Mahanadi Delta Research Articles

A 2600-yr multiproxy record for climate and vegetation reconstruction along the Mahanadi River delta, east coast of India

Understanding the impact of climate change on the vegetation cover in the past is crucial for predicting the future warming scenario and its consequences. The present study integrates biotic (palynological analysis) and abiotic proxy (sediment chemistry, clay mineral assemblages and grain size end member (EM) analysis) records in a chronologically constrained sedimentary sequence from the southeastern part of the Mahanadi River delta to reconstruct the hydroclimate since 2600 years. The Mahanadi delta sediments are primarily derived from felsic rock source possibly composed of granites or granulites. The dominance of herbaceous taxa, high aridity index and deposition of fine grain (EM1) sediment possibly suggest a relatively cold and dry climate in the study region during ~2600–2100 cal yr BP corresponding to the Iron Age Cold Period (IACP). Presence of diverse mangrove and tree taxa, deposition of coarser sediment (EM3) and relatively high abundance of secondary clay minerals possibly indicate high precipitation associated with the Roman Warm Period (RWP, ~2100–1800 cal yr BP). A decline in mangroves, dominance of herbaceous taxa and high deposition of fine grain (EM2) sediment from ~1800 to 1300 cal yr BP may indicate a relatively drier climate coinciding with the Dark Age Cold Period (DACP). High moisture index and an increased value of Rb/Sr during ~1300 cal yr BP may suggest a wet phase with the onset of the Medieval Climatic Anomaly (MCA) and later shifted to an arid climate during ~1100–800 cal yr BP. After ~800 cal yr BP, a sharp decline in all weathering indices and vegetation cover, dominance of illite indicates a relatively dry climate which could mark the Little Ice Age (LIA, ~800–300 cal yr BP). A small increase in the terrestrial flux, as well as the weathering indices after ~300 cal yr BP, may suggest the onset of recent warming.

Participatory Stakeholder Assessment for Drivers of Mangrove Loss to Prioritize Evidence-Based Conservation and Restoration in Bhitarkanika and Mahanadi Delta, India

In recent times, environmental stewardship of mangroves has provided the impetus to protect and restore these ecosystems for their inherent ability to protect coastal regions from climate change, sequester carbon dioxide as rich blue carbon, and support human well-being through a multitude of ecosystem services. Participatory stakeholder assessment, as a part of the present study, integrated local stakeholder perspectives in assessing drivers of mangrove loss in Bhitarkanika and Mahanadi delta, Odisha, providing empirical evidence through a mixed-method approach. The use of a Likert scale provided the methodology to develop a single composite variable as the best measure of central tendency. In total, 27.5% of the respondents were locals and were living close to the study area for generations, whereas the other 72.5% represented researchers, academics, and forest department officials. Stakeholder responses at the ground level indicated that Bhitarkanika and Mahanadi delta were facing increased frequency of extreme climatic events followed, by aquaculture and other land-use changes, which can be considered potential drivers causing mangrove loss. Co-development of future scenarios by integrating concerns of all the stakeholders emerged as a potential solution to effectively address the trade-offs arising from local anthropogenic interferences, as well as large-scale developmental activities. This study highlights the need for convergence of multi-disciplinary knowledge from diverse stakeholder groups, including traditional and indigenous knowledge, for the purpose of developing accurate plausible alternative scenarios. Interactive governance and incentivization approaches, along with alternative livelihood opportunities, are proposed as the means to improve conservation and restoration in the region based on the present study. Understanding of the coupled socio-ecological system and its relevance is found to be critical to improve bi-directional linkages of ecosystem health and human well-being.

Land surface temperature distribution in Mahanadi delta: impact of land use land cover change

Land surface temperature distribution in Mahanadi delta: impact of land use land cover change

Monitoring Land Use and Land Cover Changes Prospects Using Remote Sensing and GIS for Mahanadi River Delta, Orissa, India

