Hasil untuk "River, lake, and water-supply engineering (General)"

Christiane do Nascimento Monte, Edinelson Correa Saldanha, Igor Costa et al.

The study of water quality in the Amazon region is important for understanding the functioning of ecological mechanisms. The standard that governs water quality in Brazil, including the Amazon, is Resolution CONAMA 357/05, which uses criteria inspired by standards from other countries. However, this resolution does not consider characteristics of Amazonian aquatic ecosystems, and this can lead to incorrect interpretation of the data. Furthermore, there are few studies on the physical-chemical characteristics of clearwater rivers in the Amazon and the influence of the forest-water interface. Therefore, water samples were collected from four clearwater tributary watersheds of the Amazonas and Tapajós Rivers during the dry season in the city of Santarém, Pará. Most of the points were collected in pristine areas in order to capture the natural physicochemical characteristics of clearwater rivers, as well as to show the importance of ecoregional aspects in water quality management. All samples were below pH 6.0, which represents non-compliance with the CONAMA resolution. Statistical tests yielded negative correlations between pH and conductivity (r = −0.87, p < 0.05), Therefore, the rivers of lower ionic load are influenced by the type of surrounding vegetation, which are characteristics that have been widely reported for blackwater rivers. HIGHLIGHTS The forest-water interface directly influences physicochemical factors in clearwater rivers.; Rivers with lower ionic load are influenced by dissolved colloidal substances.; Conductivity can be used as an indicator of organic matter in clearwater rivers.; Parameters in natural conditions do not comply with the CONAMA standards.; The standards require adaptation to the characteristics of Amazonian rivers.;

PENG Qian, YAO Shunyu, LIU Zhanling et al.

In the process of mass concrete construction,the crack temperature control directly affects the quality of construction.Taking the mass concrete construction of a flood control wall floor in Huangpu River as an example,in order to avoid the occurrence of harmful cracks,this paper takes the corresponding temperature control measures,and conducts the temperature monitoring.The measured data of typical measuring points show that the inner surface,surface and environmental temperature differences of each measuring point are within the limits,and no temperature cracks are found on the concrete surface after removal of form,which verifies the rationality of the design and temperature control construction measures,and provides guidance for the implementation of subsequent projects.

ZHOU Xuexin, ZHAO Xiaochen, ZHANG Shu et al.

To protect and improve the water environment,this paper takes rivers and Gaoming river in Mingcheng Town as research objects,researches the current status of the water environment of 36 monitoring sections,analyzes the spatial variation of six water quality indexes i.e.DO,COD_Mn,COD,BOD₅,NH₃-N and TP by GIS technique and mathematical statistics method,and discusses the influence of land use types on spatial variation of water quality.The results of research show that:the overall water quality of rivers in Mingcheng Town was poor.Water quality indexes showed significantly spatial variation,and the coefficient of variation of NH₃-N and TP was higher than other water quality indexes.In terms of space,compared with other research units,R7 water quality was poorer.Part of the water quality indexes showed obvious spatial concentration and positive spatial autocorrelation.In wet season,there was a significant correlation between land use types such as vegetation,cultivated land and water area and water quality indexes.The agricultural runoff pollution and aquaculture pollution may be the important factors that affect water quality.In dry season,there was no obvious correlation of land use types with water quality indexes.The poor water quality may be caused by the domestic pollution sources,industrial pollution sources and agricultural non-point sources.

Arthur da Fontoura Tschiedel, Rodrigo Cauduro Dias de Paiva, Fernando Mainardi Fan

ABSTRACT In this research study, the MGB-IPH (acronym for Large Scale Model in Portuguese - Modelo de Grandes Bacias) was used to simulate the propagation of a dam breach hydrograph estimated from predictor equations for the Três Marias Hydropower Dam, considered one of the largest in South America. The results of the peak flow, peak time and flood spot were compared with results of the Hec-Ras 5.06 model, typically used for local-scale dam break studies. As for the extent of the flood, a hit rate of 84% and a median error of 2.1 meters deep, along 4,055 km2 of the flooded area downstream was obtained. Maximum errors of 13% were observed in the prediction of the peak flow and of 20% for the peak time in distant locations up to 526 km downstream from the dam, thus establishing itself within the limits of the typical uncertainties associated with dam break studies. Thus, the potential of using this type of approach in previous studies of large dam failures is explored, configuring this method as an alternative to the use of robust or simplified models for determining downstream areas potentially affected by these disasters.

