Periodic Dredging Research Articles

Geochemical fractionation of trace metals and ecological risk assessment of surface sediments in Sepetiba Bay, Brazil.

The Sepetiba Bay (Southeast Brazil) is a known Cd- and Zn-contaminated site that received spills of a large slag pile leachate from a Zn smelter. With important harbors, Sepetiba Bay demands periodic dredging operations which affect the mobility of the metals. The main goal of this work was to assess metal mobility in sediments and its associated toxicity in a fictive dredging area, to evaluate the risks of the operation. To achieve this goal, 18 superficial sediment samples were collected and characterized for pH and Eh. Sediments were analyzed for grain size, organic carbon, and total nitrogen, and metal mobility was evaluated with a sequential extraction procedure, proposed by the European Community Bureau of Reference (BCR). The results demonstrate that Cd and Zn are mainly associated with the exchangeable fraction (mean concentrations 1.4mgkg-1 and 149.4mgkg-1, respectively) and reducible fractions (mean concentrations 0.3mgkg-1 and 65.5mgkg-1, respectively), while Fe, Cr, Cu, Ni, and Al were associated with the residual fraction. Metals in the residual fraction are probably associated with the mineral lattice of the sediment and should not represent an environmental risk for the biota. The application of the enrichment factor and three risk assessment indexes (Risk Assessment Code, Risky Pollution Index, and Bioavailability Risk Assessment Index) show that the sediments are considerably enriched in metals that constitute a relevant risk for the sediment biota. In the case of dredging operations, Cd and Zn should be released to the overlying waters and be available to organisms, threatening the whole ecosystem. The proposed approach was shown to be much more precise than what is frequently presented in the Environmental Impact Assessments that only consider the threshold limits of the legislation.

Retaining of dredging waste using geotextile tubes: analysis of the dewatering and undrained shear resistance of the sludge cake

The city of Rio Grande has its economy linked to coastal and port activities and has a port complex of high economic importance for the region. To maintain the depth of the port channels, periodic dredging operations are carried out, as occurred in the Port of Rio Grande between 2018 and 2020. Approximately 16 million m³ of sediments were removed from the channel and deposited in disposal zones. There has been an attempt to develop techniques that carry out the reuse and disposal of dredging waste more appropriately, seeking to minimize environmental impacts by avoiding inappropriate open-sea or onshore disposal. Within this context, this work aims to evaluate the potential of the retaining and dewatering process of dredging waste in geotextile tubs (linear geoforms, geobags e etc). This technique reduces the volume of dredged mud through desiccation and allows the geotextile tubs to be installed in sedimentation basins onshore or coastal protection structures. Thus, the present study evaluated the dewatering and filtration efficiency of these systems through tests of small bags. The advantages of adding flocculation polymer and the behavior of undrained shear strength over time of the retained cake were evaluated.

Optimized Drainage System Design for Andesite Mining at PT. Rolas Nusantara Tambang, Kejayan, East Java

This study presents a systematic approach to designing a filtration system aimed at efficiently managing rainwater and surface runoff outside mining areas. Utilizing a quantitative method, the data collection predominantly involves secondary sources. The data is processed through a series of steps: rainfall projection, delineation of rainwater catchment areas, calculation of rainfall intensity and inflow rate, and determination of open channel and settling pond dimensions. The designed open channels have a trapezoidal shape with specific dimensions including a base width of 0.51 m, a side length of 0.62 m, a slope angle of 60°, and a channel depth of 0.54 m. These channels span a total length of 2.216 m. The accompanying settling ponds are rectangular with dimensions encompassing a length of 31 m, a width of 11 m, a depth of 6 m, and an area of 341 m². These ponds have a volume capacity of 2,046 m³, achieving an impressive 90.89% efficiency. Notably, maintenance of the settling pond involves periodic dredging using the Kobelco SK200 Excavator at intervals of roughly 16 years (5,817 days). Given that this maintenance duration surpasses the expected mine lifespan, no further interventions are required for the pond during the mine's operational period.

