autumn; high-altitude and mid-mountain rivers in the spring and summer; mid-mountain rivers in the autumn; and foothill rivers in the first half of the summer. The supertype uniting species found in all habitats is represented by one type of preference, namely, found throughout the whole year. It is shown that of the 154 recorded bird species, most were found in undeveloped habitats, and 6 and 12 times less were in built-up areas and rivers, including their banks. In undeveloped areas, most bird species prefer high- and mid-mountainous landscapes and half as many prefer foothill landscapes. In residential landscapes, most species tend to the foothills, and among rivers, they prefer high-altitude and mid-mountain areas. At to the seasons, the maximum number of species was recorded in the spring-summer and summer periods.

The flow Confluence of river systems of the Pskem and Koksu river basins

In the Bostanlyk district of the Tashkent region, there are high-mountain breakthrough lakes located in the Pskem and Koksu rivers basin, which pose a particular danger to the downstream territories. The river system of the basins of the Pskem and Koksu rivers located in the Tashkent region is characterized by the presence of many nodes of a confluence of tributaries that form the hydrographic network of the basins of the high-mountain rivers under consideration. In the event of man-made and natural emergencies, a breakthrough wave can form on high-mountain outburst-hazardous lakes. The main purpose of these studies is to develop a method for the hydraulic calculation to determine the depths of flows in the confluence nodes. Based on the use of the law of conservation of momentum, a model and method for calculating the junction of open water streams have been developed. To determine the depth h2 in the main channel after the confluence point, we recommend using the well-known hydraulic methods for determining the depth of water in open channels. Determination of the depths h1 and h0 of the main flow and inflow, respectively, can be analytically obtained based on the obtained dependences (9) and (10).

A New and Simplified Approach for Estimating the Daily River Discharge of the Tibetan Plateau Using Satellite Precipitation: An Initial Study on the Upper Brahmaputra River

Collecting in situ observations from remote, high mountain rivers presents major challenges, yet real-time, high temporal resolution (e.g., daily) discharge data are critical for flood hazard mitigation and river management. In this study, we propose a method for estimating daily river discharge (RD) based on free, operational remote sensing precipitation data (Tropical Rainfall Measuring Mission (TRMM), since 2001). In this method, an exponential filter was implemented to produce a new precipitation time series from daily basin-averaged precipitation data to model the time lag of precipitation in supplying RD, and a linear-regression relationship was constructed between the filtered precipitation time series and observed discharge records. Because of different time lags in the wet season (rainfall-dominant) and dry season (snowfall-dominant), the precipitation data were processed in a segmented way (from June to October and from November to May). The method was evaluated at two hydrological gauging stations in the Upper Brahmaputra (UB) river basin, where Nash–Sutcliffe Efficiency (NSE) coefficients for Nuxia (>0.85) and Yangcun (>0.80) indicate good performance. By using the degree-day method to estimate the snowmelt and acquire the time series of new active precipitation (rainfall plus snowmelt) in the target basins, the discharge estimations were improved (NSE > 0.9 for Nuxia) compared to the original data. This makes the method applicable for most rivers on the Tibetan Plateau, which are fed mainly by precipitation (including snowfall) and are subject to limited human interference. The method also performs well for reanalysis precipitation data (Chinese Meteorological Forcing Dataset (CMFD), 1980–2000). The real-time or historical discharges can be derived from satellite precipitation data (or reanalysis data for earlier historical years) by using our method.

Eco-Environmental Risk Evaluation for Land Use Planning in Areas of Potential Farmland Abandonment in the High Mountains of Nepal Himalayas

Land use change, especially that due to farmland abandonment in the mountains of Nepal, is being seen as a major factor contributing to increasing eco-environmental risk, undesirable changes in the socio-cultural landscape, biodiversity loss, and reduced capacity of the ecosystem to provide key services. This study aims to: i) evaluate eco-environmental risk for one of the high mountain river basins, the Dordi river basin in Nepal, that has a growing potential of farmland abandonment; and ii) develop a risk-based land use planning framework for mitigating the impact of risk and for enhancing sustainable management practices in mountain regions. We employed a multi-criteria analytic hierarchy process (AHP) to assign risk weightage to geophysical and socio-demographic factors, and performed spatial superposition analysis in the model builder of a geographic information system (GIS) to produce an eco-environmental risk map, which was subjected to a reliability check against existing eco-environmental conditions by ground truthing and using statistical models. The result shows that 22.36% of the basin area has a high level of risk. The very high, extreme high, moderate, and low zones accounted 17.38%, 7.93%, 28.49%, and 23.81%, respectively. A high level of eco-environmental risk occurs mostly in the north and northwest, but appears in patches in the south as well, whereas the level of moderate risk is concentrated in the southern parts of the river basin. All the land use types, notably, forest, grassland, shrub land, and cultivated farmland, are currently under stress, which generally increases with elevation towards the north but is also concentrated along the road network and river buffer zones where human interference with nature is the maximum. The risk map and the framework are expected to provide information and a scientific evidence-base for formulating and reasonable development strategies and guidelines for consensus-based utilization and protection of eco-environmental resources in the river basin. As an awareness raising tool, it also can activate social processes enabling communities to design for and mitigate the consequences of hazardous events. Moreover, this risk assessment allows an important link in understanding regional eco-environmental risk situation, land use, natural resources, and environmental management.