Piranti Agatha, Waluyo Gentur, Rahayu Diana R.U.S.

The water of Lake Rawa Pening is used as a source of drinking water. Indonesian Government Regulation Number 82 of 2001 on Management of Water Quality and Water Pollution Control stated that the water quality of Lake Rawa Pening should meet the quality standard of first grade and be categorized as no polluted water. The purpose of this research was to assess the water quality based on Indonesian regulation and to assess water quality based on international regulations. The quality of water was assessed using a survey method in 7 sites of the Lake Rawa Pening 3 times for 3 months. Parameters measured were all the water quality parameters required in accordance with Government Regulation No. 82 of 2001. The results indicated that there were 13 values that exceeded the water quality standard of first grade. These exceeded parameters were total suspended solids (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), orthophosphate (PO4), NO3, As, Se, Cd, Mn, Cu, Pb, H2S, faecal coliform, and total coliform. Water quality status of Lake Rawa Pening was categorized as heavily polluted. The water quality of Lake Rawa Pening should be improved by reducing the pollutants entering the lake by restriction of human activities causing lake pollution.

Qi-ming Zhong, Sheng-shui Chen, Zhao Deng

A simplified physically-based model was developed to simulate the breaching process of the Gouhou concrete-faced rockfill dam (CFRD), which is the only breach case of a high CFRD in the world. Considering the dam height, a hydraulic method was chosen to simulate the initial scour position on the downstream slope, with the steepening of the downstream slope taken into account; a headcut erosion formula was adopted to simulate the backward erosion as well. The moment equilibrium method was utilized to calculate the ultimate length of a concrete slab under its self-weight and water loads. The calculated results of the Gouhou CFRD breach case show that the proposed model provides reasonable peak breach flow, final breach width, and failure time, with relative errors less than 15% as compared with the measured data. Sensitivity studies show that the outputs of the proposed model are more or less sensitive to different parameters. Three typical parametric models were compared with the proposed model, and the comparison demonstrates that the proposed physically-based breach model performs better and provides more detailed results than the parametric models. Keywords: Concrete-faced rockfill dam, Physically-based breach model, Parametric breach model, Sensitivity analysis, Gouhou CFRD

Wan-zheng Ai, Jia-hong Wang

Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

Manuella Salgueiro Gondim, Antonio Celso Dantas Antonino, Suzana Maria Gico Lima Montenegro et al.

Os estados do nordeste brasileiro suprem a demanda de exportação de manga nos meses em que a oferta é inexistente. Um dos fatores responsáveis pelo aumento da produção destes frutos é a presença de substâncias reguladoras de crescimento vegetal. Entre elas destaca-se o paclobutrazol (PBZ). Porém, este composto pode permanecer ativo no solo durante alguns anos, sendo necessário estudar os destinos e as conseqüências de seu transporte no solo. Os modelos matemáticos atuam como boas ferramentas no estudo de compostos químicos no solo. O transporte do paclobutrazol foi simulado com o modelo Hydrus1D em dois solos classificados como Argissolo e Vertissolo numa estação experimental em Juazeiro-BA, localizada na região do Vale do São Francisco. O objetivo deste trabalho foi realizar estudos de caso, aproximando a aplicação do PBZ às condições reais de campo durante um período de quatro anos e analisar a possibilidade de contaminação do lençol freático. Considerando um lençol freático a uma profundidade de100 cm, observou-se, em ambos os solos, uma maior mobilidade quando o PBZ foi aplicado para o Argissolo em ambos os tempos de pulso estudados.

