Jobin Thomas

University of Mississippi | UM · Geology & Geological Engineering

Purpose Soil texture identification is vital for various agricultural and engineering applications but generally involves rigorous laboratory work, especially for estimating USCS (Unified Soil Classification System) soil texture classes. Soil texture influences soil water storage capacity, soil fertility, compaction characteristics, and soil streng...

Assessing anthropogenic climate change in a regional context is challenging due to the spatial heterogeneity of climatic variables and is more complicated than at the global scale. Especially in the Tropics, such spatial variations are expected to increase, warranting the identification of homogeneous climatic zones for assessing regional climate c...

The Edenville Dam, an earthen embankment in Midland, MI, failed on May 19, 2020, after 3 days of elevated rainfall (3.83–8.0 in.; 9.7–20 cm), which caused flooding downstream of the dam. Dam infrastructure similar to that at the Edenville Dam is not uncommon in the United States and hence requires periodic monitoring. A pre-failure analysis was con...

Urbanization is the predominant driver of global land use/land cover (LU/LC) changes, resulting in long-lasting or irreversible environmental degradation. The study of LU/LC changes and its impact on land surface temperature (LST), an indicator of climate change, can be effective in environmental management. The significant increment of LST will le...

Unprecedented floods from extreme rainfall events worldwide emphasize the need for flood inundation mapping for floodplain management and risk reduction. Access to flood inundation maps and risk evaluation tools remains challenging in most parts of the world, particularly in rural regions, leading to decreased flood resilience. The use of hydraulic...

Significant changes in rainfall patterns are critical to agriculture, and the dependency of cropping systems on rainfall variability would engender appropriate farming practices and agriculture policies for a climate-resilient agriculture system. This study analyses the significance of rainfall variability on agriculture productivity in the Wayanad...

Terrain traversability is critical for developing Go/No-Go maps for ground vehicles, which significantly impact a mission’s success. To predict the mobility of terrain, one must understand the soil characteristics. In-situ measurements performed in the field are the current method of collecting this information, which is time-consuming, costly, and...

The rapid growth of urban areas and population as well as associated development over recent decades have been a major factor controlling ambient air quality of the urban environment in Kerala (India). Being located at the southwestern fringe of the Indian peninsula, Kerala is one of the regions that has been significantly influenced by the activit...

This study assesses the effectiveness of the green walls for the modification of urban microclimate in different seasons of an urban academic campus in a humid tropical climate using the ENVI-met model. The hourly variation of the surface and ambient air temperatures of locations with differing underlying surfaces, such as asphalt (ASP), interlocke...

Due to the unique blend of physiography, climate, and socio-economic factors, the windward slopes of the southern Western Ghats (WG) are highly susceptible to the occurrence of landslides. The present study compares the efficiency of advanced deep learning and machine learning techniques, such as deep neural network (DNN), and random forest (RF) wi...

Rainfall is a vital input to model watershed hydrology, and the availability of numerous gridded and point-observed rainfall datasets poses a major challenge to the modellers to choose the appropriate data. This study compares three gridded rainfall datasets (i.e., 1° × 1°, 0.5° × 0.5°, and 0.25° × 0.25°) and point rainfall observations of the Indi...

Deterioration of ambient air quality associated with urbanisation is a serious concern in many parts of the world. In India, air pollution, primarily due to particulate matter, has increased exponentially in the last few decades due to rapid urbanization, industrialization and population growth. This study investigates the non-uniform influence of...

Soil erosion is a severe environmental problem worldwide, especially in tropical regions. The Revised Universal Soil Loss Equation (RUSLE), one of the universally accepted empirical soil erosion models, is quite commonly used in tropical climatic conditions to estimate the magnitude and severity of soil erosion. This study, apart from identifying t...

The extensive damages of extreme rainfall events (EREs) and associated natural disasters on the natural and anthropogenic resources and the enormous economic losses underscore the requirement for developing early warning systems to mitigate the impact of such disasters. However, accurate forecasting of EREs at a regional scale and at higher lead ti...