Natural landscapes have altered dramatically via anthropogenic activity, particularly in places that are heavily influenced by climate change and population increase, such as nation like India. It is crucial for sustainable development, particularly effective water management methods, to know about the influence of land use and land cover (LULC) changes. Geographic information systems (GIS) and remote sensing (RS) were employed for monitoring land use changes utilising quantum ArcGIS and ERDAS Imagine were done for prediction of LULC changes. This research studied the variations in LULC in the Mahanadi river basin delta, Orissa for the years 2010, 2015, and 2020. Landsat satellite pictures were employed to track the land use changes. For the categorization of Landsat images, maximum- likelihood supervised classification was applied. The broad categorization identifies four basic groups in the research region, including (i) waterbodies, (ii) agriculture fields (iii) forests (iv) barren lands (v) built-up areas, and (vi) aquaculture. The findings indicated a big growth in forests from the year 2010 to 2020, but a substantial increase in barren lands had happened by the year 2020, while built-up lands use has witnessed a quick climb. The kappa coefficient was used to measure the validity of identified photos, with an overall kappa coefficient of 0.82, 0.84, and 0.90 for the years 2010, 2015, and 2020, respectively. However, a large drop will occur in agriculture fields in the predicted years. The study effectively demonstrates LULC alterations showing substantial pattern of land use change in the Mahanadi delta. This information might be valuable for land use management and future planning in the region

Vulnerability assessment of environmental degradation due to coastal hazards using geospatial technology—a study of Puri coast along the Mahanadi Delta, India

Vulnerability assessment of environmental degradation due to coastal hazards using geospatial technology—a study of Puri coast along the Mahanadi Delta, India

An environmental magnetic record of Holocene climatic variability from the Chilika Lagoon, Southern Mahanadi Delta, east coast of India

Core sediments from the Chilika Lagoon in the eastern part of the Core Monsoon Zone (CMZ) of India have provided a record of local environmental changes and catchment processes during the past 7800 cal. years B.P. Variations in the rock magnetic parameters (χlf, χhf, χARM and IRM's at varying field strengths) of sediment samples reflect climate-induced changes in the Chilika Lagoon catchment. The down-core variations in the concentration-dependent magnetic parameters indicate an intensified summer monsoon and enhanced terrigenous input to the lagoon during the Early to Mid-Holocene (∼7.8 ka to ∼ 5.5 ka B.P.). In contrast, the Mid- to Late Holocene period witnessed a weaker Indian Summer Monsoon Rainfall (ISMR) and less terrigenous input to the lagoon, with an intermediate phase of strengthened monsoon around 2 to 1 ka B.P. Spectral analysis of sedimentary magnetic susceptibility (χlf) data show significant periodicities (at 95 % significance level) of 2523, 573, 147, 93, 59, and 55 years, which are in agreement with the periodicities shown by other paleoclimatic proxies from the region.

Anthropocene Trails on Geomorphology of Meghalayan Chilika Basin Odisha

The Chilika gulf in the pre-Meghalayan era has transformed into Greater Chilika, later a leaky lagoon and now downsizing. During early Anthropocene epoch (1950) became a restricted lagoon with the stable southern half of the barrier spit and fragile the northerly half. The sediment balance governed by the inland riverine flood flows from south Mahanadi delta (SMD), and through diurnal tides during other periods. The present anthropogenic development are the emerging Bhubaneswar capital (1948), rising population, and peripheral growth of urbans. Chilika, have deteriorated its eco-bio-hydro system and its associated delta. The anthropogenic interventions to flow by dams, barrages, new mouth dredging, Gobakund cut and natural sea-level changes, frequent storms, high waves, and longshore drift, have altered the geomorphology of the area. The present search envisages the physical changes that occurred in about 6000km2 of study area. The Remote Sensing and GIS technology and the ERDAS software tool were in use to concoct for the years 1984, 1994 and 2022, and compared the basic geophysical features geospatially (1975 to 2022). The erratic changes have developed over the lacustrine area, tidal inlets variability, increase in stable barrier spit and ecosystem with the land slamming of storms. Excess tourism activities, exploitation of fishery, motorized communications, poaching and increase of stakeholders have lost its forests, hills, solitude, and tranquility within.

