Ganga Plain Research Articles

Book Review: Sheena Panja, Arun K. Nag and Sunando Bandyopadhyay, Living with Floods: Archaeology of a Settlement in the Lower Ganga Plains, c. 600–1800 CE

Book Review: Sheena Panja, Arun K. Nag and Sunando Bandyopadhyay, <i>Living with Floods: Archaeology of a Settlement in the Lower Ganga Plains, c. 600–1800 CE</i>

Micro-Tremor Induced Gravity and Seismic Noise Spectra in the Garhwal Himalaya and the Adjoining Regions

ABSTRACT The characteristic site response spectra of soft sedimentary rocks in the Garhwal Himalaya and a few localities in the adjoining Ganga plain and Himachal Himalaya have been studied through short period passive seismic source experiment using ambient noise data. Along with this, stand-alone temporal gravity data in the Doon valley was also acquired. It has been observed that there exist two extreme frequency bands in the gravity and seismic response spectra of alluvial soft sediments in the Doon valley and the adjoining regions, when it subjected to micro-seismic and gravity-tidal oscillation. The concept of damped harmonic oscillator was used to study the fundamental long period modes in the density driven diffusive fluid flow in the valley alluvial pore spaces, and observed that the flow was continued from minutes to a few days. In this case, apart from the diurnal component, the observed fundamental modes are in the bands from 0.42 to 1.83 days. The characteristic frequencies of seismic response spectra for the fundamental modes of thick soft sediments were also studied using the spectral ratio (HVSR) method of Nakamura. In the Ganga basin, a moderate resonant frequency of 3 Hz is sufficient for thick soft sediment to cause relatively large vertical amplitude, which suggest possibility for sub-surface secondary seismic effects like liquefaction. However, the hard rock terrains in the lesser Himalaya, where only a veneer of soft sediment is present, show relatively high frequency values of 15 to 18 Hz even to produce an H/V amplitude ratio of 1 and 1.7 and hence could be considered as relatively stable.

Long-term aerosol climatology over Indo-Gangetic Plain: Trend, prediction and potential source fields

Long-term aerosol climatology is derived using Terra MODIS (Collection 6) enhanced Deep Blue (DB) AOD retrieval algorithm to investigate decadal trend (2006–2015) in columnar aerosol loading, future scenarios and potential source fields over the Indo-Gangetic Plain (IGP), South Asia. Satellite based aerosol climatology was analyzed in two contexts: for the entire IGP considering area weighted mean AOD and for nine individual stations located at upper (Karachi, Multan, Lahore), central (Delhi, Kanpur, Varanasi, Patna) and lower IGP (Kolkata, Dhaka). A comparatively high aerosol loading (AOD: 0.50 ± 0.25) was evident over IGP with a statistically insignificant increasing trend of 0.002 year−1. Analysis highlights the existing spatial and temporal gradients in aerosol loading with stations over central IGP like Varanasi (decadal mean AOD±SD; 0.67 ± 0.28) and Patna (0.65 ± 0.30) exhibit the highest AOD, followed by stations over lower IGP (Kolkata: 0.58 ± 0.21; Dhaka: 0.60 ± 0.24), with a statistically significant increasing trend (0.0174–0.0206 year−1). In contrast, stations over upper IGP reveal a comparatively low aerosol loading, having an insignificant increasing trend. Variation in AOD across IGP is found to be mainly influenced by seasonality and topography. A distinct “aerosol pool” region over eastern part of Ganges plain is identified, where meteorology, topography, and aerosol sources favor the persistence of airborne particulates. A strong seasonality in aerosol loading and types is also witnessed, with high AOD and dominance of fine particulates over central to lower IGP, especially during post-monsoon and winter. The time series analyses by autoregressive integrated moving average (ARIMA) indicate contrasting patterns in randomness of AOD over individual stations with better performance especially over central IGP. Concentration weighted trajectory analyses identify the crucial contributions of western dry regions and partial contributions from central Highlands and north-eastern India, in regulating AOD over stations across IGP. Although our analyses provide some attributes to the observed changes in aerosol loading, we conclude that the spatial and temporal pattern of aerosol properties is highly complex and dynamic over IGP, and require further investigation in order to reduce uncertainty in aerosol-climate model.

