Karnali River Research Articles

Soil erosion assessment of a Himalayan river basin using TRMM data

Abstract. In this study, an attempt has been made to assess the soil erosion of a Himalayan river basin, the Karnali basin, Nepal, using rainfall erosivity (R-factor) derived from satellite-based rainfall estimates (TRMM-3B42 V7). Average annual sediment yield was estimated using the well-known Universal Soil Loss Equation (USLE). The eight-year annual average rainfall erosivity factor (R) for the Karnali River basin was found to be 2620.84 MJ mm ha−1 h−1 year−1. Using intensity–erosivity relationships and eight years of the TRMM daily rainfall dataset (1998–2005), average annual soil erosion was also estimated for Karnali River basin. The minimum and maximum values of the rainfall erosivity factor were 1108.7 and 4868.49 MJ mm ha−1 h−1 year−1, respectively, during the assessment period. The average annual soil loss of the Karnali River basin was found to be 38.17 t ha−1 year−1. Finally, the basin area was categorized according to the following scale of erosion severity classes: Slight (0 to 5 t ha−1 year−1), Moderate (5 to 10 t ha−1 year−1), High (10 to 20 t ha−1 year−1), Very High (20 to 40 t ha−1 year−1), Severe (40 to 80 t ha−1 year−1) and Very Severe (>80 t ha−1 year−1). About 30.86% of the river basin area was found to be in the slight erosion class. The areas covered by the moderate, high, very high, severe and very severe erosion potential zones were 13.09%, 6.36%, 11.09%, 22.02% and 16.64% respectively. The study revealed that approximately 69% of the Karnali River basin needs immediate attention from a soil conservation point of view.

Population status and habitat occupancy of endangered river dolphins in the Karnali River system of Nepal during low water season

AbstractGanges river dolphin abundance has undergone a predominant decline across its range since monitoring began. In Nepal, disappearance from some of the rivers it once used has already occurred. Today this species can only be found in three river systems in Nepal, the Karnali, Sapta Koshi, and Narayani, but numbers are low in these locations. To determine the abundance of dolphins remaining in the Karnali system (which includes the Karnali, Geruwa, and Mohana), and factors affecting dolphin habitat use, we conducted surveys where we recorded dolphin presence. Dolphins within this river system were sighted only in the Karnali and an abundance estimate of 5.04 ± 0.753 SE was calculated. This pattern of ranging differed from that previously reported (from previous sightings only in the Geruwa to current sightings only in the Karnali). River depth likely contributed to the presence or absence of dolphins. Shifts in available habitat between the Geruwa and Karnali have resulted from changes in the course of the main stream Karnali following construction of the Chisapani irrigation intake. Because of the low numbers of dolphins reported, there is great concern that loss of this species in Nepal is likely in the near future.

Karnali Cable-Stayed Bridge: Development of Finite Element Model and Free Vibration Analysis

This paper describes an analytical investigation on Karnali cable stayed bridge across the Karnali River. The primary objective of the investigation is to develop a three dimensional finite element model capable of representing essential feature of the long span cable-stayed bridge. Various parametric studies on the simple cable-stayed bridge model are performed before the actual development of a complex three dimensional model. Deformed equilibrium configuration due to the dead load is calculated using the cable tension and applied dead loads. Importance of incorporating large displacement geometric nonlinearity during the dead load deformed equilibrium configuration is analyzed .Starting from the deformed equilibrium configuration; modal analysis of the bridge is carried out. Different observed modes are classified based on the dominant modal components. Comparisons of the global modal behavior using the two separate models utilizing different cable modeling techniques are made. Parametric study on effect of cable local vibration and the modeling of deck concrete of the composite deck on overall global modal characteristics is presented. DOI: http://dx.doi.org/10.3126/jie.v10i1.10873Journal of the Institute of Engineering, Vol. 10, No. 1, 2014 pp. 14-24

Petrography of Miocene Siwalik Group sandstones, Karnali River section, Nepal Himalaya: Implications for source lithology and tectonic setting

