Palar River Research Articles

Geochemical Insights into Heavy Metal Contamination and Health Hazards in Palar River Basin: A Pathway to Sustainable Solutions

The pollution of groundwater by heavy metals is becoming an increasingly urgent problem due to the rapid growth of industrialization and urbanization. A detailed geochemical investigation of physicochemical properties and heavy metal contamination was conducted on 140 groundwater samples in the Vellore district around the Palar River, Tamil Nadu, India, to assess the metal index risk in groundwater. The water quality is significantly contaminated with Cr, Co, Cu, Cd, and Fe, and moderately contaminated with Mn, Ni, and Zn, according to the groundwater assessment using the heavy metal index, contamination factor, and Igeo index. This contamination is associated with various health problems, including mental illness, stomach and skin cancer, liver failure, and kidney damage. Based on contour maps created with GIS, most of the region is heavily contaminated with heavy metals, rendering the groundwater unfit for human consumption. The Health Risk Assessment Index (HRAI) rose to 9028.6, indicating an extremely high health risk. In addition to identifying the extent of contamination, the study also proposes sustainable solutions to mitigate these risks. These include the adoption of advanced water treatment technologies, the promotion of green chemistry practices in local industries, the establishment of stricter regulatory frameworks, and the implementation of community-based water management strategies. These measures are essential to ensuring safe drinking water and achieving Sustainable Development Goal 6 (SDG 6). The findings underscore the urgent need for comprehensive monitoring and proactive remediation strategies in industrially contaminated regions.

Assessing groundwater contamination risk in industrial zone of Ranipet district, Southern India: A modified DRASTIC and Fuzzy-AHP approach

Groundwater plays a substantial function in sustaining the water requirements of Ranipet district, Tamil Nadu, India, across a variety of domains, including drinking water, agriculture, and industry. However, rising demand and industrial activities have caused concern about groundwater pollution and susceptibility in the region. So, this study employed a modified DRASTIC model to find the regions that are most vulnerable to groundwater contamination. The model includes a novel parameter, "proximity to industry,” in addition to the seven traditional factors (depth to water level, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity) to account for the industrial nature of the study region. The fuzzy-analytical hierarchy process (FAHP) was used to compute parameter weights and ratings. All the parameters are overlayed in ArcGIS software to create the groundwater vulnerability map (GWVM). The map revealed that the central area along the Palar River is highly vulnerable to contamination. The southern and northern parts have medium to extremely low groundwater contamination risks. The depth of the water table was the most significant component impacting the vulnerability, as per the sensitivity analysis. The model is further validated by chromium concentrations, which were shown to be high in highly sensitive zones and low in low-risk zones. This study also suggests the need for extensive and periodic groundwater quality assessments in highly vulnerable zones for sustainable water resource management.

Analysis of drainage morphometry and spectral indices using earth observation datasets in Palar River basin, India

In this research we analyzed the morphometric parameter of Palar River basin by using the satellite data from open sources for monitoring drainage network. Palar River basin covers 1972.27 sq.km areas with elevation of 226.9 m as highest and 38.01 m lowest above mean sea level. In this research it detected that Palar River basin having 5th order stream with drainage density of 0.40 km/km2 and drainage pattern of dendritic to rectangular. We also draw aspect map, relief map and slope map for the research area by using digital elevation model (DEM) data of 30 m resolution. In this research we also employed spectral indices like normalized difference vegetation index (NDVI), normalized difference water index (NDWI), and soil adjusted vegetation index (SAVI) for the vegetation, water and soil characteristics of the research area. In this research it found that there are major changes in land use/land cover as water bodies and land during these periods of 15 years. Highly positive correlation show between morphometric parameter and spectral indices. In this research groundwater level data for the year 2005 and 2020 are used to validation the study. This research work is very useful in developing solutions for dealing with different types of drought and management of groundwater extraction plans.

Estimation of Groundwater Drought Propagation in the Selected Districts of Palar River Basin, Southern Peninsular India

Estimation of Groundwater Drought Propagation in the Selected Districts of Palar River Basin, Southern Peninsular India

Demarcation of groundwater potential zones in Ponnai sub-basin, Southern India using remote sensing, GIS and fuzzy-AHP approaches

ABSTRACT Groundwater is an essential source for household, irrigation and industry needs. The amount of groundwater and its quality are rapidly declining because of urbanization and industrialization. Groundwater resources in hard rock regions should be handled properly to maximize their utilization. This work aims to demarcate the Groundwater Potential Zones (GWPZ) in a part of the Palar River Basin (Ponnai sub-basin) by combining Remote Sensing (RS), Geographic Information System (GIS) and Fuzzy-Analytical Hierarchy Process (FAHP). The factors which influence the groundwater like geology, land use/land cover (LULC), geomorphology, slope, soil, rainfall, lineament density (LD), drainage density (DD), normalized difference vegetation index (NDVI), topographic wetness index (TWI) and topographic position index (TPI) are considered for mapping of GWPZ. The weightage is allocated to these parameters on the basis of the FAHP technique and the obtained groundwater potential map was classified as, very poor (13.5%), poor (21.76%), moderate (31.5%), good (20.66%) and very good (8.54%). The GWPZ map was validated with the actual well yield of the Ponnai sub-basin. The research work will serve as a guideline for the effective use of groundwater and long-term sustainable management of the aquifer in the Ponnai sub-basin.

Assessment of multi-source satellite products using hydrological modelling approach

Multi-source satellite products performance evaluation for varied geographical locations aids in quantification of hydrological variables and is useful in the strategy making and conservation of the hydrological resources available in a basin. The work was focused on assessing utility of multi-source satellite datasets to obtain the estimation of hydrologic variables and provide solution for areas that are poorly gauged. Assessment of the multi-source-satellite products was performed for the poorly gauged river basin with the help of SWAT concerning the Palar River basin, India. We analysed time series at the monthly, seasonal, and annual scales to quantify surface runoff, water yield, ET, & PET at the calibration station and for the entire basin for the period 2003 to 2021. SWAT model estimated highest monthly water yield during November–December, with annual water yield being maximum (220 mm in 2010) and average (99.4 mm), which can be used to understand water resources for irrigation, drinking aspects, and net storage. Average monthly surface runoff patterns were similar for SWAT, TerraClimate, and FLDAS. The FLDAS and SWAT simulated surface runoff show a resemblance in pattern and magnitude for the monthly and annual time series of the average basin scenario. The monthly PET obtained from SWAT and ERA-5 show a similar pattern for the entire basin and at the calibration site. The ET derived from satellite observation has over-predicted the model output at both the calibration site and entire basin.

Assessment of influencing level of rainfall and physical factors on groundwater level for a semi-arid flat terrain watershed using grid-based geospatial analysis: a case study from Lower Palar Basin, Tamil Nadu, India.

Understanding natural phenomena with the help of modern scientific approaches helps to reach sustainable solutions for current and future water-related problems. In this context, present study aims to assess relative influencing level of physical factors in controlling groundwater level, using a novel grid-based delineation technique, in Lower Palar River Basin, in Kanchipuram and Chengalpattu districts of South India. The influencing factors viz-a-viz: rainfall, soil texture, land use/land cover, terrain slope, geomorphology, lithology, and drainage characteristics were considered for the study. Archived data (2011 to 2020) of monthly rainfall at four rain gauge stations and monthly groundwater level of 22 locations, soil texture, lithology, and geomorphology data were considered for the study. SRTM digital elevation model with 30-m resolution was used for analyzing drainage characteristics and terrain slope. Thematic maps for considered factors were prepared, using common grid delineation method in GIS platform that divided study area into 52 grids, to inter-relate the discrete and continuous parameters with groundwater level. Results indicate that level of influence increases in the order of precipitation followed by lithology, land use/land cover, terrain slope, geomorphology, infiltration number, and soil texture. The study shows groundwater resilience is highly influenced by soil texture and infiltration number compared to other factors considered. It can be concluded that grid-based delineation successfully identifies grids with significant influence of individual factors by comparing with groundwater resilience. Common grid-based delineation method proves to be more effective in assessing groundwater resilience and can be used more efficiently in groundwater studies.