Rossana Cristina Vasconcellos Soares, Celso de Oliveira Loureiro

O estudo da circulação hídrica subterrânea é de fundamental importância na gestão integrada dos recursos hídricos e a inclusão dessa fonte manancial nos sistemas de gestão representa um desafio nos dias atuais. O objetivo dos estudos aqui descritos foi a caracterização dos recursos hídricos subterrâneos na porção sudoeste da Bacia Representativa de Juatuba em termos de distribuição, ocorrência, hidrodinâmica, reservas e interação com as águas superficiais e com o uso e ocupação dos solos. Para tal foi realizada a identificação da geologia, do clima, da morfologia, dos tipos de solos e de cobertura vegetal da bacia. A determinação dos parâmetros hidrodinâmicos dos principais litotipos presentes na área em estudo, assim como o estabelecimento do modelo conceitual também foram realizados. A bacia do ribeirão Mato Frio está localizada no Complexo Granito-Gnaissico Belo Horizonte, onde os principais tipos de solo são os Latossolos e Argissolos. As taxas de recarga na bacia variam em torno de 18%, contribuindo às reservas dos aqüíferos livres e seguindo ao meio fraturado.

LI Guo-yu

Helder Manuel da Costa Santos, Claus Emio Cirino da Silva, João Wilson Coelho Ribeiro et al.

Na cidade de Coari/AM, cerca de 90% da população que mora no centro se abastece, exclusivamente, de água subterrânea sem que tenham sido realizados estudos para testar a potabilidade da mesma. Para avaliar a sua qualidade, foram selecionados poços de uma escola, do mercado municipal, de um Hotel, de uma padaria e de quatro comunidades para análises físicas,químicas e bacteriológicas. As análises físico-químicas compreenderam: pH,condutividade elétrica, alcalinidade, cor, turbidez, dureza, nitrato,amônia, ferro total, ferro dissolvido, cálcio, magnésio, sódio, potássio e cloro; e as análises bacteriológicas as bactérias heterotróficas (coliformes totais) e bactérias termotolerantes (coliformes fecais). Os resultados tiveram como referência a Portaria 518/2004 do Ministério da Saúde e, apenas a água do poço da padaria está adequada para o consumo humano. Nos demais poços, foi observada a presença de coliformes totais e fecais, bem como valores altos de nitrato que as tornam inadequadas para o consumo. As demais variáveis apresentaram valores abaixo do padrão para o consumo humano estabelecidos por essa portaria, embora sejam águas ácidas. Os poços possuem baixa profundidade, variando de 30 a 60 m.

Joaquim Xavier Cerqueira Neto, Joaquina Lacerda Leite, Vânia Campos Rocha

Ana Catarina Catarina Fernandes Coriolano, Emanuel Ferraz Jardim de Sá, Carlos César Nascimento da Silva

As zonas de fraturas correspondem aos principais alvos para locação de poços em terrenos cristalinos. A determinação precisa destas estruturas é uma tarefa complexa, sendo que os métodos atualmente utilizados para locação de poços são em geral baseados no exame de fotografias aéreas e na geologia de superfície. Está sendo realizado um estudo de casos na porção oriental do Estado do Rio Grande do Norte, utilizando análise estrutural com ênfase ao contexto neotectônico, na tentativa de determinar com maior precisão as estruturas acumuladoras de água em subsuperfície. Foram gerados mapas de lineamentos e correlacionados com poços já locados na região. Em campo, a análise foi feita na escala do poço/afloramento, com o objetivo de discriminar diferentes grupos de fraturas pela orientação, idade dos marcadores afetados e nível crustal, inferidas para o seu desenvolvimento. Em alguns casos, não foi possível fazer correlação entre as fraturas distinguidas em campo e os critérios presumidos utilizados na locação dos poços (p.ex., fraturas inferidas a partir da rede de drenagem). Neste caso, pode não haver um condicionamento por estruturas frágeis, e sim pela combinação de feições como anisotropias das rochas, modo de alteração e presença de coberturas inconsolidadas.

LU Hai

陈志江