Himalayan Rivers Research Articles

Historical and Projected Variations of Precipitation and Temperature and Their Extremes in Relation to Climatic Indices over the Gandaki River Basin, Central Himalaya

Changes in precipitation and temperature, especially in the Himalayan region, will have repercussions for socio-economic conditions in the future. Thus, this study aimed to understand the climatic trend and changes in one of the Himalayan River basins, i.e., Gandaki River Basin (GRB), Nepal. In particular, we analysed the historical (1985–2014) and projected (2015–2100) precipitation and temperature trend and their extremes using observation and 13 bias-corrected Coupled Model Intercomparison Project phase 6 (CMIP6) datasets. Additionally, the relationship between extreme precipitation/temperature indices and ocean-atmospheric circulation patterns were also analysed. The results showed an increasing trend of precipitation amount and temperature at annual and seasonal scales with the highest upward trend for precipitation in monsoon season and temperature in winter season. Among nine precipitation indices analysed, the wet extremes are projected to increase in all Shared Socioeconomic Pathways (SSP) scenarios; with the highest increment of high-intensity related extremes (R10 mm and R20 mm). In contrast, dry spells will decline in the distant-future (2075–2100) as compared to near (2015–2044) and mid-future (2045–2074). Further, increment in temperature trend resulted in a decrease in cold related temperature extremes and an increase in warm related extremes. Furthermore, it was observed that the changes in precipitation and temperature extremes over GRB were influenced by large-scale ocean-atmospheric circulation patterns. The Atlantic Multidecadal Oscillation (AMO), Sea Surface Temperature (SST) and Southern Oscillation Index (SOI) were found to have a major role in driving precipitation extremes while AMO, SST and Pacific Decadal Oscillation (PDO) have strong influence on temperature extremes. The results of this study will be useful for better understanding the implications of historical and future changes in precipitation and temperature and their extremes over the GRB.

Decoupling of physical and chemical erosion in the Himalayas revealed by radiogenic Ca isotopes

Decoupling of physical and chemical erosion in the Himalayas revealed by radiogenic Ca isotopes

Evidence for paleo-continental margin and folding of relic fragment of oceanic lithosphere, northeast Indian subcontinent

Evidence for paleo-continental margin and folding of relic fragment of oceanic lithosphere, northeast Indian subcontinent

Computational analysis and functional characterisation of Tor putitora toll-like receptor 4 with the elucidation of its binding sites for microbial mimicking ligands

Computational analysis and functional characterisation of Tor putitora toll-like receptor 4 with the elucidation of its binding sites for microbial mimicking ligands

Insights into the morphometric characteristics of the Himalayan River using remote sensing and GIS techniques: a case study of Saryu basin, Uttarakhand, India

Insights into the morphometric characteristics of the Himalayan River using remote sensing and GIS techniques: a case study of Saryu basin, Uttarakhand, India

Spatial water quality assessment of a mountain stream in northwestern India using multivariate statistical techniques.

The water quality of Himalayan rivers and streams is deteriorating due to multitude of anthropogenic and natural influences and the changes are more pronounced in smaller hill basins with high human influx. Inadequate data and lack of monitoring further exacerbate the situation. The surface water quality of one such hill stream, Neeru was evaluated for potability and irrigation quality. The water quality parameters were analysed at 25 sampling stations over a stretch of 30km across four seasons during a 2-year study from January 2014 to December 2015. The CCME Water Quality Index (WQI) indicated excellent water quality in upstream stations, while the midstream and a few downstream stations revealed varying degrees of impaired water quality. Although the irrigation quality of the stream was excellent, pollution levels near urban areas were rather high, necessitating considerable treatment for human consumption. The factor analysis yielded seven components with Eigenvalues greater than one that accounted for 83.656% of the variance and enabled the grouping of selected parameters based on comparable characteristics. The hydrogeochemical characteristics of the water samples indicated that they lie within the zone of rock dominance, while the trilinear diagram depicted the Ca-bicarbonaterich stream water. The study concluded that the upstream stations revealed pristine water quality, which significantly degraded towards human settlements. It thus calls for regular and long-term monitoring of the surface water quality to ensure the continuous and sustainable use of this important water body.

