A system for environmental monitoring of hydroelectric reservoirs in Brazil

Alcântara, Enner; Curtarelli, Marcelo; Ogashawara, Igor; Stech, José; Souza, Arley Ferreira de

doi:10.4136/ambi-agua.1088

Cited by 72 publications

(9 citation statements)

References 22 publications

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“…This analysis ascribed a positive heat balance (heat gain) to the stratification of the water column and a negative heat balance to a mixing in the water column. Figure 5 shows the heat balance analysis from March 2009, to February 2010, that was calculated from the data at the Integrated System for Environmental Monitoring (SIMA) installed at the Itumbiara Reservoir [43,44] near the dam. In the figure, the estimated chl-a time series for the same pixels of the SIMA were plotted.…”

Section: Time Seriesmentioning

confidence: 99%

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo- to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

et al. 2014

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Monitoring chlorophyll-a (chl-a) concentrations is important for the management of water quality, because it is a good indicator of the eutrophication level in an aquatic system. Thus, our main purpose was to develop an alternative technique to monitor chl-a in time and space through remote sensing techniques. However, one of the limitations of remote sensing is the resolution. To achieve a high temporal resolution and medium space resolution, we used the Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m reflectance product, MOD09GA, and limnological parameters from the Itumbiara Reservoir. With these data, an empirical (O14a) and semi-empirical (O14b) algorithm were developed. Algorithms were cross-calibrated and validated using three datasets: one for each campaign and a third consisting of a combination of the two individual campaigns. OPEN ACCESSRemote Sens. 2014, 6 1635 Algorithm O14a produced the best validation with a root mean square error (RMSE) of 30.4%, whereas O14b produced an RMSE of 32.41% using the mixed dataset calibration. O14a was applied to MOD09GA to build a time series for the reservoir for the year of 2009. The time-series analysis revealed that there were occurrences of algal blooms in the summer that were likely related to the additional input of nutrients caused by rainfall runoff. During the winter, however, the few observed algal blooms events were related to periods of atmospheric meteorological variations that represented an enhanced external influence on the processes of mixing and stratification of the water column. Finally, the use of remote sensing techniques can be an important tool for policy makers, environmental managers and the scientific community with which to monitor water quality.

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Section: Time Seriesmentioning

confidence: 99%

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo- to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

et al. 2014

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“…The meteorological data were acquired hourly between 21 December 2012 and 21 March 2013 by an autonomous system called “Integrated System for Environmental Monitoring” (SIMA, from the Portuguese spelling). SIMA [ Stech et al ., ; Alcântara et al ., ] consists of a set of hardware and software designed for meteorological and limnological data acquisition and monitoring of natural and man‐made aquatic systems. The primary characteristics of the meteorological sensors used are summarized in Table , and the SIMA position within the THR is shown in Figure .…”

Section: Methodsmentioning

confidence: 99%

Influence of summertime mesoscale convective systems on the heat balance and surface mixed layer dynamics of a large Amazonian hydroelectric reservoir

et al. 2014

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We evaluated the impacts of summertime mesoscale convective systems (MCS) on the heat balance and diel surface mixed layer (SML) dynamics of the Brazilian Amazon's Tucuru ı Hydroelectric Reservoir (THR). We used a synergistic approach that combines in situ data, remote sensing data, and three-dimensional (3-D) modeling to investigate the typical behavior of the components of the heat balance and the SML dynamics. During the study period (the austral summer of 2012-2013), 22 days with MCS activity were identified. These events occurred approximately every 4 days, and they were most frequent during January (50% of the observations). An analysis of local meteorological data showed that when MCS occur, the environmental conditions at THR change significantly (p-value < 0.01). The net longwave flux, which was the heat balance component most strongly impacted by MCS, increased more than 32% on days with MCS activity. The daily integrated heat balance became negative (254 W m 22) on MCS days, while the balance was positive (19 W m 22) on non-MCS days. In response to the changes in the heat balance, the SML dynamics changed when a MCS was over the THR. The SML depth was typically 28% higher on the days with MCS ($1.6 m) compared with the days without MCS ($1.3 m). The results indicate that MCS are one of the main meteorological disturbances driving the heat balance and the mixing dynamics of Amazonian hydroelectric reservoirs during the summer. These events may have implications for the water quality and greenhouse gas emissions of Amazonian reservoirs.

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“…2a-p). The autonomous system, called "Integrated System for Environmental Monitoring" (SIMA, from the Portuguese spelling, Stech et al, 2006;Alcântara et al, 2013), acquired hourly data between 21 December 2012 and 21 September 2013. The meteorological data collected by SIMA (except wind speed and direction) were recorded every hour, as a result from a mean of 30 samples collected by a burst sampling of 0.3 ms duration at a 10 ms rate.…”

Section: Surface Meteorology Datasetmentioning

confidence: 99%

Carbon dioxide emissions from Tucuruí reservoir (Amazon biome): New findings based on three-dimensional ecological model simulations

Curtarelli

Ogashawara

Araújo

et al. 2016

Science of The Total Environment

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We used a three-dimensional model to assess the dynamics of diffusive carbon dioxide flux (F(CO2)) from a hydroelectric reservoir located at Amazon rainforest. Our results showed that for the studied periods (2013 summer/wet and winter/dry seasons) the surface averaged F(CO2) presented similar behaviors, with regular emissions peaks. The mean daily surface averaged F(CO2) showed no significant difference between the seasons (p>0.01), with values around -1338mg Cm-2day-1 (summer/wet) and -1395mg Cm-2day-1 (winter/dry). At diel scale, the F(CO2) was large during the night and morning and low during the afternoon in both seasons. Regarding its spatial distribution, the F(CO2) showed to be more heterogeneous during the summer/wet than during the winter/dry season. The highest F(CO2) were observed at transition zone (-300mg Cm-2h-1) during summer and at littoral zone (-55mg Cm-2h-1) during the winter. The total CO2 emitted by the reservoir along 2013 year was estimated to be 1.1Tg C year-1. By extrapolating our results we found that the total carbon emitted by all Amazonian reservoirs can be around 7Tg C year-1, which is 22% lower than the previous published estimate. This significant difference should not be neglected in the carbon inventories since the carbon emission is a key factor when comparing the environmental impacts of different sources of electricity generation and can influences decision makers in the selection of the more appropriate source of electricity and, in case of hydroelectricity, the geographical position of the reservoirs.

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A system for environmental monitoring of hydroelectric reservoirs in Brazil

Cited by 72 publications

References 22 publications

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo- to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo- to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

Influence of summertime mesoscale convective systems on the heat balance and surface mixed layer dynamics of a large Amazonian hydroelectric reservoir

Carbon dioxide emissions from Tucuruí reservoir (Amazon biome): New findings based on three-dimensional ecological model simulations

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