Chandra shekhar prasad Ojha

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• PhD, Imperial College, London
• Professor (Full) at Indian Institute of Technology Roorkee

Evaluation of local groundwater levels (GWL) is crucial for sustainable water resource management. This study introduces a novel approach leveraging field gravity data to optimize machine learning (ML) models for local GWL evaluation. This unique approach holds the potential to bring about significant breakthroughs in groundwater management. The pe...

The intricate relationship between groundwater and surface water has garnered significant attention due to the formidable challenges in model validation and calibration. These challenges mainly stem from the dynamic exchange at the soil–water interface, which becomes more intricate at smaller scales, posing significant obstacles for researchers. Ho...

Recent studies show variations in precipitation‐gridded data set accuracy with changing geographical parameters. Ensemble precipitation products, combining diverse data sets, offer global‐scale effectiveness, but applying them to regional studies, particularly in small to medium‐sized sub‐basins, presents challenges in addressing precipitation depe...

To address the current challenge of climate change at the local and global levels, this article discusses a few important water resources engineering topics, such as estimating the energy dissipation of flowing waters over hilly areas through the provision of regulated stepped channels, predicting the removal of silt deposition in the irrigation ca...

This study explored using ultrafiltration (UF) membranes to treat pulp and paper mill wastewater, implementing a novel Taguchi experimental design to optimize operating conditions for pollutant removal and minimal membrane fouling. Researchers examined four factors: pH, temperature, transmembrane pressure, and volume reduction factor (VRF), each at...

Riverbank erosion poses a significant threat to the stability and integrity of river training structures. River training structures such as groynes are important components of sustainable development as they play a crucial role in mitigating flood risks, controlling erosion, and supporting the habitat for aquatic organisms. The habitats vary largel...

The current research examines the after-effects of climate-induced disasters in India's Himalayan region, as well as the consequences of highway damage. To avoid the damages caused by heavy rain, cloudbursts, and landslides, a design of stepped storm waterway downstream of the underpass rainwater drainage is recommended to overcome such failure in...

Given the challenges posed by climate change and the scarcity of water, it is essential to adopt sustainable irrigation practices that do not compromise crop yields. Research studies are crucial to determine the optimal deficit soil moisture levels to be maintained for cultivation in different soil types. This study examines the response of maize g...

This study delves into the analysis of recession characteristics of spring base flow, focusing on the Hill Campus Spring (elevation of approximately 2,150 m) and Fakua spring (elevation of approximately 1,850 m) in the Tehri Garhwal district of Uttarakhand, India. Spanning from January 1999 to December 2004, discharge data from G.B. Pant University...

This research aimed to assess the vulnerable locations of landslide using GIS modeling. This study was performed on Uttarakhand state of India. Most of roads and settlements are lies on sharp to moderate slopes regions. This state has experienced number of historical landslide events that led to loss of public properties. So, there has been need to...

The present study discusses and analyses the influence of composite roughness on the stage-discharge relationships and flow characteristics in compound channels with different channel roughness. An analytical solution to predict depth-averaged velocity, non-dimensional coefficient, integration constants and composite roughness is developed by consi...

The present work explores the process of mathematical representation for the complex geometry of a wide alluvial river with high braiding intensities. It primarily focuses on an approach to developing a numerical solution algorithm for representing the complex channel geometry of the braided Brahmaputra River. Traditional elliptic PDEs with boundar...

Land degradation is a noteworthy environmental risk causing water quality issues, reservoir siltation, and loss of valuable arable lands, all of which negate sustainable development. Analysis of the effect of land use changes on erosion rate and sediment yield is particularly useful to identify critical areas and define catchment-area treatment pla...

River bank protection is a vital component of sustainable development. This study investigates and compares the scour and flow features around two different types of groynes, an unsubmerged I-head groyne (IHG) and T-head groyne (THG), to provide insights into their performance and efficiency in river reaches. Experiments were conducted to examine t...

The friction factor is a widely used parameter in characterizing flow resistance in pipes and open channels. Recently, the application of machine learning and artificial intelligence (AI) has found several applications in water resource engineering. With this in view, the application of artificial intelligence techniques on Moody’s diagram for pred...

Landfill leachate is a complex mix of organics, inorganics and heavy metals produced from conventional and engineering landfilling practices. The adverse effects of landfill leachate on human and environmental health have forced the relevant authorities to stipulate stringent disposal requirements, producing the need for ground-breaking technologic...

Landfill leachate is a complex mix of organics, inorganics and heavy metals produced from conventional and engineering landfilling practices. The adverse effects of landfill leachate on human and environmental health have forced the relevant authorities to stipulate stringent disposal requirements, producing the need for ground-breaking technologic...

Landfill leachate is a complex mix of organics, inorganics and heavy metals produced from conventional and engineering landfilling practices. The adverse effects of landfill leachate on human and environmental health have forced the relevant authorities to stipulate stringent disposal requirements, producing the need for ground-breaking technologic...

Statistical downscaling (SD) is preferable to dynamic downscaling to derive local-scale climate change information from large-scale datasets. Many statistical downscaling models are available these days, but comparison of their performance is still inadequately addressed for choosing a reliable SD model. Thus, it is desirable to compare the perform...

Leachate is a highly digested by-product of waste degradation originating from municipal landfills. It has high pollution potential and needs to be treated before disposal. Environmentally sustainable technology like microbial fuel cells (MFCs) is becoming a novel choice as it treats and also produces energy from leachate. Nevertheless, the suitabi...

Increasing frequency of extreme rainfall induced catastrophic urban flood events in recent decades demands proactive efforts to assess flood risk and vulnerability. Here, we develop an integrative framework for fine spatiotemporal scale assessment of urban flood response to historical and future projected changes in extreme precipitation. The frame...

Hydrological sustainability is a significant phenomenon associated with several processes in the biosphere. This study analyzes the land-based remote sensing inputs for the hydrological sustainability of the upper Ramganga Catchment in the Himalayas. The catchment units (117) are delineated from the SRTM-DEM. The spectral indices, NDBSI, NDVI, NDWI...

Modeling hydrological processes for managing the available water resources effectively is often complex due to the existence of high nonlinearity, and the associated prediction uncertainty mainly arising from model inputs, parameters, and structure. Despite several attempts to quantify the model prediction uncertainty, reducing the same for improvi...

Elevated Landfill temperatures have an undesirable effect on landfill cover, stability, slope and leachate migration pattern. Thus, to predict the temperature profile in the landfill a distributed numerical model using MacCormack finite difference method is developed. The developed model considers stratification of the upper and lower layers of the...

Groynes are river training structures which are constructed across the river extending outwards from the channel bank towards the mainstream to channelize the stream, protect banks from erosion and improve navigability of the channel. When constructed in series, in addition to local effect, groyne fields, formed between two consecutive groynes, con...

Slopy agricultural lands are more susceptible to soil erosion and hence are priority sites for the application of protective soil management practices. A conservation agriculture field experiment was established at a 6% field slope in 2011 at the ICAR-IISWC Research Farm, Dehradun, Uttarakhand, which is situated in the Northwestern Himalayan Region...

The curve number method is a universally accepted and widely explored model in the last four decades which is used to estimate event-based surface runoff. Its simplicity and versatility have made it popular, and the basic equation is used as an important part of various hydrological models. In the development of the SCS-CN model, various advanced a...

A very simple and widely used SCS-CN method is a time-independent method that is used to calculate accumulated runoff corresponding to a single rainfall event. The method requires only two parameters initial abstraction coefficient (λ) and the potential maximum retention (S) expressed in terms of curve number (CN). The CN value incorporates many fa...

Environmental sustainability assessment is a crucial part of the management of natural resources. Remote Sensing based environmental land cover indices such as Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Normalized Difference Built-up Index (NDBI), Normalized Difference Moisture Index (NDMI), and its ass...

A FIXED DEPTH HORIZONTAL SOIL PROFILE SAMPLER ( Patent No. : 476627, Application No. : 202311027263) The invention provides a fixed depth horizontal soil profile sampler. The soil sampler comprises a lower rod, and an upper rod. The upper rod is slidably connected to the lower rod and the upper rod is extended in a specific direction with respect...

Water and carbon footprint assessment can be a good indicator of sustainable agricultural production. The present research quantifies the potential impact of near-future (2026–2050) climate change on water footprint (WF) and carbon footprint (CF) of farm-level kharif rice production of three locally grown varieties (Khandagiri, Lalat, and Swarna) i...

In several low‐ and middle‐income countries, such as India, the rapid construction of toilets to combat open defecation has not been matched with adequate wastewater treatment, resulting in extreme fecal contamination of the receiving environments. The sewage‐receiving surface water bodies, typically close to the residences, are a potential hotspot...

A vortex tube silt ejector is a curative hydraulic structure used to remove sediment deposits from canals and is recognized as one of the most efficient substitutes for physically removing canal sediment. The spatially varied flow in the channel and the rotational flow behavior in the tube make the silt removal process complex. It is even harder to...

Occurrences of extreme events, especially floods, have become more frequent and severe in the recent past due to the global impacts of climate change. In this context, possibilities for generating a near‐accurate streamflow forecast at higher lead times, which could be utilized for developing a reliable flood warning system to minimize the effects...

Montana fume is derived from Parshall fume by eliminating diverging part and throat. The mass transfer of oxygen from the atmosphere into the water is known as aeration. The dissolved oxygen (D.O.) concentration in the water body determines water quality. The experiment was performed on six diferent Montana fumes fxed in a tilting prismatic rectang...

Rainfall occurrence (or rainy days) during the Indian summer monsoon (ISM) exhibits a significant decline over the last century, that is considerably more widespread than the decline observed in rainfall magnitude. Here, we investigate the teleconnections of monsoon rainfall occurrence in India with prominent large-scale climate systems to examine...

Statistical downscaling (SD) is preferable to dynamic downscaling to derive local-scale climate change information from large-scale datasets. Many SD models are available these days, but comparison of their performance is still inadequately addressed for choosing a reliable SD model. Thus, it is desirable to compare the performance of SD models to...

Phytoremediation is considered an effective and economical method for metal recovery along with removing toxic chemicals from contaminated soil. The studies done so far concentrate on the factors responsible for uptake of a single heavy metal from the soil. However, in nature, pollutants are generally found as a mixture of various heavy metals. Fur...

A novel pilot scale post-anoxic integrated biofilm activated sludge system of capacity 50 m³/d, was used to treat municipal wastewater. Treatment process comprised of three biological reactors which includes aerobic tank with PVA-gel beads followed by anoxic tank and aerobic tank. The plant was operated at HRT of 6 h, with an average SRT of 10 days...

Agro-waste having lignocellulosic biomass is considered most effective (heating value 16 MJ/kg) for energy production through anaerobic digestion (AD). However, recalcitrant lignocellulosic fraction in agro-waste obstructs its biotransformation and is a rate-limiting step of the process. This study investigated the effects of hydrothermal and therm...

Water resources in India's Indo-Gangetic plains are over-exploited and vulnerable to impacts of climate change. The unequal spatial and temporal variation of meteorological, hydrological and hydrogeological parameters has created additional challenges for field engineers and policy planners. The groundwater and surface water are extensively utilize...

Agro-waste (wheat straw) is considered most effective (heating value 16 MJ/kg) for energy recovery through anaerobic digestion (AD). However, the complex lignocellulosic structure obstructs their biotransformation and is a rate-limiting step of the AD process. The pretreatment of agro-waste could remove the physical and chemical barriers and accele...

The Himalaya plays a vital role in regulating the freshwater availability for nearly a billion people living in the Indus, Ganga, and Brahmaputra River basins. Due to climate change and constantly evolving human-hydrosphere interactions, including land use/cover changes, groundwater extraction, reservoir or dam construction, water availability has...

Background: Wheat is an important crop of India That is grown in the winter season (October to April). A field study was conducted for nine plots having a dimension of 3 × 2 meter and different nutrient was applied to test the biomass yield. The objectives are to describe (a): To conduct field experiments under controlled conditions and vary the do...

In the present study, a numerical model is developed to simulate the soil moisture flow and root water uptake under the limiting conditions in the root zone. The model solves the Richards equation by a mass conservative fully implicit finite difference scheme. The model is applied to two problems, i.e. numerical experiments on wheat grown in silt l...

In this study, a hybrid approach has been used to increase the predictive efficiency of the SCS-CN model. A recently proposed Ajmal model (developed after randomized configuration) that ignored initial abstraction and maximum potential retention has been given the conceptual framework of the SCS-CN model and a new outcome-based hybrid model (Miv) w...

In this study, four batch assays were performed to ensure the synergic effects of co-digestion and find out the best inoculums to substrate ratio (ISR), carbon to nitrogen ratio (C:N), and total solid (TS) percentage in sequence. The co-digestion of three feedstocks had a 20% higher biogas yield (416 mL/gVS added) than mono-digestion with 21% volat...

Montana flume is derived from Parshall flume by eliminating diverging part and throat. The mass transfer of oxygen from the atmosphere into the water is known as aeration. The dissolved oxygen (D.O.) concentration present in the water body determines water quality. The experiment was performed on six different Montana flumes fixed in a tilting pris...

Spatial and temporal variation in flow rate for any particular area are prevalent due to various meteorological and other factors existing in nature. However, significant variations in these factors cause extreme events (e.g., floods and droughts). Farakka barrage is located on the Ganges River, and the discharge data are classified for several yea...

Safe drinking water and sanitation are very important for the survival of human life. With the rapid proliferation of industries, growth in population and different forms of pollution, i.e. in water, air, soil and sediments, the living environment and the ecosystem is constantly polluted. In this context, integrating different water resources for e...

Quality discharge measurements and frequency analysis are two major prerequisites for defining a design flood. Flood frequency analysis (FFA) utilizes a comprehensive understanding of the probabilistic behavior of extreme events but has certain limitations regarding the sampling method and choice of distribution models. Entropy as a modern-day tool...

Bottom racks are widely used in mountainous regions as intake structures for diverting water from the mainstream for different purposes. Most of the studies on bottom rack flow consider the concept of invariant specific energy. The present study experimentally investigates the specific energy loss in horizontal transverse bottom rack flow for Froud...

The leachates emanating from the landfills are high in organic loads and thus become potential sources of contamination for both surface and groundwater. As the landfill ages, the nature of leachate changes from acidic to alkaline. The change in pH level affects the chemical oxygen demand (COD)/biochemical oxygen demand (BOD) ratio and when it is l...

A deficit in rainy days can affect crop production and escalate groundwater abstraction leading to groundwater depletion, thus may threaten food and water security in the Indian subcontinent. The available researches on rainfall occurrence in India represent inconsistency in several fundamental considerations (spatial scale of analysis, the definit...

Recent studies have shown the cold and arid trans-Himalayan region comprises significant areas underlain by permafrost. While the information on the permafrost characteristics of this region started emerging, the governing energy regime is of particular interest. This paper presents the results of a surface energy balance (SEB) study carried out in...

In this paper, a 2-D turbulent closure model, based on the pollutant mass conservation equation, is adopted to estimate the local and background pollutants in the predominant wind direction for the stable atmosphere during winter mornings. The background concentration of pollutants can severely affect the regional pollution level, and its monitorin...

The present study analyzes the effect of salinity on crop growth and root zone soil moisture dynamics. A newly developed root water uptake (RWU) model was used for simulation of soil moisture and RWU for irrigation field experiments where paddy was grown with irrigation water with varying salinity concentrations (0.5, 7.9, 14.7, and 21.2 dS/m). The...