Evaluation of water quality and dam for sustaining the fish population dynamics

Bhagirathi is a Himalayan River, which flows in Uttrakashi district in Uttarakhand state. It is one of the most important streams of the Ganga River. This river is famous for dam construction and fisheries development. The fishes of commercial importance in cold water are Mahaseer, Snow Trout. The fish production depends on the physical, chemical as well as biological qualities of water. In the present paper, water quality evaluation and dam in the sustaining fish population dynamics have been reviewed to make aware the fish culturist and environmentalist about the water quality factors which influence health of a pond and to increase the fish yields to meet the growing demands of present time scenario of the our country. The construction of dams causes many problems. Water quality and discharge of water from the dam wall systems also indirectly affect the fish populations. In this study, we also review some of the important impacts associated with dams and their recommended mitigation measures. There is a negative impact on fish population dynamics, especially for downstream habits due to dams. Water quality is measured like temperature, turbidity, carbon dioxide, pH, alkalinity, hardness, BOD, TDS, Turbidity. The maximum oxygen content of water was recorded in January 13.02 ± 0.166 mg l−1 and minimum 9.4 ± 0.05 mg l−1 in July in site I phase I (before the reservoir dam wall). While in site II and phase I (After the dam), the maximum DO was observed in the month of January of 12.1 mg l−1 and minimum in July of 8.93 mg l−1. This is because water level is minimized in site II almost dried in winter. The CO2 of the Maneri Bhali phase I -Site I (before dam) was recorded maximum in April 3.10 ± 0.012 mg l−1. In Maneri Bhali phase I -Site II (After dam), the CO2 was recorded maximum 3.01 ± 0.003 mg l−1 in the month July. The river of Garhwal Himalaya harbors a rich aquatic diversity, the most common endemic fish species that inhabit this fresh water is the Schizothorax species. The maximum no. of fish were observed in winter and minimum in monsoon. At present, the production of these fishes from the streams is very poor and is not well managed from recreational and conservation point of view. If such is developed properly, it can have revenue potential for our state government. Sports, fisheries, tourism should be promoted.

An overview of open channel monsoon hydraulics of Himalayan foothill rivers, West Bengal, India

An overview of open channel monsoon hydraulics of Himalayan foothill rivers, West Bengal, India

Investigating the effect of different support vector classifier variants to predict the flood risk of Himalayan river

Investigating the effect of different support vector classifier variants to predict the flood risk of Himalayan river

Energy fluxes, mass balance, and climate sensitivity of the Sutri Dhaka Glacier in the western Himalaya

Various regional climatic factors influence glacier mass balance and thus control the water budget of the Himalayan rivers. However, the scarcity of observational data hinders a detailed understanding of the processes governing glacier mass balances in the Himalaya. Here we analyze the mass balance of the Sutri Dhaka Glacier, a debris-free glacier in the Chandra basin (western Himalaya) combining field observations and a physically based model to understand the drivers of mass balance variability. The modeled energy flux showed that net shortwave radiation contributed 56% to the total surface energy fluxes, followed by net longwave radiation (27%), sensible heat (8%), latent heat (5%), and ground heat flux (4%). However, over the ablation zone, inward fluxes account for most of the total heat flux, resulting in strong summertime melting. The model estimated glacier mass balance was −1.09 ± 0.31 and −0.62 ± 0.19 m w.e. during 2015/16 and 2016/17, which matches well with the in situ glaciological mass balance of −1.16 ± 0.33 and −0.67 ± 0.33 m w.e., respectively. A sensitivity analysis demonstrates that the mass balance of the glacier is affected by both air temperature (−0.21 m w.e. a−1 °C−1) and precipitation (0.19 m w.e. a−1 (10%)−1) changes. Our study suggests that, the mass balance of the Sutri Dhaka Glacier is less sensitive to changes in the partitioning of precipitation into snow and rain because the majority of precipitation falls as snow during the winter when the temperature is well below 0°C.

