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During their flow through an area, the streams are used to erode, transport and re-deposit sediments in the number of cycles following the climatic variation in an area. This cycle in turn affect the chemistry of these sediments and hence the geochemical study of these sediments helps to understand the palaeo-climate, source-area weathering and provenance of the study area. In order to understand the geochemical classification of sediments, palaeo-climate, source-area weathering and provenance for stream sediments of the Eastern Ghats Mobile Belt (EGMB), 364 stream sediment samples were collected from the area around Daringbadi, Kandhamal district, Odisha, India and analyzed for major oxides, trace elements and rare earth elements. These sediments are geochemically classified as shaly and wacke type, moderately mature and derived through the high intensity of weathering of source rock under warm and humid climatic condition. The positive correlation between Al2O3 and Fe2O3, MnO, and MgO, indicates multiple sources for sediment and these oxides are associated with clay minerals. The discrimination function diagram suggests a felsic igneous as well as quartzo-sedimentary provenance for these sediments whereas the ratio of Al2O3/TiO2 and concentration of V-Ni-Th suggest a felsic igneous source rock. The high concentration of LREE, slight enrichment of HREE and negative Eu anomaly indicate terrestrial or continental crust source rock. Hence the source rock for these sediments are granite gneiss, charnokite and khondalite present in and around Daringbadi area. [ABSTRACT FROM AUTHOR]

Black, K.P.; Baba, M.; Mathew, J.; Kurian, N.P., and Ilic, A., 2021. Guidelines to prepare India's coast for climate change. Journal of Coastal Research, 37(6), 1117–1129. Coconut Creek (Florida), ISSN 0749-0208. India's first coastal protection guidelines for climate-change adaptation are described. The guidelines are holistic, recognizing the links between engineering, economic, physical, legal, social, environmental, and governmental intricacies. Robust protection solutions under climate change for millions of coastal residents may occur only when all these facets are improved within the complex regulatory, budgetary, and practical circumstances in India. Fifty-seven specific guidelines are presented in nine categories ranging from administrative to best-practice coastal protection. An "environmental softness ladder" that ranks coastal protection methods was developed as a scientific tool to guide policy development and project implementation. "Minimum floor level" for safe building was defined for each Indian coastal state using climate-change data produced for the study by Indian and international institutes. Beaches are more stable when the net sediment transport fluxes are close to neutral. "Grand schemes," which make large-scale changes to the coast rather than continuing with piecemeal localised works, are recommended. With diverse dynamics over a long coastline in India, the 4-year study engaged an exceptionally large number of experts, agencies, government bodies, development partners, and other stakeholders. [ABSTRACT FROM AUTHOR]

Impact of climate change on glaciers brings the favorable conditions of lakes formation within glacier moraines. These lakes may produce outburst floods and transport the huge amount of debris (debris flow) in downstream settlements. The present study addresses the current knowledge on mass movement activity occurred in the Gangotri glacier area, Garhwal Himalaya Uttarakhand. Temporal response (terminus retreat and frontal area loss) of Meru glacier during 1976–2019 using the images of Landsat (MSS, 1976; TM, 1990, 2011; ETM+, 2001; OLI, 2019) and event of intense mass movement occurred along Meru glacier during 2017 is assessed. Our estimations clearly reveals that the Meru glacier is retreating continuously since 1976 with inconsistent rate. Considering the time span 1976–1990, 1990–2001, 2001–2011, 2011–2019 the terminus receded with 12.42 m y−1, 7.72 m y−1, 6.00 m y−1, 11.50 m y−1 and vacated the frontal area at the rate of 2330.70 m2 y-1, 2185.88 m2 y-1, 1425.18 m2 y-1, 1452.66 m2 y-1 respectively. Field observations and high resolution imagery of LISS IV suggest that the lower area of Meru glacier experienced the event of intense mass movement in July, 2017. This event breached the continuity of left morainic wall of Bhagirathi valley. This mass movement event influenced the initial course of Bhagirathi River (~1559 m length) and also modified the morphology of the Gaumukh region. The precipitation data from Indian Meteorological Department (IMD) and satellite images of different years suggest that the multiple factors such as intense precipitation, large amount of sediment transport from the upper reaches to lower area, slope failure, collapse of frontal part of Meru glacier were the main causative factors for this event. [ABSTRACT FROM AUTHOR]