Changes in the Indian Summer Monsoon during the past 600 years: A high-resolution record from the Anshupa Lake, Upper Mahanadi Delta, Core Monsoon Zone of India

• Indian summer monsoon experienced alternate episodes of high and low rainfall. • The little ice age (LIA) was dominated by arid conditions. • Dominance of bacterial magnetism during LIA suggest low sedimentation rate . • Periodicities in χ lf reaffirm solar influence on Indian summer monsoon. The core monsoon zone (CMZ) is an ideal region for reconstructing the Indian summer monsoon rainfall (ISMR). Mineral magnetic and organic geochemical parameters have been measured for an AMS 14 C-dated sediment core from the Anshupa Lake, situated in the eastern part of the CMZ, to reconstruct changes in the paleo-monsoonal precipitation on a sub-decadal scale during the past 600 years. Based on the data obtained, two phases may be recognised in the sedimentation history of the lake over the past six centuries: Phase-I (1397 to 1850 CE) comprising sediments deposited during the Little Ice Age (LIA), and Phase-II (1850 CE to the Present) comprising sediments deposited after the LIA. The measured proxies show decadal to sub-decadal scale variations. The relatively low values of mineral magnetic parameters ( χ lf , χ hf , χ fd , SIRM, χ ARM / χ lf , χ ARM / S I R M , χ ARM / χ lf , and χ ARM / S I R M ) and more positive δ 13 C values during Phase-I suggest a weak ISMR compared to Phase-II. The variations in mineral magnetic parameters suggest that the ISMR was the lowest during the Spörer, Maunder and Dalton Minima, but strong during the intervening periods. This inference resonates with the δ 13 C and C/N profiles of the core. Bacterial magnetite is documented during the mid-16th to mid-17th century, suggesting warm and humid conditions in the intervening phase between the Spörer and Maunder Minima. The magnetic susceptibility ( χ lf ) data exhibit a number of periodicities similar to those shown by cosmogenic nuclide-derived Total Solar Irradiance (TSI) data, reaffirming a solar influence on the Indian summer monsoon in the core monsoon zone of India.

Assessing coastal vulnerability and governance in Mahanadi Delta, Odisha, India

The geo-climatic setting of the Odisha coast is prone to natural calamities like cyclones, storm surges, inundation, along with changing sea level, which indicates a higher level of coastal vulnerability. Climate-induced natural hazards are frequent on the Odisha coast, which leads to adverse impacts on life and property and intensive crop damage. The frequent natural hazards and sea-level rise (SLR) are accelerating the probable impact from severe storm surges and high waves in the future. The futuristic projection of the cyclone, storm surge, inundation and SLR has been estimated. Also, their probable impact on the coastal community has been portrayed.

Assessment of Groundwater Flow Dynamics Using MODFLOW in Shallow Aquifer System of Mahanadi Delta (East Coast), India

Despite being a biodiversity hotspot, the Mahanadi delta is facing groundwater salinization as one of the main environmental threats in the recent past. Hence, this study attempts to understand the dynamics of groundwater and its sustainable management options through numerical simulation in the Jagatsinghpur deltaic region. The result shows that groundwater in the study area is extensively abstracted for agricultural activities, which also causes the depletion of groundwater levels. The hydraulic head value varies from 0.7 to 15 m above mean sea level (MSL) with an average head of 6 m in this low-lying coastal region. The horizontal hydraulic conductivity and the specific yield values in the area are found to vary from 40 to 45 m/day and 0.05 to 0.07, respectively. The study area has been calibrated for two years (2004–2005) by using these parameters, followed by the validation of four years (2006–2009). The calibrated numerical model is used to evaluate the net recharge and groundwater balance in this study area. The interaction between the river and coastal unconfined aquifer system responds differently in different seasons. The net groundwater recharge to the coastal aquifer has been estimated and varies from 247.89 to 262.63 million cubic meters (MCM) in the year 2006–2007. The model further indicates a net outflow of 8.92–9.64 MCM of groundwater into the Bay of Bengal. Further, the outflow to the sea is preventing the seawater ingress into the shallow coastal aquifer system.

Gender dimensions of the migration, sustainability and care nexus: The case study of the Mahanadi delta, India

Migration and environmental change are deeply interconnected processes, intimately linked to development pathways. The gender dimension of these complex interactions is often overlooked. Yet there are profound linkages and implications. This paper focuses on the gender division of labour to investigate how migration and environmental change relate to gender equality and sustainability. The study draws on research conducted in the Mahanadi delta, in the eastern Indian state of Odisha. In the Mahanadi delta labour migration is largely male dominated. Women remain behind in vulnerable environments facing social and economic challenges having impacts on their empowerment and wellbeing. The findings show shifts in work burden, as women often engage in new activities alongside the traditional domestic and social reproductive work but highlight differences across age and household headship. Firstly, this paper identifies the connections between gender, sustainability and care –conceptually and empirically. Secondly, it explores the gender division of labour in the study area by discussing its structural causes. Thirdly, it provides insights into migration dynamics and examines how they feed back into gender equality and sustainability. Finally, it argues for the need of integrated analytical approaches that reflect ecological and social-equity challenges.

