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Abstract(s)
A China Ć© o paĆs mais populoso do mundo, com mais de 1350 milhƵes de habitantes, sendo tambĆ©m um dos paĆses do mundo com maior Ć”rea. Contudo, a distribuiĆ§Ć£o dos recursos hĆdricos no territĆ³rio nĆ£o Ć© homogĆ©nea havendo cada vez mais problemas graves de escassez de Ć”gua, especialmente no nordeste do paĆs. Na Ćŗltima dĆ©cada, a qualidade da Ć”gua dos lagos e albufeiras da China degradou-se devido a vĆ”rias causas, sendo a mais relevante das quais a grande populaĆ§Ć£o do paĆs. A poluiĆ§Ć£o da Ć”gua e a destruiĆ§Ć£o dos ecossistemas aquĆ”ticos tem causado danos enormes nas funƧƵes e na integridade dos recursos hĆdricos. Aproximadamente 298 milhƵes de chineses que vivem em Ć”reas rurais nĆ£o tĆŖm acesso a Ć”gua potĆ”vel e, em 2011, 40% dos rios da China estavam poluĆdos por resĆduos industriais e agrĆcolas.
O objetivo deste trabalho Ć© identificar os problemas mais comuns que afetam a qualidade da Ć”gua em lagos e albufeiras da China e analisar as variĆ”veis que controlam a qualidade da Ć”gua, com base na pesquisa de publicaƧƵes cientĆficas, bases de dados de artigos cientĆficos, mapas do Google e outras fontes de informaĆ§Ć£o. Da pesquisa inicial foram selecionados 58 artigos cientĆficos que descrevem o estado de 52 massas de Ć”gua. Esta informaĆ§Ć£o foi sumariada num quadro com as caracterĆsticas mais relevantes, nomeadamente a identificaĆ§Ć£o do lago / albufeira, as fontes de poluiĆ§Ć£o, os parĆ¢metros de qualidade da Ć”gua avaliados e as metodologias utilizadas nos estudos. Esta anĆ”lise faculta uma visĆ£o global da situaĆ§Ć£o nos lagos e albufeiras da China.
Verificou-se que os poluentes mais comuns sĆ£o o azoto e o fĆ³sforo. Isto sugere que as massas de Ć”gua na China estĆ£o com problemas sĆ©rios de eutrofizaĆ§Ć£o resultantes de prĆ”ticas agrĆcolas. Outra fonte de poluiĆ§Ć£o difusa, as atividades de exploraĆ§Ć£o mineira, foram consideradas em 6 dos 58 trabalhos selecionados. Por outro lado, as fontes mais relevantes de poluiĆ§Ć£o pontual sĆ£o os efluentes de atividades industriais e instalaƧƵes de uso pĆŗblico ou domĆ©stico.
Atendendo Ć s Normas Chinesas para a Qualidade de Ćguas Superficiais (GB3838), verifica-se que a qualidade da Ć”gua na maioria dos 52 lagos e albufeiras Ć© da classe 3. Nove das onze massas de Ć”gua classificadas como da classe 1 ou 2 sĆ£o albufeiras e duas delas sĆ£o lagos. Quinze das dezoito massas de Ć”gua das classes 4, 5 e acima de 5 sĆ£o lagos, sendo as trĆŖs restantes albufeiras.
Portanto, parece que na China a qualidade da Ɣgua em albufeiras tende a ser melhor que em lagos.
De entre aquelas 53 massas de Ć”gua, selecionaram-se seis casos de estudo como representativos dos lagos e albufeiras da China. O critĆ©rio foi ter 2 grupos de massas de Ć”gua de dimensƵes comparĆ”veis (volume de Ć”gua e Ć”rea da bacia hidrogrĆ”fica) mas colocadas em regiƵes de precipitaĆ§Ć£o mĆ©dia anual distintas. De acordo com este critĆ©rio, definiram-se dois grupos. O Grupo 1 inclui os lagos Poyang, Dongting e Hulun cujos volumes sĆ£o, respetivamente, 276 x108m3, 170 x108m3 e 131 x108m3 e a precipitaĆ§Ć£o mĆ©dia anual de 1639 mm, 1350 mm e 319 mm. As massas de Ć”gua do Grupo 2 sĆ£o mais pequenas; sĆ£o elas as albufeiras de Shitoukoumen (12.6 x108m3; 565 mm) e Yuqiao (15,6 x108m3; 750 mm ) e o lago Dianchi (15,7x108m3; 1007 mm).
Foi reunida informaĆ§Ć£o adicional para melhor se entender e comparar o estado da qualidade da Ć”gua nestes 6 estudos de caso, incluindo-se a anĆ”lise do grau de eutrofizaĆ§Ć£o em cada caso.
