Journal Articles

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    Application of soft computing techniques in coastal study – A review
    (Shanghai Jiaotong University, 2016) Dwarakish, G.S.; Nithyapriya, B.
    Coastal zone is the triple interface of air, water and land and it is so dynamic in nature which requires expeditious management for its protection. Impulsive change in shoreline and submergence of low lying areas due to sea level rise are the solemn issues that need to be addressed. Indian coastline of about 7516 km is under threat due to global warming and related human interventions. Remote sensing data products provide synoptic and repetitive view of the earth in various spatial, spectral, temporal and radiometric resolutions. Hence, it can be used in monitoring coastal areas on a temporal scale. Critical Erosion hotspots have to be given proper protection measures to avoid further damages. Satellite images serve in delineating shoreline and extracting the hotspots to plan the mitigation works. Coastal inundation maps can be created using remote sensing and geospatial technologies by assuming different sea level rises. Those maps can serve as a base for planning management activities. Soft computing techniques like Fuzzy Logic, Artificial Neural Network, Genetic Algorithm and Support Vector Machine are upcoming soft computing algorithms that find its application in classification, regression, pattern recognition, etc., across multi-disciplinary sciences. They can be used in classifying remote sensing images which in turn can be used for studying the coastal vulnerability. The present paper reviews the works carried out for coastal study using conventional remote sensing techniques and the pertinency of soft computing techniques for the same. © 2016 Shanghai Jiaotong University
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    Use of geoinformatics and geophysical applications in landslide studies: An overview
    (World Research Association Vijay Nagar A.B. Road Indore 452 010, 2019) Thejashree, G.; Lokesh, K.N.; Dwarakish, G.S.
    Landslide is one of the hazardous geological phenomena which is gaining attention worldwide because of destruction caused by it. Due to the drastic increase in urbanization and human intervention in hilly regions, the destruction caused by mass wasting is increasing day by day. Landslides are far from the control of humans. But the destruction and losses caused by these calamites can be minimized, if their occurrence is known before time. This review paper aims at discussing how remote sensing, GIS and geophysical techniques can be utilized for investigation of landslides and mapping of landslide susceptible areas. Geophysical techniques can provide important information on physical characteristics linked with landslide mechanism. Complementarily, remote sensing and Geographical Information System (GIS) techniques play an important role in the generation of thematic layers related to landslide occurrences which aid to produce susceptible, hazard zonation and landslide inventory maps. Such integrated approach on landslides studies can bring about better understanding and help to take up mitigation measures to reduce the landslide hazards. © 2019, World Research Association. All rights reserved.
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    Uncertainties in predicting impacts of climate change on hydrology in basin scale: a review
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Jose, D.M.; Dwarakish, G.S.
    The sensitivity of the hydrological system to climate change and the role of hydrological systems in the environment have motivated researchers to study the impacts of climate change on hydrology. Modelling the hydrological impacts of climate change is generally done in various stages and has uncertainty associated with each of them. These include scenario uncertainty in climate scenario selection, model uncertainty in climate simulation by global climatic models (GCMs), uncertainties while downscaling GCMs, biases in downscaled data, erroneous input to the hydrological model, and uncertainty in the structure and parameterisation of the hydrological model. The present paper aims at reviewing the uncertainties involved at each stage of climate change impact assessment of hydrology. In the near future, climate scenario uncertainties would be smaller than those associated with the choice of GCMs. Multi-model ensemble approach takes better account of uncertainties involved with GCMs. Moreover, considering a range of possible climate scenarios is recommended than using a single best or average case climate scenario. GCMs shall be downscaled by statistical or dynamical methods (regional climatic models (RCMs)) before using them for regional studies. Bias correction methods can considerably improve the RCM simulations. Evaluation of model performance is recommended for regional-scale studies for the preparation of adaptation strategies. Taking into account the uncertainties associated with climate impact studies can help formulate effective adaptation strategies. © 2020, Saudi Society for Geosciences.
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    Water erosion assessment methods: a review
    (Taylor and Francis Ltd., 2021) Ketema, A.; Dwarakish, G.S.
    Water erosion is the removal of topsoil particles from the surface due to raindrop impact and runoff. Planning and implementation of conservation measures involve knowledge of the spatial pattern of erosion risk. For evaluating the spatial variation of soil erosion, selecting proper method of assessment is critical. The result of the review revealed that there is no single universal method that works everywhere in the world for assessing water erosion. Universal Soil Loss Equation (USLE) and its derivatives (revised [RUSLE] and modified [MUSLE]) were more popular empirical models in water erosion assessment. If the competition is between USLE and its derivatives, choose USLE or RUSLE for predicting long-time average soil loss and the area is dominated by rill and inter-rill water erosion. But, if the intention is to predict sediment yield from particular rainstorm events and the area is dominated by gully erosion, select MUSLE. Moreover, USLE is more suitable for agricultural land and low slope gradients, whereas RUSLE can be used in the nonagronomic area and a wide range of slope gradients. Water erosion assessment methods to be selected based on the intention of assessment and their appropriateness, applicability, and compliance with local conditions. © 2019 Indian Society for Hydraulics.
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    Soil erosion in diverse agroecological regions of India: a comprehensive review of USLE-based modelling
    (Springer Science and Business Media Deutschland GmbH, 2023) Makhdumi, W.; Shwetha, H.R.; Dwarakish, G.S.
    Soil erosion caused by water refers to the removal of topsoil by rainfall and runoff. Proper selection of an assessment method is crucial for quantifying the spatial variance of soil erosion. The Universal Soil Loss Equation (USLE) and its revised version (RUSLE) are widely used for modelling soil erosion. This study aimed to evaluate the effectiveness of the USLE-based soil erosion modelling in different agroecological regions of India, identify potential issues, and provide suggestions for future applications. The review revealed that little attention has been given to estimate soil erosion in high-priority land degradation regions of India. Additionally, many studies failed to thoroughly verify the authenticity of stated soil loss rates in their research regions either by overestimating or underestimating at least one of the five soil loss parameters. Furthermore, flaws in the application of methods to calculate these parameters leading to erroneous values were identified and suggestions for improvement were made. The USLE-based soil erosion modelling is an effective tool for quantifying soil erosion risk, but researchers should put emphasis on thoroughly verifying the methodologies adopted, unit conversions, and data availability for the estimation of soil loss parameters to improve the accuracy of their final results. This paper provides valuable insights to assist researchers in implementing USLE-based erosion models in diverse agroecological regions in India and elsewhere. However, for effective soil conservation and sustainable agriculture, further research is necessary to develop efficient techniques for using USLE-based soil erosion modelling to achieve a comprehensive understanding of erosion risk across different agroecological regions. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    State-of-the-art hydrological models and application of the HEC-HMS model: a review
    (Springer Science and Business Media Deutschland GmbH, 2023) Sahu, M.K.; Shwetha, H.R.; Dwarakish, G.S.
    The hydrologic model is a simplified representation of an existing hydrologic system that helps water resources comprehension, forecasting, and management. Hydrological models are a vital component and essential tool for water resources, environmental planning and management. Urbanization and industrialization significantly impact hydrologic processes locally and globally due to the rapid expansion of population worldwide. Thus, development planning and managing various water resources must meet multiple water demands. However, acquiring gauge discharge data have always been difficult since measurements cannot be taken at every point along the river. Hydrological models are tools, used extensively to simulate many processes of the hydrological cycle. The various ongoing researches are on topics in which the model gives more compatible results with observed discharges. However, it is argued that complex modelling does not provide better results due to soil heterogeneity and climatic changes that play vital roles in streamflow behaviour. Recently, several studies have been conducted to examine the compatibility of model results with streamflow measurements. This paper aims is to provide comprehensive state-of-the-art technology hydrological modelling by briefly discussing different hydrological models and evaluate their application based on Nexus assessment. Furthermore, this paper discussed the different loss methods such as Soil Conservation Service Curve Number (SCS-CN), Soil Moisture Accounting (SMA), Green and Ampt (G.A.), Deficit and constant (D.C.) available in Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS). The literature review suggested that that the HEC-HMS is feasible compared to other models. In additions the review demonstrates that the HEC-HMS performed well for dendritic watershed drainage patterns. This study observed that the SCS-CN method and the SMA method are the most widely methods for event-based and continuous modelling. Compared to other models the D.C. loss approach of the HEC-HMS is the least utilized but found to be straightforward and provide accurate results. This study guides modellers in identifying the type of hydrological models that need to employ to a particular catchment for a specific problem. It also equally helps water resources managers and policymakers by providing them with an executive summary of hydrological studies and sustainable development. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    A Critical Review of the Soil Conservation Services – Curve Number Method in Hydrological Modelling
    (Springer Science and Business Media B.V., 2024) Sreejith, K.S.; Kumar, G.P.; Dwarakish, G.S.