The current state of the Southern Bug River mouth ecosystem

The article considers the pre-war conditions main components of the Southern Bug mouth ecosystem. The results of sediments samples study have shown transformation of lagoonal accumulation, appearance of reducing condition spots in sediments, presence of exceeding MAP for lead. An estuarine water analysis given an idea about hydrochemical features mouth section of river, namely: high concentration of suspended solids – on an average 11,4 mg/dm3; increasable concentration BOD5 – an indicator of easily oxidized organic substances content; periodic significant exceeding MAC of ammonium and nitrite nitrogen. Hydrobiological changes primarily concern a decrease in primary productivity due to a decline in phytoplankton biodiversity; there was also a reduction of zooplankton. The current state of the Southern Bug River mouth ecosystem is formed predominantly under the periodic dredging of shipping channels followed by the formation silt dumps. The post-war revitalization of the Southern Bug estuary ecosystem should include measures to mitigate the negative effects of anthropogenic activity especially the consequences of hydraulic engineering works.

Late Holocene filling of the Canale di Imbocco (Portus, central Italy): a multidisciplinary palaeoenvironmental perspective

Portus was the main port of imperial Rome from the 2nd century AD to the 5th century AD, with an inner, hexagonal port (Trajan basin) and an outer port (Claudius basin) linked by a channel bounded by quays. Six sedimentary facies have been differentiated in the geological analysis of a core extracted in this channel, basically composed of poorly classified bioclastic muds typical of restricted environments, accumulations of Posidonia oceanica (Linnaeus) Delile, 1813 and a final anthropic fill. The subfossil record of bivalves, foraminifera and ostracods is characteristic of Mediterranean brackish environments (lagoons, estuaries, deltas) with significant environmental stress, due to changes in the physical-chemical parameters and probably the periodic dredging of this seaway during a period of about 300 years. The presence of “Neptune balls” points to the development of probable stormy periods that deposit these unique structures in the internal areas of this historic port.

Sedimentation processes in the navigation channel of Patos Lagoon Estuary, southern Brazil

The morphology of estuarine navigation channels varies in time and space. Siltation occurs in areas where flow conditions enable sediment trapping and it limits navigability in most cases, requiring periodic dredging. Identifying sedimentation patterns is fundamental to designing ports to reduce siltation. The Port of Rio Grande, located in the Patos Lagoon estuary, holds strategic significance and it is a key example for understanding the evolution of large estuarine access channels. We used 19 bathymetric surveys from April 2001 to February 2018 to generate Digital Elevation Models and evaluate the evolution in time of bed morphology in the Porto Novo basin and its access channel (located in Port of Rio Grande). Also, we considered hydrological data available from September 2005 to December 2011. Major siltation rates were observed in the northwestern portion of the basin and the convex margin of the access channel, whereas other locations exhibited stable conditions. Channel configuration and position were determinants to define spatial variations of sedimentation processes. Hydrological conditions, mainly when discharge exceeds 4,000 m3/s over long periods, strongly controlled siltation magnitude in the Porto Novo basin and its access channel.

Life Cycle Assessment (LCA) of Substrate Mixes Containing Port Sediments for Sustainable 'Verna' Lemon Production.

The increase in maritime trade and its global economic importance have forced port management actors to carry out the periodic dredging of their sediments to maintain an adequate depth for the passage of large ships to maintain their operation and competitiveness. During the dredging process, large volumes of port sediment are generated. Dredged port sediment is currently considered a waste material and its disposal is regulated. Finding ways to safely reuse port sediments is necessary for sustainable development. In this study, a life cycle assessment (LCA) methodology was applied to identify the environmental impact of port sediments when used as a culture medium for lemon trees. A total of 90 lemon trees (Citrus limon L. Burm var ‘Verna’) were used in the trial. The trees were grown under controlled conditions using three substrates, with different portions of peat and port sediment (25%, 50%, and 75%) to identify the real impacts of the culture media on the growth process. The LCA was calculated and analyzed according to the ISO 14040:2006 standard, using the SimaPro v. 9.3 software (PRé Sustainability B.V, Amersfoort, The Netherlands). The functional unit defined for the three-culture media was 1 kg of lemons. The LCA results showed a significant increase in the environmental impact of lemon cultivation proportional to port sediment content (75%), due to the decrease in fruit production caused by the sediment. However, the least impact was identified for the culture medium at 50% peat and 50% port sediment. The greatest impacts were more related to crop management rather than the port sediment content. The results showed that the use of the port sediment, mixed with other substrates as an agricultural medium amendment, is a viable option for lemon growers.