The Siwalik Group constitutes an important archive of Himalayan uplift and related climate changes. Compositional and textural properties of Siwalik sandstones are important parameters for the reconstruction of source lithology, uplift, and the unroofing history of the Himalaya. This study examines fluvial sandstones of the Siwalik Group along the Karnali River, where the large paleo-Kamali River is expected to have flow ed. Modal QFL analysis shows that the sandstones are mainly sub-litharenites or litharenites. Multivariate statistical analysis using Principal Component Analysis (PCA)and the Weltje method shows light variations in sediment composition occur between the Chisapani and Baka Formations. These variatio ns are mainly linked to the source area and tectonics rather than to facies, grain size, or climate. The detrital modes of the sandstones indicate recycled orogen provenance. Comparison of the detrital modes with previous studies indicates that the Higher Himalaya and Lesser Himalaya zones were a common source area throughout the time of deposition. However, subtle changes in feldspar and biotite contents indicate significant supply of detritus derived from the Higher Himalaya after 9.6 Ma.

Middle to late Miocene vegetation and climate from the Siwalik sediments (Karnali River section), far Western

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Finger Print of Arsenic Contaminated Water in India-A Review

The present study deals primarily with the arsenic contamination occur in ground water in all over India, its causes, effects and recommendation. Arsenic above permissible limit in ground water of phreatic younger alluvium of Ganga and Ghaghara rivers along meandering course and shallow aquifer, has reported as the main source of arsenic contamination. Several studies have been carried out on this context; which is still limited by a lack of data thus, a review study has been undertaken on the sources, causes and health prospective, arsenic is likely to disastrous effects on human. Due to excess of Arsenic in ground water people are reported to be suffering from diseases like skin cancer, ulcer and pigmentation in skin and hardening in palm skin. Different analytical methods have been proposed for further analysis to provide details to know the quantity of arsenic in water, its impact, identify the risk factors and possible to makes recommendation for the prevention and management of arsenic poisoning cases and study of probability of other heavy metals. This review work suggests that the arsenic concentration increase day by day through different channel. It’s directly and indirectly affecting human being; needs to be investigating thoroughly arsenic problem in India.

Pattern of Freshwater Fish Diversity, Threats and Issues of Fisheries Management in an Unexplored Tributary of the Ganges Basin, Northern India

The present study was conducted to assess the current freshwater fish biodiversity status of an unexplored river Ghaghara, a major tributary of river Ganga in Uttar Pradesh, India. Altogether, 62 species of fish representing 48 genera and 24 families were described. The various diversity index packages have been used to assess the fish diversity and diversity is also correlated with habitat variables. The Cypriniformes was recorded to be the most predominated order, contributing to 41.8% of fish species followed by Siluriformes (36.4%). The study shows that this river supports considerable percentage of food fish (79.0%), aquarium fish (48.4%), highly priced fishes (33.9%) and also sport fish (9.7%). The threat status as per current IUCN Red List criteria showed that most of the species are under lower risk least concern (LRlc) category, however, Indian assessment shows that about 23% fish species under threatened list (EN= 4, VU=10). Several anthropogenic activities like barrages, waste water dumping, over fishing, sedimentation, change in land use pattern etc. were found responsible to threaten the fish diversity. As the threats to fish biodiversity in the Ghaghara river are slowly becoming serious and conservation of fishes has become urgent, and integrated and sustainable fisheries management plan should therefore be developed.