    The Soil Conservation Service Curve Number (SCS-CN) method is popular for predicting surface runoff due to its simplicity, ease of application, and widespread acceptance. However, it has limitations, such as the neglect of storm duration, a lack of guidance on antecedent moisture conditions, and the assumption of a constant initial abstraction coefficient (λ = 0.2), leading to uncertainty. Its reliance on static land use classifications and empirical assumptions limits its accuracy across diverse geographic regions and complex hydrological scenarios, particularly under extreme weather conditions. Furthermore, selecting the most suitable watershed CN values remains a subject of global debate. Moreover, the model is widely applied beyond its originally intended purpose. Its basic assumptions, flexibility in dealing with different hydrological conditions, and susceptibility to variables including soil type, land use, and antecedent moisture conditions have all drawn criticism for the method. To overcome the original curve number method limitations, many studies have been made on improving the SCS-CN method. Despite these advancements, significant gaps remain, particularly in the method's applicability across diverse geographic regions and its accuracy in extreme weather events. This paper revisits the popular SCS-CN method, its history, development of methodology, limitations, and refinements that occurred to the original method with the progress of science and technology. It also explores the need for further research to improve its applicability, highlighting opportunities for more robust, flexible runoff estimation models. © The Author(s), under exclusive licence to Society of Wetland Scientists 2024.
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    State-of-the-art hydraulic modelling: a comprehensive review of HEC-RAS for 1D and 2D applications
    (Taylor and Francis Ltd., 2025) Gupta, J.P.; Sahu, M.K.; Dwarakish, G.S.; Shwetha, H.R.
    Hydrodynamic models simplify natural water systems, aiding in water resource management by simulating water movement in various bodies. They are essential for flood forecasting, hazard mapping and decision-making. Despite challenges in predicting floods due to complex terrain and drainage patterns, ongoing research aims to improve model accuracy. This paper reviews state-of-the-art hydrodynamic models, evaluating their application based on parameters like accessibility, time and space discretization. It focuses on one-dimensional (1D) and two-dimensional (2D) models, including coupled 1D–2D models within the HEC-RAS framework, highlighting HEC-RAS as an effective tool for flood modelling. The integration of hydrological and hydraulic models offers a comprehensive approach to flood forecasting and mitigation. This study guides researchers in model selection for specific catchments and assists water resource managers and policymakers by summarizing key hydrodynamic research and sustainable development strategies. © 2025 IAHS.
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    A Comprehensive Review of Cutting-Edge Flood Modelling Approaches for Urban Flood Resilience Enhancement
    (Springer Nature, 2025) Snikitha, S.; Kumar, G.P.; Dwarakish, G.S.
    Urban environments face a growing threat from floods, driven by factors like excessive rainfall, inadequate drainage, rapid urbanization, and climate-amplified extreme weather events. These floods inflict significant economic losses, endanger public health, and impede disaster response. This review tackles a critical issue by exploring the most effective flood modelling approaches for urban areas. Through a comprehensive analysis, it examines various hydrologic and hydraulic models such as SWAT, HEC-HMS, VIC, TOPMODEL, HBV, ANUGA, LISFLOOD, HEC-RAS, SWMM, MIKE URBAN, and others, highlighting their strengths and limitations, and offering a structured comparison based on criteria for selecting the appropriate model. The research revealed that integrating HEC-HMS and HEC-RAS produced the most favourable outcomes for urban flood modelling when open channels are key components, where the spatial extent of the flood, water surface profile, and velocity are easily determined by the HEC-RAS model. Conversely, SWMM integrates surface runoff and underground drainage, providing comprehensive urban water management. This nuanced understanding underscores the importance of selecting appropriate modelling approaches based on the unique characteristics of urban environments, ensuring effective flood management strategies tailored to the specific challenges each area presents. These urban flood modelling techniques serve as indispensable tools in forecasting flood patterns, evaluating vulnerability levels, and formulating effective strategies to mitigate risks. By empowering informed decision-making in urban planning and disaster management, these models are critical for minimizing the devastating effects of floods on communities and infrastructure. This review provides valuable insights for developing resilient urban areas prepared to navigate the complex challenges of urban flooding. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2024.
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    The coastal zone of Mangalore is acquiring an ever-increasing importance due to its rich ocean resources and favourable conditions for development of port based industries. All weather New Mangalore Port (NMP) Trust is the administrative unit of the port, which caters to the needs of large, medium and small-scale industries. The NMP is situated 10 km North of Mangalore, along Karnataka Coast, West Coast of India. The present study was carried out with a view to (i) understand sediment dynamics (ii) erosion/accretion pattern and (iii) study the coastal processes in the vicinity of the NMP breakwaters. Beach face sediment samples were collected and statistical parameters were determined using Folk and Ward (1957) formulae and then Sediment Trend Matrix (STM) was prepared. The STM was used to draw Sediment Transport Paths (STP), from which predominant sediment transport direction was identified. The performance of breakwaters at NMP was assessed by lead line soundings data. Based on the present study it is concluded that the net sediment transport in the vicinity of the NMP coast is very small. There are no significant changes observed in the bathymetry and shoreline in the vicinity of NMP due to breakwaters construction.
    (Prediction of shoreline evolution by statistical analysis of beach samples and surveys at new Mangalore Port) Dwarakish, G.S.; Natesan, U.
    2005