Construction of nearshore underwater terrain model by coastline detection on open satellite images for different water levels

2021 ◽  
Author(s):  
Alexei E. Hmelnov ◽  
Andrey S. Gachenko ◽  
Gennady M. Ruzhnikov
Keyword(s):  
Satellite Images ◽  
Water Levels ◽  
Terrain Model

Spatial analysis of riverine microplastic in a Rhine floodplain soil in Germany

2021 ◽  
Author(s):  
Markus Rolf ◽  
Martin G. J. Löder ◽  
Hannes Laermanns ◽  
Lukas Kienzler ◽  
Florian Steininger ◽  
...  
Keyword(s):  
Spatial Analysis ◽  
Soil Depth ◽  
Digital Terrain Model ◽  
Water Levels ◽  
Rhine River ◽  
Flood Events ◽  
Floodplain Soil ◽  
Terrain Model ◽  
Flooded Area ◽  
Alluvial Floodplains

<p>The Rhine River flows through six European countries and is in exchange with diverse land use forms and human activities that potentially release microplastics (MPs). The Rhine interacts permanently with its surrounding banks and floodplains by changing water-levels. Several studies have documented the presence of MPs in the Rhine along its course as well as in its tributaries. However, the spatial distribution of MPs due to certain flood events in alluvial floodplains remains widely unclear. The knowledge about the amount and distribution of MPs and on their potential entry pathways into Rhine floodplains is essentially important for an ecological risk assessment. In this study, we analysed the amount and distribution of MPs in a floodplain soil in the nature reserve Merkenich-Langel, in the northern periphery of Cologne (Germany). We hypothesize that MPs are transported by the Rhine and are deposited at the site during flood events. For spatial analysis we used the MIKE software (DHI A/S, Hørsholm Denmark) merged with a digital terrain model of the study site to analyse past flood events and their potential deposition of MP. We chose three sampling transects located within the past flooded area each with three sampling spots with increasing distance and elevation to the river. Samples were taken from two different soil depths (0–5 cm and 5–20 cm) and the samples of the three sampling spots and same depth were combined to one mixed soil sample per transect. MP concentrations were analysed via ATR-FTIR and µ-FPA-FTIR spectroscopy after density separation and enzymatic-oxidative purification. We found an increase of MP concentration per kg of dry soil in the depth 5–20 cm with increasing distance to the river ranging from 25.612 particles/kg to 85.076 particles/kg. The results of MP concentration in 0–5 cm topsoil layer will be compared to the concentration in the soil depth of 5–20 cm. We correlate these results to the frequency of flood events.</p>

scholarly journals Combining high-resolution satellite images and altimetry to estimate the volume of small lakes

2014 ◽  
Vol 18 (5) ◽  
pp. 2007-2020 ◽  
Author(s):  
F. Baup ◽  
F. Frappart ◽  
J. Maubant
Keyword(s):  
High Resolution ◽  
Satellite Data ◽  
Satellite Images ◽  
Temporal Variations ◽  
Water Levels ◽  
Water Volume ◽  
Small Scale ◽  
Altimetry Data ◽  
Small Lakes ◽  
High Resolution Satellite Images

Abstract. This study presents an approach to determining the volume of water in small lakes (<100 ha) by combining satellite altimetry data and high-resolution (HR) images. In spite of the strong interest in monitoring surface water resources on a small scale using radar altimetry and satellite imagery, no information is available about the limits of the remote-sensing technologies for small lakes mainly used for irrigation purposes. The lake being studied is located in the south-west of France and is only used for agricultural irrigation purposes. The altimetry satellite data are provided by an RA-2 sensor onboard Envisat, and the high-resolution images (<10 m) are obtained from optical (Formosat-2) and synthetic aperture radar (SAR) antenna (Terrasar-X and Radarsat-2) satellites. The altimetry data (data are obtained every 35 days) and the HR images (77) have been available since 2003 and 2010, respectively. In situ data (for the water levels and volumes) going back to 2003 have been provided by the manager of the lake. Three independent approaches are developed to estimate the lake volume and its temporal variability. The first two approaches (HRBV and ABV) are empirical and use synchronous ground measurements of the water volume and the satellite data. The results demonstrate that altimetry and imagery can be effectively and accurately used to monitor the temporal variations of the lake (R2ABV = 0.98, RMSEABV = 5%, R2HRBV = 0.90, and RMSEABV = 7.4%), assuming a time-varying triangular shape for the shore slope of the lake (this form is well adapted since it implies a difference inferior to 2% between the theoretical volume of the lake and the one estimated from bathymetry). The third method (AHRBVC) combines altimetry (to measure the lake level) and satellite images (of the lake surface) to estimate the volume changes of the lake and produces the best results (R2AHRBVC = 0.98) of the three methods, demonstrating the potential of future Sentinel and SWOT missions to monitor small lakes and reservoirs for agricultural and irrigation applications.

