lais amorim | Universidade Estadual de Maringa (original) (raw)
Papers by lais amorim
<p>Lakes and reservoirs are standing surface water bodies that provide several environmenta... more <p>Lakes and reservoirs are standing surface water bodies that provide several environmental services and anthropic uses. As driving forces, climate conditions, sediment loads and pollutants influence the hydrodynamic behaviour of lakes, affecting the thermal stratification and mixing regime patterns that play expressive roles in the water quality condition. Therefore, the analysis of climate change scenarios allows the planning and implementation of preventive and mitigative actions. Mathematical modelling can simulate the thermal regime of lakes and reservoirs, considering different boundary conditions. Three-dimensions models are often used to better assess the changes on these environments, however, the extensive set of information required, along with its elevated processing parameters, can determine the selection of simpler models for long periods simulations, provided that the results accuracy remains appropriated. This paper intends to evaluate the differences and similarities between a one-dimension (GLM) and a three-dimensions (DELFT3D) transport models, used to assess the impacts of different climate scenarios on the thermal regime of a small lake. The case study was conducted on the Hedberg Dam, located about 90 km from Sao Paulo city, Brazil. It is a 0,2 km²-4.5m depth pond, built in the beginnings of the 19th century. Its hydrological catchment area is partially protected, with some sparse urban occupations. Both models used morphology characteristics, atmospheric variables and flow as input data. The calibration and validation were performed using water thermal profiles from high-frequency sensor data, observed from 2016 to 2018. Two climate change scenarios, optimistic and pessimistic, based on Eta Regional Climate Model, were simulated considering changes in radiation, air temperature, wind, precipitation and flow. Both results indicate changes in the thermal profiles regime, with increasing occurrence of mixing events and variations on the stratification patterns. However, differences can be noted in the water balance and in the thermal profiles results.</p>
SN Applied Sciences, 2021
Conservation and improvement of water quality in water bodies is an important matter to maintain ... more Conservation and improvement of water quality in water bodies is an important matter to maintain all of its uses as well as other human necessities like microclimate regulation and leisure. Lakes and reservoirs have a complex circulation behavior with vertical temperature profiles changes along the time, resulting in differences in water density and a vertical stratification condition. This characteristic can directly affect the water quality conditions perturbing its main indicators. This study aims to evaluate the quasi-3D models' capacity to represent the hydrodynamic behavior of a tropical lake and its effects on the main variables that characterize its water quality. To achieve this objective, high-frequency monitoring data were collected, the lake was represented in a quasi-3D model, and the accuracy of the result was evaluated by applying statistical indices. The evaluation showed good agreement between field measures and simulated results when compared with other applica...
&amp;lt;p&amp;gt;Lakes are lentic environmental with unique hydrodynamic, which d... more &amp;lt;p&amp;gt;Lakes are lentic environmental with unique hydrodynamic, which depends on the morphology, in and outflows, and atmospheric variables. This last driving force has its influence represented, mostly, by radiation and wind. All the interactions in the water column are harmed when the water column is divided into layers with different densities.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;This condition means no gas or nutrients exchanges, impairing the food channel, and oxygen availability across the lake. Lakes and reservoirs play a key role for the development of populations, industries, human activities that need water, and also as a landscape component, this context increases the necessity to ensure its availability during the year. In this perspective, the interest in understanding lakes&amp;amp;#8217; hydrodynamics and their effects on the water quality grew, aiming for appropriate management of the reservoirs and contributing areas.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;To collaborate with the knowledge in this area this research intended to improve the reservoir operator&amp;amp;#8217;s capacity to forecast situations that can compromise their uses. This objective was achieved by investigating the possibility of a functional relationship between the atmospheric forces and the lake thermal status changing.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Stratification can be postulated as an energy balance considering the energy incident from solar radiation and the kinetic energy transferred by the wind in terms of the surface wind-drag force. The lake&#39;s thermal conditions can be affected when an instability factor is inserted in the system. The wind&#39;s speed fluctuation produces the instability that transfers an amount of energy to the water column, provoking oscillations on the isothermals or internal waves.