scholarly journals Algal Boom Characteristics of Yeongsan River Based on Weir and Estuary Dam Operating Conditions Using EFDC-NIER Model

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2295
Author(s):  
Darae Kim ◽  
Changmin Shin
Keyword(s):  
Water Level ◽  
Algal Blooms ◽  
Water Security ◽  
Water Levels ◽  
Operating Conditions ◽  
The Yellow Sea ◽  
Management Level ◽  
Average Water ◽  
Reduced Water ◽  
Regional Water

A number of hydraulic structures have been installed along the Yeongsan River, including an estuary dam and two weirs (Seungchon and Juksan). While these structures aid in regional water security and use and reduce flooding, they reduce water flow in the summer, thereby frequently causing algal blooms. This study simulated algal bloom and water quality characteristics of sections of the Yeongsan River in South Korea under different weir and estuary dam operating conditions using the Environmental Fluid Dynamics Code—National Institute of Environment Research (EFDC-NIER) model. Results showed that when the management levels of the Juksan Weir and estuary dam were maintained, simulated water levels were EL. 3.7 m in the weir section and EL. −1.2 m (below average water level of the Yellow Sea) in the dam section. When both the weir and dam were open, the water levels varied with the tide; in contrast, when the Juksan Weir alone was open, the water level was between EL. −1.2 and −0.9 m, in line with the management level of the estuary dam. Opening the weir alone reduced algal blooms by 72–84% in the weir region, and opening the estuary dam alone reduced the algal blooms by 83% in the dam region. This improvement was attributed to the reduced water retention time and dilution due to seawater inflows.

Limnological succession in reservoirs: a paleolimnological comparison of two methods of reservoir formation

1999 ◽  
Vol 56 (6) ◽  
pp. 1109-1121 ◽  
Author(s):  
Roland I Hall ◽  
Peter R Leavitt ◽  
Aruna S Dixit ◽  
Roberto Quinlan ◽  
John P Smol
Keyword(s):  
Water Level ◽  
Sediment Cores ◽  
Hydrological Regime ◽  
Community Change ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Lake Diefenbaker ◽  
Fossil Records ◽  
Variable Versus ◽  
Reduced Water

Analysis of diatoms, algal pigments, and chironomids in sediment cores from two otherwise similar prairie reservoirs demonstrated that differences in reservoir formation (river valley impoundment versus lake inundation) and hydrological regime (variable versus stable water level) resulted in distinct patterns of aquatic community change. Lake Diefenbaker, a 500-km2 reservoir created by damming the South Saskatchewan River in 1968, experiences water level fluctuations of 6 m·year-1. In contrast, impoundment of Buffalo Pound Lake in 1952 flooded a natural lake, raised mean water levels ~2.0 m, and reduced water level fluctuations from ~3 to <1 m·year-1. Comparison of fossil records showed that reservoir formation did not inevitably lead to eutrophication. Lake Diefenbaker exhibited typical reservoir ontogeny with three trophic periods, including an initial ~4-year period of eutrophy, a decade of mesotrophy, and a gradual shift to modern productive conditions. Planktonic taxa dominated diatom communities at all times, whereas benthic chironomid and algal remains were rare. In contrast, pigment analyses suggested that phytoplankton standing crops declined after impoundment in Buffalo Pound Lake but that chironomid and macrophyte populations expanded. Such site specificity in trophic development appears to result from differences in the extent of inundation (500 versus ~5 km2) and the magnitude of subsequent water level fluctuations (6.3 versus <1 m).

scholarly journals Computer-aided estimates of drainage charges - a Dutch case study.

1978 ◽  
Vol 26 (3) ◽  
pp. 278-287
Author(s):  
S.W. Bie ◽  
A.F. van Holst ◽  
J.N.M. Stricker
Keyword(s):  
Soil Moisture ◽  
Water Level ◽  
Open Water ◽  
Harvard University ◽  
Water Levels ◽  
Small Cells ◽  
Water Board ◽  
Mapping Techniques ◽  
Regional Water

