scholarly journals Integration of satellite image–derived temperature and water depth for assessing fish habitability in dam controlled flood plain wetland

2022 ◽  
Author(s):  
Sonali Kundu ◽  
Swades Pal ◽  
Swapan Talukdar ◽  
Susanta Mahato ◽  
Pankaj Singha
Keyword(s):  
Water Depth ◽  
Satellite Image ◽  
Flood Plain ◽  
Controlled Flood

scholarly journals Integration of Satellite Image Derived Temperature and Water Depth for Assessing Fish Habitability in Dam Controlled Flood Plain Wetland

2021 ◽  
Author(s):  
Sonali Kundu ◽  
Swades Pal ◽  
Swapan Talukdar ◽  
Susanta Mahato ◽  
Pankaj Singha
Keyword(s):  
Water Depth ◽  
Thermal Environment ◽  
Satellite Image ◽  
Flood Plain ◽  
Habitable Zones ◽  
Optimum Depth ◽  
Field Information ◽  
Controlled Flood ◽  
Fish Survival ◽  
Future Work

Abstract The present study attempted to investigate the changes in temperature conducive to fish habitability during the summer months in a hydrologically modified wetland following damming over a river. Satellite image-driven temperature and depth data calibrated with field data were used to analyse fish habitability and the presence of thermally optimum habitable zones in some fishes such as Labeo Rohita, Cirrhinus mrigala, Tilapia fish, Small shrimp, and Cat fishes. The study was conducted both at the water's surface and at the optimum depth of survival. It is very obvious from the analysis that a larger part of wetland has become an area that destroyed aquatic habitat during the post-dam period and existing wetlands have suffered significant shallowing of water depth. This has resulted in a shrinking of the thermally optimum area of fish survival in relation to surface water temperature (from 100.09 km2 to 74.24 km2 before the dam to 93.97 km2 to 0 km2 after the dam) and an improvement in the optimum habitable condition in the comfortable depth niche of survival. In the post-dam period, it increased from 75.49 % to 99.765%. Since the damming effect causes a 30.53 to 100% depletion of the optimum depth niche, improving the thermal environment has no effect on fish habitability. More water must be released from dams for restoration. Image-driven depth and temperature data calibrated with field information has been successfully applied in data sparse conditions, and it is further recommended in future work.

scholarly journals Utilisation of satellite data in identification of geomorphic landform and its role in arsenic release in groundwater

2014 ◽  
Vol II-8 ◽  
pp. 29-35 ◽  
Author(s):  
R. P. Singh ◽  
N. Singh ◽  
S. Shashtri ◽  
S. Mukherjee
Keyword(s):  
Organic Matter ◽  
Iron Hydroxide ◽  
Satellite Image ◽  
Flood Plain ◽  
Spectral Signature ◽  
Brahmaputra River ◽  
Arsenic In Groundwater ◽  
Groundwater Samples ◽  
Geomorphic Features ◽  
Geomorphic Units

The present study was conducted to explore the influence of geomorphic features of the area on the mobilization of arsenic in groundwater. In this study, remote sensing and GIS techniques were used to prepare the geomorphic and slope map of the area. Different geomorphic features were identified on the basis of spectral signature on the LISS III and Landsat satellite image and field survey. Groundwater samples were collected from each representative geomorphic feature to inspect the arsenic contamination in the area. The study area is drained by the Brahmaputra river and its tributaries and contain mainly fluvial geomorphic units especially older flood plain, palaeochannels, oxbow lakes, channel islands; and hilly areas at some of the places. In this study it was observed that enrichment of arsenic in groundwater varies along the geomorphic units in following trends Paleochannel> Younger alluvial plain> Active flood plain> channel island > dissected hills. The above trend shows that a higher concentration of arsenic is found in the groundwater samples collected from the fluvial landforms as compared to those collected from structural landforms. Brahmaputra River and its tributaries carry the sediment load from the Himalayan foothills, which get deposited in these features during the lateral shift of the river’s courses. Arsenic bearing minerals may get transported through river and deposit in the geomorphological features along with organic matter. The flat terrain of the area as seen from the slope map provides more residence time to water to infiltrate into the aquifer. The microbial degradation of organic matter generates the reducing environment and facilitates the dissolution of iron hydroxide thus releasing the adsorbed arsenic into the groundwater.