Micromorphology and Sequence Stratigraphy of the Interfluve Paleosols from the Ganga Plains: a Record of Alluvial Cyclicity and Paleoclimate During the Late Quaternary

Micromorphology and Sequence Stratigraphy of the Interfluve Paleosols from the Ganga Plains: a Record of Alluvial Cyclicity and Paleoclimate During the Late Quaternary

Spatial Distribution of Pollution Indexes of Heavy Metals in Road Dust Associated With Different Landuse Types in an Urban Centre of Central Ganga Plain, India

Spatial Distribution of Pollution Indexes of Heavy Metals in Road Dust Associated With Different Landuse Types in an Urban Centre of Central Ganga Plain, India

Pollen based vegetation and climate change records deduced from the lacustrine sediments of Kikar Tal (Lake), Central Ganga Plain, India

A 2.0 m thick sediment profile from Kikar Tal, Raebareli District is studied for the pollen assemblage to infer the vegetation and climate variability scenario during the Holocene period. Four distinct palynozones were demarcated based on the palynological succession in the core sediment. However, the radiocarbon dates for the profile could not be procured; therefore, the lake profile is corroborated with the chronology of adjacent lake ‘Chaudhary–Ka–Tal’, Raebareli District. It is envisaged that during 8,000–7,200 cal yrs BP, (Pollen Zone KT–I), forest groves with Holoptelea, Acacia, Madhuca indica, Syzygium and Prosopis as major tree taxa were present in the adjoining area of the lake. The forest groves were interspersed with wider stretches of open vegetation comprising grasses, Tubuliflorae, Liguliflorae, Chenopodiaceae/Amaranthaceae, etc. and shrubs of Adhatoda vasica and Acanthaceae. This vegetation scenario reflects that the region was under a warm and humid climate during that time. The existence of lake is also envisaged by the presence of aquatic elements, Lemna and Typha. Subsequently, during 7,200–4,200 cal yrs BP (Pollen Zone KT–II), the forest groves became more diversified and dense in composition as evidenced by the expansion of most of the existing trees as well as presence of Emblica officinalis, Aegle, Adina cordifolia, Symplocos and Sapotaceae and thickets of Adhatoda vasica and Mimosa pudica. This significant change in the vegetation mosaic as a whole implies the initiation of a warm and more–humid climatic condition, owing to climate amelioration. The encounter of Cerealia and concomitant cropland weeds, viz. Cheno/Am. Cannabis sativa, Brassica, etc. suggests that the vicinity of the lake was under agrarian practice and other anthropogenic activities. The ground flora was still dominated by grasses; however, it also turned more profuse than before. The increasing trend of Cerealia coupled with concomitant cropland weeds signifies the augmentation in Cereal–based agrarian practice owing to favourable climatic condition. The lake expanded as manifested by the increase in aquatic elements, such as Typha, Potamogeton and Lemna during this period. During the time bracket of 4,200–1,800 cal yrs BP (Pollen Zone KT–III), the arboreals reveal a decrease in their frequency and diversity of major tree taxa with incursion of Moringa and Bombax ceiba suggesting warm and moderately humid climate with reduced monsoon. The last zone (Pollen Zone KT–IV), from 1,800 cal yrs BP–Present, elucidates open grassland vegetation corresponding to reduced monsoon precipitation, with the shrinkage of lake area. The presence of Cerealia and other culture pollen taxa suggests the prevalence of intense agrarian practice in the vicinity of the lake.

Tectonic forcing of evolution and Holocene erosion rate of ravines in the Marginal Ganga Plain, India

Understanding the processes of ravine formation and estimates of Specific Sediment Yields (SSY) of these regions help in formulating mitigation policies significantly. Upto now, in the Ganga Plain, the work done on ravine formation, erosion and SSY estimates has been speculative. Here, utilizing (i) high resolution Digital Elevation Models (DEMs) prepared from Real Time Kinematic (RTK) survey and CARTOSAT images of ravined zones and (ii) luminescence chronology, we provide the first estimate of SSY from the ravines. The results indicate that SSY in the Marginal Ganga Plain (MGP) ravines may range between 600 ± 100t/km2/yr and 1600 ± 200t/km2/yr.The correspondence between the orientations of fractures and that of first order ravine suggests that the ravine growth is genetically related to extensional stress regime of the peripheral forebulge. Further, the clay sedimentology indicates that besides regional tectonics, action of swelling clays may have accelerated development of the badlands. The geomorphic relationship between the length of ravined catchments and incision in the trunk channels indicates that the river-incision associated base level change is not playing an overarching role in the ravine formation in the MGP.