Flood Forecasting in Large River Basins Using FOSS Tool and HPC

The Indian subcontinent is annually affected by floods that cause profound irreversible damage to crops and livelihoods. With increased incidences of floods and their related catastrophes, the design, development, and deployment of an Early Warning System for Flood Prediction (EWS-FP) for the river basins of India is needed, along with timely dissemination of flood-related information for mitigation of disaster impacts. Accurately drafted and disseminated early warnings/advisories may significantly reduce economic losses incurred due to floods. This study describes the design and development of an EWS-FP using advanced computational tools/methods, viz. HPC, remote sensing, GIS technologies, and open-source tools for the Mahanadi River Basin of India. The flood prediction is based on a robust 2D hydrodynamic model, which solves shallow water equations using the finite volume method. The model is open-source, supports geographic file formats, and is capable of simulating rainfall run-off, river routing, and tidal forcing, simultaneously. The model was tested for a part of the Mahanadi River Basin (Mahanadi Delta, 9225 sq km) with actual and predicted discharge, rainfall, and tide data. The simulated flood inundation spread and stage were compared with SAR data and CWC Observed Gauge data, respectively. The system shows good accuracy and better lead time suitable for flood forecasting in near-real-time.

Evolution of Marine Bars under Micro and Mesotidal Settings of Mahanadi Delta Coast

Shoreward migration process of longshore bar is an important aspect of shoreline changes in the Mahanadi delta front. It involves coalescence of individual bars to form large complex bars just before welding on to the shoreline. Such welding sometimes results in the formation of large hook spits. Bar welding mechanism can be an extremely important form of natural beach nourishment. This study aims to detect stages of evolution of longshore bars and consequent welding with mainland. Multi-dated Landsat images have been used to detect evolution of longshore bar and welding processes. QGIS platform has been used to process images and compose required maps.

Prediction by Soft Computing, Planning, and Strategy Building of Aquatic Catch: Chilika Lagoon, Odisha, India

Introduction: The Chilika lagoon in south Odisha, India was ecologically degraded from 1985 onwards by reduction of its aquatic (fish + prawn + shrimp) catches along with reduction in salinity, hydraulic regime, water exchange, aquatic weeds invasion, and sediment influx. The aquatic catch was 8669MT in year 1985-1986 gradually reduced to 1274MT during 1995-1996 from Odisha Fisheries Dept. records which resulted in poor economic condition of ≈0,2million fishermen and they migrated to adopt other livelihood. One direct tidal inlet dredged (Sipakuda) and Naraj barrage in the apex of South Mahanadi Delta were the major hydraulic interventions made to regain hydraulic regime. After the hydraulic interventions, the eco system restored, and the aquatic catch surged but it was insufficient to livelihood sustenance for the fishermen community of the Chilika, so that they are forced for alternate occupation and migration.
 Methodologies: Fish catch data collected for 30 years and soft computing models linear regression, Multi Linear Perception (ANN), SMOorg (SVM) and the Random Forest algorithms (Weka Software) are used to predict the fish catch data of the lagoon for coming decade from 2020 to 2030. The effects of major hydraulic interventions are analyzed and the soft computing method of the fish and shrimp catch prediction of the Chilika has been attempted for the first time except some statistical approaches.
 Results: The Random Forest is found to be the preferred algorithm followed by the MLP model. The amount of catch remained around 12-13TMT if the variables and the present status of the lagoon is maintained. The combined effect of the Sipakuda Tidal inlet and the effective operation of the Naraj barrage have maintained the sustainable aqua catch. The present study shall be an immense help for the lake users and policy makers to augment aquatic catch, and alternate livelihood fishers community of the Chilika lagoon.

