scholarly journals Estimation of chlorophyll-a concentration using Landsat 8 in the Cassaffousth reservoir

2019 ◽  
Vol 19 (7) ◽  
pp. 2021-2027 ◽  
Author(s):  
María Micaela Ledesma ◽  
Matías Bonansea ◽  
Claudia Rosa Ledesma ◽  
Claudia Rodríguez ◽  
Joel Carreño ◽  
...  
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Field Data ◽  
Warning System ◽  
Landsat 8 ◽  
Chl A ◽  
Physico Chemical ◽  
Regression Techniques ◽  
Remote Sensing Techniques

Abstract The physico-chemical and biological composition of a reservoir's effluents directly influences water quality. The values of variables such as high values of concentrations of chlorophyll-a (Chl-a) are indicators of pollution. The objective of this work was to monitor the trophic status and water quality of the Cassaffousth reservoir (Córdoba, Argentina) through the development of statistical models based on field data and satellite information. During 2016 and 2017, samples were taken bimonthly. Seven sampling sites were selected and physico-chemical and biological parameters were assessed. By using regression techniques, Landsat 8 information was related with field data to construct and validate a statistical model to determine the distribution of Chl-a in the reservoir (R2 = 0.87). The generated algorithm was used to generate maps which contained information about the dynamics of Chl-a in the entire reservoir. Remote sensing techniques can be used to expand the knowledge of the dynamics of the Cassaffousth reservoir. Moreover, these techniques can be used as baselines for the development of an early warning system for this and other reservoirs in the region.

scholarly journals Assessing the potential of integrating Landsat sensors for estimating chlorophyll-a concentration in a reservoir

2017 ◽  
Vol 49 (5) ◽  
pp. 1608-1617 ◽  
Author(s):  
Matias Bonansea ◽  
Claudia Rodriguez ◽  
Lucio Pinotti
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Landsat Imagery ◽  
Quality Parameters ◽  
Landsat 8 ◽  
Chlorophyll A Concentration ◽  
Chl A ◽  
Sensing Applications ◽  
Wide Range ◽  
Quality Assessments

Abstract Landsat satellites, 5 and 7, have significant potential for estimating several water quality parameters, but to our knowledge, there are few investigations which integrate these earlier sensors with the newest and improved mission of Landsat 8 satellite. Thus, the comparability of water quality assessing across different Landsat sensors needs to be evaluated. The main objective of this study was to assess the feasibility of integrating Landsat sensors to estimate chlorophyll-a concentration (Chl-a) in Río Tercero reservoir (Argentina). A general model to retrieve Chl-a was developed (R2 = 0.88). Using observed versus predicted Chl-a values the model was validated (R2 = 0.89) and applied to Landsat imagery obtaining spatial representations of Chl-a in the reservoir. Results showed that Landsat 8 can be combined with Landsat 5 and 7 to construct an empirical model to estimate water quality characteristics, such as Chl-a in a reservoir. As the number of available and upcoming sensors with open access will increase with time, we expect that this trend will certainly further promote remote sensing applications and serve as a valuable basis for a wide range of water quality assessments.

scholarly journals The The impact of Cirebon coal-fired power plants on water quality in Mundu Bay, Cirebon Regency

2020 ◽  
Vol 4 (3) ◽  
pp. 189-204
Author(s):  
Millary Agung Widiawaty ◽  
Nurhanifah Nurhanifah ◽  
Arif Ismail ◽  
Moh. Dede
Keyword(s):  
Water Quality ◽  
Power Plant ◽  
Chlorophyll A ◽  
Power Plants ◽  
Field Measurements ◽  
Landsat 8 ◽  
Marine Biota ◽  
Coastal Morphology ◽  
The Impact