Abstract: We present new major and trace element data, together with U–Pb ages for zircon sand grains from the major tributaries of the Indus River, as well as the adjacent Ghaggar and Yamuna Rivers and from bedrocks within the Sutlej Valley, in order to constrain the origin of the sediment reaching the Arabian Sea. Zircon grains from the upper Indus are generally younger than 200Ma and contrast with those from the eastern tributaries eroded from Himalayan sources. Grains younger than 15Ma, which typify the Nanga Parbat Massif, comprise no more than 1–2% of the total, even in the upper Indus, showing that this terrain is not a major sediment producer, in contrast with the Namche Barwe Massif in the eastern Himalayan syntaxis. The Sutlej and Yamuna Rivers in particular are very rich in Lesser Himalayan-derived 1500–2300Ma zircons, while the Chenab is dominated by 750–1250Ma zircons, mostly eroded from the Greater Himalaya. The upper Indus, Chenab and Ravi yield zircon populations broadly consistent with the outcrop areas, but the Jhelum and the Sutlej contain many more 1500–2300Ma zircons than would be predicted from the area of Lesser Himalayan rock within their drainages. A significant population of grains younger than 200Ma in the sands of the Thar Desert indicates preferential eolian, monsoon-related transport from the Indus lower reaches, rather than reworking from the local rivers. Modelling of observed zircon ages close to the delta contrasts with modern water discharge. The delta is rich in zircons dating 1500–2300Ma, while discharge from modern rivers carrying such grains is low. The modest size of the Sutlej, the richest source of these materials in the modern system, raises the possibility that the compositionally similar Yamuna used to flow westwards in the recent past. Our data indicate a non-steady state river with zircon transport times of 5–10k.y. inferred from earlier zircon dating of delta sands. The modern delta zircons image an earlier, likely Early-Mid Holocene, erosional state, in which the Lesser Himalaya were more important as sediment suppliers. Early-Mid Holocene sands show much less erosion from the Karakoram–Transhimalaya compared to those deposited at the Last Glacial Maximum, or calculated from the modern discharge. We favour variations in summer monsoon intensity as the primary cause of these temporal changes. [Copyright &y& Elsevier]

In order to have an understanding of the coastal processes along the southwest coast of India (8u49 N, 77u 339 E to 8u139 N, 77u149 E), a data set available for the changes in beach width for a period of 5 years (1993-1998) over a length of about 50 km was categorized and analysed in relation to the seasons. Since the study area is densely populated and was also affected partially by the great Indian Ocean tsunami, a freshmeasurement campaign of beach profile changes up to a water depth of 6 m at four different locations along the coast was carried out. These measurements have been adopted to validate a finite difference-based numerical model that employs the empirical formulation of Larson and Kraus (1989) for the prediction of beach profile changes. We simulated the offshore wave climate from National Centre for Environmental Prediction wind data using the Wave AnalysisModel (WAM), whereas the nearshore wave climate was derived by adopting theMIKE21 ParabolicMild Slope module. Results compared well with each other. The prediction from the numerical model revealed that the average onshore-offshore transport varies from about 50 to 200 m3 y21m21 width of the beach. [ABSTRACT FROM AUTHOR]

• Hydrology and sediment supply in regulated Godavari R., India simulated using SWAT. • Simulations illustrate importance of reservoirs in distributed hydrologic modelling. • Geomorphic stability index computed from pre/post- dam flow and sediment transport. • Observed incision is related to the simulated geomorphic stability index. • Climate change could move rivers below existing dams toward states of net erosion. Long-term geomorphic evolution of rivers depends both on the amount of sediment supply and on the river's ability to transport that sediment. Climate change is anticipated to change flow frequency distributions and sediment yield and could thus alter the geomorphic trajectory of many regulated rivers. We aim to examine the possible geomorphic response of the upper Godavari River, India, to climate change using two well-accepted metrics: the frequency of the sediment-transporting flows (T*) and the ratio of the sediment flux below and above a dam (S*). Soil and Water Assessment Tool (SWAT) was used to simulate streamflow and sediment yield in the basin. We calibrated and validated the model using SWAT-CUP for pre- (1971–75) and post-dam (1976–81) conditions downstream of Jayakwadi dam. The model performance was good (NS value > 0.6 for discharge and PBIAS < ± 10 for sediment) with low uncertainty (p-factor > 0.6 and r-factor <1) and it improved significantly by factoring the operation of the reservoirs into the simulation. We ran the model for 10 years consecutively in the pre and post-dam states for baseline (1971–81) and future (2090–99) climate conditions derived from NEX-GDDP climate projections (Emission scenario RCP 8.5 & 4.5). A linear relationship between T*/S* and observed erosion (m) below the dam provided the basis for estimating the amount of erosion associated with future climate states. Our simulations show substantially larger T* below the dam site in 40% of the 2090s scenarios relative to the baseline conditions. These could be associated with 4–6 times the erosion compared to the baseline. Severe erosion is indicated only under RCP 8.5. Simulations suggest that amplified peak releases from dams in the future could lead to greater downstream erosion potential. [ABSTRACT FROM AUTHOR]