Coastal groundwater is ubiquitously under threat due to a variety of natural and anthropogenic activities. Groundwater occurring along a stretch of the coastal tract (L = 15 km) of Thiruvananthapuram district, Kerala, India, was analyzed for hydrogeochemical characterization, identification of factors influencing water chemistry, suitability for dr...

The increasing demand for food and clean energy, such as biofuel calls for a sustainable food-energy nexus in the agriculture sector. Mixed cropping pattern of food and biofuel crops is a viable strategy to meet the escalating demands of the biofuel production at the cost of food production. The implementation of the proposed solutions of simulatio...

The recurrent forest fires have been a serious management concern in southern Western Ghats, India. This study investigates the applicability of various geospatial data, machine learning techniques (MLTs) and spatial statistical tools to demarcate the forest fire susceptible regions of the forested landscape of the Wayanad district in the southern...

This study assesses the effect of lockdown, due to the coronavirus disease (COVID-19) pandemic, on the concentration of different air pollutants and overall air quality of a less industrialized region (Kerala) of India. We analysed data from four ambient air quality stations over three years (January to May, 2018-2020) with pairwise comparisons, tr...

The increasing demands for the groundwater resources along with decreasing availability, especially in the hard-rock aquifers, call for sustainable groundwater management in India. The present study attempts to identify the potential zones for groundwater recharge, through water conservation measures, in a tropical river basin of Kerala (India), vi...

The present study examines the extent of erosion and deposition along the banks of the lower reaches of the Krishna River (India) between 1973 and 2015, by analyzing the shifts in the bank lines using Landsat images of the years 1973, 1991 and 2015. The analysis is limited to the river segment downstream of the Nagarjuna Sagar Dam up to the Krishna...

Kerala state (India) experienced a devastating flood event during the month of August 2018. While an extreme rainfall event (ERE) was the primary reason for this flood, there was criticism at various levels that the authorities failed to manage the flood effectively through reservoir operations. One of the worst affected basins, Periyar River Basin...

Basin-wise DEM-based Automated Morphometry (BaDAM) toolbox, an automated solution for drainage basin morphometric analysis, is presented in this paper. The toolbox, being scripted in Python, can be easily integrated with ArcGIS 10.0 version, and customizations can be implemented effortlessly. The BaDAM toolbox has been tested for computation of mor...

An automated solution for drainage basin morphometric analysis

Soil erosion and deposition in a tropical mountainous river basin, viz., Pambar River Basin (PRB), in a rain shadow region of the southern Western Ghats (India) were modelled using Revised Universal Soil Loss Equation (RUSLE) and transport limited sediment delivery (TLSD) function in GIS. Mean gross soil erosion in the basin is 11.70 t ha⁻¹ yr⁻¹, a...

Revised Universal Soil Loss Equation (RUSLE) model coupled with transport limited sediment delivery (TLSD) function was used to predict the longtime average annual soil loss, and to identify the critical erosion-/deposition-prone areas in a tropical mountain river basin, viz., Muthirapuzha River Basin (MRB; area = 271.75 km²), in the southern Weste...

The long-term average annual soil loss (A) and sediment yield (SY) in a tropical monsoon-dominated river basin in the southern Western Ghats, India (Muthirapuzha River Basin, MRB; area: 271.75 km²) were predicted by coupling the Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratio (SDR) models. Moreover, the study also delineate...

Gridded precipitation data are being increasingly used as input to watershed hydrological models for better representation of spatial variability of the precipitation. The spatial variability of gridded data is best utilized by distributed and semi-distributed hydrological models, compared to the lumped models. Among the numerous watershed hydrolog...

The Achankovil Shear Zone (AKSZ) in the Southern Granulite Terrain separates the Trivandrum block from the Madurai block. Various geomorphic indices and longitudinal profiles of the river systems in the AKSZ, viz., Achankovil river basin (ARB) and Kallada river basin (KRB), were derived from SRTM DEM to decipher the influence of shearing and deform...

The present study examined the factors controlling shallow groundwater quality in two coastal panchayaths (viz., Chennam-Pallippuram and Thykkattussery) of Alappuzha district, Kerala, India, for three sampling seasons: pre-monsoon, monsoon and post-monsoon. The hydrochemical analysis shows significant seasonal fluctuations in groundwater quality, w...

