A Study of the Average Flow in Open Channel with Baffle Blocks Distributed Uniformly

10.29007/zx1w ◽  
2018 ◽  
Author(s):  
Dung Tien Tran ◽  
Anh Tuan Le ◽  
Hong Nhung Le ◽  
Viet Hung Ho
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Open Channel ◽  
Block Size ◽  
Average Flow ◽  
Modelling Studies ◽  
Baffle Block

A study of average flow in open channel with baffle blocks distributed uniformly has been considered by using channel with varied slopes. In this article, experimental and modelling studies were introduced when the correlation between the water depth and baffle block size is significant. The objective of the work is to give the rudimentary relations between discharge and water level in the channels. When the water depth is large, the effect of bottom channel friction on the flow is relatively small. This paper also gives applications of the software ‘Telemac-2D’ to simulate the flow under different conditions.

scholarly journals Effects of Water Depth on the Growth of the Submerged Macrophytes Vallisneria natans and Hydrilla verticillata: Implications for Water Level Management

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2590
Author(s):  
Qisheng Li ◽  
Yanqing Han ◽  
Kunquan Chen ◽  
Xiaolong Huang ◽  
Kuanyi Li ◽  
...  
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Deep Water ◽  
Submerged Macrophytes ◽  
Hydrilla Verticillata ◽  
Water Level Fluctuations ◽  
Total Biomass ◽  
Intermediate Water ◽  
Factors Affecting ◽  
Vallisneria Natans

Water level is one of the most important factors affecting the growth of submerged macrophytes in aquatic ecosystems. The rosette plant Vallisneria natans and the erect plant Hydrilla verticillata are two common submerged macrophytes in lakes of the middle and lower reaches of the Yangtze River, China. How water level fluctuations affect their growth and competition is still unknown. In this study, three water depths (50 cm, 150 cm, and 250 cm) were established to explore the responses in growth and competitive patterns of the two plant species to water depth under mixed planting conditions. The results show that, compared with shallow water conditions (50 cm), the growth of both submerged macrophytes was severely suppressed in deep water depth (250 cm), while only V. natans was inhibited under intermediate water depth (150 cm). Moreover, the ratio of biomass of V. natans to H. verticillata gradually increased with increasing water depth, indicating that deep water enhanced the competitive advantage of V. natans over H.verticillata. Morphological adaptation of the two submerged macrophytes to water depth was different. With increasing water depth, H. verticillata increased its height, at the cost of reduced plant numbers to adapt to poor light conditions. A similar strategy was also observed in V. natans, when water depth increased from 50 cm to 150 cm. However, both the plant height and number were reduced at deep water depth (250 cm). Our study suggests that water level reduction in lake restoration efforts could increase the total biomass of submerged macrophytes, but the domination of key plants, such as V. natans, may decrease.

Seedling recruitment of 11 wetland plant species along a water level gradient: shared or distinct responses?

1985 ◽  
Vol 63 (10) ◽  
pp. 1876-1879 ◽  
Author(s):  
Paul A. Keddy ◽  
Timothy H. Ellis
Keyword(s):  
Water Level ◽  
Plant Species ◽  
Water Depth ◽  
Seedling Recruitment ◽  
Substrate Surface ◽  
Lythrum Salicaria ◽  
Water Levels ◽  
Acorus Calamus ◽  
Spartina Pectinata ◽  
Sagittaria Latifolia

Where many different plant species occupy an environmental gradient, the responses of their offspring to that gradient could show one of two patterns. All species could have similar requirements for maximum recruitment, in which case all would show maximum germination and emergence in the same region of the gradient ("shared responses"). Alternatively, each species could have different requirements for recruitment and therefore would show maximum recruitment in different regions of the gradient ("distinct responses"). The objective of this study was to test between these two alternatives in plants occurring along a water level gradient. Seeds of 11 wetland species were allowed to germinate in sand along a gradient of water depth, ranging from 10 cm above to 5 cm below the substrate surface. Scirpus americanus, S. validus, Sagittaria latifolia, Typha angustifolia, and Lythrum salicaria showed no significant response to this gradient, while Spartina pectinata, Polygonum punctatum, Bidens cernua, Acorus calamus, Alisma plantago-aquatica, and Eupatorium perfoliatum did. However, the six species in the latter group did not exhibit shared preferences along the water depth gradient. These different recruitment patterns were consistent with adult distributions in the field. Most species showed some recruitment at all water levels examined, suggesting that they have broad tolerance limits for water level in the recruitment phase of their life history.