Catálogo comentado de musgos, hepáticas y antoceros acuáticos del río Teatinos (Boyacá, Colombia)

espanolLos briofitos acuaticos son un componente conspicuo de la vegetacion de rios de alta montana tropical. Sin embargo, solo seis estudios abordan la taxonomia y ecologia de estas plantas en Colombia. Este trabajo tiene como objetivo conocer la riqueza de especies de briofitos que se establecen en el rio Teatinos y aportar informacion sobre la forma de crecimiento, tipo de sustrato colonizado, abundancia, caracteristicas del habitat y altitud para cada una de las especies. Se ubicaron 12 puntos de muestreo cada 100 m altitudinales, donde se colectaron las especies de briofitos que crecen sobre suelo y roca. Se presenta el catalogo comentado de briofitos acuaticos del rio Teatinos donde se registran 70 especies, organizadas alfabeticamente por familias, generos y especies en cada grupo (musgos, hepaticas y antoceros). EnglishAquatic bryophytes are a conspicuous component of the vegetation of high tropical mountain rivers. However, only six studies address the taxonomy and ecology of these plants in Colombia. This work aims to know the richness of bryophytes species that grow in the Teatinos River and provide information about their growth forms, substrate, abundance, habitat, and altitude for each of the species. Twelve sampling points were located every 100 m altitude, where bryophyte species that grow on soil and rock were collected. A commented checklist of aquatic bryophytes in the Teatinos River is presented trough a record of 70 species, organized by alphabetical order of families, genera, and species in each group (mosses, liverworts and hornworts).

Introducing <i>PebbleCounts</i>: a grain-sizing tool for photo surveys of dynamic gravel-bed rivers

Abstract. Grain-size distributions are a key geomorphic metric of gravel-bed rivers. Traditional measurement methods include manual counting or photo sieving, but these are achievable only at the 1–10 m2 scale. With the advent of drones and increasingly high-resolution cameras, we can now generate orthoimagery over hectares at millimeter to centimeter resolution. These scales, along with the complexity of high-mountain rivers, necessitate different approaches for photo sieving. As opposed to other image segmentation methods that use a watershed approach, our open-source algorithm, PebbleCounts, relies on k-means clustering in the spatial and spectral domain and rapid manual selection of well-delineated grains. This improves grain-size estimates for complex riverbed imagery, without post-processing. We also develop a fully automated method, PebbleCountsAuto, that relies on edge detection and filtering suspect grains, without the k-means clustering or manual selection steps. The algorithms are tested in controlled indoor conditions on three arrays of pebbles and then applied to 12 × 1 m2 orthomosaic clips of high-energy mountain rivers collected with a camera-on-mast setup (akin to a low-flying drone). A 20-pixel b-axis length lower truncation is necessary for attaining accurate grain-size distributions. For the k-means PebbleCounts approach, average percentile bias and precision are 0.03 and 0.09 ψ, respectively, for ∼1.16 mm pixel−1 images, and 0.07 and 0.05 ψ for one 0.32 mm pixel−1 image. The automatic approach has higher bias and precision of 0.13 and 0.15 ψ, respectively, for ∼1.16 mm pixel−1 images, but similar values of −0.06 and 0.05 ψ for one 0.32 mm pixel−1 image. For the automatic approach, only at best 70 % of the grains are correct identifications, and typically around 50 %. PebbleCounts operates most effectively at the 1 m2 patch scale, where it can be applied in ∼5–10 min on many patches to acquire accurate grain-size data over 10–100 m2 areas. These data can be used to validate PebbleCountsAuto, which may be applied at the scale of entire survey sites (102–104 m2). We synthesize results and recommend best practices for image collection, orthomosaic generation, and grain-size measurement using both algorithms.