Estimation of littoral drift for non monsoon using beach and nearshore profiles

ABSTRACT Beach profile measurements spatially and temporally or information on periodical dredging helps in assessing the littoral drift in an area. Beach profiling is one of the traditional methods to understand the beach as well as nearshore morphology in a short term. Exact quantification is always a challenging task near coasts as a part of coastal zone management activities due to the lack of enough information pertaining to sediments and its movement. In this study, the long and crossshore movements of sediments were analysed by using beach and nearshore profiles at three typical locations along South Karnataka coast in non-monsoon season. The rates of changes in areas and volumes were estimated along Gokarna, Honnavar and Malpe locations. All the locations are connected with inlets or estuaries or ports. The analysis of nearshore profiles indicated marginal changes in areas at Gokarna and Honnavar. The change is relatively more at Malpe site. The rate of volume changes of sediment over a study period increases towards south from Gokarna to Malpe and varies from 0.14 M m3 to 0.17 M m3. The potential longshore drift along the coast was also estimated whose correlation is strong with the shoreline orientations of the locations considered.

Disaster risk reduction of mount agung cold lava flood at the Bali cultural centre in Klungkung Regency

The Bali Province Government plans the development of Bali Cultural Centre as a comprehensive cultural information centre to support the development of Culture-oriented Bali Tourism. The Bali Cultural Centre site is situated in an area of post-mining remnants in Klungkung Regency. The sites located at coordinates 8°32‘41.35” - 8°34‘30.94” South Latitude and 115°24‘54.92” - 115°26‘6.99” East Longitude. This site is also portion of estuary area of the Unda River which has a high potential for the danger of cold lava flood from the Mount Agung eruption. The structure to manage cold lava floods at the Unda River estuary is being conducted. The construction is divided into two locations which design to satisfactory a 50-year design flood with discharge of 1436.11 m3 per second. The first location is at upstream (north side of Prof. Ida Bagus Mantra Street) using a single rectangular cross section. The second location is at downstream (south area of Prof. Ida Bagus Mantra Street) using a combine double rectangular cross section. These two types of cross sections are designed to accommodate the capacity of water discharge under normal conditions and still able to drain water discharge in the 50-year return period. The presence of this channel allows the cold lava flood flow directly towards the sea-shore and so as to reduce the risk. It is possible that the sediments settle at the base of the channel, therefore, channel shape normalization and periodic dredging for maintenance are essential.

Reutilização de barragem como armadilha de sedimento e reserva hídrica

ABSTRACT One of the dilemmas that characterizes the end of active service of small hydroelectric plants (SHPs) is regarding the destination of the dams. This is the case of the Pandeiros SHP, located in the state of Minas Gerais, Brazil. Several alternatives are being considered to make its decommissioning feasible, such as opening the bottom discharge gate and removing the reservoir containment dike. However, in a review of recent research in the basin, more than 200 active gullies were found upstream of the dam, contributing to the silting up of the reservoir and of the Pantanal Mineiro, an extensive wetland downstream of the SHP that is vital to the biodiversity of the region. Following a worldwide movement to reuse such structures, periodic dredging of part of the sediment retained in the reservoir is proposed, converting it into a trap to reduce the silting of the wetland by the upstream sediment, in addition to the creation of a reserve volume of water needed for agriculture and human consumption.