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A curve that represents this concept was constructed by crossing high-frequency field data from four lakes from two proxies, S* Rad-1 and W* S*&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. The proxies describe the effectiveness of energy transfer from the atmospheric to the water column, and so, which is the ruling energy on balance at the moment. The variables included in it are &amp;lt;strong&amp;gt;Rad&amp;lt;/strong&amp;gt; (total amount of the incident radiation on the last 24h (J m&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt;&amp;amp;#178;)); &amp;lt;strong&amp;gt;W*&amp;lt;/strong&amp;gt; (mean of the wind&amp;amp;#8217;s speed variance in a time window (m s&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;), multiplied by the air density (kg m&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt;) and the lake&#39;s depth (m)); and the &amp;lt;strong&amp;gt;S*&amp;lt;/strong&amp;gt; (Schmidt Number mean of the last 24h (J m&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt;&amp;amp;#178;)).&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The determined curve represents the thermal condition of the lake as a balanced result of the external variables and potential energy contained in the water column. This tool was able to represent the lakes&amp;amp;#8217; thermal status rapidly and well, with little data information. Its performance was tested against most known lakes&amp;amp;#8217; indices (Lake Number and Wedderburn Number) presenting more accurately with fewer data. Those outcomes allow an improvement to the reservoirs&amp;amp;#8217; management tools and operations.&amp;lt;/p&amp;gt;
38th IAHR World Congress - "Water: Connecting the World", 2019
The excessive use of water capacity, due to problems of availability, high demand and surface wat... more The excessive use of water capacity, due to problems of availability, high demand and surface water pollution have caused great water stress. However, surface runoff have been identified as the cause of significant impacts on water and the aquatic habitat. Much is known about punctual pollution, which are easy to quantify, predict and their locations are known. Thus, it is essential to develop methods and concepts to quantify the pollutant load present in the superficial flows. The most striking feature of nonpoint pollution is the great variability of the concentration of the pollutants present on the surfaces captured by runoff. Concentrations vary by orders of magnitude between river basins, between different precipitation events, and also over the same event. Nonpoint loads can be quantified and estimated by several methods, such as: Exports Coefficients (EC) or Unit Loads, Event Mean Concentration (EMC) and Mathematical Simulation Models, many others or even combinations, improving reliability. Basically two approaches to model diffuse pollution are identified. The more widely used are lumped-parameter models, while more complex models are based on the distributed-parameter concept. Four models (USGS, HSPF, STORM, SWMM) were described briefly. Finally, it is shown that computer simulation models which accommodate the processes that water undergoes (in terms of quantity and quality) in the upland watershed and downstream waterbodies are highly needed. Techniques available for analysis and prediction of nonpoint source (NPS) pollution loads, concentrations and modeling are reviewed in this paper. This review indicates the need for extensive further research on the subject.
38th IAHR World Congress - "Water: Connecting the World", 2019
Saline stratification is one of the most important physical processes in estuarine areas, which c... more Saline stratification is one of the most important physical processes in estuarine areas, which can affect water uses for urban or industrial purposes. It is a complex phenomenon and depends on the estuary geometry, tidal processes, fresh water inputs and human interference on the estuarine environment, such as hydroelectric power plants discharges, water abstractions for human and industrial use, river canalization and so on. The aim of this paper is to present a field survey on saline stratification in Cubatão River, in Brazil, and investigate its relationship with the natural fresh water and Henry Borden Hydroelectric Power Plant water's discharge. Cubatão River has an estuarine reach located at Santos estuarine system in São Paulo, Brazil and it is an indispensable source of water resources for urban and industrial supply. Fieldwork was conducted for approximately four months, from 03 November 2016 to 04 March 2017 and the monitoring parameters were salinity concentration, water level, precipitation and Henry Borden Discharge. Salinity concentration was measured in three different depths in the water column in order to examine the stratification patterns. Salinity stratification presented a complex behavior due to the effects of Henry Borden Hydroelectric Power Plant discharge, precipitation and tidal activity. During dry periods and reduced Henry Borden discharges, salinity concentration becomes high and saline stratification is distinguishable in the water column; while during higher Henry Borden discharges combined with high precipitation events, salinity concentration decreases significantly, indicating that seawater is flushed out Cubatão River. The most important finding of this monitoring period is that the salinity stratification pattern in Cubatão River varies considerably under different forcing events. Freshwater flow is the primary environmental factor controlling the stratification pattern in Cubatão River, but it is also strongly affect by hydroelectric power plant discharge and rainfall events. Salinity stratification investigation provided a framework for characterizing and understanding spatial patterns in estuaries and their variability over time. The field survey provided a unique observation of the hydroelectric power plant discharge effects on saline stratification in an estuarine river and the results are valuable for further water uses in Cubatão River particularly.
38th IAHR World Congress - "Water: Connecting the World", 2019
Lake's mixing regime affects physical, chemical and biological processes. Each time the vertical ... more Lake's mixing regime affects physical, chemical and biological processes. Each time the vertical stratification is broken an upward velocity is created. But is this velocity strong enough to re-suspend bed material and affect water turbidity? This is a key question in water quality studies, once that turbidity is an important index in those evaluations and bed material could include heavy metals, high load of nutrients or even pesticides, all harmful for the environmental. To respond this question turbidity measures and tools of environmental evaluation are needed. In this subject, two stratified tropical lakes, located in São Paulo-BR were used as study sites. Aiming to measure variations on the water turbidity due mixing events and evaluate them according to the temperatures profiles, also assess a model 3D capacity to represent the vertical velocities due to mixing events on the lake. The first lake is called Billings, it is bigger and deeper, than the second site, Hedberg reservoir, different sizes of lakes were chosen to be able to include the size effects on the lakes' mixing regime. Both lakes had their temperature profile and the relative turbidity measured in campaigns that were performed for more than a month and with 1min and 1s time steps, respectively. With the data collected the information were plotted and evaluated looking into specifics moments when the water column mix, and then the lakes were modeled in Delft3D which provided calculated vertical velocities. The measures on the field shows that the relative turbidity, that is, the difference between previous and current turbidity, increase when mixing events begin to happen, proving those events can re-suspend deposited materials. When the same period is modeled in Delft3D the higher vertical velocities are found at same time that turbidity peak occurs, evidencing the efficient of a calibrated model in represent physical conditions and relations in the lake.
&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp... more &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;Lakes and reservoirs are environments with many important uses in social activities, such as hydropower generation, water supply, landscape element, irrigation and flood containment. An ecosystem with so many environmental services needs to have its water quality well preserved, and besides that, inland waters have a key role in climate change studies, because of their faster response to variability in external forces.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;Water circulation in a reservoir is the result of a combination of morphometry and energetic driving forces. A lake&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217;s hydrodynamic characteristics vary with morphometric, meteorological and hydrological conditions. The heat balance involves exchanges at the surface, which are actively mixed and energised by the transfers occurring at the air-water interface, and also the exchanges in the water-soil interface near the banks and bottom, which depend on currents and internal waves; while in the main water column, the heat transfer is influenced by light penetration.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;In the context of climate changes and water scarcity worldwide, the development of tools to better understand, maintain and improve water quality in lakes and reservoirs becomes an essential ally to environmental research and limnology. This research aims to demonstrate the lake mixing regime by a different approach, testing two different methods to forecast the climate change influence on a lakes&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217; mixing regime, using data from climate models.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The first tool is a thermal limit curve proposed by the authors which can forecast water column thermal limits for stability or mixing condition in a lake, based on wind speed, radiation and water profile temperature data. The second applied tool is a quasi-3D mathematical model, well known and reputed in the simulation field.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The results obtained for different experimental lakes in temperate and tropical zones showed that both methods have a good performance in representing lakes hydrodynamics accurately. The curve allows a faster response and minor need for data input, on the other hand, the quasi-3D models are capable to produce more detailed results. Possibly in the lakes&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217; management, it would be more indicated the use of those two methods together, using the curve to analyse faster the period&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s trend and be able to delimitate the exact period which needs more detailed studies.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The climate change simulations conducted for two experimental lakes considering different scenarios of climate changes showed the driving forces&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; strong influence on the lake&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s mixing regime. The number of mixing events is an interesting proxy to analyse this influence. It was greater in the pessimistic scenarios but still less than in the current situation. This means longer periods of stratification, which can cause dissolved oxygen depletion in the deeper layers.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The pessimistic scenarios have mixing events with greater amplitude, which results from a powerful stratification in previous periods. Mixing events with greater amplitudes create higher vertical velocities, resuspending more organic load and dropping dissolved oxygen levels along the water column, impairing the water quality.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;
RBRH
Hydrological models are one of the most effective ways of assessing water behavior and flood risk... more Hydrological models are one of the most effective ways of assessing water behavior and flood risk, although the quality of their results is determined by the input data representativity, especially rainfall. Normally, only rain gauge data is used, unable to represent rain spatial variability. Aiming to reduce the model’s uncertainties, hydrological model performance was evaluated in determining the runoff based on distributed rainfall data applied in an urban watershed with macro drainage structures. A distributed rainfall data, derived from a conditional merging of radar and field measurements, was used as the hydrological model’s input data, and led to very accurate runoff results. The analysis of the results demonstrated that to model urban watersheds with accuracy, distributed rainfall data is required, as well as knowledge about the sewage and drainage systems, reinforcing the need to use tools that are compatible with the site complexity.
&lt;p&gt;Modelling water quality of polluted heavy loaded water courses as those ... more &lt;p&gt;Modelling water quality of polluted heavy loaded water courses as those crossing highly urbanized catchment areas are a complex task that involves several processes based on coefficients like unit loads, decay rates and self-depuration effects among others. The fate of pollutants as organic matter and nutrients are usually done through transport equations added by sourcing and sinking terms that implies the use of decay factors. The so-called k&amp;#8217;s coefficients are present in the literature and were derived from typical water samples that don&amp;#8217;t represent the local conditions founded in the urban rivers, usually affected by the catchment scale. This article presents an approach method used for local determination of the k&amp;#8217;s coefficient for Biological Oxygen Demand (BOD-k1), Atmospheric Reaeration (AR-k2) and Sediment Oxygen Demand (SOD-k4) and compares results to typical adopted values bye modelists. The approach is based on local waters and sediment laboratory tests adjusted to consider specific driving forces as water temperature, constituent concentration and flow turbulence. Considering the catchment area (286 km&amp;#178;) and the river reach (25 km long) 4 sampling stations were defined to collect depth integrated water samples and the bed material. The k1 coefficient is the most sensible one due to the influence of the biological components and the relation between labile and refractory fractions, that varies along the reach with the contribution from the sub catchments&amp;#8217; land use and sanitary infrastructure. Considering Fujimoto&amp;#8217;s and Thomas&amp;#8217; equations, different values of local dependent k1 were found. For k2, the concept of river shear stress velocity was applied to correlate the oxygen mass transferred to the water in the JAR test run for the observed range of velocity gradients in the natural flow. Results lead to a more realistic air entrainment rate due to hydraulic, superficial tension and presence of oils and greases. The SOD-k4 were determined after bottom sediment samples collected in the same defined stations for 3 different concentrations in clean water. The continuous oxygen demand for each sample was taken hourly in the first day and daily in the next 5, and then converted to the Toro&amp;#8217;s active sediment layer demand considering local porosity and specific weight. Results showed considerably lower than the typical values referenced in the literature for all k&amp;#8217;s, denoting the influence of the above-mentioned characteristics and the level of uncertainties that could affect modelling results when non-local parameters are employed.&lt;/p&gt;
<p>Lakes and reservoirs are standing surface water bodies that provide several environmenta... more <p>Lakes and reservoirs are standing surface water bodies that provide several environmental services and anthropic uses. As driving forces, climate conditions, sediment loads and pollutants influence the hydrodynamic behaviour of lakes, affecting the thermal stratification and mixing regime patterns that play expressive roles in the water quality condition. Therefore, the analysis of climate change scenarios allows the planning and implementation of preventive and mitigative actions. Mathematical modelling can simulate the thermal regime of lakes and reservoirs, considering different boundary conditions. Three-dimensions models are often used to better assess the changes on these environments, however, the extensive set of information required, along with its elevated processing parameters, can determine the selection of simpler models for long periods simulations, provided that the results accuracy remains appropriated. This paper intends to evaluate the differences and similarities between a one-dimension (GLM) and a three-dimensions (DELFT3D) transport models, used to assess the impacts of different climate scenarios on the thermal regime of a small lake. The case study was conducted on the Hedberg Dam, located about 90 km from Sao Paulo city, Brazil. It is a 0,2 km²-4.5m depth pond, built in the beginnings of the 19th century. Its hydrological catchment area is partially protected, with some sparse urban occupations. Both models used morphology characteristics, atmospheric variables and flow as input data. The calibration and validation were performed using water thermal profiles from high-frequency sensor data, observed from 2016 to 2018. Two climate change scenarios, optimistic and pessimistic, based on Eta Regional Climate Model, were simulated considering changes in radiation, air temperature, wind, precipitation and flow. Both results indicate changes in the thermal profiles regime, with increasing occurrence of mixing events and variations on the stratification patterns. However, differences can be noted in the water balance and in the thermal profiles results.</p>
SN Applied Sciences, 2021
Conservation and improvement of water quality in water bodies is an important matter to maintain ... more Conservation and improvement of water quality in water bodies is an important matter to maintain all of its uses as well as other human necessities like microclimate regulation and leisure. Lakes and reservoirs have a complex circulation behavior with vertical temperature profiles changes along the time, resulting in differences in water density and a vertical stratification condition. This characteristic can directly affect the water quality conditions perturbing its main indicators. This study aims to evaluate the quasi-3D models' capacity to represent the hydrodynamic behavior of a tropical lake and its effects on the main variables that characterize its water quality. To achieve this objective, high-frequency monitoring data were collected, the lake was represented in a quasi-3D model, and the accuracy of the result was evaluated by applying statistical indices. The evaluation showed good agreement between field measures and simulated results when compared with other applica...
&amp;lt;p&amp;gt;Lakes are lentic environmental with unique hydrodynamic, which d... more &amp;lt;p&amp;gt;Lakes are lentic environmental with unique hydrodynamic, which depends on the morphology, in and outflows, and atmospheric variables. This last driving force has its influence represented, mostly, by radiation and wind. All the interactions in the water column are harmed when the water column is divided into layers with different densities.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;This condition means no gas or nutrients exchanges, impairing the food channel, and oxygen availability across the lake. Lakes and reservoirs play a key role for the development of populations, industries, human activities that need water, and also as a landscape component, this context increases the necessity to ensure its availability during the year. In this perspective, the interest in understanding lakes&amp;amp;#8217; hydrodynamics and their effects on the water quality grew, aiming for appropriate management of the reservoirs and contributing areas.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;To collaborate with the knowledge in this area this research intended to improve the reservoir operator&amp;amp;#8217;s capacity to forecast situations that can compromise their uses. This objective was achieved by investigating the possibility of a functional relationship between the atmospheric forces and the lake thermal status changing.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Stratification can be postulated as an energy balance considering the energy incident from solar radiation and the kinetic energy transferred by the wind in terms of the surface wind-drag force. The lake&#39;s thermal conditions can be affected when an instability factor is inserted in the system. The wind&#39;s speed fluctuation produces the instability that transfers an amount of energy to the water column, provoking oscillations on the isothermals or internal waves.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A curve that represents this concept was constructed by crossing high-frequency field data from four lakes from two proxies, S* Rad-1 and W* S*&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. The proxies describe the effectiveness of energy transfer from the atmospheric to the water column, and so, which is the ruling energy on balance at the moment. The variables included in it are &amp;lt;strong&amp;gt;Rad&amp;lt;/strong&amp;gt; (total amount of the incident radiation on the last 24h (J m&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt;&amp;amp;#178;)); &amp;lt;strong&amp;gt;W*&amp;lt;/strong&amp;gt; (mean of the wind&amp;amp;#8217;s speed variance in a time window (m s&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;), multiplied by the air density (kg m&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt;) and the lake&#39;s depth (m)); and the &amp;lt;strong&amp;gt;S*&amp;lt;/strong&amp;gt; (Schmidt Number mean of the last 24h (J m&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt;&amp;amp;#178;)).&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The determined curve represents the thermal condition of the lake as a balanced result of the external variables and potential energy contained in the water column. This tool was able to represent the lakes&amp;amp;#8217; thermal status rapidly and well, with little data information. Its performance was tested against most known lakes&amp;amp;#8217; indices (Lake Number and Wedderburn Number) presenting more accurately with fewer data. Those outcomes allow an improvement to the reservoirs&amp;amp;#8217; management tools and operations.&amp;lt;/p&amp;gt;
38th IAHR World Congress - "Water: Connecting the World", 2019
The excessive use of water capacity, due to problems of availability, high demand and surface wat... more The excessive use of water capacity, due to problems of availability, high demand and surface water pollution have caused great water stress. However, surface runoff have been identified as the cause of significant impacts on water and the aquatic habitat. Much is known about punctual pollution, which are easy to quantify, predict and their locations are known. Thus, it is essential to develop methods and concepts to quantify the pollutant load present in the superficial flows. The most striking feature of nonpoint pollution is the great variability of the concentration of the pollutants present on the surfaces captured by runoff. Concentrations vary by orders of magnitude between river basins, between different precipitation events, and also over the same event. Nonpoint loads can be quantified and estimated by several methods, such as: Exports Coefficients (EC) or Unit Loads, Event Mean Concentration (EMC) and Mathematical Simulation Models, many others or even combinations, improving reliability. Basically two approaches to model diffuse pollution are identified. The more widely used are lumped-parameter models, while more complex models are based on the distributed-parameter concept. Four models (USGS, HSPF, STORM, SWMM) were described briefly. Finally, it is shown that computer simulation models which accommodate the processes that water undergoes (in terms of quantity and quality) in the upland watershed and downstream waterbodies are highly needed. Techniques available for analysis and prediction of nonpoint source (NPS) pollution loads, concentrations and modeling are reviewed in this paper. This review indicates the need for extensive further research on the subject.
38th IAHR World Congress - "Water: Connecting the World", 2019
Saline stratification is one of the most important physical processes in estuarine areas, which c... more Saline stratification is one of the most important physical processes in estuarine areas, which can affect water uses for urban or industrial purposes. It is a complex phenomenon and depends on the estuary geometry, tidal processes, fresh water inputs and human interference on the estuarine environment, such as hydroelectric power plants discharges, water abstractions for human and industrial use, river canalization and so on. The aim of this paper is to present a field survey on saline stratification in Cubatão River, in Brazil, and investigate its relationship with the natural fresh water and Henry Borden Hydroelectric Power Plant water's discharge. Cubatão River has an estuarine reach located at Santos estuarine system in São Paulo, Brazil and it is an indispensable source of water resources for urban and industrial supply. Fieldwork was conducted for approximately four months, from 03 November 2016 to 04 March 2017 and the monitoring parameters were salinity concentration, water level, precipitation and Henry Borden Discharge. Salinity concentration was measured in three different depths in the water column in order to examine the stratification patterns. Salinity stratification presented a complex behavior due to the effects of Henry Borden Hydroelectric Power Plant discharge, precipitation and tidal activity. During dry periods and reduced Henry Borden discharges, salinity concentration becomes high and saline stratification is distinguishable in the water column; while during higher Henry Borden discharges combined with high precipitation events, salinity concentration decreases significantly, indicating that seawater is flushed out Cubatão River. The most important finding of this monitoring period is that the salinity stratification pattern in Cubatão River varies considerably under different forcing events. Freshwater flow is the primary environmental factor controlling the stratification pattern in Cubatão River, but it is also strongly affect by hydroelectric power plant discharge and rainfall events. Salinity stratification investigation provided a framework for characterizing and understanding spatial patterns in estuaries and their variability over time. The field survey provided a unique observation of the hydroelectric power plant discharge effects on saline stratification in an estuarine river and the results are valuable for further water uses in Cubatão River particularly.
38th IAHR World Congress - "Water: Connecting the World", 2019
Lake's mixing regime affects physical, chemical and biological processes. Each time the vertical ... more Lake's mixing regime affects physical, chemical and biological processes. Each time the vertical stratification is broken an upward velocity is created. But is this velocity strong enough to re-suspend bed material and affect water turbidity? This is a key question in water quality studies, once that turbidity is an important index in those evaluations and bed material could include heavy metals, high load of nutrients or even pesticides, all harmful for the environmental. To respond this question turbidity measures and tools of environmental evaluation are needed. In this subject, two stratified tropical lakes, located in São Paulo-BR were used as study sites. Aiming to measure variations on the water turbidity due mixing events and evaluate them according to the temperatures profiles, also assess a model 3D capacity to represent the vertical velocities due to mixing events on the lake. The first lake is called Billings, it is bigger and deeper, than the second site, Hedberg reservoir, different sizes of lakes were chosen to be able to include the size effects on the lakes' mixing regime. Both lakes had their temperature profile and the relative turbidity measured in campaigns that were performed for more than a month and with 1min and 1s time steps, respectively. With the data collected the information were plotted and evaluated looking into specifics moments when the water column mix, and then the lakes were modeled in Delft3D which provided calculated vertical velocities. The measures on the field shows that the relative turbidity, that is, the difference between previous and current turbidity, increase when mixing events begin to happen, proving those events can re-suspend deposited materials. When the same period is modeled in Delft3D the higher vertical velocities are found at same time that turbidity peak occurs, evidencing the efficient of a calibrated model in represent physical conditions and relations in the lake.
&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp... more &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;Lakes and reservoirs are environments with many important uses in social activities, such as hydropower generation, water supply, landscape element, irrigation and flood containment. An ecosystem with so many environmental services needs to have its water quality well preserved, and besides that, inland waters have a key role in climate change studies, because of their faster response to variability in external forces.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;Water circulation in a reservoir is the result of a combination of morphometry and energetic driving forces. A lake&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217;s hydrodynamic characteristics vary with morphometric, meteorological and hydrological conditions. The heat balance involves exchanges at the surface, which are actively mixed and energised by the transfers occurring at the air-water interface, and also the exchanges in the water-soil interface near the banks and bottom, which depend on currents and internal waves; while in the main water column, the heat transfer is influenced by light penetration.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;In the context of climate changes and water scarcity worldwide, the development of tools to better understand, maintain and improve water quality in lakes and reservoirs becomes an essential ally to environmental research and limnology. This research aims to demonstrate the lake mixing regime by a different approach, testing two different methods to forecast the climate change influence on a lakes&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217; mixing regime, using data from climate models.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The first tool is a thermal limit curve proposed by the authors which can forecast water column thermal limits for stability or mixing condition in a lake, based on wind speed, radiation and water profile temperature data. The second applied tool is a quasi-3D mathematical model, well known and reputed in the simulation field.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The results obtained for different experimental lakes in temperate and tropical zones showed that both methods have a good performance in representing lakes hydrodynamics accurately. The curve allows a faster response and minor need for data input, on the other hand, the quasi-3D models are capable to produce more detailed results. Possibly in the lakes&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217; management, it would be more indicated the use of those two methods together, using the curve to analyse faster the period&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s trend and be able to delimitate the exact period which needs more detailed studies.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The climate change simulations conducted for two experimental lakes considering different scenarios of climate changes showed the driving forces&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; strong influence on the lake&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s mixing regime. The number of mixing events is an interesting proxy to analyse this influence. It was greater in the pessimistic scenarios but still less than in the current situation. This means longer periods of stratification, which can cause dissolved oxygen depletion in the deeper layers.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The pessimistic scenarios have mixing events with greater amplitude, which results from a powerful stratification in previous periods. Mixing events with greater amplitudes create higher vertical velocities, resuspending more organic load and dropping dissolved oxygen levels along the water column, impairing the water quality.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;
RBRH
Hydrological models are one of the most effective ways of assessing water behavior and flood risk... more Hydrological models are one of the most effective ways of assessing water behavior and flood risk, although the quality of their results is determined by the input data representativity, especially rainfall. Normally, only rain gauge data is used, unable to represent rain spatial variability. Aiming to reduce the model’s uncertainties, hydrological model performance was evaluated in determining the runoff based on distributed rainfall data applied in an urban watershed with macro drainage structures. A distributed rainfall data, derived from a conditional merging of radar and field measurements, was used as the hydrological model’s input data, and led to very accurate runoff results. The analysis of the results demonstrated that to model urban watersheds with accuracy, distributed rainfall data is required, as well as knowledge about the sewage and drainage systems, reinforcing the need to use tools that are compatible with the site complexity.
&lt;p&gt;Modelling water quality of polluted heavy loaded water courses as those ... more &lt;p&gt;Modelling water quality of polluted heavy loaded water courses as those crossing highly urbanized catchment areas are a complex task that involves several processes based on coefficients like unit loads, decay rates and self-depuration effects among others. The fate of pollutants as organic matter and nutrients are usually done through transport equations added by sourcing and sinking terms that implies the use of decay factors. The so-called k&amp;#8217;s coefficients are present in the literature and were derived from typical water samples that don&amp;#8217;t represent the local conditions founded in the urban rivers, usually affected by the catchment scale. This article presents an approach method used for local determination of the k&amp;#8217;s coefficient for Biological Oxygen Demand (BOD-k1), Atmospheric Reaeration (AR-k2) and Sediment Oxygen Demand (SOD-k4) and compares results to typical adopted values bye modelists. The approach is based on local waters and sediment laboratory tests adjusted to consider specific driving forces as water temperature, constituent concentration and flow turbulence. Considering the catchment area (286 km&amp;#178;) and the river reach (25 km long) 4 sampling stations were defined to collect depth integrated water samples and the bed material. The k1 coefficient is the most sensible one due to the influence of the biological components and the relation between labile and refractory fractions, that varies along the reach with the contribution from the sub catchments&amp;#8217; land use and sanitary infrastructure. Considering Fujimoto&amp;#8217;s and Thomas&amp;#8217; equations, different values of local dependent k1 were found. For k2, the concept of river shear stress velocity was applied to correlate the oxygen mass transferred to the water in the JAR test run for the observed range of velocity gradients in the natural flow. Results lead to a more realistic air entrainment rate due to hydraulic, superficial tension and presence of oils and greases. The SOD-k4 were determined after bottom sediment samples collected in the same defined stations for 3 different concentrations in clean water. The continuous oxygen demand for each sample was taken hourly in the first day and daily in the next 5, and then converted to the Toro&amp;#8217;s active sediment layer demand considering local porosity and specific weight. Results showed considerably lower than the typical values referenced in the literature for all k&amp;#8217;s, denoting the influence of the above-mentioned characteristics and the level of uncertainties that could affect modelling results when non-local parameters are employed.&lt;/p&gt;