Time-lapse photography for monitoring reservoir leakages (Montejaque dam, Andalusia, southern Spain)

2017 ◽  
Vol 49 (1) ◽  
pp. 281-290 ◽  
Author(s):  
Santiago García-López ◽  
Verónica Ruiz-Ortiz ◽  
Juan José Muñoz-Pérez
Keyword(s):  
Water Level ◽  
River Flow ◽  
Digital Terrain Model ◽  
Time Lapse ◽  
Water Levels ◽  
Water Volume ◽  
Climate Data ◽  
Calcite Dissolution ◽  
Terrain Model ◽  
Use Of Time

Abstract A methodology based on the use of time-lapse photographs is presented to evaluate the leakages over time of a reservoir (Montejaque dam, Málaga Province, Spain) that feeds a karstic aquifer. In particular, photographic control allows the evolution of water levels in the dam and the river that feeds it to be monitored. Through changes in water volume, which are calculated from the level differences, daily leakages are evaluated, and the relationship between leakages and the water level of the reservoir is established. The proposed method includes adjusting the hydric balance and the use of digital terrain model and climate data. The inputs (river flow and direct precipitation) and other outputs (direct evaporation) are also evaluated. Values between 4 m3/s and 0.35 m3/s are obtained for the reservoir infiltration, clearly superior to the values obtained at the time of the construction of the dam in the 1920s. Mobilisation of the filling of fractures and conduits in karstic massif and calcite dissolution are processes that can influence this behaviour. When the water level is very low, the obtained values are below the historical leakages due to deposition of clay sediments at the reservoir bottom.

scholarly journals Impact of Uncertainty of Floodplain Digital Terrain Model on 1D Hydrodynamic Flow Calculation

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1308 ◽  
Author(s):  
Adam Kiczko ◽  
Dorota Mirosław-Świątek
Keyword(s):  
Flow Model ◽  
Digital Terrain Model ◽  
Confidence Bands ◽  
Water Levels ◽  
Spatial Dependency ◽  
Noticeable Effect ◽  
Terrain Model ◽  
Digital Terrain ◽  
Model Explanation ◽  
High Uncertainty

This study investigates the effect of the Digital Terrain Model (DTM) uncertainty effect on the output of a 1D flow model. The analysis is performed for the lowland river Biebrza, covered with dense wetland vegetation, with a high uncertainty of terrain elevations. The DTM uncertainty is modeled in two ways: (1) accounting for the uncertainty spatial dependency on the basis of the correlogram function and (2) neglecting the correlation of the elevation points. The model explanation of water levels improves when elevation uncertainty is being included. Without the elevation uncertainty, the model provided a good fit only for peak flows, with uncertainty also representation of lower flows is better. It was shown that the correlation of the elevation uncertainty had a noticeable effect on the modeling outcomes, especially for near bankfull flows, where for the uncorrelated case water levels were underestimated by 5 cm, comparing to the correlated case. The effect was also present for inundation extents, obtained by an interpolation of computed water levels. The correlation of the elevation uncertainty strongly affects estimates of standard deviations of computed water levels, which were almost twice smaller when correlation was neglected. In the result, only when the correlation of the elevation uncertainty was included, it was possible to obtain confidence bands that enclosed observation points.

scholarly journals Combining high-resolution satellite images and altimetry to estimate the volume of small lakes

2013 ◽  
Vol 10 (12) ◽  
pp. 15731-15770 ◽  
Author(s):  
F. Baup ◽  
F. Frappart ◽  
J. Maubant
Keyword(s):  
High Resolution ◽  
Satellite Data ◽  
Satellite Images ◽  
Temporal Variations ◽  
Water Levels ◽  
Water Volume ◽  
Altimetry Data ◽  
Small Lakes ◽  
In Situ Data ◽  
High Resolution Satellite Images