Behaviour of Precariously Balanced Rocks under Seismic Excitation

A naturally occurring geological formation is precariously balanced rocks (PBRs) which might easily topple by an earthquake with severe ground motion. These rocks have been at the same place for many years. Strong ground accelerations have not occurred in the area for thousands of years as shown by the zone of unstable rocks. So, they are significant in both the engineering and seismological domains since they provide source of data for the maximum earthquake ground motion occurring at a site over the rock’s life time. The precariously balanced rock taken for this study is Krishna Butter Ball which is in Mahabalipuram, Chengalpattu district. In the numerical analysis, the peak ground acceleration at which the Krishna butter ball may topple is obtained. To identify the possible future earthquake, deterministic seismic hazard analysis has been carried out for Chengalpattu district. For this analysis, fault details have been obtained from Geological Survey of India. Arc map 10.1 version in Geographical Information System (GIS) platform is used for the interpretation of data like fault length, source (fault) to site (Mahabalipuram) distance from the fault details given by GSI. From the results of Deterministic Seismic Hazard Analysis (DSHA), it is observed that the possible future earthquake may have the magnitude in the range of 6.03 to 7.9. The computed peak ground acceleration (PGA) value corresponding to those magnitude ranges from 0.027g to 0.49g. The maximum PGA value 0.49g corresponds to the Palar river fault which is just 28.53 km away from the Krishna butter ball. From the results of numerical analysis, the behavior of Krishna butter ball for three different PGA i.e. 0.05g, 0.1g, 0.15g has been observed. Newmark sliding block analysis said that the rock may topple at the PGA of 0.35g. From this it can be concluded that the toppling acceleration of Krishna butter ball is relatively low.

Geochemometrics of primordial radionuclides and their potential radiological risk in coastal sediments of Southeast Coast of India

In recent years, the contamination of the earth's materials with radioactive elements as naturally occurring radioactive material has been a source of concern. This study is aimed at the environmental radioactivity of beach sediments and the gamma dose levels along the south-eastern coastal region of the Indian subcontinent, from the Palar River mouth (Kadalur Kuppam) to the Pulicat Lake or Pazhaverkadu coast. Furthermore, to analyze the gamma dosage level, as well as the spatial variation of the activity concentrations of 238U, 232Th, and 4 K, as well as the acid-leachable trace elements Ni, Pb, Mn, Zn, Cu, Co, Fe, and Cr in coastal sediments. In addition, radiological risk and hazard indices are assessed in the study domain. The MiniTRACE CSDF survey meter was used to determine the ambient gamma dose level and the activity concentration of primordial radionuclides (238U, 232Th, and 4 K) was quantified using gamma-ray spectroscopy with a NaI (Tl) detector, as well as trace elements studied in atomic absorption spectroscopy. The primordial radionuclides activity concentration (238U, 232Th, and 4 K) in collected coastal sediments of the proposed region were found in the range of ≤3–1953, ≤3–1180, and 41–753 Bq/kg, respectively. The annual effective dose rate was found in the order of 4 K > 232Th > 238U. Based on the geochemometric approach, the data collected for various radiological parameters were combined with radiological risk indices, and trace element concentrations were compared on a regional and global scale. The current study could provide a new research pathway in the areas of coastal monitoring, environmental health, and radiation safety measures.

Late Quaternary Evolution of Peninsular Rivers: A Case Study from Palar River, Southern India

Late Quaternary Evolution of Peninsular Rivers: A Case Study from Palar River, Southern India

Tannery Wastewater affects the Drinking Water Quality and Heavy Metals in the Palar River Water Pollution in Vellore District Tamil Nadu

A large number of chemicals are used in the tanneries to convert the rawhide into finished leather. The chemicals used by the tanneries are ends in wastewater. This wastewater is dumped into nearby rivers and canals that create water pollution heavy metals in the water. The aim of this process is to access the chemicals used in the tannery industry post tanning process and to evaluate the drinking water quality of the wastewater released by the tanneries in the Palar river basin in Vellore district Tamil Nadu. To analyze the perception of the people in the study area affected by health due to wastewater from the tanneries. This study was performed as a cases study of the current drinking water sources used by households and how they perceive the quality of water. The second objective is to analyze the relationship between water quality and health hazards among households in the Vellore district. Primary data was collected from the respondents with the help of a questionnaire, total sample size of the respondent was 500, multistage random sampling technique was used to collect the data with the help of questioner method, the descriptive and statistical tools were used to analyse the data with SPSS and R statistical packages. The result shows that the people in the river basing suggested controlling the wastewater for the tanneries, and they demanded compensation from the tanneries. Finally, to suggest policy measures to control the water pollution in the study area.

Investigation and correlation of radioactive hazards with magnetic parameters and heavy metals of dwelling sand from two major rivers in south India – A comparative study

Cauvery and Palar, two major rivers in Tamilnadu, India, have importance for irrigation, drinking, electricity and river sand is used as a major material of building construction in India. The natural radionuclides such as uranium, thorium and potassium (238U, 232Th, 40K) isotopes are investigated through gamma ray spectrometer with NaI(Tl) detector. The average values of radionuclides and in-situ dose are measured. Related parameters like absorbed dose (ADin & ADout), Annual Effective Doe Equivalent (Ein & Eout), and also hazard indices to assess radiation exposure to human such as average radium equivalent (Raeq), external (Hex)and internal (Hin) hazard indices, Radioactive heat production (RHP), internal and external Excess Lifetime Cancer Risk (ELCRin and ELCRout), Alpha (Iα), Gamma Index (Ig) and Annual Gonadal dose (AGDE) are computed and correlated. This study exhibits that almost all the radioactive parameters are in control by comparing to the world average. Nevertheless, the Cauvery River except site no.20 does not produce a radiological hazard. But, the palar river does slightly produce a radiological risk especially site no.6 shows three times of the world average.

Holocene evolution of the Palar river, Southern India: Tracking history of migration, provenance, weathering and tectonics

This study examines the catchment and source morphodynamics of the Palar River, Southern Peninsular India. Here, we applied a multidisciplinary approach (Remote sensing Techniques, Lineament Analysis, Geochemistry and Ground Penetration Radar) for a better understanding of its evolution during Holocene times. The lineaments present in the Palar River basin are showing dominantly NE-SW trend. There are five major faults identified in the Palar River basin. Fault F1 (strike slip fault) occurs in the upper part of the Palar River following the NE-SW trend. Other major faults F2 and F3 occurs in the middle reaches with a transition zone where frequent smaller magnitude earthquake occured and fault F4 traverses in parallel to the Cheyyar River. Fault F-5 nearer to the east coast indicates a passive tectonic activity regime. The after-effects of tectonic activity in the basin is further implicit from the GPR Profile. The sediments of active Palar River are dominantly litharenite, arkose, wacke; while, the paleochannels are shale in composition. Weathering proxies such as CIA, PIA, elemental ratios along with A–CN–K plot indicate a post-depositional intense weathering due to climatic variability for paleochannel sediments. Due to ongoing tectonic activity in the sources region along with subsequent aggradation and degradation in fluvial regimes, the sediments of active Palar River shows low to moderate weathering. Moreover, the geochemical data also reveals that the sediments from the Palar River and paleochannels are predominately from active continental and passive continental margins respectively. Moreover, the Major Oxide, Trace Elements and REE elements data indicate that Palar River sediments are from a felsic source while paleochannels are from mafic source. Hence, our study suggests that the catchment area of the Palar River has been shifted to the southward during the Holocene period due to tectonic uplift. Subsequently, the sediments of the paleochannels have undergone post-depositional weathering. Due to ongoing tectonic activity and intense precipitation in the region, enhances rapid erosion in the catchment area results in the deposition of the huge thickness of sediments from the middle to lower reaches of active Palar River.

Assessment and evaluation of groundwater vulnerability index maps of Upper Palar River Basin, Tamilnadu, India

The present study focuses on the assessment of groundwater vulnerability in the Upper Palar river basin, Tamil Nadu, India using the DRASTIC method, which consists of seven parameters obtained from various sources and created as map layers. To determine the groundwater vulnerable zones, the net recharge parameter considered in the DRASTIC model is estimated by four different methods, viz., SCS-CN, Piscopo, Chaturvedi, and groundwater fluctuation recharge methods and the results were compared. The vulnerability maps were generated by four recharge estimation methods, such as water table fluctuation method, Piscopo, SCS-CN and empirical formulae of Chaturvedi methods. This vulnerability class were validated with the observed groundwater quality (nitrate concentration) measured from 30 wells in the study area. The results were classified into four categories such as low, moderate, high, and very high. From the results obtained using DRASTIC with the Chaturvedi method, very high vulnerability is observed in the southern regions and low vulnerability in the north and southwest regions. Using the Piscopo method, the very high vulnerability is distributed along the lower half of the river and southeast side, and the low vulnerability covers the north part of the river basin. Similarly using the SCS-CN method, the very high vulnerability is seen along the river basin and low vulnerability along the central-north and south regions. Using the groundwater fluctuation method, very high vulnerability falls under the small part of the southeast side, but low vulnerability covers the south-west and east sides of the river basin. The different methods adopted to estimate the recharge rate in the study revealed the dependency level of the vulnerability on that parameter. Also, the study area characteristic is best observed by the results of these four methods. All the four methods gave very good results and better knowledge about each factor and a better understanding of the groundwater susceptible zones to pollution in the study area. Among the four methods, Piscopo and WTF methods were found to be best applicable for the selected study area.

Coastal Sediment Transport along Kalpakkam using Sediment Trend Exploaration and Numerical Modelling

The impact of coastal sediment transport in the nearshore region is significant and the need for improved sediment quantification techniques appears to be universally accepted. The coastal sediment transport models presently in use were derived empirically from very sparse measurements of waves and currents and from laboratory experiments. The shoreline of Kadalur fishing villages near Kalpakkam has been experiencing erosion due to occurrence of cyclones every monsoon. Palar River with its confluence in the Bay of Bengal at the northern tip of the Kadalur villages has its mouth closed due to negligible river flow. The purpose of this study is to assess sediment dynamics in the Kalpakkam coast using two independent approaches; namely Sediment Trend Analysis (STA) and two dimensional numerical modelling. The latter can track the movement of individual particles. Numerical modelling approach is based on Delft3D model which allows the coupling of flow and wave modules. STA and numerical modelling results can provide sediment transport direction. The combination of both approaches provides a means of verification of sedimentation processes. The basic assumption in STA is that sediment transport can be responsible for the differences in sediment grain size distributions. For Grain Size Trend Analysis, grab samples were collected throughout the nearshore area. Grain Size Trend Analysis was then carried out and subsequent results were plotted to obtain the sediment transport pattern for the region. The results obtained are compared with the numerical model results and also used for validation of sediment transport evaluated using the numerical model.

Assessment of Groundwater Vulnerability Using GIS and DRASTIC for Upper Palar River Basin, Tamil Nadu

ABSTRACT Groundwater is one of the valuable resources and due to increase in the population, industrialization and agriculture practices, the groundwater stress has increased to a greater extent. Once the groundwater gets contaminated, remediation is very difficult. The steps to measure the groundwater vulnerability must be taken for sustainable groundwater protection and management planning. In this paper, the DRASTIC model is applied to find out and generate a small-scale map of groundwater vulnerability to assess the contamination in the upper Palar river basin, Tamil Nadu, India. A number of tanneries are located along the banks of the river basin. The quality of groundwater in and around river basin area has been affected very much due to the untreated effluent of the tanneries discharged directly to the river. The DRASTIC model consists of seven hydrogeological parameters including depth to water table, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity; each factor is assigned by weight and rating which depends upon the influence of the seven hydrological layers of the river basin area. The ArcGIS 10.3 software was used to create the groundwater vulnerability map by overlaying the seven layers, which is intended to show potential areas of groundwater contamination. The results of the study shows that, 50% of the study area falls under very high pollution potential zone, 20% under high pollution potential, 15% under moderate pollution potential, 10% under low pollution potential, and the remaining 5% of the area has no risk. The very high vulnerability class which is covered by the alluvium along the river course is most likely to pollution due to the very lower slope terrains in the direction of the central part, which allows better percolation of contaminants into the groundwater. The low vulnerability class lies in the area covered by the hard rock and clay loam soil in the upper reach of the Palar river which contains mountains and hard rock terrain.

Comparative assessment of chlorine reactivity and trihalomethanes formation potential of three different water sources

Trihalomethanes (THMs) are carcinogenic compounds formed during water chlorination. Nature of source water and treatment conditions significantly influence its formation. Chlorine reactivity and trihalomethanes formation potential of water samples taken from three different sources such as the sea, open reservoir, and Palar river subsoil were assessed for a period from 2013 to 2017 with respect to key determinants. UV absorbance (254 nm) values of all the water samples (n = 175) varied from 0.033 to 0.09 with dissolved organic carbon (DOC) ranged between 1.08–1.88, 0.69–2.15, 0.66–1.98 mg/L for seawater, open reservoir and Palar subsoil water respectively. Though UV absorbance (UV254) was positively correlated with DOC content, specific UVA254 (SUVA254) did not correlate with DOC. Consistent nonlinear increase in chlorine demand with increasing dose and time was observed which differs in magnitude for three water sources. THM formation potential followed the order: Reservoir > Seawater > Palar subsoil. The seasonal average of THMs (5 mg/L dose; 24 h contact time) was the highest for open reservoir water samples ranging from 151.62 (southwest monsoon)-198.25 μg/L (post northeast monsoon) as compared to that of the seawater (max. 105.60 μg/L) and Palar subsoil water (max. 119.66 μg/L). Among the three sources, THM in open reservoir water sample only exhibited positive correlation with its DOC. Water quality parameters such as pH, temperature, dissolved oxygen, nitrate, total nitrogen failed to establish a clear correlation with THMs yield, which indicated the overriding influence of simultaneous occurring reactions. Among all the parameters chlorine demand appeared to be a better surrogate to predict trihalomethanes formation regardless of water sources.

Quantitative analysis of the drainage and morphometric characteristics of the Palar River basin, Southern Peninsular India; using bAd calculator (bearing azimuth and drainage) and GIS

ABSTRACTThe Palar River basin is one of the major rivers in southern peninsular India. Morphometric analysis coupled with drainage network analysis was carried out for the Palar River basin to understand its drainage characteristics and the drainage network geometry with reference to tectonics. The morphometric analysis has been carried out using ‘bearing azimuth and drainage (bAd) calculator’ which a new and easy methodology for extraction of watershed morphometric parameters. The entire Palar River basin has been divided into five major sub-basins and various linear, areal, and relief morphometric parameters were calculated. The sub-basins I, II, and III reflect low to medium stream frequency (Fs) and moderate drainage density (Dd) and a high bifurcation ratio of various stream orders signifies that they are surging through tectonically active areas, followed by high overland flow and less recharge into the subsurface resulting in low groundwater potential. Moreover, sub-basins IV and V show the relatively low overland flow, which helps to percolate water, hence ground water potential will be higher. The morphometric result suggests that the drainage network geometry is variously controlled by recent tectonics. Lineaments trending majorly NW-SE, NE-SW, and E-W mark the major drainage network in Palar River drainage basin. Lower order streams and higher order streams follow NW-SE, NE-SW lineaments. Which also points toward the tectonic control of drainage in Palar River. As a result of channel orientation due to tectonic activity: (i) most channels are A-type or B-type associated with the lineaments, (ii) the pattern of the drainage network is dendritic, rectangular sometime trellis too, and (iii) the main rivers flow longitudinally to the predominant lineament direction.