Comparando a qualidade da Ć”gua dos dois grupos, verificou-se que o lago Poyang embora tenha graves problemas de poluiĆ§Ć£o por fĆ³sforo Ć© o que tem melhor qualidade da Ć”gua (classe 4) no Grupo 1. Os lagos Dongting e Hulun tĆŖm problemas com poluiĆ§Ć£o por azoto sendo da classe 5 e acima da classe 5, respetivamente. Nas albufeiras Shitoukoumen e Yuqiao, do Grupo 2, a poluiĆ§Ć£o por azoto Ć© mais grave que a poluiĆ§Ć£o por fĆ³sforo, sendo a qualidade da Ć”gua similar para ambas(classe 3). Por outro lado, entre os casos de estudo do Grupo 2 o lago Dianchi Ć© o que apresenta a pior qualidade da Ć”gua, estando acima da classe 5.
Na China existem diferenƧas sazonais na quantidade de precipitaĆ§Ć£o e na temperatura.
Verificou-se que 4 das 6 massas de Ć”gua, nomeadamente os lagos Poyang, Dongting e Dianchi e a albufeiras Yuqiao tĆŖm mudanƧas sazonais na qualidade da Ć”gua. Apenas o lago Hulun e a albufeira Shitoukoumen nĆ£o exibem este fenĆ³meno, provavelmente porque ambas as regiƵes tĆŖm precipitaĆ§Ć£o mĆ©dia anual baixa e, consequentemente, caracterĆsticas hidrolĆ³gicas relativamente estĆ”veis. Em ambos os grupos hĆ” massas de Ć”gua que exibem os seguintes padrƵes: 1) qualidade da Ć”gua na estaĆ§Ć£o hĆŗmida melhor que na estaĆ§Ć£o sĆŖca (lagos Poyang e Dianchi); 2) qualidade da Ć”gua na estaĆ§Ć£o sĆŖca melhor que na estaĆ§Ć£o hĆŗmida (lago Donting e albufeira Yuqiao); 3) qualidade da Ć”gua sem variaĆ§Ć£o ao longo do ano (lago Hulun e albufeira Shitoukoumen). O primeiro e o segundo padrĆ£o podem dever-se ao fato de a diluiĆ§Ć£o dos poluentes numa massa de Ć”gua ser reforƧada em regiƵes com estaĆ§Ć£o hĆŗmida mais longa. Bem como com precipitaĆ§Ć£o mĆ©dia anual mais elevada, resultando em concentraƧƵes de poluentes mais baixas na estaĆ§Ć£o sĆŖca quando comparadas com as da estaĆ§Ć£o hĆŗmida.
A observaĆ§Ć£o e anĆ”lise destes 6 casos de estudo mostram como a qualidade das Ć”gua superficiais estĆ” relacionada com vĆ”rias caracterĆsticas da bacia hidrogrĆ”fica, nomeadamente com condiƧƵes climĆ”ticas e geogrĆ”ficas. A produĆ§Ć£o de poluentes Ć© desencadeada por atividades humanas e as que tĆŖm maior impacto nos lagos e albufeiras da China sĆ£o: a agricultura, a aplicaĆ§Ć£o de produtos quĆmicos, o desenvolvimento urbano e industrial, os sistemas de irrigaĆ§Ć£o e drenagem e o turismo.
Leis ou regulamentos de Ć”gua e o envolvimento pĆŗblico na fiscalizaĆ§Ć£o podem desempenhar um papel construtivo na proteĆ§Ć£o do ambiente. No futuro prĆ³ximo, para proteger a Ć”gua de mais contaminaĆ§Ć£o, a China deve tomar medidas para controlar os diversos tipos de poluiĆ§Ć£o difusa e pontual que ainda ameaƧam a qualidade da Ć”gua, em especial nas Ć”guas residuais da agricultura, indĆŗstria e de usos domĆ©sticos. SĆ£o necessĆ”rias normas ambientais mais rigorosas para a qualidade da Ć”gua para apoiar estratĆ©gias de proteĆ§Ć£o e gestĆ£o.