scholarly journals Effects of water depth and water level fluctuation on the total and bio-available element concentrations in riverine reed stands

2020 ◽  
Vol 114 ◽  
pp. 106328
Author(s):  
Attila I. Engloner ◽  
Kitti Németh ◽  
Dóra Gere ◽  
Dávid Stefán ◽  
Mihály Óvári
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Water Level Fluctuation ◽  
Level Fluctuation ◽  
Element Concentrations

scholarly journals Response of Submerged Aquatic Vegetation to Water Depth in a Large Shallow Lake after an Extreme Rainfall Event

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2412 ◽  
Author(s):  
Jinge Zhu ◽  
Jiancai Deng ◽  
Yihui Zhang ◽  
Zhaoliang Peng ◽  
Weiping Hu
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Submerged Aquatic Vegetation ◽  
Community Dynamics ◽  
Aquatic Vegetation ◽  
Lake Taihu ◽  
Extreme Rainfall ◽  
Rainfall Event ◽  
Cumulative Probability ◽  
Extreme Rainfall Event

Submerged aquatic vegetation (SAV) is an important part of lake ecosystems, and a proper SAV community structure is the key factor in keeping a clear-water state. Although the response of SAV to water depth has been widely studied in different aquatic environments, little is known about the response of the SAV community to changes in water depth of a large lake after an extreme rainfall event. To examine this question, 780 samples were collected from Lake Taihu, China, between 2013 and 2017 to analyze the variations in SAV and water depth. The water level of the lake ranged from 2.75 to 4.87 m, and the water depth at sampling sites ranged from 1.07 to 3.31 m. The SAV biomass at the sampling sites ranged from 0 to 17.61 kg/m2. The influence of water depth on SAV biomass and frequency of occurrence differed by seasons and by species. The adaptation of SAV species to increasing water depth is a key element for community dynamics, which in turn contributes to water level regulation. A new method was proposed to identify the optimal water depth for SAV biomass accumulation based on calculation of the cumulative probability and probability density.

Effects of nutrients and water levels on emergent macrophyte biomass in a prairie marsh

1990 ◽  
Vol 68 (5) ◽  
pp. 1007-1014 ◽  
Author(s):  
Christopher Neill
Keyword(s):  
Water Level ◽  
Nutrient Limitation ◽  
Water Depth ◽  
Nitrogen Limitation ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Depth Range ◽  
Dry Conditions ◽  
Second Year ◽  
Water Depths

Nitrogen and phosphorus fertilizers were added over two growing seasons to marshes dominated by whitetop grass (Scolochloa festucacea) or cattail (Typha glauca) in a prairie lacustrine marsh to assess nutrient limitation and the interaction of nutrient limitation with water depth. For each species, stands were selected at the deep and shallow extremes of its water depth range. Water levels were high during the first year of fertilization and low during the second year, exposing the fertilized stands to a variety of water depths. Nitrogen limited growth in whitetop and cattail marshes. Water level, by controlling whether the soil was flooded or the water table was below the soil surface, affected growth and the degree of nitrogen limitation. In whitetop marshes, nitrogen increased biomass more when the soil was flooded or when standing water was deeper and in cattail marshes, it increased biomass more under intermediate water depths (approximately 0–20 cm) than under more deeply flooded (20–40 cm) or dry conditions. Nitrogen reduced biomass in whitetop marshes the second year, apparently because growth was inhibited by fallen litter from the previous year. Nitrogen did not limit cattail marsh biomass in the driest locations during a year of low water levels. Phosphorus caused a small increase in growth of both species after 2 years. Changes of nitrogen limitation with flooding suggest that annual water level fluctuations, by creating alternating flooded and dry conditions, may influence the primary production of emergent macrophytes through effects on nitrogen cycling.