Anthropocene Physiography and Morphology of Chilika; India

Introduction: Based on stratigraphy, events, ecology and climatology, the present time is assigned Anthropocene epoch due to dominance Homosapiens over geo- bio-hydro-aero spheres of the mother earth during its accepted Anthropocene epoch succeeding the official 11700 years old Holocene epoch from 1950. Asia’s largest shallow brackish water lagoon, the Chilika housed over about 1000km2, behind 64.3km barrier spit with multiple tidal inlets to Bay of Bengal. It is sinking and shrinking due to rapid dimensional diminution, environmental degradation, sedimentation, salinity depletion, phytoplankton invasion. Present study envisages the elementary morphology, formation mechanism, sediment transport, and dynamic performance of tidal inlets and the lagoon by applying GIS methodology between the year 1930 and 2017 including its local catchment land use changes within the lagoon and associated south Mahanadi delta. Under vulnerability, the brackish water lagoon is constantly deteriorating its ecosystem, it is required for wise use of the wetland that can alleviate the poverty, uplift lagoon users economy, and disallowing the stakeholders living standard during present Anthropocene epoch

Multiple values of Bhitarkanika mangroves for human well-being: synthesis of contemporary scientific knowledge for mainstreaming ecosystem services in policy planning

Bhitarkanika National Park and Mahanadi Delta are the most biologically diverse mangrove patches of India. Due to inadequate representation of the value of the mangroves in decision-making, mangroves of Bhitarkanika and Mahanadi delta have undergone a rapid decline in the last fifty years. Thus, there is a growing need to assess the ecosystem services and multiple values of mangrove ecosystems in the region, and to identify the various anthropogenic and environmental drivers acting upon them. In this paper, we conducted a bibliometric analysis, followed by a synthesis of contemporary knowledge to understand the diverse ecosystem services of the Bhitarkanika mangroves and the existing data gaps for the protection and sustainable management of mangroves. It was observed that Bhitarkanika mangroves primarily serve as a buffer to coastal storms, tsunamis and cyclones, and they also contribute immense provisioning, and cultural ecosystem services for human well-being. The present review provides a comprehensive database projecting important ecosystem services and multiple values (including carbon sink potential, pollinator benefits and protection from storm surges) of Bhitarkanika mangrove forests. We found that there is a significant pressure on the mangroves of Bhitarkanika due to increasing aquaculture, environmental pollution, industrialization, storm surges and frequent cyclones. The present study helps to understand the urgent need of protecting the existing mangroves and to devise a coastal zone policy framework and strengthening participatory approaches for preservation of dense and intact mangroves of Bhitarkanika and Mahanadi delta.

Horseshoe Crab: A Keystone Species of Mangrove Forests of Coastal Belts of Sunderban

The mangroves within the biosphere reserve of Sundarban and Mahanadi Delta at Bhitarkanika and Kendrapara along the coastal belt of Bay of Bengal have been under considerable human impingement especially over the last few decades. Land reclamation for settlements along with agriculture and unplanned aquaculture practices, mechanized fishing in addition to non sustainable tourism activities proved deterrent to the ecosystem. It effect not to mention the additional burdens of pollution and changes in hydrological regimes that in turn causing adverse influence on subsistence dwellers in and around north-east coastal belt of Bay of Bengal. The horseshoe crabs are the creature on this earth surviving for the past 450 million years or so. Most of the biogenic activities of the horseshoe crab occur in the open ocean at a deeper zone. They specifically migrate regularly towards the shore for the purpose of breeding. Among the two Indian horseshoe crab species namely, Tachypleus gigas and Carcinoscorpius rotundicauda, the later species prefers mangrove habitat for breeding along the north-east coast of India. However, in spite of all previous studies on T. gigas such as spawning migration, feeding behaviour, breeding biology and several other aspects, no concerted efforts have been made for C. rotundicauda to develop effective strategies in protecting and conserving both the habitat and population of this valuable species along the coastal areas of India. The depleting population and losing important biodiversity has prompted us to undertake such a novel project. The degradation and destruction of the ground in the mangrove ecosystem of this species by natural and anthropogenic activities have also resulted in mass depletion of the population of this species along the north-east coast of West Bengal and Odisha. A mature female of this species carries hundreds of eggs under its prosoma but releases only a few eggs in one spawning act in a nest on suitable muddy breeding grounds in mangrove areas. The total number of eggs laid varied from 18 to 258 in each nest. The nest of the horseshoe crab is a depression in mud made by the female for laying their gametes. After fertilization, most of the pairs migrate to their natural habitat.