Abstract. This study presents an approach to determine the volume of water in small lakes (<100 ha) by combining satellite altimetry data and high-resolution (HR) images. The lake being studied is located in the south-west of France and is only used for agricultural irrigation purposes. The altimetry satellite data are provided by RA-2 sensor on board Envisat, and the high-resolution images (<10 m) are obtained from optical (Formosat-2) and synthetic aperture radar (SAR) sensors (Terrasar-X and Radarsat-2) satellites. The altimetry data (data are obtained every 35 days) and the HR images (45) have been available since 2003 and 2010, respectively. In situ data (for the water levels and volumes) going back to 2003 have been provided by the manager of the lake. Three independent approaches are developed to estimate the lake volume and its temporal variability. The first two approaches are empirical and use synchronous ground measurements of the water volume and the satellite data. The results demonstrate that altimetry and imagery can be effectively and accurately used to monitor the temporal variations of the lake (R2altimetry = 0.97, RMSEaltimetry = 5.2%, R2imagery = 0.90, and RMSEimagery = 7.4%). The third method combines altimetry (to measure the lake level) and satellite images (of the lake surface) to estimate the volume changes of the lake and produces the best results (R2 = 0.99) of the three methods, demonstrating the potential of future Sentinel and SWOT missions to monitor small lakes and reservoirs for agricultural and irrigation applications.

scholarly journals Visualization of Lake Mead Surface Area Changes from 1972 to 2009

2021 ◽  
Author(s):  
K. Wayne Forsythe ◽  
Barbara Schatz ◽  
Stephen J. Swales ◽  
Lisa-Jen Ferrato ◽  
David M. Atkinson
Keyword(s):  
United States ◽  
Water Level ◽  
Surface Area ◽  
Satellite Images ◽  
Strong Relationship ◽  
The United States ◽  
Water Levels ◽  
Lake Area ◽  
Lake Mead ◽  
Landsat Satellite

For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series.

scholarly journals Morphotectonic Characteristics Of Cisadane Watersshed Based On Satellite Images Analysis

2019 ◽  
Vol 20 (3) ◽  
pp. 175
Author(s):  
Sonny Mawardi ◽  
Emi Sukiyah ◽  
Iyan Haryanto
Keyword(s):  
Satellite Images ◽  
Digital Terrain Model ◽  
Tectonic Deformation ◽  
Surface Model ◽  
Landsat 8 ◽  
Infrastructure Development ◽  
Economic Activities ◽  
Terrain Model ◽  
Digital Terrain ◽  
Geomorphological Units

Cisadane Watershed is one of the most rapidly growing areas and infrastructure development, and has developed as a residential, industrial, administrative centers and other economic activities. The purpose of this paper is to use remote sensing satellite imageries to identify the morphotectonic characteristics of the Cisadane watershed both qualitatively and quantitatively. Processing stereomodel, stereoplotting and stereocompilation on TerraSAR-X Digital Surface Model (DSM) and SPOT 6 imageries, produced the  Digital Terrain Model (DTM) image, which has not been affected by land cover. Fusion of the DTM  and Landsat 8 RGB 567+8 images  is used to interpret the distribution of lithology, geomorphological units, and lineaments, which are an indication of geological structures. The morphotectonic characteristics of sub-watersheds qualitatively was carried out a bifurcation ratio calculation (Rb) which indicates tectonic deformation. Based on the analysis of satellite images both qualitatively and quantitatively, the morphotectonic characteristics of the upstream, middle and downstream Cisadane Watershed have been deformed.Keywords : satellite images, morphotectonic, DSM, DTM, Cisadane Watershed.

scholarly journals ANALYSIS OF GEOMETRIC AND ORTHOGONAL CORRECTION ACCURACY FOR CAS-500 SATELLITE IMAGES

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 57-61
Author(s):  
Y. Lee ◽  
T. Kim
Keyword(s):  
South Korea ◽  
Korean Peninsula ◽  
North Korea ◽  
Satellite Images ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Digital Terrain ◽  
Ground Control Points ◽  
High Resolution Images ◽  
Geolocation Accuracy