Abstract: China is the world's most populous country with over 1.35 billion inhabitants; also in area, China is one of the world's largest countries. However, the distribution of water resources in the whole territory of China is not homogeneous and there are increasingly severe water shortages, particularly in the north-east of the country. Over the past decade, the water quality of lakes and reservoirs in China has degraded due to many causes, especially the large population. Water pollution and destruction of aquatic ecosystems have caused massive damage to the functions and the integrity of water resources. Roughly, 298 million Chinese in rural areas do not have access to safe drinking water, and 40% of China's rivers were, by 2011, polluted by industrial and agricultural waste. The aim of this study is to identify the most common water quality problems in lakes and reservoirs in China and to analyze the variables that control the water quality, based on research on scientific publications, international journals databases, Google maps, and other available sources of information. After the initial literature research, 58 papers were selected; they described the conditions of 52 water bodies. This information was summarized in a Table with the most relevant characteristics, namely: the identification of the lake/reservoir, the pollution sources, the water quality parameters evaluated and the methodologies used in the study. This analysis provides an overview of the situation of Chinese lakes and reservoirs. It was observed that nitrogen and phosphorus are the most common pollutants. This suggests Chinese water bodies are suffering from serious eutrophication problems, resulting from agriculture practices. Other diffuse pollution source, mining activities, have been considered by 6 of the 58 selected papers. On the other hand, the most relevant point pollution sources are effluents from industry and public or household facilities. According to the Chinese Surface Water Quality Standard (GB3838), it is observed that the water quality of most of the 52 lakes and reservoirs are of class 3. Nine of the eleven water bodies regarded as class 1or 2, are reservoirs and two of them are lakes. Fifteen of the eighteen water bodies of class 4, class 5 and lower than class 5 are lakes; the remaining three being reservoirs. Therefore, it seems that in China the water quality of reservoirs is likely to be better than that of lakes. Six case studies were selected among the 53 water bodies, as representative of lakes and reservoirs in China. The criterium was to have 2 groups of water masses of comparable dimensions (volume of water and catchment area) but placed in regions of different mean annual precipitation. According to these criteria, two groups were set. Group 1 includes Poyang Lake, Dongting Lake and Hulun Lake, with volumes of, respectively, 276 x108m3, 170 x108m3 and 131 x108m3 and mean annual rainfalls of 1639 mm, 1350 mm and 319 mm. The water bodies of Group 2 have smaller sizes; they are Shitoukoumen Reservoir (12.6 x108m3; 565 mm), Yuqiao Reservoir (15,6 x108m3; 750 mm) and Dianchi Lake (15,7x108m3; 1007 mm). Additional data was gathered to better understand and compare the water quality situation of these 6 case studies; including analyzing the degree of eutrophication of each case. Concerning the comparison of water quality of the two groups, it was found that Poyang Lake although having serious phosphorus pollution is the one with the best water quality (class 4) in Group 1. Dongting Lake and Hulun Lake have problems with nitrogen pollution and are of class 5 and inferior class 5, respectively. In both reservoirs Shitoukoumen and Yuqiao from Group 2 nitrogen pollution is more serious than phosphorus; their water quality is similar (class 3). On the other hand, among Group 2 case studies Dianchi presents a worse water quality having less then class 5.It China there are different seasons characterized by the amount of precipitation and temperature. It was found that 4 of the 6 water bodies, namely Poyang Lake, Dongting Lake, Yuqiao Reservoir and Dianchi Lake have seasonal water quality changes. Only Hulun Lake and Shitoukoumen Reservoir do not show this phenomenon, probably because both regions have low annual mean rainfall, and therefore relatively stable hydrological characteristics. In both groups there are water bodies showing the following patterns: 1) wet season water quality better than that of the dry season (Poyang and Dianchi Lakes); 2) dry season water quality better than that of the wet season (Dongting Lake and Yuqiao Reservoir); 3) the water quality is similar along the year (Hulun Lake and Shitoukoumen Reservoir). The reason for the first and the second pattern may be related to the fact that the dilution of pollutants in a water body is enhanced in regions with a longer wet season, as well as a higher annual average rainfall, resulting in lower concentration of pollutants in the wet season compared to the dry season. The observation and analysis of these 6 case studies illustrate how surface water quality is related to several natural characteristics of the catchment, such as climate and geographic conditions. The production of pollutants is trigged by human activities and the ones with higher impacts in lakes and reservoirs in China are: agriculture, application of chemicals, urban and industrial development, irrigation and drainage systems, and tourism. Water laws or regulations and public involvement in enforcement can play a constructive role in environmental protection. In the near future, in order to protect water from further contamination, China should take actions in order to control the various kinds of diffuse and point pollution that still threatens the water quality, in particular of agriculture and industrial and urban wastewater. Stricter environmental regulations for water quality are required to support protection and management strategies.