Fluvial response to Late Quaternary sea level changes along the Mahanadi delta, east coast of India

This study presents the fluvial response to late Quaternary sea level changes in the Mahanadi delta. Channel morphological adjustments indicative of sea level changes, such asanastomosing-meandering transition, dendritic channels, and river mouth shift, have been used to reconstruct the paleo-coastlines. Major rivers in the Mahanadi delta (e.g., Mahanadi, Devi, Brahmani, and Baitarani) show alteration of anastomosing and meandering fluvial systems at the late Quaternary strandlines. Two generations of dendritic channels, i.e., Early to Mid- (>5 ka) and Mid-to Late (<5 ka) Holocene, have been identified based on OSL ages and affinity to the paleostrandlines. Lateral shift of river mouths in response to sea level changes have been observed in the lower deltaic plain. The delta distributaries such as Bhargavi, Kushabhadra, Brahmani and Baitarani rivers shifted their mouths due to Early to Mid-Holocene (6–7 ka) marine transgression. Different generations of paleochannels in the Mahanadi delta indicate episodes of the delta progradation since Mio-Pliocene. The distributary paleochannels along the Mio-Pliocene strandline indicate the initial stage of Mahanadi delta development. The river morphological response to the changing coastline of the Mahanadi delta is similar to paleo-fluvial morphological adjustments observed along the paleostrandlines of major deltas around the world.

Evaluation and planning of existing drainage project for reclamation of waterlogged area: a case study

Due to the flat topography and poor drainage condition, major parts of the Mahanadi delta command suffer from waterlogging problems. The sustainability of farm operations are highly affected by spatial and temporal rainfall variability. Thus, estimation of drainage design layout and identification of vulnerable area for waterlogging is the most vital operation for achieving maximum yield of paddy in cultivated land. This research investigation aimed to achieve an optimum level of soil moisture in the study area so that the yield of crops could be enhanced. Probability analysis of 25 years daily rainfall data was done to evaluate the appropriate drainage coefficient and runoff. Drainage coefficient for the study area was estimated to be 35.50 mm/day by SCS-Curve Number (CN) method, which was adopted for the design of surface drainage system with the 7 consecutive day storm and 10-year return period. The design discharge and peak discharge were evaluated to be 0.43 m3/s by SCS-CN method and 4.92 m3/s by the rational formula respectively, which were used for the design of the channel and the outlet structure, respectively. Standard procedures were adopted for the design of the channel as well as dimensions of the broad-crested drop spillway as outlet structure, respectively. The benefit-cost ratio of the new designed drainage system was found to be 2.48, which proved the new drainage system to be more efficient than the existing design.

Effects of climate change and management policies on marine fisheries productivity in the north-east coast of India

The study covers two important deltaic systems of the north-east coast of India, viz. the Bengal and Mahanadi delta that support about 1.25 million people. The changes in potential marine fish production and socio-economic conditions were modelled for these two deltas under long-term changes in environmental conditions (sea surface temperature and primary production) to the end of the 21st century. Our results show that an increased temperature (by 4 °C) has a negative impact on fisheries productivity, which was projected to decrease by 5%. At the species level, Bombay duck, Indian mackerel and threadfin bream showed an increasing trend in the biomass of potential catches under the sustainable fishing scenario. However, under the business as usual and overfishing scenarios, our results suggest reduced catch for both states. On the other hand, mackerel tuna, Indian oil sardine, and hilsa fisheries showed a projected reduction in potential catch also for the sustainable fishing scenario. The socio-economic models projected an increase of up to 0.67% (involving 0.8 billion USD) in consumption by 2050 even under the best management scenario. The GDP per capita was projected to face a loss of 1.7 billion USD by 2050. The loss of low-cost fisheries would negatively impact the poorer coastal population since they strongly depend upon these fisheries as a source of protein. Nevertheless, adaptation strategies tend to have a negative correlation with poverty and food insecurity which needs to be addressed separately to make the sector-specific efforts effective. This work can be considered as the baseline model for future researchers and the policymakers to explore potential sustainable management options for the studied regions.