Geomorphological maps as the basis of hazard mapping in Japan

Abstract. Japanese Islands are situated along the tectonically very active zone. Earthquakes occur frequently, and there are many active volcanoes. Climatically Japan is located in the east Asian monsoon zone and has high annual precipitation. Tropical cyclones (typhoons) or baiu (early summer rain season) sometimes lead to torrential rainfall. Such natural conditions have created broad high mountain areas and rivers of strong erosional process. Mountain slopes are geologically open to collapse, and debris flows often occur in streams in mountainous areas. While the area of alluvial plains, underlain by thick unconsolidated sediment, account for only 25% of the whole of Japan, approximately 80% of the population is concentrated in these weak-ground areas. Owing to such geographical characteristics, people have suffered many and various natural disasters (earthquake ground motion, liquefaction, landslide, debris flow, river flood, high tide, tsunami, etc.) in Japan.In 1959, a very strong typhoon (Isewan Typhoon or Typhoon Vera) brought the greatest flood damage in Nagoya City and its surrounding area. More than 5,000 people were killed or missing by it. The major damage was caused by high tide inundation in the delta of the Nobi plain. Three years before the disaster, Masahiko OYA (1923–2005) made a 1 : 50,000 geomorphological map of the plain. The damaged area had been shown in the map which was based on geomorphic features. After this, it became well-known that geomorphological mapping is effective for understanding flood risks.Since then, the various natural disasters have been studied by Japanese geomorphologists and the relationship between the damage and geomorphological condition has been revealed. Nowadays we know that the geomorphological land condition influences very much not only the damage by earthquake strong motion but also occurrence of ground liquefaction. It is also well-known that landforms derived by landslide or debris flow shown in a geomorphological map mean that the place is open to damage in the future.The national government carried out and is carrying out some geomorphological mapping projects for the purpose of hazard assessments. Nowadays, national and local governments prepare various kinds of “hazard map” which show probably dangerous zones, and some of them are made using the information provided from geomorphological maps.Major geomorphological mapping projects are as follows:Chikei Burui Zu (Landform Classification Map) 1 : 50,000, 1953–This project intended not to use for hazard assessment but to contribute to the development conservation and higher utilization of land in the rapid population growth period. At first, this project executed by the Geographical Survey Institute (national survey and mapping agency of Japan, present name: Geospatial Information Authority of Japan, GSI), but most of maps has been prepared by prefectural governments. Most part of Japan has been covered. We can see the maps on a website of the Ministry of Land, Infrastructure and Transport and on the web-GIS (Chiriin Chizu) of GSI.http://nrb-www.mlit.go.jp/kokjo/inspect/landclassification/land/l_national_map_5-1.htmlSuigai Chikei Bunrui Zu (Geomorphological Survey Map of River Basins Showing Classification of Flood Stricken Areas) 1956–200135 maps of this series, the scale of which are mainly 1 : 50,000 or 1 : 25,000, were made by OYA and his co-workers. The above-mentioned geomorphological map of the Nobi plain is the first one. The mapping was made from a viewpoint that the micro-landforms of a plain reflect the history of flooding because they have been formed by the deposition process during the flood time, and therefore they enable us to estimating flooding in the future. The project was sponsored by some government organizations, especially river offices. Oya and his co-workers also made 10 maps in foreign countries of Asia and Africa. Today, we can see the maps on the website of the National Research Institute for Earth Science and Disaster Resilience (NIED).

Unidimensional, non-stationary modeling of a high mountain river in southern Ecuador

Floods represent a severe cause of deaths and economic loss. In order to prevent, mitigate, and reduce flood risks and their consequences, hydraulic models allow analysing and mapping floods. The results of an appropriate model that works under local conditions are a valuable tool for local governments leading to sustainable management of floodplains. Around the world, high-mountain rivers have been poorly modelled; their orography and data scarcity present an extra research difficulty. Considering that all one-dimensional models assume that the river bed slope is small, this study evaluated two widely applied one-dimensional models: Mike11 and HEC-RAS, for modelling a high mountain river. Their best configuration under complex topographical conditions and their potential use was assessed by calibration and validation of the models. We found that the HEC-RAS model was not able to define a stable solution of the hydrodynamic modelling of the river, while Mike11 yielded stable results. Furthermore, the validation of the Mike11 model showed good performance. This study sets a precedent in the 1D modelling of high-mountain rivers with data scarcity.