Geomorphological Changes of a Migrating Sandbank: Multidecadal Analysis as a Tool for Managing Conflicts in Coastal Use

While beach erosion and sand loss are typically of great concern to the tourism industry, managing rapid morphological changes linked to large amounts of moving sediments is the challenge facing Grado, an important seaside resort in the northern Adriatic, Italy. The cause of the unusual management conflict is the presence of the Mula di Muggia Bank, a nearshore depositional system made up of relict and active migrating sandbanks extending up to 2 km seawards from the touristic beachfront. A reconstruction of the morpho-sedimentary evolution of the coastal system over a 200-year period was done using a large dataset which includes historical cartography, topographic maps, aerial photos and topo-bathymetric surveys. The results show the growth of a significant urban development aimed at creating a tourist destination by occupying the waterfront along fetch-limited coastal tracts with very shallow water and scarce hydrodynamics. Furthermore, a number of sandy dynamic landforms (longshore migrating bars, a bypass corridor, an ebb-tidal delta) and accumulation zones attest to a sediment excess which can be mostly attributed to the eastern river supplies. The progressive constant migration rate of 12.6 my−1 allowed the bank to induce the expansion of the low-energy silty backbarrier environment, characterised by abundant seagrass meadows a short distance directly in front of the tourist beaches of Grado. As a result of historical analysis and more current observations, areas with diverse morphosedimentary features and with varying tourist/recreational, ecological, and conservation values have been identified. These can be considered as basic units for future accurate planning and re-evaluation of coastal management choices to balance environmental protection and tourist use. A soft coastal defence approach is proposed which includes either the preservation of specific environments or the proper use of excess sand for beach nourishment via periodic dredging or sediment bypassing.

Distribution of Butyltin Compounds in the Coastal Environment of the Bahía Blanca Estuary, Argentina.

This study evaluates for the first time the distribution and accumulation of butyltin compounds (BTs) in different compartments such as seawater, sediments, suspended particulate matter (SPM), and mussels (Brachidontes rodriguezii) in the Bahía Blanca estuary. The samples were collected from six sampling sites with different anthropogenic impacts. A better visualization and interpretation of data was achieved using chemometric tools (Tucker4 model), which made it possible to reveal the main relationships among the variables. This analysis showed the presence of BTs in all the estuarine environmental compartments, even in sites with low human intervention. The relationships found among BTs levels, seasons, and environmental matrices show the importance of biological processes such as phytoplankton blooms and remobilization of sediments (by tidal dynamics and/or periodic dredging) in BTs distribution and degradation. In addition, partition coefficients showed that mussels mainly bioaccumulate tributyltin from sediment, water and, to a lesser extent, SPM.

Determination of Water Depth in Ports Using Satellite Data Based on Machine Learning Algorithms

One of the fundamental maintenance tasks of ports is the periodic dredging of them. This is necessary to guarantee a minimum draft that will enable ships to access ports safely. The determination of bathymetries is the instrument that determines the need for dredging and permits an analysis of the behavior of the port bottom over time, in order to achieve adequate water depth. Satellite data processing to predict environmental parameters is used increasingly. Based on satellite data and using different machine learning algorithm techniques, this study has sought to estimate the seabed in ports, taking into account the fact that the port areas are strongly anthropized areas. The algorithms that were used were Support Vector Machine (SVM), Random Forest (RF) and the Multi-Adaptive Regression Splines (MARS). The study was carried out in the ports of Candás and Luarca in the Principality of Asturias. In order to validate the results obtained, data was acquired in situ by using a single beam provided. The results show that this type of methodology can be used to estimate coastal bathymetry. However, when deciding which system was best, priority was given to simplicity and robustness. The results of the SVM and RF algorithms outperform those of the MARS. RF performs better in Candás with a mean absolute error (MAE) of 0.27 cm, whereas SVM performs better in Luarca with a mean absolute error of 0.37 cm. It is suggested that this approach is suitable as a simpler and more cost-effective rough resolution alternative, for estimating the depth of turbid water in ports, than single-beam sonar, which is labor-intensive and polluting.