Abstract: China is the world's most populous country with over 1.35 billion inhabitants; also in area, China is one of the world's largest countries. However, the distribution of water resources in the whole territory of China is not homogeneous and there are increasingly severe water shortages, particularly in the north-east of the country. Over the past decade, the water quality of lakes and reservoirs in China has degraded due to many causes, especially the large population. Water pollution and destruction of aquatic ecosystems have caused massive damage to the functions and the integrity of water resources. Roughly, 298 million Chinese in rural areas do not have access to safe drinking water, and 40% of China's rivers were, by 2011, polluted by industrial and agricultural waste. The aim of this study is to identify the most common water quality problems in lakes and reservoirs in China and to analyze the variables that control the water quality, based on research on scientific publications, international journals databases, Google maps, and other available sources of information. After the initial literature research, 58 papers were selected; they described the conditions of 52 water bodies. This information was summarized in a Table with the most relevant characteristics, namely: the identification of the lake/reservoir, the pollution sources, the water quality parameters evaluated and the methodologies used in the study. This analysis provides an overview of the situation of Chinese lakes and reservoirs. It was observed that nitrogen and phosphorus are the most common pollutants. This suggests Chinese water bodies are suffering from serious eutrophication problems, resulting from agriculture practices. Other diffuse pollution source, mining activities, have been considered by 6 of the 58 selected papers. On the other hand, the most relevant point pollution sources are effluents from industry and public or household facilities. According to the Chinese Surface Water Quality Standard (GB3838), it is observed that the water quality of most of the 52 lakes and reservoirs are of class 3. Nine of the eleven water bodies regarded as class 1or 2, are reservoirs and two of them are lakes. Fifteen of the eighteen water bodies of class 4, class 5 and lower than class 5 are lakes; the remaining three being reservoirs. Therefore, it seems that in China the water quality of reservoirs is likely to be better than that of lakes. Six case studies were selected among the 53 water bodies, as representative of lakes and reservoirs in China. The criterium was to have 2 groups of water masses of comparable dimensions (volume of water and catchment area) but placed in regions of different mean annual precipitation. According to these criteria, two groups were set. Group 1 includes Poyang Lake, Dongting Lake and Hulun Lake, with volumes of, respectively, 276 x108m3, 170 x108m3 and 131 x108m3 and mean annual rainfalls of 1639 mm, 1350 mm and 319 mm. The water bodies of Group 2 have smaller sizes; they are Shitoukoumen Reservoir (12.6 x108m3; 565 mm), Yuqiao Reservoir (15,6 x108m3; 750 mm) and Dianchi Lake (15,7x108m3; 1007 mm). Additional data was gathered to better understand and compare the water quality situation of these 6 case studies; including analyzing the degree of eutrophication of each case. Concerning the comparison of water quality of the two groups, it was found that Poyang Lake although having serious phosphorus pollution is the one with the best water quality (class 4) in Group 1. Dongting Lake and Hulun Lake have problems with nitrogen pollution and are of class 5 and inferior class 5, respectively. In both reservoirs Shitoukoumen and Yuqiao from Group 2 nitrogen pollution is more serious than phosphorus; their water quality is similar (class 3). On the other hand, among Group 2 case studies Dianchi presents a worse water quality having less then class 5.It China there are different seasons characterized by the amount of precipitation and temperature. It was found that 4 of the 6 water bodies, namely Poyang Lake, Dongting Lake, Yuqiao Reservoir and Dianchi Lake have seasonal water quality changes. Only Hulun Lake and Shitoukoumen Reservoir do not show this phenomenon, probably because both regions have low annual mean rainfall, and therefore relatively stable hydrological characteristics. In both groups there are water bodies showing the following patterns: 1) wet season water quality better than that of the dry season (Poyang and Dianchi Lakes); 2) dry season water quality better than that of the wet season (Dongting Lake and Yuqiao Reservoir); 3) the water quality is similar along the year (Hulun Lake and Shitoukoumen Reservoir). The reason for the first and the second pattern may be related to the fact that the dilution of pollutants in a water body is enhanced in regions with a longer wet season, as well as a higher annual average rainfall, resulting in lower concentration of pollutants in the wet season compared to the dry season. The observation and analysis of these 6 case studies illustrate how surface water quality is related to several natural characteristics of the catchment, such as climate and geographic conditions. The production of pollutants is trigged by human activities and the ones with higher impacts in lakes and reservoirs in China are: agriculture, application of chemicals, urban and industrial development, irrigation and drainage systems, and tourism. Water laws or regulations and public involvement in enforcement can play a constructive role in environmental protection. In the near future, in order to protect water from further contamination, China should take actions in order to control the various kinds of diffuse and point pollution that still threatens the water quality, in particular of agriculture and industrial and urban wastewater. Stricter environmental regulations for water quality are required to support protection and management strategies.
Description
Dissertation elaborated for the partial fulfilment of the requirements of the Master Degree in Civil Engineering in the Speciality Area of Hydarulics
Keywords
Qualidade da Ɣgua Water quality Recursos hidricos Water resources Qualidade de Ɣguas superficiais Surface water quality
Citation
LUHENG, Yan - Water quality in lakes and reservoirs in China. Lisboa: Instituto Superior de Engenharia de Lisboa, 2015. DissertaĆ§Ć£o de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa