Hydro-meteorological Effects on Water Quality Variability in Paldang Reservoir, Confluent Area of the South-Han River-North-Han River-Gyeongan Stream, Korea

2016 ◽  
Vol 49 (4) ◽  
pp. 354-374 ◽  
Author(s):  
Soon-Jin Hwang ◽  
Keonhee Kim ◽  
Chaehong Park ◽  
Wanbum Seo ◽  
Bong-Geun Choi ◽  
...  
Keyword(s):  
Water Quality ◽  
The South ◽  
Han River ◽  
Meteorological Effects

scholarly journals Analysis of the Water Circulation Structure in the Paldang Reservoir, South Korea

2020 ◽  
Vol 10 (19) ◽  
pp. 6822
Author(s):  
Hwangjeong Choi ◽  
Ingu Ryu ◽  
Minji Park ◽  
Yongsik Song ◽  
Soonju Yu ◽  
...  
Keyword(s):  
Water Quality ◽  
South Korea ◽  
Discharge Rate ◽  
Water Circulation ◽  
The South ◽  
Han River ◽  
The North ◽  
Study Results ◽  
Instantaneous Discharge ◽  
Layer Flow

In this study, results are presented for depth-specific hydraulic and water quality surveys, as well as meteorological observations, at key monitoring sites in the Paldang Reservoir, South Korea. These results were used to determine the water circulation characteristics that represent the main contributors to water quality changes. In the section before the confluence point of the two rivers, a different type of two-layer flow appeared for each. In the North Han River, backwater flowing backward in the upstream direction occurred in the surface layer, and was accompanied by two-layer flow, during the zero-discharge period of the Cheongpyeong Dam. On the other hand, in the South Han River, two-layer flow was observed in the upper layer in the downstream flow, and the thickness of upper and lower layers varied depending on the discharge rate of the Paldang Dam. Strong flow fluctuations were observed near the Paldang Dam (3 km upstream), and these were dependent on its instantaneous discharge rate. In particular, if the instantaneous discharge from the Paldang Dam remained below 400 m3/s for several days, the flow velocity in the lower layer decreased below 2 cm/s or no flow occurred. The comparison between flows during different periods associated with depth-specific water temperature variations showed that the average flow prevailed across all layers in the downstream direction at all monitoring sites during the vertical mixing period. In contrast, spatiotemporal variations in flow, such as two-layer flow and backwater, were observed during the stratification period in the South Han River and the North Han River. This led to increased residence times and vertical stability, thus creating favorable conditions for algal blooms.

WATER QUALITY MONITORING IN THE SOUTH SHORE ESTUARIES OF LONG ISLAND, NEW YORK

2018 ◽  
Author(s):  
Rebeka Smith ◽  
◽  
Thomas Badamo ◽  
David J. Barclay ◽  
Devorah Crupar ◽  
...  
Keyword(s):  
Water Quality ◽  
New York ◽  
Long Island ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
The South ◽  
South Shore

scholarly journals 18S rRNA Analysis Reveals High Diversity of Phytoplankton with Emphasis on a Naked Dinoflagellate Gymnodinium sp. at the Han River (Korea)

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 73
Author(s):  
Buhari Lawan Muhammad ◽  
Taehee Kim ◽  
Jang-Seu Ki
Keyword(s):  
Water Quality ◽  
Quality Management ◽  
18S Rrna ◽  
Water Quality Management ◽  
Operational Taxonomic Unit ◽  
Amplicon Sequencing ◽  
Freshwater Ecosystems ◽  
Reservoir Area ◽  
Han River ◽  
Phytoplankton Communities

Biomonitoring of phytoplankton communities in freshwater ecosystems is imperative for efficient water quality management. In the present study, we present the seasonal diversity of phytoplankton from the non-reservoir area of the Han River (Korea), assessed using the 18S rRNA amplicon sequencing. Our results uncovered a considerably high eukaryotic diversity, which was predominantly represented by phytoplankton in all the seasons (38–63%). Of these, the diatoms, Cyclostephanos tholiformis, Stephanodiscus hantzschii, and Stephanodiscus sp., were frequently detected in spring and winter. Interestingly, for the first time in the Han River, we detected a large number of operational taxonomic unit (OTU) reads belonging to the naked dinoflagellate Gymnodinium sp., which dominated in autumn (15.8%) and was observed only in that season. Molecular cloning and quantitative real-time polymerase chain reaction (PCR) confirmed the presence of Gymnodinium sp. in the samples collected in 2012 and 2019. Moreover, a comparison of the present data with our previous data from a reservoir area (Paldang Dam) revealed similar patterns of phytoplankton communities. This molecular approach revealed a prospective toxic species that was not detected through microscopy. Collectively, resolving phytoplankton communities at a level relevant for water quality management will provide a valuable reference for future studies on phytoplankton for environmental monitoring.

scholarly journals Animal-based agriculture, phosphorus management and water quality in Brazil: options for the future

2006 ◽  
Vol 63 (2) ◽  
pp. 194-209 ◽  
Author(s):  
Francirose Shigaki ◽  
Andrew Sharpley ◽  
Luís Ignácio Prochnow
Keyword(s):  
Water Quality ◽  
Production Systems ◽  
Poultry Manure ◽  
Agricultural Runoff ◽  
Animal Production ◽  
Feed Additives ◽  
Poultry Production ◽  
The South ◽  
Transport Management ◽  
Animal Production Systems