Spatial Prediction of Erosion Risk of a Small Mountainous Watershed Using RUSLE: A Case-Study of the Palar Sub-Watershed in Kodaikanal, South India

An erosion model using the Revised Universal Soil Loss Equation (RUSLE) equation derived from the Advanced Spaceborne Thermal Emission and Reflection Global Digital Elevation Model (ASTER G-DEM) and LANDSAT 8 is presented in the study. This model can be a cost-effective, quick and less labor-intensive tool for assessing erosion in small watersheds. It can also act as a vital input for the primary assessment of environmental degradation in the region, and can aid the formulation of watershed development planning strategies. The Palar River, which drains into Shanmukha Nadi, is a small mountain watershed. The town of Kodaikanal, a popular tourist attraction in Tamilnadu, forms part of this sub-watershed. This quaint, hill-town has been subjected to intense urbanization and exhaustive changes in its land use practices for the past decade. The consequence of this change is manifested in the intense environmental degradation of the region, which results in problems such as increased numbers of landslides, intense soil erosion, forest fires and land degradation. The nature of the terrain, high precipitation, and intense agriculture exponentially increase the rate of soil erosion. Spatial prediction of soil erosion is thereby a valuable and mandatory tool for sustainable land use practices and economic development of the region. A comprehensive methodology is employed to predict the spatial variation of soil erosion using the revised soil loss equation in a geographic information system (GIS) platform. The soil erosion susceptibility map shows a maximum annual soil loss of 3345 Mg·ha−1·y−1, which correlates with scrub forests, degraded forests, steep slopes, high drainage density and shifting cultivation practices. The erosion map shows that the central region is subjected to intense erosion while the inhabited southern part is less prone to erosion. A small patch of severe soil loss is also visible on the eastern part of the northern fringe. About 4% of the sub-watershed is severely affected by soil erosion and 18% falls within a moderate erosion zone. The growing demand for land and infrastructure development forces the shift of urbanization and agriculture to these less-managed spaces. In light of this scenario, the spatial distribution of erosion combined with terrain and hydro-morphometry can aid in sustainable development and promote healthy land use practices in the region.

Lower Palar River Sediments, Southern Peninsular, India: Geochemistry, Source-Area Weathering, Provenance and Tectonic Setting

Abstract This present study describes the geochemistry of fluvial sediments of the Palar river (lower reaches), Southern Peninsular India, with an aim to evaluate their provenance, weathering and tectonic setting. The bulk sediment chemistry is influenced by grain size. The river sediments are enriched with SiO2 and depleted in Al2O3, K2O, CaO, Na2O, MgO, P2O5, MnO, Fe2O3 as compared with UCC values. Geochemical classification indicate that the sediments are mainly arkose, wacke and shale in composition. Discriminant diagrams together with immobile element ratio plots reveal that, the Palar river sediments are mostly derived from rocks formed in an active continental margin. Additionally, the rare earth element ratios as well as chondrite-normalized REE patterns with flat HREE, LREE enrichment, and negative Eu anomalies indicate felsic rock sources. The chemical indices of alteration suggest that Palar river sediments are chemically immature and have experienced low chemical weathering effects. This is further supported by the Th/U Rb/Sr ratio and A-CN-K ternary diagram, with most of the sample data points falling close to the plagioclase-smectite line. The bivariate plot of Th/Sc versus Zr/Sc suggest a moderate recycled origin of the sediments.