Discharge estimation in high-mountain regions with improved methods using multisource remote sensing: A case study of the Upper Brahmaputra River

River discharge is an important variable in the water cycle that is related to water supply, irrigation, and flood forecasting. However, gauging stations are extremely limited across most high-mountain regions such as the Tibetan Plateau (TP), known as the Asia's water towers. Remote sensing, in combination with partial in situ discharge measurements, bridges the gap in monitoring river discharge over ungauged and poorly gauged basins. Of great importance for the successful retrieval of river discharge using remote sensing are river width (water surface area) and water level (water surface elevation), but it is challenging to retrieve accurate discharge values for high-mountain regions because of narrow river channels, complex terrain, and limited observations from a single satellite platform. Here, we used 1237 high-spatial-resolution images (Landsat series and Sentinel-1/2) to derive water surface areas with the Google Earth Engine (GEE), and satellite altimetry (Jason-2/3 and Satellite with Argos and AltiKa (SARAL/Altika)) to derive water levels for the Upper Brahmaputra River (UBR, the Yarlung Zangbo River in China) in the TP where the river width is typically less than 400 m. Using three power function equations, discharge was estimated for cross-sections around the four gauging stations in the UBR with triangular cross-sections outperforming their trapezoidal counterparts. It was also found that the equation combining both river width and water level produced the best discharge estimates whereas the other two equations (requiring either river width or water level as the input data) were complementary and could be used to extend the time series of discharge estimates. The Nash–Sutcliffe efficiency coefficient values for the discharge estimates range from 0.68 to 0.98 during the study period 2000–2017. The proposed method is feasible to estimate discharge in the UBR and potentially other high-mountain rivers globally.

Are We Underestimating Benthic Cyanotoxins? Extensive Sampling Results from Spain

Microcystins (MCs) are potent hepatotoxins, and their presence in water bodies poses a threat to wildlife and human populations. Most of the available information refers to plankton, and much less is known about microcystins in other habitats. To broaden our understanding of the presence and environmental distribution of this group of toxins, we conducted extensive sampling throughout Spain, under a range of conditions and in distinct aquatic and terrestrial habitats. More than half of the tested strains were toxic; concentrations of the hepatotoxin were low compared with planktic communities, and the number of toxic variants identified in each sample of the Spanish strains ranged from 1–3. The presence of microcystins LF and LY (MC-LF and MC-LY) in the tested samples was significant, and ranged from 21.4% to 100% of the total microcystins per strain. These strains were only detected in cyanobacteria Oscillatoriales and Nostocales. We can report, for the first time, seven new species of microcystin producers in high mountain rivers and chasmoendolithic communities. This is the first report of these species in Geitlerinema and the confirmation of Anatoxin-a in Phormidium uncinatum. Our findings show that microcystins are widespread in all habitat types, including both aerophytic and endolithic peat bogs and that it is necessary to identify all the variants of microcystins in aquatic bodies as the commonest toxins sometimes represent a very low proportion of the total.

Habitat preferences in freshwater benthic macroinvertebrates: Algae as substratum and food resource in high mountain rivers from Mexico

The diversity of benthic macroinvertebrates in lotic systems is closely related to the availability and heterogeneity of habitats. These habitats may be of inorganic origin, such as the rocky substratum associated with the river bed, or organic such as macroscopic algae. The objective of this study was to determinate the importance of five species of algae that differ in their morphological type as a substratum and food resource regarding the associated establishment of macroinvertebrate assemblages taking account the climatic seasonality (warm dry, cool dry and rainy). We then evaluate the differences in macroinvertebrates assemblages with respect to the inorganic substratum by sampling high mountain rivers in central Mexico. The mucilaginous colonies of Nostoc parmelioides and Placoma regulare, the pseudoparenchymatous bambusiform thallus of Paralemanea mexicana and the laminate thallus of Prasiola mexicana had the highest densities of macroinvertebrates, represented by the genera Cricotopus, Paramerina, Simulium and Tanytarsini tribe. The relationship between algal morphological type and the richness and diversity of macroinvertebrates was positively related to specific conductivity, total dissolved solids and discharge variables. The dominant taxa associated with the inorganic substratum belonged mainly to the Trichoptera, Diptera and Ephemeroptera orders. Water temperature, discharge and concentration of orthophosphates were the main environmental variables able to explain the diversity of macroinvertebrates on this substratum. The dominance of detritivorous macroinvertebrates in these mountain rivers suggests the contribution of allochthonous organic matter possibly of anthropogenic origin. The assemblages of macroinvertebrates on inorganic substratum did not significantly differ among sites or climatic seasons.