Eutrophication has become a major threat to water quality in the U.S., Europe, and Australasia. In most cases, freshwater eutrophication is accelerated by increased inputs of phosphorus (P), of which agricultural runoff is now a major contributor, due to intensification of crop and animal production systems since the early 1990s'. Once little information is available on the impacts of Brazilian agriculture in water quality, recent changes in crop and animal production systems in Brazil were evaluated in the context of probable implications of the fate of P in agriculture. Between 1993 and 2003, there was 33% increase in the number of housed animals (i.e., beef, dairy cows, swine, and poultry), most in the South Region (i.e., Paraná, Rio Grande do Sul, and Santa Catarina States), where 43 and 49% of Brazil's swine and poultry production is located, respectively. Although grazing-based beef production is the major animal production system in Brazil, it is an extensive system, where manure is deposited over grazed pastures; confined swine and poultry are intensive systems, producing large amounts of manure in small areas, which can be considered a manageable resource. This discussion will focus on swine and poultry farming. Based on average swine (100 kg) and poultry weights (1.3 kg), daily manure production (4.90 and 0.055 kg per swine and poultry animal unit, respectively), and manure P content (40 and 24 g kg-1 for swine and poultry, respectively), an estimated 2.5 million tones of P in swine and poultry manure were produced in 2003. Mostly in the South and Southeast regions of Brazil (62%), which represent only 18% of the country's land area. In the context of crop P requirements, there was 2.6 times more P produced in manure (1.08 million tones) than applied as fertilizer (0.42 million tonnes) in South Brazil in 2003. If it is assumed that fertilizer P use represents P added to meet crop needs and accounts for P sorbed by soil in unavailable forms each year, if swine and poultry manure were to replace fertilizer, there would be an annual P surplus of 0.66 million tonnes in the South region alone. These approximations and estimates highlight that, similarly to other parts of the world, there is a potential for surplus P to quickly accumulate in certain regions of Brazil. Unless measures are developed and implemented to utilize manure P, repeated annual surpluses will create an increasingly difficult problem to solve. These measures can be grouped as source and transport management. Source management attempts to decrease dietary P, use feed additives, manure treatment and composting, as well as careful management of the rate, timing, and method of manure applications. Transport management attempts to control the loss of P in runoff from soil to sensitive waters via use of conservation tillage, buffer or riparian zones, cover crops, and trapping ponds or wetlands. These measures are discussed in the contest of Brazil's climate, topography, and land use, and how successful remediation programs may be implemented at farm and watershed level.

scholarly journals Hurricane Effects on a Shallow Lake Ecosystem and Its Response to a Controlled Manipulation of Water Level

2001 ◽  
Vol 1 ◽  
pp. 44-70 ◽  
Author(s):  
Karl E. Havens ◽  
Kang-Ren Jin ◽  
Andrew J. Rodusky ◽  
Bruce Sharfstein ◽  
Mark A. Brady ◽  
...  
Keyword(s):  
Water Quality ◽  
Plant Communities ◽  
Large Scale ◽  
Growing Season ◽  
Water Levels ◽  
Surface Elevation ◽  
Submerged Plant ◽  
Lake Surface ◽  
The South ◽  
Water Depths

In order to reverse the damage to aquatic plant communities caused by multiple years of high water levels in Lake Okeechobee, Florida (U.S.), the Governing Board of the South Florida Water Management District (SFWMD) authorized a "managed recession" to substantially lower the surface elevation of the lake in spring 2000. The operation was intended to achieve lower water levels for at least 8 weeks during the summer growing season, and was predicted to result in a large-scale recovery of submerged vascular plants. We treated this operation as a whole ecosystem experiment, and assessed ecological responses using data from an existing network of water quality and submerged plant monitoring sites. As a result of large-scale discharges of water from the lake, coupled with losses to evaporation and to water supply deliveries to agriculture and other regional users, the lake surface elevation receded by approximately 1 m between April and June. Water depths in shoreline areas that historically supported submerged plant communities declined from near 1.5 m to below 0.5 m. Low water levels persisted for the entire summer. Despite shallow depths, the initial response (in June 2000) of submerged plants was very limited and water remained highly turbid (due at first to abiotic seston and later to phytoplankton blooms). Turbidity decreased in July and the biomass of plants increased. However, submerged plant biomass did not exceed levels observed during summer 1999 (when water depths were greater) until August. Furthermore, a vascular plant-dominated assemblage (Vallisnera, Potamogeton, and Hydrilla) that occurred in 1999 was replaced with a community of nearly 98% Chara spp. (a macro-alga) in 2000. Hence, the lake’s submerged plant community appeared to revert to an earlier successional stage despite what appeared to be better conditions for growth. To explain this unexpected response, we evaluated the impacts that Hurricane Irene may have had on the lake in the previous autumn. In mid-October 1999, this category 1 hurricane passed just to the south of the lake, with wind velocities over the lake surface reaching 90 km h-1 at their peak. Output from a three-dimensional hydrodynamic / sediment transport model indicates that during the storm, current velocities in surface waters of the lake increased from near 5 cm s-1to as high as 100 cm s-1. These strong velocities were associated with large-scale uplifting and horizontal transport of fine-grained sediments from the lake bottom. Water quality data collected after the storm confirmed that the hurricane resulted in lake-wide nutrient and suspended solids concentrations far in excess of those previously documented for a 10-year data set. These conditions persisted through the winter months and may have negatively impacted plants that remained in the lake at the end of the 1999 growing season. The results demonstrate that in shallow lakes, unpredictable external forces, such as hurricanes, can play a major role in ecosystem dynamics. In regions where these events are common (e.g., the tropics and subtropics), consideration should be given to how they might affect long-term lake management programs.

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