Vegetation cover dynamics along two Himalayan rivers: Drivers and implications of change

Rivers are dynamic landscape features that change in response to natural and anthropogenic factors through hydrological, geomorphic and ecological processes. The severity and magnitude of human impacts on river system and riparian vegetation has dramatically increased over the last century with the proliferation of valley-spanning dams, intensification of agriculture, urbanization, and more widespread channel engineering. This study aims to determine how changes in geomorphic form and dynamics caused by these human alterations relate to changes in channels and riparian vegetation in the lower Beas and Sutlej Rivers. These rivers are tributaries of the Indus that drain the Western Himalayas but differ in the type and magnitude of geomorphic change in recent decades. Winter season vegetation was analysed over 30 years, revealing increasing trends in vegetated land cover in the valleys of both rivers, consistent with large-scale drivers of change. Greater trends within the active channels indicate upstream drivers are influencing river flow and geomorphology, vegetation growth and human exploitation. The spatial patterns of vegetation change differ between the rivers, emphasizing how upstream human activities (dams and abstraction) control geomorphic and vegetation community response within the landscape context of the river. The increasing area of vegetated land is reinforcing the local evolutionary trajectory of the river planform from wide-braided wandering to single thread meandering. Narrowing of the active channels is altering the balance of resource provision and risk exposure to people. New areas being exploited for agriculture are exposed to greater risk from river erosion, inundation, and sediment deposition. Moreover, the change from braided to meandering planform has concentrated erosion on riverbanks, placing communities and infrastructure at risk. By quantifying and evaluating the spatial variations in vegetation cover around these rivers, we can better understand the interaction of vegetation and geomorphology alongside the impacts of human activity and climate change in these, and many similar, large systems, which can inform sustainable development.

Role of Depth, Habitat and Current Velocity on Distribution of Benthic Macroinvertebrate Fauna in the Himalayan River, Ramganga

Role of Depth, Habitat and Current Velocity on Distribution of Benthic Macroinvertebrate Fauna in the Himalayan River, Ramganga

Modelling of hydrological and environmental flow dynamics over a central Himalayan river basin through satellite altimetry and recent climate projections

AbstractThe Himalayan region is vulnerable to climate change, which is triggering extreme hydrological events. To understand the impact of climate emission scenarios on different hydrological flow dynamics of the Himalayan region, a thorough hydrological investigation is needed for improved water resource management. Hence, this research exemplifies the use of remote sensing, modelling techniques, and recent climate projections (CMIP5 and CMIP6) for the assessment of hydrological flow dynamics in the central Himalayan catchment. The SWAT model is calibrated/validated using gauge observation and satellite altimetry‐derived river discharge and used for long‐term hydrological simulations (1979–2100). CMIP6 models predicted that there would be a steady rise in high flows in all the projected scenarios. Flow duration curve for CMIP5 and CMIP6 models depicted that high flow of short duration would be frequent in future. The environmental flow components (EFCs) were calculated using the indicator of hydrologic alteration tool. The SWAT model simulations of hydrological and EFCs under CMIP6 climate projections are found to be significantly more vulnerable to climate warming than CMIP5, which could be due to socioeconomic pathway emission scenarios.

Snowmelt runoff estimation Using Combined Terra-Aqua MODIS Improved Snow product in Western Himalayan River Basin via degree day modelling approach

Snow sustains Himalayan rivers as an abundant source of water. Although, seasonal snow cover is the significant parameter in a hydrological system of a basin, its contribution is restricted to the spring season when snow-melt and base-flow comprise two parts of the inflow. The current study assessed the snowmelt contribution in the total streamflow for the Beas River up to the Pandoh dam using Snowmelt Runoff Model (SRM). The study area is divided into seven elevation classes and snow cover has been computed. The snow-covered area varies from 10% to 80% in the basin. The efficiency of the model was evaluated using Coefficient of Determination (R2), Nash-Sutcliffe Efficiency and Volume difference. The R2, NSE and Volume Difference during the calibration and validation period was ranges from 0.79 to 0.87, 0.72 to 0.79, -0.025% to 7.2% and 0.72, 0.67, -4.65 % respectively. The major finding of the present study suggest that a major part of the streamflow is generated in summer and monsoon season and the contribution of the snowmelt was ranges from 10-45%. The present study will provide a baseline information towards the contribution of snowmelt in the streamflow and also provide the information towards the availability of freshwater.

