scholarly journals Effectiveness of a groundsill structure in reducing scouring problem at Cimadur River, Banten Province

2021 ◽  
Vol 880 (1) ◽  
pp. 012026
Author(s):  
Arniza Fitri ◽  
Li Yao ◽  
Dian Pratiwi ◽  
Arlina Phelia ◽  
Susarman ◽  
...  
Keyword(s):  
Water Body ◽  
Water Velocity ◽  
Sedimentation Rates ◽  
Bridge Structure ◽  
Small Reduction ◽  
Before And After ◽  
Downstream Area

Abstract Groundsill is a transverse threshold structure that can be built on water body as one alternative in reducing the upstream water velocity and therefore could maintain the upstream sedimentation rates. Due to scouring problems faced in the Cimadur River, Banten Province, a groundsill structure has been constructed at one location in Cimadur River which is near to the Bantar Karang bridge structure. The scouring problem is worried to damage the abutment of the bridge structure. This study aims to investigate the effectiveness of the groundsill structure in reducing the scouring problem in Cimadur River, Banten Province. The effectiveness is determined by comparing the riverbed elevation around the Bantar Karang bridge structure, before and after 5 months construction of the groundsill structure. The results showed that the presence of the groundsill structure has increased the riverbed elevation especially around the abutment of the Bantar Karang bridge (approximately 25 cm in average after 5 months installation of the groundsill structure). It is therefore can slowly reduce the local scouring problem around Bantar Karang bridge. Besides, the results also showed that there is small reduction of riverbed elevation at the downstream area of the groundsill structure approximately about 10 cm in average. It can be concluded that the groundsill structure is quite effective in reducing the local scouring problem in Cimadur River, especially upstream area of their structure around Bantar Karang bridge.

scholarly journals Depth-Average Velocity from Spray Underwater Gliders

2018 ◽  
Vol 35 (8) ◽  
pp. 1665-1673 ◽  
Author(s):  
Daniel L. Rudnick ◽  
Jeffrey T. Sherman ◽  
Alexander P. Wu
Keyword(s):  
Average Velocity ◽  
Dead Reckoning ◽  
Water Velocity ◽  
Accurate Estimation ◽  
Underwater Glider ◽  
Underwater Gliders ◽  
Before And After ◽  
The Difference ◽  
Using Data ◽  
Acoustic Doppler Current Profilers

AbstractThe depth-average velocity is routinely calculated using data from underwater gliders. The calculation is a dead reckoning, where the difference between the glider’s velocity over ground and its velocity through water yields the water velocity averaged over the glider’s dive path. Given the accuracy of global positioning system navigation and the typical 3–6-h dive cycle, the accuracy of the depth-average velocity is overwhelmingly dependent on the accurate estimation of the glider’s velocity through water. The calculation of glider velocity through water for the Spray underwater glider is described. The accuracy of this calculation is addressed using a method similar to that used with shipboard acoustic Doppler current profilers, where water velocity is compared before and after turns to determine a gain to apply to glider velocity through water. Differences of this gain from an ideal value of one are used to evaluate accuracy. Sustained glider observations of several years off California and Palau consisted of missions involving repeated straight sections, producing hundreds of turns. The root-mean-square accuracy of depth-average velocity is estimated to be in the range of 0.01–0.02 m s−1, consistent with inferences from the early days of underwater glider design.

scholarly journals Damage Identification of Multi-span Bridge Structure Based on the Recognition of Influence Line

2021 ◽  
Vol 233 ◽  
pp. 03002
Author(s):  
Zhang Yunkai ◽  
Xie Qingli ◽  
Li Guohua ◽  
Ye Yuntao
Keyword(s):  
Information Fusion ◽  
Damage Identification ◽  
Sensory Information ◽  
Bridge Structure ◽  
Damage Site ◽  
Damage Location ◽  
Influence Line ◽  
Before And After ◽  
Bridge Damage ◽  
Combining Information

The stress and deflection effects of the line changes before and after the bridge damage are used as indicators to evaluate the bridge damage and the initial damage site. Then a method of combining information is proposed to improve the accuracy of the damage site. Three-span continuous reinforced concrete was used in the analysis. According to the test, the effectiveness of damage identification based on the damage change of the influence line and the feasibility of the damage location method based on multi-sensory information fusion are confirmed.

Temperature Field of Doublet-Wells Aquifer Thermal Energy Storage in Sanhejian Coal Mine

2012 ◽  
Vol 430-432 ◽  
pp. 746-749
Author(s):  
Yi Zhang ◽  
Dong Ming Guo
Keyword(s):  
Temperature Field ◽  
Energy Storage ◽  
Thermal Energy ◽  
Coal Mine ◽  
Thermal Energy Storage ◽  
Water Body ◽  
Small Reduction ◽  
Irrigation Flow ◽  
Aquifer Thermal Energy Storage ◽  
Cold Energy

Utilizating of tube-well irrigation, the technology of aquifer thermal energy storage (ATES) store rich cold energy in winter and cheap warm energy in summar into aquifers seasonally. In this paper, taking Sanhejian Coal Mine as an example, we discuss that with the same pumping and irrigation flow in doublet wells, distribution and change of temperature field in aquifers both at the end of energy storage and after the period of no pumping and no irrigation. The simulation results of aquifer temperature field show that 2~10°C water body of aquifers is decreasing in the period of no pumping and no irrigation, but it is only a small reduction with a stable trend. And after the period of no pumping and no irrigation, about 11°C water body of aquifers stores steadily in the aquifer, so the selected aquifers is suitable and its effect of energy storage is good.