Analysis of the Spatio-Temporal Evolution of Dredging from Satellite Images: A Case Study in the Principality of Asturias (Spain)

One of the fundamental tasks in the maintenance of port operations is periodic dredging. These dredging operations facilitate the elimination of sediments that the coastal dynamics introduce. Dredging operations are increasingly restrictive and costly due to environmental requirements. Understanding the condition of the seabed before and after dredging is essential. In addition, determining how the seabed has behaved in recent years is important to consider when planning future dredging operations. In order to analyze the behavior of sediment transport and the changes to the seabed due to sedimentation, studies of littoral dynamics are conducted to model the deposition of sediments. Another methodology that could be used to analyze the real behavior of sediments would be to study and compare port bathymetries collected periodically. The problem with this methodology is that it requires numerous bathymetric surveys to produce a sufficiently significant analysis. This study provides an effective solution for obtaining a dense time series of bathymetry mapping using satellite data, and enables the past behavior of the seabed to be examined. The methodology proposed in this work uses Sentinel-2A (10 m resolution) satellite images to obtain historical bathymetric series by the development of a random forest algorithm. From these historical bathymetric series, it is possible to determine how the seabed has behaved and how the entry of sediments into the study area occurs. This methodology is applied in the Port of Luarca (Principality of Asturias), obtaining satellite images and extracting successive bathymetry mapping utilizing the random forest algorithm. This work reveals how once the dock was dredged, the sediments were redeposited and the seabed recovered its level prior to dredging in less than 2 months.

Modeling of Sediment Distribution and Changes of Morphology in Estuary Flow Kapuas River, West Kalimantan

Pontianak Dwikora Port is a port that has been owned by Pontianak City since the Dutch colonial era and has been used as a trade center to export and import goods needed by West Kalimantan Province. Dwikora Port is located inside the Kapuas Kecil River and under the auspices of PT Pelabuhan Indonesia II (PELINDO II). Due to the location of the port in the river, the shipping channel is often disrupted due to silting (sedimentation) at the river mouth. So that the ships do not run aground, periodic dredging is carried out. This is to find out how much sediment is in the estuary. So, this study continues previous research by performing numerical modeling using Mike 21 software [1] to determine the sediment distribution flow patterns that affect silting that occurs in the Kapuas Kecil River Estuary. The data to be used are tidal data from field measurements, wind data from BMKG, wave generation data, river discharge, and TSS from previous research journals. The TSS used is derived from the river with the maximum taken from previous studies, namely 0.63 gr / L. The result is that the flow pattern of sediment distribution is strongly influenced by the confluence of flow patterns from rivers and sea. Sediment originating from the river slows down at the estuary as a result of the width of the river and is held back by waves from the sea, coupled with the tidal effect that occurs, the sediment oscillates and settles on the bottom of the mouth of the Kapuas Kecil River, causing changes in the basic morphology of the estuary.

Assessment impact of the Damietta harbour (Egypt) and its deep navigation channel on adjacent shorelines

Deep navigation channels have a great impact on adjacent beaches and crucial economic effects because of periodic dredging operations. The navigation channel of the Damietta harbour is considered a clear example of the sedimentation problem and deeply affects the Northeastern shoreline of the Nile Delta in Egypt. The aim of the present study is to monitor shoreline using remote sensing techniques to evaluate the effect of Damietta harbour and its navigation channel on the shoreline for the last 45 years. Also, the selected period was divided into two periods to illustrate the effect of man-made interventions on the shoreline. Shorelines were extracted from satellite images and then the Digital Shoreline Analysis System (DSAS) was used to estimate accurate rates of shoreline changes and predict future shorelines evolution of 2030, 2040, 2050 and 2060. The Damietta harbour created an accretion area in the western side with an average rate of 2.13 m yr-1. On the contrary, the shoreline in the eastern side of the harbour retreated by 92 m on average over the last 45 years. So, it is considered one of the main hazard areas along the Northeastern shoreline of the Nile Delta that needs a sustainable solution. Moreover, a detached breakwaters system is predicted to provide shore stabilization at the eastern side as the implemented one at Ras El-Bar beach. Predicted shoreline evolution of 2060 shows a significant retreat of 280.0 m on average.