The presence of Cirebon coal-fired power plant I and II caused negative effects to coastal morphology and the quality of marine waters. This also have negative impacts to the fisherman around that sea. This study aims to examine the impact of the Cirebon coal-fired power plant on the water quality of Mundu Bay, Cirebon Regency. Water quality is determined based on total suspended solids (TSS), sea surface temperatures (SST), chlorophyll-A, and salinity in the range 1999 – 2019. Data collection was carried out using satellite imagery of Landsat-5 TM, Landsat- 7 ETM+, and Landsat-8 OLI verified with in-situ field measurements, Sentinel-2 A MSI, and MODIS Aqua imageries. Changes in water quality due to the infrastructure of the two power plants are known through the Mann-Whitney U-Test and Spearman’s correlation analysis. This research shows that two Cirebon coal-fired power plant has a significant effect on changes in the quality of Mundu Bay waters. Changes in water quality are shown by a significant increase in TSS concentrations and SST values ​​accompanied by a decrease in chlorophyll-A levels and salinity levels. Changes in the quality of these waters also disrupt marine biota habitat and cause fishermen in around are difficult to get the ideal catchment yield.

scholarly journals In Situ and Satellite Observation of CDOM and Chlorophyll-a Dynamics in Small Water Surface Reservoirs in the Brazilian Semiarid Region

2017 ◽  
Author(s):  
Christine Coelho ◽  
Birgit Heim ◽  
Saskia Förster ◽  
Arlena Brosinsky ◽  
José Carlos De Araújo
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Semiarid Region ◽  
Landsat 8 ◽  
Small Surface ◽  
Entire Study ◽  
Chl A ◽  
Brazilian Semiarid

We aimed at analyzing Chlorophyll-a and CDOM dynamics from field measurements and at assessing the potential of multispectral satellite data for retrieving water-quality parameters in three small surface reservoirs in the Brazilian semiarid region. More specifically, this work comprises i) analysis of Chl-a and trophic dynamics; ii) characterization of CDOM; iii) estimation of Chl-a and CDOM from OLI/Landsat-8 and RapidEye imagery. The monitoring lasted 20 months within a multi-year drought, which contributed to water-quality deterioration. Chl-a and trophic state analysis showed a highly eutrophic status for the perennial reservoir during the entire study period, while the non-perennial reservoirs ranged from oligotrophic to eutrophic, with changes associated with the first events of the rainy season. CDOM characterization suggests that the perennial reservoir is mostly influenced by autochthonous sources, while allochthonous sources dominate the non-perennial ones. Spectral-group classification assigned the perennial as CDOM-moderate and highly eutrophic reservoir, whereas the non-perennial ones were assigned as CDOM-rich and oligotrophic-dystrophic reservoirs. The remote sensing initiative was partially successful: the Chl-a was best modelled using RapidEye for the perennial; whereas CDOM performed best with Landsat-8 for non-perennial reservoirs. This investigation showed high potential for retrieving water quality parameters in dry areas with small reservoirs.

scholarly journals Seasonal Monitoring Of Chlorophyll-A With Landsat 8 Oli In The Madura Strait, Pasuruan, East Java, Indonesia

2021 ◽  
Vol 14 (2) ◽  
pp. 22-29
Author(s):  
Arief Darmawan ◽  
Endang Yuli Herawati ◽  
Millati Azkiya ◽  
Rizka Nur Cahyani ◽  
Siti Hasanah Aryani ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Distribution Pattern ◽  
Chlorophyll A ◽  
Coastal Area ◽  
Field Data ◽  
Spatial Distribution Pattern ◽  
Landsat 8 ◽  
Water Runoff ◽  
Landsat 8 Oli ◽  
Chl A

Chlorophyll-a (Chl-a) is a type of pigment is most common and predominant in all oxygen-evolving photosynthetic organisms such as higher plants, red and green algae. The concentrations of high chlorophyll-a (Chl-a) in coastal waters tend to be lower offshore due to land through river water runoff. The Madura Strait is one of the Indonesian basins that is widely used for fisheries activity, which directly impacts and puts quite high pressure on the aquatic resources. In addition, the development of urban areas and changes of land use in the hinterland areas of East Java Province due to increasing population are also intensive. The objectives of this research were: (1) to map the distribution of chlorophyll-a, its concentration and dynamics in the Madura Strait near the Pasuruan coastal area using remote sensing for both dry and rainy seasons, (2) figure out the influence of rivers or other oceanographic factors that may occur, and (3) calculate the accuracy of the estimation compared to the field data. The Landsat 8 OLI imagery was used to determine the concentration of Chl-a and analyze its seasonal spatial distribution pattern. The results show that (1) spatial distribution of chlorophyll-a (Chl-a), its concentration and dynamics in the Madura Strait waters near the Pasuruan coastal area varies between dry and rainy months or seasons, (2) input from rivers, waves, tidal level, and eddy circulation constitute the oceanographic parameters that influence the spatial distribution pattern of chlorophyll-a (Chl-a) in the Madura Strait waters near the Pasuruan coastal area, and (3) validation of the estimated Chl-a concentrations from Landsat 8 OLI using field data has shown RMSE value of 0.49.

scholarly journals Mapping chlorophyll-a concentrations in a cyanobacteria- and algae-impacted Vaal Dam using Landsat 8 OLI data

2018 ◽  
Vol 114 (9/10) ◽  
Author(s):  
Oupa E. Malahlela ◽  
Thando Oliphant ◽  
Lesiba T. Tsoeleng ◽  
Paidamwoyo Mhangara
Keyword(s):  
Water Quality ◽  
Quality Assessment ◽  
Chlorophyll A ◽  
Water Quality Assessment ◽  
Water Bodies ◽  
Landsat 8 ◽  
Landsat 8 Oli ◽  
Inland Water ◽  
Chl A ◽  
Vaal Dam

Mapping chlorophyll-a (chl-a) is crucial for water quality management in turbid and productive case II water bodies, which are largely influenced by suspended sediment and phytoplankton. Recent developments in remote sensing technology offer new avenues for water quality assessment and chl-a detection for inland water bodies. In this study, the red to near-infrared (NIR-red) bands were tested for the Vaal Dam in South Africa to classify chl-a concentrations using Landsat 8 Operational Land Imager (OLI) data for 2014–2016 by means of stepwise logistic regression (SLR). The moderate-resolution imaging spectroradiometer (MODIS) data were also used for validating chl-a concentration classes. The chl-a concentrations were classified into low and high concentrations. The SLR applied on 2014 images yielded an overall accuracy of 80% and kappa coefficient (κ) of 0.74 on April 2014 data, while an overall accuracy of 65% and κ=0.30 were obtained for the May 2015 Landsat data. There was a significant (p less than 0.05) negative correlation between chl-a classes and red band in all analyses, while the NIR band showed a positive correlation (0.0001; p less than 0.89) for April 2014 data set. The 2015 image classification yielded an overall accuracy of 83% and κ=0.43. The difference vegetation index showed a significant (p less than 0.003) positive correlation with chl-a concentrations for May 2015 and July 2016, with chl-a ranges of between 2.5 μg/L and 1219 μg/L. These correlations show that a class increase in chl-a (from low to high) is in response to an increase in greenness within the Vaal Dam. We have demonstrated the applicability of Landsat 8 OLI data for inland water quality assessment.

scholarly journals Retrieval of Chlorophyll-a Concentrations in the Coastal Waters of the Beibu Gulf in Guangxi Using a Gradient-Boosting Decision Tree Model

2021 ◽  
Vol 11 (17) ◽  
pp. 7855
Author(s):  
Huanmei Yao ◽  
Yi Huang ◽  
Yiming Wei ◽  
Weiping Zhong ◽  
Ke Wen
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Spatial Distribution ◽  
Decision Tree ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Gradient Boosting ◽  
Beibu Gulf ◽  
Landsat 8 ◽  
Chl A

Remote sensing for the monitoring of chlorophyll-a (Chl-a) is essential to compensate for the shortcomings of traditional water quality monitoring, strengthen red tide disaster monitoring and early warnings, and reduce marine environmental risks. In this study, a machine learning approach called the Gradient-Boosting Decision Tree (GBDT) was employed to develop an algorithm for estimating the Chl-a concentrations of the coastal waters of the Beibu Gulf in Guangxi, using Landsat 8 OLI image data as the image source in combination with field measurements of Chl-a concentrations. The GBDT model with B4, B3 + B4, B3, B1 − B4, B2 + B4, B1 + B4, and B2 − B4 as input features exhibited higher accuracy (MAE = 0.998 μg/L, MAPE = 19.413%, and RMSE = 1.626 μg/L) compared with different physics models, providing a new method for remote sensing inversion of water quality parameters. The GBDT model was used to study the spatial distribution and temporal variation of Chl-a concentrations in the coastal sea surface of the Beibu Gulf of Guangxi from 2013 to 2020. The results showed a spatial distribution with high concentrations in nearshore waters and low concentrations in offshore waters. The Chl-a concentration exhibited seasonal changes (concentration in summer > autumn > spring ≈ winter).

scholarly journals Study of Water and Sediment Quality in the Bay of Dakhla, Morocco: Physico-Chemical Quality and Metallic Contamination

2020 ◽  
Author(s):  
Mimouna Anhichem ◽  
Samir Benbrahim
Keyword(s):  
Water Quality ◽  
Trace Elements ◽  
Urban Area ◽  
Chlorophyll A ◽  
Sediment Quality ◽  
Chemical Quality ◽  
Metallic Trace Elements ◽  
Physico Chemical ◽  
Cadmium Lead

The present study contributes to the evaluation of the impact of the various activities developed around the Bay of Dakhla in Morocco through the study of the physico-chemical quality of the waters and sediments of the Bay. For this purpose, a spatial and temporal monitoring of the physicochemical and metallic pollution indicator parameters was conducted between May 2014 and March 2015. The main physicochemical descriptors of water quality were monitored, namely: temperature, salinity, pH, dissolved O2, nutrients (ammonium, nitrites, nitrates, phosphates) and chlorophyll (a). A qualification of the waters of the Bay was drawn up based on water quality assessment grids. The quality of the sediments was assessed through the determination of granulometry, the total organic carbon content and the contents of the main metallic trace elements (cadmium, lead, mercury, chromium, copper and zinc). The results of the present study show the beginning of nutrient enrichment of the water bodies of the bay, especially the stations located near the urban area, where 1.83 mg l−1 of nitrates, 0.37 mg l−1 of phosphate and 7.42 μg l−1 of chlorophyll (a) were recorded. For the sediment, the maximum concentrations of metallic trace elements were recorded in the station near the harbour basin. These results allowed to establish a quality grid for the waters of the bay, generally qualified as “Good”, except for the sites located near the urban area for which the quality is qualified as “Average”. The sediment quality of the bay was assessed according to the criteria established by the Canadian Council of Ministers of the Environment. The levels of metallic trace elements remain below the toxicity thresholds, except for the sediments taken from the harbour basin.

scholarly journals Indicative Lake Water Quality Assessment Using Remote Sensing Images-Effect of COVID-19 Lockdown

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Poonam Wagh ◽  
Jency M. Sojan ◽  
Sriram J. Babu ◽  
Renu Valsala ◽  
Suman Bhatia ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Lake Water ◽  
Water Quality Assessment ◽  
Quality Parameters ◽  
Landsat 8 ◽  
Lake Water Quality ◽  
Chl A ◽  
Pollution Levels ◽  
Remote Sensing Techniques

The major lockdown due to the COVID-19 pandemic has affected the socio-economic development of the world. On the other hand, there are also reports of reduced pollution levels. In this study, an indicative analysis is adopted to understand the effect of lockdown on the changes in the water quality parameters for Lake Hussain Sagar using two remote sensing techniques: (i) spectral reflectance (SR) and (ii) chromaticity analysis (Forel-Ule color Index (FUI) and Excitation Purity). The empirical relationships from earlier studies imply that (i) increase in SR values (band B2) indicates a reduction in Chlorophyll-a (Chl-a) and Colored Dissolved Organic Matter (CDOM) concentrations, and (ii) increase in FUI indicates an increase in Total Suspended Solids (TSS). The Landsat 8 OLI satellite images are adopted for comparison between (i) January to May of year 2020: the effect of lockdown on water quality, and (ii) March and April for years 2015 to 2020: historical variations in water quality. The results show notable changes in SR values and FUI due to lockdown compared to before lockdown and after unlock suggesting a significant reduction in lake water pollution. In addition, the historical variations within April suggest that the pollution levels are least in the year 2020.