Abstract. This paper reports on geolocation accuracy of image products generated from Precision Image Processing (PIP) system developed for CAS-500 Satellite images. CAS-500, launched on 22 March, 2021, will be used mainly for land monitoring and 1:5000 scale mapping over the Korean Peninsula. For this purpose, ground control points (GCPs) and a Digital Terrain Model (DTM) have been collected over the Peninsula and integrated into the PIP for the generation of precision image product in an automated manner. The goal of this paper is to analyze the geolocation accuracy of image products generated from the PIP. Target geolocation accuracy of the PIP was set as 2 pixel RMSE using the internal GCP DB and DTM. Since CAS-500 images were not distributed yet, the analysis was performed using 13 KOMPSAT-3A satellite images, having similar specifications to CAS-500. The result showed that the accuracy of precise sensor models were about 1.797 pixels in South Korea and 1.907 pixels in North Korea. The accuracy of orthoimages were about 1.24 meters in South Korea and 1.59 meters in North Korea. Overall, the geolocation over North Korea was not as good as that over South Korea. It was judged that the quality of GCPs and DTM over North Korea affected the geolocation accuracy and, however, the accuracy gap was not too severe. The PIP system should produce image products within the targeted geolocation accuracy when CAS-500 delivers high resolution images over the Korean Peninsula.

scholarly journals Modélisation hydraulique du système Sebou-Fouarat, ville de Kenitra, Maroc - Cas des inondations de 2010

2017 ◽  
Vol 13 (12) ◽  
pp. 368
Author(s):  
Abdellah Bourak ◽  
Abdelbasset Midaoui ◽  
Abderrahim Lahrach ◽  
Abdelkarim Elarrim ◽  
Abdel-Ali Chaouni
Keyword(s):  
Digital Terrain Model ◽  
Maximum Flow ◽  
Hydraulic Modeling ◽  
Temporal Variations ◽  
Water Levels ◽  
Terrain Model ◽  
Digital Terrain ◽  
Arc Gis ◽  
The Stability ◽  
The City

The city of Kenitra, located in the extreme downstream of the Sebou basin, is threatened by floods caused by the overflowing of the Oued Sebou and the rise of Oued Fouarat. The hydraulic modeling study of the Sebou Fouarat system in transient mode is carried out by the HEC-RAS software and has implicated the two rivers. Two geometric models were constructed on the basis of a digital terrain model (DTM) using the Arc-GIS and HECGeoRAS softwares after processing the collected topographic data. The first model, of which the areas of Merja Fouarat and Al Assam have been represented by cross-section, is one-dimensional. The second one is also onedimensional in which the two areas of Merja Fouarat and Al Assam are introduced as water storage zones. The components of these models are the stream sections, lateral links, storage areas and junctions between the branches of each model. The flood hydrographs of the Sebou and Fouarat rivers are introduced as conditions at the upstream limits of the models while the tidal is introduced as a downstream condition. After the stability and calibration of the models, the results of the consulted hydraulic simulations are the variations of the water levels as well as the temporal variations of the flow rates for each section, the maximum flow velocities and the propagation times of the flood waves. The analysis and comparisons of these results strongly suggest using the second model for the treatment of the flood issues as a decision-making tool helping to manage floods during times of crisis.

Using space observations to monitor reservoir operations in the Lancang River

2021 ◽  
Author(s):  
Dung Trung Vu ◽  
Thanh Duc Dang ◽  
Stefano Galelli
Keyword(s):  
Surface Area ◽  
Water Surface ◽  
Satellite Images ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Altimetry Data ◽  
Lancang River ◽  
Water Surface Area ◽  
Hydropower Potential ◽  
Over Time

&lt;p&gt;Being a part of the Water Tower of Asia, the Mekong River originates from the Tibetan Plateau and flows through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. Its upper portion, also called the Lancang River, has abundant hydropower potential, which has been largely exploited during the three recent decades. To date, there are 11 operational dams (10 of them have a volume larger than 100 MCM) on the mainstream of the Lancang, controlling about 40% of the annual flow at Chiang Saen (the most upstream station of the Lower Mekong). The amount of water withheld in these dams is a potential source of controversy between China and downstream countries because it affects both the timing and volume of available water. Assessing the real impacts of these dams is a challenging task owing to the chronic lack of data on reservoirs' storage and operating patterns. To overcome this challenge, we exploit satellite images and altimetry data. The analysis focuses on 10 reservoirs and is conducted in three steps. First, we estimate the relationship between water elevation and surface area (E-A curve) for each reservoir. For this purpose, we either use DEM data or water surface area data (derived from satellite images) paired with altimetry-derived water levels. Second, with the Elevation-Area-Storage curve converted from each E-A curve, we calculate storage variability over time by using satellite image-derived reservoir water surface area. The result is collated with storage variability derived from altimetry data. In the last part of our analysis, focusing on the period 2008-2020, we show how the total withheld storage changed over time, we determine the rule curve of each reservoir and elucidate the role of reservoir filling strategies.&lt;/p&gt;

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