Seabed Topography Changes in the Sopot Pier Zone in 2010–2018 Influenced by Tombolo Phenomenon

Bathymetric surveys of the same body of water, performed at regular intervals, apart from updating the geospatial information used to create paper and electronic maps, allow for several additional analyses, including an evaluation of geomorphological changes occurring in the coastal zone. This research is particularly important in places where the shape of the coastal zone has been violently disturbed, including by human activity. Tombolo is such a phenomenon and it dynamically shapes the new hydrological conditions of the coastal zone. Apart from natural factors, it may be caused by the construction of hydrotechnical facilities in the littoral zone. It causes a significant disturbance in the balance of the marine environment, resulting in the bottom accretion and dynamic changes in the coastline. This has been the case since 2010 in Sopot, where the rapidly advancing tombolo is not only changing environmental relations but also threatening the health-spa character of the town by stopping the transport of sand along the coast. This paper analyses changes in seabed shape in the pier area in Sopot between 2010 and 2018. In the analysis, both archival maps and bathymetric surveys over a period of 8 years were used; based on these, numerical bottom models were developed and their geospatial changes were analyzed. The results showed that changes in the seabed in this area are progressing very quickly, despite periodic dredging actions organized by administrative bodies.

Tectonic appraisal of the Mid-Thane Creek of Mumbai, India: An integrated geophysical approach

Integrated geophysical surveys, comprising marine magnetic, high resolution shallow seismic and single-beam bathymetry were conducted to assess subsurface tectonics of the Mid-Thane Creek (MTC) of Mumbai. The bathymetry in the intertidal zone of MTC varies drastically due to periodic dredging, with maximum depth up to 6.4 m and a minimum of ~−1.6 m. High resolution shallow seismic sections up to the depth of ~35 m from the sea-floor are generated to analyze the neotectonic activity of the creek. Imprints of deep-seated lineaments are recognized from magnetic anomaly map of the MTC. To delimit lateral extent of the lineaments/faults, results of several derivative methods including tilt derivative and standard Euler deconvolution are merged with the selected crest value of the horizontal derivative. To estimate depth to the source, Euler deconvolution, tilt derivative, analytic signal, and source parameter imaging method have been used. However, the depth estimation for the lineaments/faults is highly discrepant for this region, because of the complex tectonics associated with the periodic emplacements of Deccan flood basalt. To confine the top and bottom boundary of this highly magnetized basaltic layer, we have carried out spectral analysis considering 18 windows of 2000 × 2000 m with an overlap of 500 m. The average depth to the top and bottom of the source body estimated using spectral analysis is consistent with the depth estimated from the derivative filters. This confirms that the lineaments identified by the derivative filters may embed in the basaltic layer of MTC. The most prominent lineament interpreted from the seismic and magnetic data, in the central region of MTC is inferred as the marine analogue of Alibagh–Uran Fault passing through the mainland of Alibagh and Uran close to Mumbai city.

Hidrodinamika dan produk sedimen terhadap Bendung Irigasi Keumala, Sungai Krueng Baro, Provinsi Aceh

Bendung Kumala dibangun di Sungai Krueng Baro yang merupakan salah satu sungai strategis di Provinsi Aceh untuk mengairi lahan irigasi dan air minum bagi masyarakat di hilirnya, namun sungai ini memiliki permasalahan yang cukup besar sehubungan dengan jalurnya yang panjang dan melewati berbagai formasi geologis. Kondisi ini menyebabkan konsentrasi sedimen yang tinggi pada sungai. Oleh karena itu, penelitian ini bertujuan untuk menganalisisis hidrodinamika sungai dengan menggunakan aplikasi HEC-RAS 5.0. Hasil penelitian memberikan informasi bahwa kapasitas aliran sedimen transport sepanjang dasar sungai bervariasi secara langsung dengan adanya perbedaan antara tegangan geser pada sedimen dasar dan tegangan geser kritis yang diizinkan untuk partikel yang bergerak. Semua sampel sedimen pada hulu dan hilir Bendung Keumala terjadi angkutan sedimen. Pengurangan aliran akibat adanya pembendungan menyebabkan perubahan pada saluran dan rezim alirannya, dan pengurangan pelepasan air telah menyebabkan terjadinya pengurangan angkutan sedimen melayang dan sedimen dasar ke arah hilir. Total sedimen yang terdapat di sekitar areal bendung pada saat debit normal sebesar 6.325.698,93 ton/tahun. Sedimentasi di sekitar bendung menjadi masalah yang serius karena dapat mempengaruhi fungsi dan kinerja bendung dan saluran irigasi. Selain itu pendangkalan akibat sedimentasi menyebabkan tertutupnya intake PDAM Keumala. Untuk mengatasi masalah ini, perlu dilakukan pengerukan dan pengangkutan sedimen dari dasar bendung secara berkala. Pengerukan dan pengangkutan sedimen akan meningkatkan kinerja Bendung Keumala untuk mengairi Daerah Irigasi Krueng Baro. Kapasitas pengaliran intake bendung dapat tetap terjaga untuk mengairi lahan irigasi sesuai dengan areal rencana.

Bathymetry Estimation using Multispectral Imagery over an Inland Water Body – Vembanad Lake, Kerala, India

Rupam, K.; Ferrer, V.A., and Ramachandran, K.K., 2020. Bathymetry estimation using multispectral imagery over an inland water body – Vembanad Lake, Kerala, India. In: Sheela Nair, L.; Prakash, T.N.; Padmalal, D., and Kumar Seelam, J. (eds.), Oceanic and Coastal Processes of the Indian Seas. Journal of Coastal Research, Special Issue No. 89, pp. 126-131. Coconut Creek (Florida), ISSN 0749-0208.The biological and biophysical characteristics of the nearshore and inland (estuarine) water bodies are mainly dependent on their bathymetry which also drives the coastal/estuarine hydrodynamics and other nearshore processes. The study of bathymetry in inland navigational backwaters of the coastal regions gain further importance due to the periodical dredging activities undertaken to maintain the required draft for navigation. The carrying capacity of the lakes gets affected due to sedimentation from the river inflow gradually altering the bathymetry. Conventional bathymetric soundings are highly time consuming and man power intensive which can be successfully augmented and made faster through remote sensing (RS) methods. The RS method can provide better spatial data compared to point-based measurements and also have the advantage of capturing temporal information. The present study explores the feasibility of retrieving bathymetry using satellite based remote sensing techniques for an inland coastal water body, aiming to provide synoptic inexpensive method for estimating and updating bathymetry data making it handy for coastal research and management. The study has been attempted in Vembanad Lake in Kerala, southwest coast of India. The ratio of the blue (450 - 515 nm) to the green (525 - 605 nm) wavelength of the Landsat satellite images as proposed by Stumpf was applied to generate the linear relationship between the reflectance and field measured depth information. The Kochi to Alappuzha National Waterway No. 3 bathymetry chart of the year 2005 is used as the in situ information for generating a site specific linear regression model which yielded a significant correlation coefficient of 0.753 (N = 707). The regression equation has been applied to generate the Satellite optical reflectance derived bathymetry map for the southern part of Vembanad Lake. The bathymetry obtained through this model has been validated with a set of independent depth sounding values (r2 = 0.92; N = 66). By and large the Stumpf model has been found helpful in recreating water depth using multispectral images in clear waters that permit proper light penetration. However, the present study has shown the potential of its application even in the inland water bodies where the light penetration is affected by a high concentration of suspended sediments and floating vegetation (water hyacinth).