scholarly journals Shallow Water Bathymetry Mapping of Xinji Island Based on Multispectral Satellite Image using Deep Learning

2021 ◽  
Author(s):  
Jiaxin Wan ◽  
Yi Ma
Keyword(s):  
Deep Learning ◽  
Shallow Water ◽  
Water Depth ◽  
Satellite Image ◽  
Absolute Error ◽  
Coastal Zones ◽  
Multispectral Data ◽  
Novel Approach ◽  
Multispectral Satellite Image ◽  
Remote Sensing Techniques

AbstractNearshore bathymetry is a basic parameter of the ocean, which is crucial to the research and management of coastal zones. Previous studies have demonstrated that remote sensing techniques can be employed in estimating bathymetric information. In this paper, we propose a deep belief network with data perturbation (DBN-DP) algorithm for shallow water depth inversion from high resolution multispectral data, and applying it in Xinji Island of Malacca Strait and Yongxing Island in China. Results show that the DBN-DP method can produce more accurate water depth estimations than other traditional methods particularly for deeper water, which reaches 1.2 m of mean absolute error (MAE) and 12.8% of mean relative error (MRE) in Xinji Island. Most of the estimated bathymetry meet the category of zone of confidence C level defined by the International Hydrographic Organization. These findings are encouraging for employing deep learning in bathymetry, which may become a novel approach for bathymetric inversion in the future.

scholarly journals Wetlands of Dhaka City: Its Past and Present Scenario

2014 ◽  
Vol 7 ◽  
pp. 83-90 ◽  
Author(s):  
Md Shahidul Islam ◽  
AKM Shahabuddin ◽  
M Mostafa Kamal ◽  
Raquib Ahmed
Keyword(s):  
Resource Constraints ◽  
Satellite Image ◽  
Flood Plain ◽  
Water Bodies ◽  
Dhaka City ◽  
Topographic Map ◽  
Urbanization Process ◽  
Gis And Remote Sensing ◽  
Remote Sensing Technique ◽  
The City

Landscape of Dhaka city, one of the fastest growing mega cities in the world, is undergoing continuous changes and modifications due to unplanned hasty urbanization process. As the growth of urbanization taking place at an exceptionally rapid rate the city is unable to cope with changing situation due to internal resource constraints and management limitations. Dhaka city endowed with a large number of water-bodies both big and small, which includes river, khals, lakes, flood plain low-lying areas etc. However, pre and post-urban changes of water-bodies in the city were studied using topographic map of 1960 and a satellite image of 2008 (ALOS VNIR 2008) through GIS and remote sensing technique. It is found that in 1960 total areas of water-bodies and lowland were 2952.02 and 13527.58 hectares. But in 2008 total areas of water-bodies and lowland found 1990.71 and 6414.57 hectares. Categories (water-bodies and lowlands) of wetland areas were decreased harshly. Study shows that water-bodies and lowland areas were decreased 32.57% and 52.58% that means more than 49% of the wetland areas decreased over the period 1960 to 2008. The changes of low-lying areas in the south-western corner extending towards Mirpur, Muhammadpur and Pallabi-Cantonment areas and filled for the urban development. The part of Gulshan and Dhanmondi lakes has also been reduced; and some of the channels of Motijheel areas are not identifiable at present. The growth of urban infrastructures have been taking place in unplanned way; as a result it destroyed natural drainage systems, fill-up the water-bodies, causing water-loggings during rainy season in various part of the city. This study revealed that immediate necessary steps should take by concern authority to prevent from various disasters that might be occurred due to unwise and unplanned wetland changes.DOI: http://dx.doi.org/10.3329/jles.v7i0.20126 J. Life Earth Sci., Vol. 7: 83-90, 2012

scholarly journals Analysis of Very High Spatial Resolution Images for Automatic Shoreline Extraction and Satellite-Derived Bathymetry Mapping

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 172
Author(s):  
Giovanni Randazzo ◽  
Giovanni Barreca ◽  
Maria Cascio ◽  
Antonio Crupi ◽  
Marco Fontana ◽  
...  
Keyword(s):  
Shallow Water ◽  
Spatial Resolution ◽  
Water Depth ◽  
High Spatial Resolution ◽  
Satellite Image ◽  
Atmospheric Correction ◽  
Coastal Areas ◽  
Ratio Method ◽  
Very High Spatial Resolution ◽  
Very High

The amount of Earth observation images available to the public has been the main source of information, helping governments and decision-makers tackling the current world’s most pressing global challenge. However, a number of highly skilled and qualified personnel are still needed to fill the gap and help turn these data into intelligence. In addition, the accuracy of this intelligence relies on the quality of these images in times of temporal, spatial, and spectral resolution. For the purpose of contributing to the global effort aiming at monitoring natural and anthropic processes affecting coastal areas, we proposed a framework for image processing to extract the shoreline and the shallow water depth on GeoEye-1 satellite image and orthomosaic image acquired by an unmanned aerial vehicle (UAV) on the coast of San Vito Lo Capo, with image preprocessing steps involving orthorectification, atmospheric correction, pan sharpening, and binary imaging for water and non-water pixels analysis. Binary imaging analysis step was followed by automatic instantaneous shoreline extraction on a digital image and satellite-derived bathymetry (SDB) mapping on GeoEye-1 water pixels. The extraction of instantaneous shoreline was conducted automatically in ENVI software using a raster to vector (R2V) algorithm, whereas the SDB was computed in ArcGIS software using a log-band ratio method applied on the satellite image and available field data for calibration and vertical referencing. The results obtained from these very high spatial resolution images demonstrated the ability of remote sensing techniques in providing information where techniques using traditional methods present some limitations, especially due to their inability to map hard-to-reach areas and very dynamic near shoreline waters. We noticed that for the period of 5 years, the shoreline of San Vito Lo Capo sand beach migrated about 15 m inland, indicating the high dynamism of this coastal area. The bathymetric information obtained on the GeoEye-1 satellite image provided water depth until 10 m deep with R2 = 0.753. In this paper, we presented cost-effective and practical methods for automatic shoreline extraction and bathymetric mapping of shallow water, which can be adopted for the management and the monitoring of coastal areas.

scholarly journals The Contribution of Multispectral Satellite Image to Shallow Water Bathymetry Mapping on the Coast of Misano Adriatico, Italy

2020 ◽  
Vol 8 (2) ◽  
pp. 126 ◽  
Author(s):  
Anselme Muzirafuti ◽  
Giovanni Barreca ◽  
Antonio Crupi ◽  
Giancarlo Faina ◽  
Diego Paltrinieri ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
High Performance ◽  
Spectral Band ◽  
Satellite Image ◽  
Coefficient Of Determination ◽  
Ratio Method ◽  
Band Ratio ◽  
Water Classification

The results of absolute satellite-derived bathymetry (SDB) are presented in the current study. A comparative analysis was conducted on empirical methods in order to explore the potential of SDB in shallow water on the coast of Misano, Italy. Operations were carried out by relying on limited in situ water depth data to extract and calibrate bathymetry from a QuickBird satellite image acquired on a highly dynamic coastal environment. The image was processed using the log-band ratio and optimal band ratio analysis (OBRA) methods. Preprocessing steps included the conversion of the raw satellite image into top of atmosphere reflectance, spatial filtering, land and water classification, the determination of the optimal OBRA spectral band pairs, and the estimation of relative SDB. Furthermore, calibration and vertical referencing were performed via in situ bathymetry acquired in November 2007. The relative bathymetry obtained from different band ratios were vertically referenced to the local datum using in situ water depth in order to obtain absolute SDB. The coefficient of determination (R2) and vertical root mean square error (RMSE) were computed for each method. A strong correlation with in situ field bathymetry was observed for both methods, with R2 = 0.8682 and RMSE = 0.518 m for the log-band ratio method and R2 = 0.8927–0.9108 and RMSE = 0.35 m for the OBRA method. This indicated a high degree of confidence of the SDB results obtained for the study area, with a high performance of the OBRA method for SDB mapping in turbid water.

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

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