Integrating channel form and processes in the Gangetic plains rivers: Implications for geomorphic diversity

Geomorphic diversity at a variety of spatial and temporal scales has been studied in the western Ganga plains (WGP), India, to isolate the dominating factors at each scale that have the potential to cause major geomorphic change. The Ganga River and its major tributaries draining the WGP have been investigated in terms of longitudinal, cross-sectional, and planform morphology to assess the influence of potential controls such as climate, geology, topography, land use, hydrology, and sediment transport. These data were then compared with those from the rivers draining the eastern Ganga plains (EGP) to understand the geomorphic diversity across the Ganga plains and the causal factors. Our investigations suggest that in-channel geomorphic diversity over decadal scale in rivers with low width-to-depth (W/D) ratio is caused by periodic incision/aggradation, but it is driven by channel avulsion in rivers characterized by high W/D ratio. Similarly, planform (reach-scale) parameters such as sinuosity and braid-channel-ratio are influenced by intrinsic factors such as changes in hydrological conditions and morphodynamics (cutoffs, small-scale avulsion) that are in turn impacted by natural and human-induced factors. Finally, we have isolated the climatic and hydrologic effects on the longitudinal profile concavity of alluvial trunk channels in tectonically stable and unstable landscapes. We demonstrate that the rivers flowing through a tectonically stable landscape are graded in nature where higher discharge tends to create more concave longitudinal profiles compared to those in tectonically unstable landscape at 103-year scale.

Seismic Response of the Central Part of Indo-Gangetic Plain

ABSTRACTIn spite of high seismic risk, there is no numerical model of Indo-Gangetic Plain. In this paper, seismic response of the central part of Indo-Gangetic Plain, i.e., Ganga Plain is studied using a two-dimensional plane strain finite element model. Seismic source is assumed to be located beneath the Himalayas near Himalayan Frontal Thrust. Basin response is simulated for a hypothetical Mw 8.0 Himalayan earthquake. Ground motion amplification and sensitive frequency band of the basin, obtained from the numerical simulation, show that the sediment depth and epicentral distance at a site play significant role in the seismic response of the site.

Processes and Status of Land Degradation in a Plateau Fringe Region of Tropical Environment

The concept of land degradation means a temporary or permanent long-term decline in an ecosystem function and its productive capacity. Land degradation is the result of numerous factors or a combination thereof, including physical (climate change, soil degradation) as well as anthropogenic activities such as unsustainable land management practices. The present study primarily concerns the processes and status of land degradation in a part of the eastern Chotanagpur Plateau, India. The basin falls under the transitional zone, is undulating in nature and situated between the Chotanagpur Plateau area in the west and the greater Ganga plain area in the east. Largely, the basin falls under the Ganga River system. The major part of the population (>70%) of the area is dependent on agriculture which is largely affected by land degradation as well as soil erosion processes. The status of land degradation is estimated from different physical factors (geology, soil, geomorphology, slope, relief, groundwater, drainage density, rainfall intensity, green biomass cover) as well as anthropogenic factors (land use land cover change, population pressure on agricultural land, deforestation, irrigation intensity etc.). All these factors have been weighted with considerable importance to show the resultant varying intensities of land degradation. The different factor weighted raster has been multiplied in the GIS environment. The different vulnerable land degradation areas have been identified on the basis of the final weighted value. It has been shown that the upper reaches of the basin is considerably more prone to degradation due to its rugged topography, poor soil development and high drainage density. In the lower reaches of the Silabati River, the left bank is characterized by a high degreee of slope whereas the right bank shows intensive agricultural density, which couple up, to cause medium to high degree of land degradation vulnerability.

Pollen Rain Vis-à-Vis Vegetation Relationship in Kikar Tal (Lake), Raebareli District, Uttar Pradesh, Central Ganga Plain

Pollen Rain Vis-à-Vis Vegetation Relationship in Kikar Tal (Lake), Raebareli District, Uttar Pradesh, Central Ganga Plain

Morphometric assessment of Gomati river basin, middle Ganga plain, Uttar Pradesh, North India

The Gomati river is draining through the interfluves areas between Ganga and Ghaghra river, which is northern part of Indo-Gangetic foreland basin. The Gomati river basin passes through many stages of degradation and aggradations influenced by subsurface tectonic (neo) activities, base-level changes and climatic variability over time and space. The Gomati river basin covers an area of about 30,843 sq km in the middle Ganga plain. The quantitative approach of basin prioritization of the Gomati river and its four fifth-order sub-basin (SUB1–SUB4) was carried out by the morphometric parameters using LANDSAT and SRTM data. Drainage patterns are mainly in sub-dendritic to dendritic type which indicates that the Gomati river follows the natural gradient of the terrain. It is also observed that the low drainage density values of sub-basins indicate that the basins have highly permeable subsoil and thick vegetative cover. The circularity ratio value reveals that the basin is strongly elongated. The asymmetric factor, transverse topography asymmetry and profile section analysis reflect the tilt and upliftment of Gomati basin, signifying the tectonic control on the Gomati basin especially towards the confluence part. This study would help to utilize the water resources and prioritization for sustainable development of the Gomati basin area.

Soft sediment deformation associated with the East Patna Fault south of the Ganga River, northern India: Influence of the Himalayan tectonics on the southern Ganga plain

The geomorphic, tectonic and seismic aspects of the Ganga plain have been studied by several workers in the recent decades. However, the northern part of this tectonically active plain has been the prime focus in most of the studies. The region to the south of the Ganga River requires necessary attention, especially, regarding the seismic activities. The region lying immediately south of the Outer Himalayas (i.e. the Ganga plain) responds to the stress regime of the Himalayan Frontal Thrust Zone by movement along the existing basement faults (extending from the Indian Peninsula) and creating new surface faults within the sediment cover as well. As a result, several earthquakes have been recorded along these basement faults, such as the great earthquakes of 1934 and 1988 associated with the East Patna Fault. Large zones of ground failure and liquefaction in north Bihar (close to the Himalayan front), have been recorded associated with these earthquakes. The present study reports the soft sediment deformation structures from the south Bihar associated with the prehistoric earthquakes near the East Patna Fault for the first time.The seismites have been observed in the riverine sand bed of the Dardha River close to the East Patna Fault. Several types of liquefaction-induced deformation structures such as pillar and pocket structure, thixotropic wedge, liquefaction cusps and other water escape structures have been identified.The location of the observed seismites within the deformed zone of the East Patna Fault clearly indicates their formation due to activities along this fault. However, the distance of the liquefaction site from the recorded epicenters suggests its dissociation with the recorded earthquakes so far and hence possibly relates to any prehistoric seismic event. The occurrence of the earthquakes of a magnitude capable of forming liquefaction structure in the southern Ganga plain indicates the transfer of stress regime far from the Himalayan front into the peninsular region through these basement faults. Northward extension of the East Patna Fault coincides with the region of the Himalayan front, which corresponds to a less slip potential. Therefore, an association of frequent earthquakes in this region indicates strain release along the East Patna Fault.

Abrasion-set limits on Himalayan gravel flux

Rivers sourced in the Himalayan mountain range carry some of the largest sediment loads on the planet, yet coarse gravel in these rivers vanishes within approximately 10-40 kilometres on entering the Ganga Plain (the part of the North Indian River Plain containing the Ganges River). Understanding the fate of gravel is important for forecasting the response of rivers to large influxes of sediment triggered by earthquakes or storms. Rapid increase in gravel flux and subsequent channel bed aggradation (that is, sediment deposition by a river) following the 1999 Chi-Chi and 2008 Wenchuan earthquakes reduced channel capacity and increased flood inundation. Here we present an analysis of fan geometry, sediment grain size and lithology in the Ganga Basin. We find that the gravel fluxes from rivers draining the central Himalayan mountains, with upstream catchment areas ranging from about 350 to 50,000 square kilometres, are comparable. Our results show that abrasion of gravel during fluvial transport can explain this observation; most of the gravel sourced more than 100 kilometres upstream is converted into sand by the time it reaches the Ganga Plain. These findings indicate that earthquake-induced sediment pulses sourced from the Greater Himalayas, such as that following the 2015 Gorkha earthquake, are unlikely to drive increased gravel aggradation at the mountain front. Instead, we suggest that the sediment influx should result in an elevated sand flux, leading to distinct patterns of aggradation and flood risk in the densely populated, low-relief Ganga Plain.

Living with Floods:Archaeology of a Settlement in the Lower Ganga Plains, c. 600–1800 CE

Settlements on river banks are subject to seasonal floods that are recurrent during the peak of monsoon over the Indian subcontinent. Though the intensity of monsoon floods varies from region to region, some areas are prone to intense annual floods. The Ganga-Brahmaputra (G-B) Basin is known for such catastrophic events which are triggered by the monsoon system over the subcontinent, particularly during the southwest monsoon season.

Late Quaternary climatic variability in the Central Ganga Plain: A multi-proxy record from Karela Jheel (Lake)

A multi-proxy study involving phytoliths, diatoms, thecamoebians and sponge spicules was carried out on a trench profile (260 cm deep) from Karela Lake in the Central Ganga Plain to reconstruct climatic variations since ca. 17,000 cal BP. The testate amoebae record indicate spells of winter monsoon between ca. 17,000 cal BP and 13,700 cal BP. Increased diversity of diatoms, testate amoebae and sponge spicules, in addition to low Humidity/Aridity Index (Iph) values suggest strengthened monsoon inducing the expansion of lake margin and high primary productivity during ca. 13,700 to 4300 cal BP. Further between ca. 4300 and 2900 cal BP, higher Iph values and related responses of other studied proxies show a stressed lake ecosystem. Since ca. 2900 cal BP, area of the lake was reduced responding to low intensity of the Indian Summer Monsoon. Anthropogenic activities may also have played a role in the lake shrinking at least during some parts of this duration.

Erratum to: Bank vulnerability and avulsion modeling of the Bhagirathi-Hugli river between Ajay and Jalangi confluences in lower Ganga Plain, India

Erratum to: Bank vulnerability and avulsion modeling of the Bhagirathi-Hugli river between Ajay and Jalangi confluences in lower Ganga Plain, India

Households at Work: An Ethnoarchaeological Study of Variation in Ceramic Production in North India

ABSTRACTThis ethnoarchaeological study, carried out in the Upper Ganga Plains of North India, contributes to our understanding of the variation that exists in the organization of household ceramic production. The paper describes techniques, tools and facilities; division of work/tasks; location of production; range of products; differences in the scale and intensity of production between rural and urban households; and interweaves the archaeological implications in relation to the locus of production, scale, intensity and specialization.

Linking hydrology and sediment dynamics of large alluvial rivers to landscape diversity in the Ganga dispersal system, India

AbstractDischarge and sediment load data for several stations along the Ganga River and its major tributaries in the western Ganga plains (WGP) for a period of ~30 years have been analysed to understand the hydrological characteristics and sediment dynamics. In terms of hydrology, the rivers are less flood‐prone than believed, exceeding bankfull discharges less frequently than the expected 1.5 year return interval. This has been attributed to the rivers of this region occupying incised valleys formed in the Late Quaternary period. Rivers draining the WGP are supply‐limited systems compared to those draining the eastern Ganga plains (EGP) which have been characterized as transport‐limited systems. We suggest that such geomorphic diversity as a function of spatial variability in precipitation regime and hinterland geology has existed for at least the Late Quaternary period and they in turn influence the modern day hydrology of the river systems in a significant way. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Sheena Panja , Arun K. Nag &amp; Sunando Bandhopadhyay . Living with floods: archaeology of a settlement in the Lower Ganga Plains, c. 600–1800 CE. 2015. xvi+292 pages, numerous colour and b&amp;w illustrations. Delhi: Primus; 978-93-84082-59-8 hardback INR 1900.

Sheena Panja , Arun K. Nag &amp; Sunando Bandhopadhyay . Living with floods: archaeology of a settlement in the Lower Ganga Plains, <i>c.</i> 600–1800 CE. 2015. xvi+292 pages, numerous colour and b&amp;w illustrations. Delhi: Primus; 978-93-84082-59-8 hardback INR 1900.