The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers

Abstract. In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these boulders and drive incision, yet their role in regional-scale erosion is poorly understood, largely because of their rarity. Here, we find a topographic signature consistent with widespread GLOF erosion in the Nepal Himalaya. Our interpretations emerge from the analysis of normalized channel steepness patterns, knickpoint distributions, and valley wideness. In rivers with glaciated headwaters that generate GLOFs, valleys stay narrow and relatively free of sediment, with bedrock often exposed to erosion. In turn, tributaries to these valleys are steep, allowing less efficient erosional regimes to keep pace with GLOF-driven incision. Where GLOFs are less frequent, valleys are more alluviated and incision stalls. Our results suggest that the extent of headwater glaciation may play an important role in the erosion of Himalayan river valleys and deserves more attention in future work.

Study of hydrochemical and geochemical characteristics and solute fluxes in Upper Ganga Basin, India

Study of hydrochemical and geochemical characteristics and solute fluxes in Upper Ganga Basin, India

Nutritional Status, Level of Trace Metals and Human Health Risk Assessment in Fishes of Central Himalayan River Alaknanda

Nutritional Status, Level of Trace Metals and Human Health Risk Assessment in Fishes of Central Himalayan River Alaknanda

Water quality characterization and pollution source apportionment in the Himalayan river flowing through Jammu City, India, using multivariate statistical approach and geospatial techniques.

The present study evaluates and characterizes the water quality of River Tawi in Jammu city of Union Territory of J&K, using water quality index, multivariate statistical methods, and geospatial techniques. Water quality parameters were measured at fourteen selected sites along a 12 km (approx.) stretch of river (passing through the city) over two seasons (pre-monsoon and post-monsoon) using standard methods. Water quality index (WQI) results demonstrated spatial and temporal variations and the pollution level of the river increased from upstream to downstream sites. Calculated WQI revealed 35.71% of the water samples in the unfit for drinking category, 28.57% in good and poor category each, and 7.14% samples in very poor drinking water category during the study period. Comparison of analysis results with the drinking water standards prescribed by the World Health Organization and Bureau of Indian standards recorded elevated ranges of parameters like turbidity, BOD, total alkalinity, nitrate, and faecal coliform beyond the permissible limits. Hierarchical cluster analysis has transformed the sites into two clusters during pre-monsoon and three clusters during post-monsoon season indicating more water quality variation during post-monsoon season. Principal component analysis resulted in two PCs for the water quality, explaining 80.827% and 73.672% of the variance for pre-monsoon and post-monsoon periods. The prepared WQI maps confirmed and depicted deterioration of river water quality towards the midstream and downstream sites of the river basin. Entry of major sewage drains from the city particularly at the midstream sites and dumping of solid waste and agricultural runoff towards the downstream sites of the river constituted the main anthropogenic sources that decreased the river water quality. The study establishes first step towards spatial zoning of River Tawi based on pollution level which would help in improving the river water quality through proper basin management. The study also recommends installation of sewage treatment plants particularly at the midstream and downstream sites.

Unraveling the phytoplankton altitudinal dynamics in relation to environmental variables in a Himalayan River, Teesta, India

Unraveling the phytoplankton altitudinal dynamics in relation to environmental variables in a Himalayan River, Teesta, India

A New Geoscientific Predictive Model to Trace Saraswati: The Lost Himalayan River of the Saraswati Civilization

A New Geoscientific Predictive Model to Trace Saraswati: The Lost Himalayan River of the Saraswati Civilization