When regional water management is regulated centrally on a cooperative basis, methods must be developed whereby drainage charges can be estimated from agreed and objective data. Reported here is a method to compute and map, from data on altitude, the supposed open water level after a given discharge and soil characteristics for available moisture, the charges to be levied. Independent 'maps' are compiled for each of the three attributes by computer mapping techniques. The area is split into a large number of small cells (here 12.5 m X 15.5 m), for each of which the altitude is estimated by interpolation from known spot heights. For the same cells the supposed open water levels are approximated by interpolation from a number of calculated water levels in streams and ditches. Known watershed divides are introduced as barriers to interpolation. Four soil moisture classes are generated. The three 'maps' provide for each cell the basic data required by an allocation algorithm which evaluates the value for altitude, water level and soil moisture class. For each cell the appropriate drainage charge class was determined. A payment class map is generated by the allocation and can be printed on the computer lineprinter, each class being given a distinguishing printing symbol. The method is demonstrated for a 210-ha test area under the jurisdiction of the Regional Water Board Salland. Further extension to include a cadastral map to allow automated invoicing procedures are discussed. The system is implemented on a CDC Cyber 72 computer and uses SYMAP (Harvard University, USA) as one module. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Analysis of annual-averaged water level changes at the tail of Fuhe River, inflow of Poyang Lake

2020 ◽  
Vol 206 ◽  
pp. 03011
Author(s):  
Hua GE ◽  
Chunyan DENG
Keyword(s):  
Water Level ◽  
Moving Average ◽  
Water Security ◽  
Observation Data ◽  
Water Level Change ◽  
The Past ◽  
Ecological Protection ◽  
Abrupt Changes ◽  
Average Water ◽  
Change Trend

The area at the tail end of Fuhe River has an important economic and social status and ecological protection needs. Its water level change is directly related to the water security of this region. Based on the daily average water level observation data of three hydrologic stations in the end of Fuhe River in the past 70 years, the change trend of annual average water level was analysed by using Mann-Kendall and moving average methods. The results show that there has been a continuous downward trend of water level at the tail end of Fuhe River. The water level drop along the river was 1.3m to 3.5m, and abrupt changes had occurred in the 1990s and early 20th century.

Numerical Investigation on the Flow Structure and Vortex Behavior at a Large Scale Pump Sump

2007 ◽  
Author(s):  
Guohui Cong ◽  
Fujun Wang
Keyword(s):  
Water Level ◽  
Flow Structure ◽  
Large Scale ◽  
Stokes Equations ◽  
Side Wall ◽  
Water Levels ◽  
Operating Conditions ◽  
Strong Impact ◽  
Pump Station ◽  
Pump Inlet

Vortex in pump station sumps could lead to equipment operation with vibration and cavitations, and its impact is even stronger in large scale pump station sumps. In this study, the flow structure and vortex behavior in the sumps of a large scale pump station were investigated with a three dimensional CFD approach. The approach solves Reynolds averaged Navier-Stokes equations by the realizable k-ε turbulence model with wall function. The numerical simulations were carried out under three different water levels (low, standard and high) and three different pump operating combinations (operating with one, two or three pumps). The important flow feathers in the entire flow field such as submerged vortices, free-surface vortices were revealed. The strength and location of vortices under different operating conditions were presented. To reduce the vorticity magnitude in the sumps which would expand to affect the flow around pump inlet, effects of three different anti-vortex devices (DA, DB, and DC) for the pump station were also investigated numerically. It is found that the vortex attached to the floor has larger vorticity scale than that attached to side wall and back wall. The vorticity magnitude at higher sump water level is smaller than that at lower water level. The operation of multi pumps also has a strong impact to the flow patterns in sumps. Anti-vortex device DB has better performance than the two others, it decreases the floor attached and sidewall attached vortex and makes the pump inlet flow smooth.

scholarly journals Current Groundwater Conditions in Alluvial Gangetic Plains of Haridwar District, Uttarakhand, India

2016 ◽  
Vol 11 (3) ◽  
pp. 737-742 ◽  
Author(s):  
Gopal Krishan ◽  
Surjeet Singh ◽  
Anurag Khanna ◽  
R. P Singh ◽  
N.C Ghosh
Keyword(s):  
Groundwater Quality ◽  
Water Level ◽  
Continuous Monitoring ◽  
Study Data ◽  
Water Levels ◽  
Gangetic Plains ◽  
Alkaline Earths ◽  
Average Water ◽  
Precautionary Measures ◽  
Strong Acids