The Application of Matrix Compression Algorithm in Network Education Platform for the User Security Authentication

2014 ◽  
Vol 889-890 ◽  
pp. 1730-1736
Author(s):  
Nong Zheng
Keyword(s):  
Open Channel ◽  
Block Size ◽  
Matrix Decomposition ◽  
Compression Algorithm ◽  
Network Education ◽  
Cipher Text ◽  
Security Authentication ◽  
Matrix Compression ◽  
The Matrix ◽  
Education Platform

Using the matrix compression algorithm in the network education platform for the user information security certification is a good way. The sensitive user information is transfer in an open channel and it can be authentication for using the matrix compression/decompression, matrix decomposition/reduction algorithm. The client conduct random capture and compression by the user information been divided into a number of rectangular block size, corresponding to generate a key and cipher text. The server take out the corresponding data from the data queue of receiving and to extract In accordance with the key rules, then to reduce of information in corresponding positions. Thus the user identity information can be authenticity and integrity verification.

scholarly journals Coral Reef Drag Coefficients – Water Depth Dependence

2017 ◽  
Vol 47 (5) ◽  
pp. 1061-1075 ◽  
Author(s):  
S. J. Lentz ◽  
K. A. Davis ◽  
J. H. Churchill ◽  
T. M. DeCarlo
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Drag Coefficient ◽  
Water Depth ◽  
Open Channel ◽  
Momentum Balance ◽  
Laboratory Studies ◽  
Drag Coefficients ◽  
Significant Term ◽  
The Cross

AbstractA major challenge in modeling the circulation over coral reefs is uncertainty in the drag coefficient because existing estimates span two orders of magnitude. Current and pressure measurements from five coral reefs are used to estimate drag coefficients based on depth-average flow, assuming a balance between the cross-reef pressure gradient and the bottom stress. At two sites wind stress is a significant term in the cross-reef momentum balance and is included in estimating the drag coefficient. For the five coral reef sites and a previous laboratory study, estimated drag coefficients increase as the water depth decreases consistent with open channel flow theory. For example, for a typical coral reef hydrodynamic roughness of 5 cm, observational estimates, and the theory indicate that the drag coefficient decreases from 0.4 in 20 cm of water to 0.005 in 10 m of water. Synthesis of results from the new field observations with estimates from previous field and laboratory studies indicate that coral reef drag coefficients range from 0.2 to 0.005 and hydrodynamic roughnesses generally range from 2 to 8 cm. While coral reef drag coefficients depend on factors such as physical roughness and surface waves, a substantial fraction of the scatter in estimates of coral reef drag coefficients is due to variations in water depth.

scholarly journals Water physicochemistry and benthic macroinvertebrate communities in a tropical reservoir: The role of water level fluctuations and water depth

Limnologica ◽  
2015 ◽  
Vol 55 ◽  
pp. 13-20 ◽  
Author(s):  
Francis S. Magbanua ◽  
Nikki Yvette B. Mendoza ◽  
Christine Jewel C. Uy ◽  
Christoph D. Matthaei ◽  
Perry S. Ong
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Water Level Fluctuations ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Tropical Reservoir

scholarly journals Using White Star (Nymphoides humboldtiana) for lake landscaping

2019 ◽  
Vol 37 (2) ◽  
pp. 133-137
Author(s):  
Carla D Tedesco ◽  
Claudia Petry ◽  
Edson C Bortoluzzi ◽  
Alfredo Castamann
Keyword(s):  
Water Level ◽  
Leaf Area ◽  
Water Depth ◽  
Native Species ◽  
High Water ◽  
Water Levels ◽  
Vegetative Development ◽  
High Water Level ◽  
Number Of Leaves ◽  
White Star

ABSTRACT White Star (Nymphoides humboldtiana), an aquatic-environmental native species of Brazilian flora, was selected in order to be used as ornamental plant in lakes. White Star plants were submitted to two water levels (high water level, up to 30 cm water depth and, low water level until substrate saturation) and two light intensities (full sun and 50% shading) to evaluate vegetative and flowering development. The experimental design was completely randomized, in a subplot scheme, being the water level the main plot and luminosity the subplot. Seven replicates were performed, and the sample unit consisted of one plant. Data related to number of leaves and flowers, length and diameter of petioles and leaf area were submitted to analyze of variance and regression. We observed an increase in number of leaves and flowers in the treatment of high water level in full sun, and an increase of petiole length in high water level with shading. No difference between leaf area of plants grown under full sun and with shading (p<0.05) was observed. At low water level, plants presented lower vegetative development than those grown at high water level, besides the flowering inhibition in shaded condition. These results demonstrated that White Star can be used in ornamental lakes with a water depth of at least 20 cm above the rhizome and exposed to full sun.

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