Lithostratigraphy of the Silwalik Group, Karnali River section, far-west Nepal Himalaya

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Holocene tectono-geomorphic evolution of parts of the Upper and Middle Gangetic plains, India

Using multispectral scanning (MSS) images and digital elevation models (DEMs), 26 terrain morphological units were delineated in the study area between the Rapti and Kosi Rivers in the Gangetic plains. Based on the degree of soil development and the infrared stimulated luminescence chronology, these terrain morphological units have been grouped into six members of a morphostratigraphic sequence with ages ≤ 1.65, 1.65–5.3, 5.3–7.5, 7.5–8.5, 8.5–10, and > 10 Ka. Integrated use of geomorphic markers including different drainage patterns identified from MSS images, significant breaks in topographic profiles, terminal fans, and artifact terrain features (e.g., ‘cliffs’ and ‘significant breaks in slopes’) in DEMs/digital terrain models (DTMs) with highly exaggerated vertical dimensions were made to infer and map 20 nascent faults in the region between the Ghaghara and Kosi Rivers in the flat Gangetic plains. The three major tectonic blocks are; the upland Ghaghara–Rapti block of the Upper Gangetic Plain, and the Rapti–Gandak and Gandak–Kosi blocks of the Middle Gangetic Plain, marked by high rates of subsidence and sedimentation. The Ghaghara–Rapti block bounded by the incised Ghaghara and Rapti rivers is an upland region and is primarily overlain by > 10 Ka old soils. Subsequent activity along the NE-SW trending transverse normal faults led to deposition of young terminal fans. Southward tilt of the Ghaghara–Rapti block generated two E–W trending terraces on the left bank of the Ghaghara River. Southwestward tilting of the upper part of the Ghaghara–Rapti block led to development of the widest Old Ghaghara Plain and Rapti Floodplain in the SW direction. Northeastward tilting of the Rapti–Gandak block shifted the Gandak River from west to east over a distance of 80 km during the period from 10 to 8.5 Ka. Further compression from the SW caused development of four extensional normal faults. The activity of three faults between 5.7 and 1.0 Ka generated four terminal alluvial fans on this block. The Gandak–Kosi block is marked by a set of seven thrust splays off the Himalayan Frontal Thrust (HFT) in the footwall. Activity of these thrust splays in the foothill region caused progradation of the gravel piedmont and thus developed the widest piedmont zone (124 km) in the Gangetic plains. This is the first report of gravel piedmont progradation from a modern environment and role of thrust splays in such a progradation. In the southernmost part of this block, the continuous occurrence of terminal fans over a length of 140 km south of the South Muzaffarpur Fault forms a terminal fan piedmont/bajada. Orientation of the faults was used to interpret compression from the SW in the Ghaghara–Rapti Interfluve Plain in the west since ~ 10 Ka and compression from the south in the Gandak–Kosi interfan region in the east after 4.5 Ka. The Rapti–Gandak region in the central part shows the effects of mainly compression from the SW and compression from the south at different times. In addition to terminal fans formed because of low relief terrain features created by the activity of faults by involvement of the entire discharge of small meandering/braided streams, a new type of fan formed by splays from a large river on the downthrown sides of faults, called ‘splay terminal fans’ is observed from the Rapti–Gandak block.

Natural hazards in the Ghaghara River area, Ganga Plain, India

The Ganga Plain is one of the most densely populated regions of the world due to its fertile soil and availability of water. The rivers of this plain are the lifeline for millions of people of this vast alluvial plain. All rivers of this plain are characterized by narrow channel confined within wide valley. Continuously increasing pressure of population on this plain has led to the intensification of settlement even into the valley of the river. This unplanned expansion has enhanced the damage due to flooding during high-discharge period and lateral erosion during low-discharge period. Flooding and lateral erosion are identified as fluvial hazards in the Ghaghara River area. Extensive studies have been carried out on flooding, but not much attention has been paid to the phenomenon of lateral erosion. However, it has been observed that lateral erosion is an independent fluvial hazard that operates during low-discharge period. Low degree of compaction due to the presence of sandy and silty facies in the river valley deposits, mass movement, palaeocurrent pattern, and fractures initiates and enhances the lateral erosion. The present paper deals with the fluvial hazards in the Ghaghara River area.

Balitora eddsi, a new species of hillstream loach (Ostariophysi: Balitoridae) from Nepal

A new species of hillstream loach Balitora eddsi is described from the Karnali River drainage in south-western Nepal. The new species is distinguished from all its congeners by possessing the following combination of characters: six to seven unbranched pectoral-fin rays, pelvic-fin length 12-14% standard length (L(S)), dorsal surface without circular or irregular shaped dark blotches, snout pointed, median lobe between anterior rostral barbels pointed posteriorly, dorsal-fin origin posterior to pelvic-fin origin, lateral line scales 66-67, caudal peduncle length 22-23.2% L(S), caudal peduncle depth 4.1-4.2 times its length.

Priority habitats for the conservation of large river fish in the Ganges river basin

Abstract Three classes of habitat used by groups of fish species classified as conservation and management priorities were developed for the Gerua River (also known as the Girwa River, Karnali River) in the Ganges river basin. This river is large (mean annual discharge ca 1500 m3 s−1, up to 900 m wide), surrounded by protected lands of India and Nepal, and upstream of major diversions and river alterations. Fish and habitat sampling was conducted at 45 sites from 2000 to 2003. Data were analysed for 2172 fish of 14 species. Species and life stages found occupying a statistically distinct subset of the river habitats were grouped to identify classes of river habitat for conservation. Most species and life‐stage groups specialized on specific habitat conditions revealed by multivariate analyses of variance and a principal component analysis. The most numerous and diverse group (six species, 15 life stages) was associated with deep depositional habitats with sandy substrate. Two species covering three life stages were primarily oriented to erosional habitat marked by fast current velocity with pebble and cobble substrate. A third group of three species of adults and juveniles were intermediate in habitat use. River conservation for fish faunas should maintain both erosional and depositional channel habitats with depths, substrates, and current velocity inclusive of the ranges reported. The erosional and depositional nature of the key habitats requires that rivers be maintained with flows capable of channel‐forming functions. Copyright © 2006 John Wiley & Sons, Ltd.

Geomorphology, pedology and sedimentology of the Deoha/Ganga–Ghaghara Interfluve, Upper Gangetic Plains (Himalayan Foreland Basin) — Extensional tectonic implications

Regional mapping of soils helped to identify and map 24 soil-geomorphic units on the Deoha/Ganga–Ghaghara Interfluve in the Upper Gangetic Plains (Himalayan Foreland Basin). On the basis of luminescence ages soil-geomorphic units can be grouped into five members of a Morphostratigraphic Sequence with ages of ≤ 1.7 ka, 1.8–3.6 ka, 4.6–6.4 ka, 6.8–10 ka and > 10 ka. Except for two units with sandy parent material, all the members with loamy parent materials show systematic increase in the degree of soil development from Member QGMS-I to V. Major pedogenic processes are salinization, alkalinization, illuviation, calcrete development and gleying, and degradation of some micromorphological features is observed in the oldest soils. Regional mapping and dating of soils show that the Interfluve between the Deoha/Ganga–Ghaghara rivers is bounded by longitudinal faults, along the bounding rivers. The major longitudinal faults trend N–S or NNE–SSW in the northern region; turn N–S in the central region and take easterly to SEE direction in the south, giving the Interfluve a curvilinear shape. Strike of a set of six transverse extensional normal faults changes from approximately E–W to NEE–SWW in the southernmost region of the Interfluve. Downthrown sides are to the south and to the east in northern region and western region, respectively. Due to the activity of different segments of various transverse faults during a probably dry sub-humid to semi-arid climatic period of 10–5 ka, terminal fans were deposited on the downthrown blocks. Thus, role of extensional tectonics in an overall compressional regime is significant. Also, tilting of smaller blocks leading to the shifting away of large rivers seems to be an additional control on the distribution of soils and sedimentation on the Interfluve.

Tectonic and climatic control of the changes in the sedimentary record of the Karnali River section (Siwaliks of western Nepal)

Abstract A multidisciplinary study was conducted on the section of the Siwalik Group sediments, approximately 5000 m thick, exposed along the Karnali River. Analysis of facies, clay mineralogy and neodymium isotope compositions revealed significant changes in the sedimentary record, allowing discussion of their tectonic or climatic origin. Two major changes within the sedimentary fill were detected: the change from a meandering to a braided river system at ca 9.5 Ma and the change from a deep sandy braided to a shallow sandy braided river system at ca 6.5 Ma. The 9.5‐Ma change in fluvial style is contemporaneous with an abrupt increase of ɛNd(0) values following a ɛNd(0) minimum. This evolution indicates a change in source material and erosion of Lesser Himalayan rocks within the Karnali catchment basin between 13 and 10 Ma. The tectonic activity along the Ramgarh thrust caused this local exhumation. By changing the proximity and morphology of relief, the forward propagation of the basal detachment to the main boundary thrust was responsible for the high gradient and sediment load required for the development of the braided river system. The change from a deep sandy braided to a shallow sandy braided river system at approximately 6.5 Ma was contemporaneous with a change in clay mineralogy towards smectite‐/kaolinite‐dominant assemblages. As no source rock change and no burial effect are detected at that time, the change in clay mineralogy is interpreted as resulting from differences in environmental conditions. The facies analysis shows abruptly and frequently increasing discharges by 6.5 Ma, and could be linked to an increase in seasonality, induced by intensification of the monsoon climate. The major fluvial changes deciphered along the Karnali section have been recognized from central to western Nepal, although they are diachronous. The change in clay mineralogy towards smectite‐/kaolinite‐rich assemblages and the slight decrease of ɛNd(0) have also been detected in the Bengal Fan sedimentary record, showing the extent and importance of the two major events recorded along the Karnali section.

Preface

Preface

Hog deer Axis porcinus need threatened tallgrass floodplains: a study of habitat selection in lowland Nepal

In Asia, subtropical tall grasslands and their associated fauna are mostly confined to the floodplains of the large rivers draining the Himalayan range. In recent decades, cultivation and hydroelectric dam construction have severely reduced their spatial abundance. During 1998–2000, we conducted a detailed study of the habitat use of hog deer, Axis porcinus, an important prey species of tiger, Panthera tigris, in the floodplains of the large Karnali river in Royal Bardia National Park, Nepal. Strong preference for tall grass and avoidance of the successional stages following riparian forests throughout the year was revealed by analyses of tracking data from 18 radio-collared deer and from density estimates from block counts (n=46) in different habitat types. Continuously strong selection for tall grass despite the reduced availability of this habitat type during the monsoonal flooding indicated an insignificant effect of density-dependent factors in habitat selection. Reduced availability of cover following traditional cutting and burning of the tall grasslands by local villagers did not produce changes in habitat use or an increase in daily movements, indicating an absence of trade-offs between habitat preference for food and for predator avoidance. By regulating fluvial action, hydroelectric power development will lead to the loss of tall grasslands due to accelerated secondary succession, which will therefore adversely affect the viability of local populations.

Evolutionary genetics of the endemic Schizorathicine (Cypriniformes: Cyprinidae) fishes of Lake Rara, Nepal

The three endemic species of Schizothorax from Lake Rara, Nepal comprise a putative cyprinid species flock. Mitochondrial DNA sequences were compared for specimens of the endemic species S. raraensis, S. macrophthalmus, and S. nepalensis, and specimens of S. richardsonii and S. progastus from the Karnali River, Koshi River, and Kali Gandaki River drainages. An analysis of molecular variance demonstrated that S. nepalensis is genetically distinct from a group composed of S. raraensis and S. macrophthalmus. Phylogenetic analyses based on parsimony failed to corroborate or conclusively reject a hypothesis of monophyly for the three endemic species of Schizothorax from Lake Rara. The mtDNA haplotypes of S. richardsonii and S. progastus from the Karnali River drainage were not significantly differentiated from one another, but pairwise comparisons of haplotypes from the Lake Rara basin, Karnali River drainage, Koshi River drainage, and Kali Gandaki River drainage were significantly differentiated from one another.

Magnetic polarity stratigraphy of Siwalik Group sediments of Karnali River section in western Nepal

The remanent magnetization of siltstones and sandstones sampled at 476 levels/sites throughout a 3560 m thick molasse sequence belonging to the Siwalik Group (0–2015 m: Lower; 2015–3560 m: Middle) has been studied by stepwise thermal demagnetization. This section is exposed along the Karnali River in Nepal. The natural remanent magnetization (NRM) usually consists of two components: a viscous or thermoviscous component of recent field origin, and an ancient characteristic component (ChRM). The former component is of normal polarity and resides either in goethite (unblocking temperature < 150 °C; resistant to AFD up to 150 mT) or in maghemite (unblocking temperature 150–400 °C). Goethite contributes up to 90 per cent of the total intensity in the finer variegated muddy samples belonging to the lower half of the section. Maghemite content is significant in the grey mud-free lithologies from the upper half of the section. The main component, unblocked in the high-temperature range (commonly 610–680 °C) and believed to reside in haematite, presumably of mostly detrital origin, represents a characteristic remanence (ChRM). The tilt-corrected ChRM directions at individual sites show antipodal clusters (ratio of normal- to reverse-polarity sites: 0.62), and yield mean inclinations recording significant inclination shallowing—a feature well recorded in the Siwaliks. This ChRM is interpreted to represent a largely primary detrital remanence. The ChRM data from 430 sites yield the Karnali River magnetic polarity sequence, whose correlation with the geomagnetic polarity timescale (Cande & Kent 1995) suggests a depositional age of 16 Ma (younger than chron C5Cn.1n) to 5.2 Ma (around the top of chron C3r) for the 3560 m section sampled. Hence, the Karnali River exposes the oldest part of the Siwalik Group in Nepal. Estimates of the sediment accumulation rate (SAR) average to 32.9 cm kyr−1 for the 10.8 Myr time span of deposition.

Magnetic minerals and magnetic properties of the Siwalik Group sediments of the Karnali river section in Nepal

Sandstones and siltstones collected from the Siwalik molasse sequence (~ 16 to 5 Ma) of the Karnali river section have been studied for their magnetic properties. Behavior of the specimens during demagnetization (of the NRM and IRM) and magnetic susceptibility vs. temperature data suggest that goethite, maghemite/magnetite, and hematite are the main magnetic minerals in the section. Goethite, carrying a recent component, is the dominant magnetic mineral in the fine-grained lithologies from the lower part. Maghemite and magnetite, which also carry a secondary remanence, occur in the sandstones from the upper part. Hematite, mainly of detrital origin, is present in the whole sequence. The magnetic fabric is defined by mainly oblate AMS ellipsoids and a low degree of anisotropy (P′ < 1.20). The magnetic lineations (declinations: 75°–130° or 245°–310°; peak orientation: 290°/2.8°) are subparallel to the fold axes/bedding strikes/thrust fronts (WNW-ESE). The initial sedimentary-compactional fabric has been overprinted by a secondary tectonic fabric, which was probably induced by mild deformation active in the compressive tectonic setting.

Rainfall network design using the kriging technique: A case study of Karnali river basin, Nepal

Abstract Spatial variation structure of monthly and annual mean precipitation in the Karnali river basin, Nepal has been analysed by using kriging. The physiographic and climatological features of the basin are presented in sufficient detail to better understand the spatial and temporal variation pattern of the precipitation within the basin. The concept of ‘regionalized variables’ and the theory of kriging have been introduced. Based on the spatial variability of the precipitation obtained by kriging, a methodology has been developed for selecting the best locations for a given number of rain gauges planned to be added in a network. It has been demonstrated that kriging can be of valuable use in identifying the optimal locations for a set of additional rain gauges using kriging standard deviation as an indicator. The results obtained from kriging are realistic to the extent that the stationarity assumptions are true. Quantification of error nevertheless makes it possible to select locations of rain gauge...