Many coastal lakes are under serious threats due to increased pressures associated with population growth, accelerated eutrophication, invasive species and toxic contamination. The extent of the pollution depends almost entirely on the characteristics and processes taking place in the lake basin. The objective of this study was to identify the poll...

The climate of Kerala is controlled by the monsoon, and the analysis of rainfall and drought scenario, for a period of 141 years (1871-72 to 2011-12), reveals a decreasing trend in southwest monsoon, and increasing trends for post-monsoon-, winter- and pre-monsoon-rainfall. The inconsistent periodicity (2 - 8 years) of annual- and seasonal- rainfal...

River water chemistry of Pambar River Basin (PRB), draining a rain shadow region of the southern Western Ghats, India, with granite gneiss and hornblende-biotite-gneiss lithology, was monitored for three sampling seasons, such as monsoon (MON), post-monsoon (POM) and pre-monsoon (PRM) to ascertain the spatio-temporal trends in hydrochemistry. In PR...

Discriminant analysis (DA) was performed on river hydrochemistry data for three seasons (i.e., monsoon (MON), post-monsoon (POM), and pre-monsoon (PRM)) to examine the spatio-temporal hydrochemical variability of two mountain river basins (Muthirapuzha River Basin (MRB) and Pambar River Basin (PRB)) of the southern Western Ghats, India. Although th...

The drainage network of a sixth-order tropical river basin, viz. Ithikkara river basin, was extracted from different sources such as Survey of India topographic maps (1: 50,000; TOPO) and digital elevation data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) (30 m) and Shuttle Radar Topography Mapping Mission (SRTM) (90 m)...

Water samples were collected from two mountain rivers of contrasting climates, viz., humid, Muthirapuzha River Basin (MRB) and semi-arid, Pambar River Basin (PRB) during monsoon (MON), post-monsoon (POM) and pre-monsoon (PRM) seasons, and were analyzed to understand the spatio-temporal variability as well as the sources and processes controlling hy...

Digital elevation model (DEM), deriving conventionally from contour data of topographic maps, provides sufficient information regarding the continuously varying topographic surface of the Earth. Though spaceborne DEMs are increasingly being used in earth-environmental-applications, suitability of various freely available spaceborne DEMs [e.g., adva...

Accurate knowledge of sediment quality is essential because it affects the magnitude and trends of water quality constituents. There are only a few analyses of sediment quality characteristics using multivariate analysis tools. This study utilizes hierarchical cluster analysis (HCA), factor analysis (FA) and multiple regression analysis (MRA) to de...

The paper evaluates sensitivity of various spaceborne digital elevation models (DEMs), viz., Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mapping Mission (SRTM) and Global Multi-resolution Terrain Elevation Data 2010 (GMTED), in comparison with the DEM (TOPO) derived from contour data of 20 m inte...

The study on bioaccumulation of heavy metals in a lake reveals that during the nonrainy season, accumulation of cadmium in plankton is high in the upstream of the lake where anoxic freshwater condition exists resulting from inflow of urban wastes. Stern action is required to stop the bypass of sewage from the old sewer system especially in the comm...

A comprehensive and systematic study to understand various geochemical processes as well as process drivers controlling the water quality and patterns of the hydrochemical composition of river water in Muthirapuzha River Basin, MRB (a major tributary of Periyar, the longest river in Kerala, India), was carried out during various seasons, such as mo...

Soil moisture is a decisive parameter which determines the vegetation growth and it is an important variable for understanding and predicting a range of hydrological processes. The spatio-temporal heterogeneity of soil moisture is mainly the result of numerous factors such as topography, climate, soil properties, vegetation, landuse, agricultural p...

Texture plays an important role in the identification of polluted stretch in a lake system. The organic matter as well as toxic elements get accumulated in the finer sediments. The aim of the work is to show the spatio-temporal distribution of texture of the lake sediment (Akkulam-Veli lake, Kerala) and to identify the hot spot areas of contaminati...

An efficient flood alarm system may significantly improve public safety and mitigate damages caused by inundation. Flood forecasting is undoubtedly a challenging field of operational hydrology and a huge literature has been developed over the years. In this paper, we first define ordered ideal intuitionistic fuzzy sets and establish some results on...