Epibionts on Hydraena species (Coleoptera: Hydraenidae) from high mountain rivers of Pyrenees (Ordesa and Monte Perdido National Park), with the description of a new species

Macroinvertebrate samples collected during spring-summer 2013 in high mountain rivers of the Ordesa and Monte Perdido National Park (Pyrenees) contained several Hydraena species (Coleoptera: Hydraenidae) where we found two genera of suctorian ciliates as epibionts: Tokophrya and Discophrya. The individuals of the genus Tokophrya probably belong to species Tokophrya stenostyla, being the first time that this species is observed attached on arthropods. Suctorians of the genus Discophrya were identified as a new species called Discophrya ordesae sp. n. The presence and abundance of epibionts was discussed in the frame of the biological and ecological characteristics of the species of Hydraena where they were found.

Estado ecológico de los ríos incluidos dentro del parque Nacional de Ordesa y Monte Perdido (Cuenca del Ebro, Aragón), mediante indicadores de macroinvertebrados

We provide information about the ecological status of Arazas, Bellos and Yaga rivers (Ordesa y Monte Perdido National Park), obtained from samples collected by volunteers during the 2013 spring-summer season, included in the “Volunteering activities in the Parks Network” program (MAGRAMA). In each river three points have been selected, all belonging to Type 27: High mountain rivers, except one that is Type 26: Humid calcareous mountain river. For each point several macroinvertebrate indexes (IBMWP, IASPT, NFAM, NFPLE and EPT) and their ecological quality ratios (EQR) were calculated. As a whole, 72% of the IBMWP measurements show Very good or Good quality, a 22% Moderate and a 6% Deficient. The Yaga River showed all the measures as Very Good-Good while in the Arazas River we found the three classes of quality cited. In general, for each river the values of the indexes are decreasing from mouth to source, while most of values are increasing in a temporal pattern (from spring to late summer) in each sampling point, except in two points, Arazas-3 and Bellos-2, that show the opposite pattern.

Sediment storage and morphology of the Yalu Tsangpo valley due to uneven uplift of the Himalaya

The fluvial process of the Yalu Tsangpo River occurs concurrently with the uplift of the Qinghai-Tibet Plateau. Therefore, the river exhibits unique features in morphology and sediment deposition. Field investigations were performed from 2009–2011 and the depth of the interface between the sediment deposits and bed rock was detected with an electromagnetic imaging system (EH4) at 29 cross sections. Sediment deposits were sampled along the Yalu Tsangpo valley from Xietongmen to the Yalu Tsangpo Canyon. The results show that a huge amount of sediment has been deposited in four wide valley sections because the uplift rate in these sections was lower than that in the downstream gorge sections over the past million years. About 518 billion m3 of gravel and sand have been stored in the high mountain river valleys, which has changed the V-shaped mountain river valley into a U-shaped wide river valley in the four sections. In the sections with high uplift rates the river bed is incised and has formed gorges and the Yalu Tsangpo Canyon.

A New Method for Determining Thickness of River Incision Layers in High Mountain and Deep River Valley Areas

In high mountain and deep river valley areas, geological materials of river valley evolution are often missing or incomplete. To address this problem, tectonic movements at project site are analyzed using mathematical statistics based on the analysis of formation and evolution history of river terraces, and then a new method to determine the thickness of river incision layers is proposed. Taking Jiata dam area at the Western Route of South-to-North Water Transfer Project in China for an example, the reliability and reasonability of the proposed method are validated through a case study.

Populetum pamiricae ass. nova – an endemic forest association to Pamir in Tajikistan (Middle Asia)

Abstract The floristic structure, distribution and habitat requirements of a forest syntaxon, Populetum pamiricae ass. nova is described. The potential range of the Populetum pamiricae association comprises the mountains of eastern Tajikistan (Pamir Alai Mts), Kashgaria in western China (Kunlun Shan Mts) and north-eastern Afghanistan (Hindu Kush Mts) in Middle Asia. The biotope of this community comprises of high mountain river valleys situated at elevations between 2,500 and 3,200 m above sea level. Phytocoenoses of the Populetum pamiricae association are characterized by the apparent domination in the tree layer of a diagnostic species, Populus pamirica. The tree stand has a mean cover around 55%. The layer of shrubs consists primarily of the willow including Salix linearifolia and S. wilhelmsiana, and Hippophaë rhamnoides, Rosa huntica and Lonicera stenantha. The herb layer is less developed and consists of species typical for Populetea laurifolio-suaveolentis; however, in juvenile stages of the community, taxa from riverbed vegetation (i.e. Salicion eleagni) also frequently occur. Populetum pamiricae grows in areas of flood inundations caused mainly by spring thaw where the humus layer in soils is very thin or even completely absent. The forest association of Populetum pamiricae ass. nova is one of the rarest and most rapidly disappearing wood communities in Tajikistan. High conservation priority and special management is recomended for this association.