In the present study, data of 41 hydrograph stations distributed in the Haridwar district are analysed for the years 2014-15 for depth to water level and water quality. The average depth to water level during pre-monsoon is found 10.74 m and in post-monsoon there is a rise of 0.23 m in average water level and found 10.51 m. Among all the 6 blocks viz. Bhagwanpur, Bhadarabad, Khanpur, Laksar, Narsan and Roorkee, the distribution of water level shows that the water levels are deep in the entire Bhagwanpur block. For assessing the groundwater quality, the water samples were collected from 40 sites covering the entire district. The groundwater is formed as Ca-Mg-HCO3 type. In the groundwater, alkaline earths exceed the alkalis and weak acids dominate strong acids. Although groundwater quality is good for drinking as well as irrigation purpose but in few samples higher concentrations of NO3-, Cl− and SO42− ions are found and hence continuous monitoring is required for these ions as precautionary measures.

scholarly journals Efficiency of the Drawdown Flushing and Partition Desilting of a Reservoir in Taiwan

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2166
Author(s):  
Hsiao-Wen Wang ◽  
Bing-Shiou Tsai ◽  
Charnsmorn Hwang ◽  
Guan-Wei Chen ◽  
Wei-Cheng Kuo
Keyword(s):  
Water Level ◽  
Water Levels ◽  
Limited Information ◽  
Initial Water ◽  
Sediment Yields ◽  
Operation Rules ◽  
Average Water ◽  
Long Term Monitoring ◽  
Term Monitoring

Sedimentation limits the benefits of storage reservoirs, especially in areas with higher sediment yields, such as Agongdian Reservoir in southern Taiwan. Although drawdown flushing is a known strategy that releases large amounts of fine sediment into a downstream channel, there is limited information on the long-term monitoring and multiple metrics being used to evaluate flushing efficiency. The objectives of this study were three-fold: (1) to continue collecting valuable long-term observed data, since Agongdian Reservoir is one of the few reservoirs currently conducting sediment flushing operations; (2) to evaluate and identify the hydrological parameters that are highly related to the flushing efficiency; (3) to execute numerical simulations of different reservoir flushing scenarios at multiple water levels to discuss potential strategies to improve the flushing efficiency. The findings of this study revealed that long-term monitoring data was valuable for identifying factors highly related to the flushing efficiency, which included the initial water level; average water level; average velocity. Based on simulations, compartmentalizing the reservoir is a proposed strategy that has demonstrated high levels of improvement in terms of the flushing efficiency, depending on particular scenarios involving partition desilting, empty flushing, or a combination of both. Recommendations to increase the flushing efficiency include lowering the initial water level, creating a narrower gorge-like geometry by partitioning, and further considering to modify the operation rules.

scholarly journals Effect of water level regulation on gradients and levee deposits in the Lake Øyeren delta, Norway

2012 ◽  
Vol 44 (3) ◽  
pp. 523-537 ◽  
Author(s):  
Peggy Zinke ◽  
Jim Bogen
Keyword(s):  
Water Level ◽  
Water Levels ◽  
Morphological Development ◽  
Delta Plain ◽  
Water Level Changes ◽  
Lower Elevation ◽  
Flood Regulation ◽  
The Mean ◽  
Flow Gradients ◽  
Reduced Water

Water level changes resulting from a hydropower regulation have influenced water flow, gradients and sediment processes in the Lake Øyeren delta for about 150 years. They are reflected in the morphology of the islands on the delta plain. Under current regulation practices, water levels during the mean annual flood are maintained at about 1 m lower than during the previous regime prior to 1978. As the channels continue to mature, the recently deposited tongues and levees in the southern part will therefore probably maintain a distinctly lower elevation than that of the older islands. The influence of flood regulation on levee deposits during the extreme 1995 flood was estimated by comparing simulated overbank deposits resulting from different flood regulation schemes. The simulations showed that reduced water levels during floods in the presence of older islands extend the period of in-channel flow and promote the development of levee-like deposits in the lower part of the delta plain. This explains some of the characteristics observed in the morphological development, most notably the increased number of lagoons resulting from a higher number of levees.

AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

2019 ◽  
pp. 95-103
Author(s):  
Krum Videnov ◽  
Vanya Stoykova
Keyword(s):  
Water Level ◽  
Real Time ◽  
Early Warning ◽  
Water Sources ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Level Monitoring ◽  
Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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