The morphometric analysis of river basins represents a simple procedure to describe hydrologic and geomorphic processes operating on a basin scale. A morphometric analysis was carried out to evaluate the drainage characteristics of two adjoining, mountain river basins of the southern Western Ghats, India, Muthirapuzha River Basin (MRB) in the weste...

Statistical techniques represent a reliable tool for classifying, modelling and interpreting surface water quality monitoring data, particularly for lakes. The complexity associated with the analysis of a large number of measured variables, however, is a major problem in water quality assessments. Multivariate analysis, such as cluster analysis and...

The study of the spatiotemporal variation of heavy metals in lake sediments is of great importance because heavy metals can result in toxic effects on aquatic biota through bioaccumulation. This study was undertaken to evaluate the degree of heavy metal contamination in the lacustrine sediments and the corresponding environmental deterioration in a...

A flood warning system is a non-structural measure for flood mitigation. Several parameters are responsible for flood related disasters and a quick-responding flood warning system is required for effective flood mitigation measures. This work illustrates a fuzzy network analysis that has the capability to simulate the unknown relations between a se...

The rain shadow regions requisite a comprehensive watershed development and management plan for sustainable water resources management. The Pambar River Basin (PRB) lies on the rain shadow region of the southern Western Ghats, India, where climate showed marked intra-basin variation. A morphometric analysis was done to evaluate the drainage charact...

The present work accentuated the expediency of remote sensing and geographic information system (GIS) applications in groundwater studies, especially in the identification of groundwater potential zones in Ithikkara River Basin (IRB), Kerala, India. The information on geology, geomorphology, lineaments, slope and land use/land cover was gathered fr...

A flood warning system is a non-structural measure for flood mitigation. Several parameters are responsible for flood related disasters. This work illustrates an ordered intuitionistic fuzzy analysis that has the capability to simulate the unknown relations between a set of meteorological and hydrological parameters. In this paper, we first define...

Though tropical-mountain-streams, placed among the extreme fluvial environments globally, are attractive topics of research in respect of their channel morphology viz., primarily cascades, step-pools, riffle-pools etc., all along in India, the thirst in fluvial systems research more or less sidelined it. Hence, we break this tradition by taking up...

The Muthirapuzha watershed (MW) is one among the major tributaries of Periyar – the longest west flowing river in Kerala, India. A morphometric analysis was carried out to determine the spatial variations in the drainage characteristics of MW and its 14 fourth order sub-watersheds (SW1–SW14) using Survey of India topographic maps and Landsat ETM im...

Levels of heavy metals (Cu, Cr, Pb, Zn, Fe and Mn) in the surficial sediments of the four coastal wetlands, viz. Poovar, Poonthura, Akkulam-Veli and Kadinamkulam-Anjengo-Akathumuri of Thiruvananthapuram are presented in this study. Further the statistical tools like contamination factor (CF), index of geoaccumulation (Igeo) and pollution load index...

Groundwater qualities of coastal aquifers in the Chennam-Pallippuram Panchayath of Alappuzha district, Kerala have been extensively monitored in summer from January to May, 2007 to assess its suitability in relation to domestic and agricultural uses. The water samples (n=36) were analyzed for various physico-chemical attributes like temperature, pH...

The variations in the hydrochemical constituents were examined in two upland river basins that have contrasting climate and are distributed in the Western Ghats, Kerala, India. Though, there is significant variation in the rainfall regime of the basins, other factors like catchment geology, landuse, topography also have considerable contributions t...

The data on the texture and nutrient aspects of soils are very indispensable as it furnish information regarding the fertility status and the suitability of soils for various agricultural activities. Most soils are composed of a mixture of three size grades, viz., sand, silt and clay, and each fraction does not exert equal influence on the characte...

Reservoirs and lakes with clear cut boundaries represent one of the most versatile ecosystems on the surface of the earth. Like any other systems, reservoirs are characterized by inputs and outputs of materials and hence represent an ongoing chemical process. The sediments that are carried to the reservoirs by catchment erosion, get progressively s...