Annual variation of fresh water quality in the Gachang Dam reservoir

2003 ◽  
Vol 20 (3) ◽  
pp. 487-491 ◽  
Author(s):  
Joong Kon Park ◽  
Sung Kon Kim
1993 ◽  
Vol 28 (7) ◽  
pp. 197-201 ◽  
Author(s):  
Dunchun Wang ◽  
Isao Somiya ◽  
Shigeo Fujii

To understand the algae migration characteristics in the fresh water red tide, we performed a field survey in the Shorenji Reservoir located in Nabari City, Japan. From the analysis of the field data, it is found that the patterns of vertical distributions of the indices representing biomass are very different in the morning and the afternoon. Since some water quality indices have reverse fluctuations between the surface and the bottom layer in respect of the time series changes and the total biomass of the vertical water column is relatively constant, it is concluded that vertical and daily biomass variation of red tide alga is caused by its daily migration, that is the movement from the bottom layer to the surface in the morning and the reverse movement in the afternoon.


2011 ◽  
Vol 347-353 ◽  
pp. 1902-1905
Author(s):  
Hua Li You

Water is the basis of natural resources and strategic economic resources.Deteriorated water environment of streams in Shenzhen city could have a great impact on ecological safety, people's health,and economic development.Based on the data of field observation and Remote sensing (RS) image,integrated analysis of the water degradation causes,and the changes of biochemical oxygen demand in five days(BOD5)concentration by mathematical model were carried out,which is on basis of percentage of waste water disposal,fresh water transformation,and harbor excavation, respectively.The results show that degradation causes of water quality were resulted from waste water discharge, harbor construction,and ecological environment damage, which could lead to slowly water exchange. Accordingly,the pollution can be easily to store in the bay,which result in water quality changes.The most important improved countermeasure is the control of waste water, which could be had a great effectiveness to decrease pollution.In addition, fresh water must be supplied after polluted water was cut off,which can be better improvement for water quality.This would be extreme improvement for hydrological dynamics due to 15m harbor excavation,which can significantly reduce BOD5 concentration.The innovation points of this paper is to mathematical model,which is based on the basis of qualitative analysis.


2017 ◽  
Vol 24 (2) ◽  
pp. 285-298 ◽  
Author(s):  
Aneta Spyra ◽  
Justyna Kubicka ◽  
Małgorzata Strzelec

AbstractRecognition of the deteriorating conditions of rivers worldwide has called for increased efforts to improve the ecological quality of impacted river systems. This is particularly important in areas that have suffered from a significant impact of human pressure on the ecological status of water. Field studies were conducted in the Ruda River in an area that had undergone anthropogenic disturbances. The objectives of our survey were to test the biological metrics based on benthic macroinvertebrates at four study sites. Spring and autumn surveys of benthic invertebrates indicated that based on the BMWP and BMWP(PL) indices, water quality was higher in comparison with the value of Multimetric index at all of the sites that were studied. Our results revealed that the water quality was higher at the study sites that are located above the dam reservoir based on both the chemical and biological parameters. This study also indicated that both spring and autumn constitute appropriate periods for carrying out monitoring studies. The values of multimeric index indicated the same water quality (except for site 1) in both sampling periods. Anthropogenic transformations of a riverbed influence the flora and fauna and affect the ecological status of rivers.


2020 ◽  
Vol 20 (7) ◽  
pp. 2564-2576
Author(s):  
Hongxi Peng ◽  
Ya Zhang ◽  
Ruowei Wang ◽  
Jingqing Liu ◽  
Wen-Tso Liu

Abstract Stagnation occurs in building water supplies when there is little or no water usage. As a result, the number of bacteria increase, and this often leads to the deterioration of water quality. Still, the role of biofilm in stagnation remains unclear. This study used shower hoses as the model system and investigated the contribution of biofilm and microbes in fresh water to the bacterial growth in water under different stagnation times from 6 to 24 h. Bacterial counts in water were observed to increase significantly after 12 h stagnation but longer stagnation did not lead to further increase, indicating different mechanisms contributing to bacterial growth during stagnation. 16S rRNA gene sequencing and Sourcetracker2 further confirmed that the contribution of fresh water to the microbial core community did not increase significantly with stagnation time, whereas the contribution of biofilm increased significantly after 24 h stagnation (53.5%) compared with 6 h stagnation (11.2%) (p < 0.05). The present results differentiated the contribution between planktonic and biofilm phase to the bacterial growth during stagnation, and provided insights into its mechanism. These findings serve as a framework for future development of strategies to manage biological water quality at the distal end of the building water supplies.


2004 ◽  
Vol 53 (12) ◽  
pp. 1487-1493 ◽  
Author(s):  
Tomoji YOSHIDA ◽  
Sanae IKEDA

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