Dhruv Sen Singh

Upland interfluve (Doab) deposition: Alternative model to muddy overbank deposits

SummaryMajor alluvial plains contain large tracts of fine-grained muddy sediments, deposited away from the main river channels, which are mostly classed as overbank or floodplain deposits. Systematic study of the Ganga plain shows that such large tracts of deposition of muddy sediments are located several metres above the major channels, and are not flooded by overtopping of the major river channels. These surfaces are here designated as upland interfluve areas (Doab) where deposition of fine-grained sediments takes place independent of the processes operating in the main channels. The surfaces show distinct depositional domains with characteristic deposits. These include higher sloping surfaces (mottled silt), lower flat surfaces (variegated clayey silt), gulleys (sandy silt), small channels (mottled silty sand), ponds (shelly sandy clayey silt), lakes (shelly clayey silt). These deposits are prone to diagenetic changes, especially the development of calcrete horizons. Redistribution of these domains through time produces characteristic mud-dominant alluvial stratigraphy as observed in the Late Quaternary deposits of the Ganga plain. This succession shows similarity to mud-dominant deposits of the Siwalik succession. These Doab deposits are distinct from the overbank deposits formed close to the river channels affected by channel processes. It is argued that many of the thick mud-dominant fluvial deposits of the ancient fluvial record are products of deposition in upland interfluve areas.

Environmental repercussions of cane-sugar industries on the Chhoti Gandak river basin, Ganga Plain, India

Chhoti Gandak river basin, situated in the Ganga Plain, is one of India’s most productive cane-sugar industrial belts. Soil and groundwater samples were collected to investigate the impacts of these industries on the environment of the Chhoti Gandak river basin with special reference to soil and water. The results show that concentration of most metals are affected by industrial activities and surrounding agricultural practices. It is evidenced by increased heavy metal concentration in the soils as well as in the aquifers. Metals such as Pb, Cu, and Zn in the soil around the industrial sets are found significantly higher than their normal values in the soil. Metals like Fe and Mn in the groundwater are more than the permissible limit prescribed by the World Health Organization. In this study, an attempt was made to distinguish between the naturally occurring and anthropogenically induced metals in the soil. Analysis of geochemical properties, disposal of industrial wastes, inadequate application of agrochemicals, and their impact on environment indicate the sustainable implementation of integrated wastewater management plan in these industrial sets and also in similar situations.

Climatically induced levee break and flood risk management of the Gorakhpur region, Rapti River basin, Ganga Plain, India

A densely populated city, Gorakhpur, located on the bank of Rapti river in the Ganga plain, is frequently affected by flooding. The Rapti river exhibits narrow channel within wide valley, channel bars, natural levee and river terraces. Artificial levees are constructed in the valley during low discharge period to mitigate the flood and also to provide the additional land to the society. These levees break during prolonged heavy rain and induce the catastrophic flood because it is not constructed by analyzing the capacity of the bracketed channel to accommodate the high discharge of the river. The precipitation, discharge, sediment load, and river water levels are correlated by making graphs between these parameters to analyze and identify the threshold limits and main reasons for flood. It explains that discharge and sediment load increases with precipitation during monsoon season, whereas the water storage capacity of the river decreases due to siltation and artificial levee. Hence, during heavy rain in this region, water rises in the channel, which either overtops the bank or breaks the levee and creates the flood.Flood inundation map was prepared using GIS techniques from 70 m base level to 81.5 m high level, which indicate the inundated area with every 1–2.5 m rise in the Rapti river water level. Rating curves and flood frequency curves have been prepared to identify the recurrence interval for major floods. It is concluded that prolong heavy precipitation, discharge variability of the river, siltation in the river bed, artificial levee, and anthropogenic impacts on younger river terraces and river valley leads to flood. Its affect is devastating when water level, discharge and sediment loads are above 77 m, 5000 m3/sec, and 5 metric tones respectively. The flood inundation map and recurrence interval are useful parameters for flood risk management, whereas the upland terrace is flood-free surface suitable for settlement. This study can be used as a model for other flood prone regions.

Discovery of Elephas cf. namadicus from the late Pleistocene strata of Marginal Ganga Plain

We describe an elephant skull recovered from a cliff section of Dhasan river of Marginal Ganga Plain. The dental morphology and cranial features of the skull have been compared with the known species of Elephas from the Indian subcontinent. Although it shows very near resemblance to Elephas namadicus, but being an isolated specimen its specific identity cannot be proclaimed with certainty. As such, the specimen is provisionally referred as E. cf. namadicus. The Optically Stimulated Luminescence ages place this find at ~56 ka BP. This is the first chronologically well constrained report of E. cf. namadicus from the Ganga Plain.

Mercury exposure in sporadic amyotrophic lateral sclerosis patients from Ganga plain region in India: A retrospective study

Amyotrophic lateral sclerosis (ALS), a progressive disorder that usually runs a fatal course within 2–5 years of onset, is characterized by loss of motor neurons in the cortex, brain stem, and spinal cord. In this study mercury (Hg) concentrations were determined in blood samples of 40 ALS patients, of whom 24 ALS patients were from the Ganga plain region and their metal levels were found to be significantly higher. In contrast, Hg levels in the 16 ALS patients from non-Ganga plain regions whose levels were similar to those of the control subjects. Mercury in stream water samples and freshly deposited stream sediment were determined in the locations of patients’ native residences along the Ganga plain region and metal levels were found to be higher than the threshold guideline values for Hg in stream waters recommended by WHO. The geo-accumulation index in selected sites of freshly deposited stream sediment ranged from moderate to highly polluted. The high levels of Hg observed in ALS patients may potentially alter the redox status of neuronal cell components and induce cell-death pathways.

The Yamuna River: Longest Tributary of Ganga

Yamuna is the main and the longest right bank tributary of river Ganga. It is a snow-fed, braided river which rises from Yamunotri glacier near Banderpoonch peak of the higher Himalaya. After travelling a distance of about 1370 km through Ponta Sahib, Karnal, Panipat, Sonipat, New Delhi, Mathura, Agra, Etawah, Kalpi, Hamirpur and Mau, it joins the Ganga River at Allahabad. The Gambhir, Chambal, Sind, Betwa, Ken, Hindon, Karwan, Sirsa, Arind, Gambhir and Chambal are important tributaries. It is the only major river of India which receives the water and sediments from all physiographic features of India such as the Himalaya, Ganga Plain and the Peninsular Plateau.

The Great Gandak River: A Place of First Republic and Oldest University in the World

The Great Gandak is a snow-fed braided river which originates from the Nhubine Himal glacier. It is a major left bank tributary of Ganga River. After travelling a distance of about 300 km through West Champaran, East Champaran, Muzaffarpur, Gopalganj, Siwan, Saran, Vaishali and Hajipur in the alluvial plain region, it joins the river Ganga at Hajipur near Patna. Locally, it is known as Narayani because it brings the Shaligram known as Lord Vishnu in Hindu religion. The Gandak River canals provide the water for irrigation to India and Nepal. The valley of the Great Gandak is very wide, and at some places, it splits into two and then rejoins. It causes flood and lateral erosion almost every year and affects the society. The oldest university of the world Vaishali and Nalanda and the first republic of the world Vaishali are located at its bank.

Subansiri: Largest Tributary of Brahmaputra River, Northeast India

Subansiri River, a major tributary of the Brahmaputra River in the northeastern part of India, has been analyzed in detail for various studies. This chapter describes the origin and course of river, geology, major land use and land cover classification, and soil types of the river basin. It also includes the geological, geomorphological, and climatic characteristics of the Subansiri River basin. It originates in the Tibet Plateau and is the largest tributary of Brahmaputra River. The maximum elevation of the river basin is 5340 m near origin and minimum 99 m at Gerukamukh near Assam plain. The high topographic variation makes this river a potential zone for harnessing it for the hydropower. The districts situated on the bank of Subansiri River are flood prone during monsoon season. A case study on the hydrological modeling of the river basin has also been presented to assess the major parameters governing the streamflow.

Concept of Rivers: An Introduction for Scientific and Socioeconomic Aspects

Rivers, our lifeline have served as a way of life for many ancient civilizations. There are varieties of rivers in the world depending on the climate, tectonics and physiography. India exhibits different types of rivers such as snow fed, groundwater fed, and rain fed located in the Himalayas, Peninsular Plateau, and Ganga Plain and so the rivers have been classified on various criteria. These natural resource provide hydroelectric power, fertile soil, and water for the survival of society and also to the agrarian economy of India. River related scientific terminologies and geomorphic features have been described to understand the rivers in a better way. The river-related problems such as impact of climate change, river-borne hazards, and the river linking have been described in brief.

The Gomati River: Lifeline of Central Ganga Plain

Gomati is the sixth order groundwater-fed tributary of Ganga River and lifeline of the Central Ganga Plain region. The total catchment area of the Gomati River basin is more than 30,000 km2. It has three regional geomorphic surfaces T0, T1, and T2. The alluvium of the Gomati River basin is very fertile and favorable for all type of seasonal crop, i.e., Rabi, Kharif and Jayad. The monsoon season plays a major role in the water and sediment supply of the Gomati River. Urbanization, industrialization, and deforestation are adversely affecting the qualitative and quantitative changes of the water of the Gomati River. The pollution level of the Gomati River has already reached the critical limit and a water quality does not match with the drinking water standard of WHO. At present, Gomati River is on alarming stage not only for pollution but for its own existence as well and needs proper management and action.