QUALIDADE DAS ÁGUAS E NÍVEL TRÓFICO DA BACIA DO RIO PACIÊNCIA NA ILHA DO MARANHÃO, BRASIL

2019 ◽  
Vol 21 (2) ◽  
pp. 437-453
Author(s):  
Elna Lucilia Santos Corrêa ◽  
Karina Suzana Feitosa Pinheiro ◽  
Cláudio José Da Silva de Sousa ◽  
Luiz Jorge Bezerra da Silva Dias
Keyword(s):  
Water Quality ◽  
Trophic Status ◽  
The Body ◽  
Chemical Parameters ◽  
Public Supply ◽  
Physico Chemical ◽  
Great Availability ◽  
Del Rio ◽  
Fluvial Environments

O Brasil apresenta grande disponibilidade de água doce em seus mananciais. Fazendo parte desse recurso encontra-se, o rio Paciência, localizado na Ilha do Maranhão destacado pela sua importância local, principalmente por contribuir com suas águas para recarga dos mananciais subterrâneos, fonte de abastecimento público de vários bairros de São Luís, capital do estado. No entanto, este rio vem sofrendo comprometimento da qualidade de suas águas, consequência do processo de uso e ocupação dos espaços em sua bacia. Destacando-se como um dos principais problemas relacionados a qualidade de ambientes fluviais,  a eutrofização, que consiste no processo em que o corpo d’água adquire elevados níveis de nutrientes (fosfatos e nitratos), é um indicador determinante da qualidade da água. Neste sentido, o objetivo deste trabalho foi caracterizar a qualidade da água e do estado trófico na bacia hidrográfica do rio Paciência atráves dos parâmetros fisico-químico evidenciando os trechos mais comprometidos conforme os valores alcançados nas análises. Os resultados das análises foram comparados com a CONAMA No. 357/05 que indicaram uma situação preocupante quanto à qualidade da água no local de estudo.Palavras-chave: Qualidade de água; Eutrofização; Ilha do Maranhão. ABSTRACTThe Brazil has great availability of fresh water in its springs. Within these contexts, the Paciência River, located on the Island of Maranhão stands out for its local importance, mainly for contributing its waters to the recharge of the underground springs, source of public supply of several districts of São Luís, capital of the state. However, this river has been compromising the quality of its waters, a consequence of the process of use and occupation of the spaces in its basin. Highlighting as one of the main problems related to the quality of fluvial environments, eutrophication, which consists of the process in which the body of water acquires high levels of nutrients (phosphates and nitrates), is a determinant indicator of water quality. In this sense, the objective of this work was to characterize the water quality and trophic status in the Paciência river basin through the physico-chemical parameters, showing the most compromised stretches according to the values reached in the analyzes. The results of the analyzes were compared with CONAMA No. 357/05 which indicated a worrying situation regarding the quality of the water at the place of study.Keywords: Water quality; Eutrophication; Island of Maranhão. RESUMENBrasil tiene gran disponibilidad de agua dulce en sus manantiales. Parte de este recurso es el río Paciencia, ubicado en la isla de Maranhão, que destaca por su importancia local, principalmente porque contribuye con sus aguas a recargar las fuentes subterráneas, fuente de suministro público de varios barrios de São Luís, capital del estado. Sin embargo, este río se ha visto afectado por la calidad de sus aguas, como consecuencia del proceso de uso y ocupación de los espacios en su cuenca. Destacando como uno de los principales problemas relacionados con la calidad de los ambientes fluviales, la eutrofización, que consiste en el proceso en el que el cuerpo de agua adquiere altos niveles de nutrientes (fosfatos y nitratos), es un indicador determinante de la calidad del agua. En este sentido, el objetivo de este trabajo fue caracterizar la calidad del agua y el estado trófico en la cuenca del río Paciência a través de los parámetros fisicoquímicos, mostrando las secciones más comprometidas de acuerdo con los valores alcanzados en los análisis. Los resultados de los análisis se compararon con CONAMA N°. 357/05, que indicó una situación preocupante con respecto a la calidad del agua en el sitio de estudio.Palabras clave: Calidad del agua; Eutrofización, Isla Maranhão.

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