Calculation Analysis of Strengthening Arch Bridge Structure Based on Release Energy Method

2011 ◽  
Vol 71-78 ◽  
pp. 1732-1735
Author(s):  
Qing Ping Jin ◽  
Xian Bao Wang ◽  
Xue Jun Li
Keyword(s):  
Energy Method ◽  
Carrying Capacity ◽  
Safety Margin ◽  
Bridge Structure ◽  
Masonry Arch ◽  
Arch Bridge ◽  
Before And After ◽  
Arch Bridges ◽  
Calculation Analysis ◽  
Masonry Arch Bridge

The arch bridges were used widely for the good performance under the pressure in China. It was very sensitive to some factors as temperature , settlement etc so that the arch bridges occurred the disease, carrying capacity reduction or even structure destruction etc.In the paper, based on the characteristics of masonry arch bridges, reinforcement method was analyzed, according to the situation of a masonry arch bridge, release energy method was applied to strengthening project. By comparing the stress and the strain before and after the strengthening project, some conclusions could be drawn that the bridge structure carrying capacity had been raised, the energy accumulated in the bridge structure was released, the structure safety margin was improved.

scholarly journals Flood Effects on the Phytoplankton Diversity of Bega River (Banat, Romania)

2013 ◽  
Vol 15 (3) ◽  
pp. 207
Author(s):  
Hanelore Muntean ◽  
Laura Alexoaie
Keyword(s):  
Water Body ◽  
Nutrient Balance ◽  
Water System ◽  
Mountainous Area ◽  
Phytoplankton Diversity ◽  
Before And After ◽  
High Precipitation ◽  
Local Water ◽  
Flooded Area ◽  
Water Administration

ABSTRACT Situated on the Western Plains of Romania, the Banat region has an adverse natural condition that makes it a frequently-flooded area. A lack of natural drainage due to a low slope, shallow gound water, slow-moving water course densities, and precipitation in this close, mountainous area all contribute to periodic flood events. Water courses in the region have snake-like river beds and swamps present in the area before the XVIIIth century (Griselini, 1979) also create a tendency toward flood activity. The Bega is a river in the Timiș- Bega water system, originating from Poiana Rusca Mountains and the lower basin becomes channeled before entering Timișoara City. Seasonal floods and overall water quality influence the quantity and quality of phytoplankton and macrozoobenthos in the Bega River. Phytoplankton obtains energy through the process of photosynthesis and must therefore live in the well-lit surface layer of a water body. Crucially dependent on minerals, phytoplankton primarily subsist on macronutrients such as nitrate, phosphate or silicic acid, which are governed by the balance between the socalled biological pump and the upwelling of deep, nutrient-rich waters. After floods the balance of nutrients in a river is changed and the effects can be observed by discerning differences in phytoplankton biomass and families living in the water body before and after the flood event (Muzaffar, 2007). In this study, based on the information from local water administration, we provide data about the flood in 2005 and its effects on the biodiversity in the river. The measurements were made at 2 sites, one before the Bega River enters Timișoara and the other at Otelec station, 45.5 km downstream from Timișoara. The runoff in 2005, caused by high precipitation in the upper basin, disturbed the nutrient balance in the river by transporting debris and sediment discharge from upstream, and carrying the local macrozoobenthos out of their normal habitat. Upstream from Timișoara, phytoplankton is dominated by species of diatomes like Diatoma sp., Synedra sp., Navicula sp., Fragilaria sp., Rhoicospahenia sp., Gyrosigma sp., Cymatopleura sp. and Amphora sp. During floods the flow and speed of the water increases, which dilutes the water and modifies the concentration of nutrients and pollutants in the affected area, therefore changing the processes at a biological level. This specific process is important for the possibility of selfpurification in water bodies.

Removal Properties of Nitrogen and Phosphorous in Eutrophic Water with Periphyton Attached by Artificial Substrate

2011 ◽  
Vol 340 ◽  
pp. 480-486
Author(s):  
Ding Long Li ◽  
Hong Lu ◽  
Qian Chen ◽  
Jian Ying Chao ◽  
Xiang Ji Kong ◽  
...  
Keyword(s):  
Water Depth ◽  
Water Body ◽  
Removal Rate ◽  
Chemical Properties ◽  
Water Velocity ◽  
New Thought ◽  
Chl A ◽  
Eutrophic Water ◽  
Nitrogen Nutrients ◽  
Depth Water

Removal properties are researched and discussed of algae and nitrogen & phosphorus nutrients with periphyton by assembled substrate in lake-based eutrophic water body, including impacts on removal effects of several physical & chemical properties as water depth, water velocity, DO, temperature and PH. The results show that: the removal rate of NH4-N, other nitrogen nutrients, phosphorus nutrients and Chl-a were 96%, 40%, 80%, 65% respectively. With the growth of water velocity(from 0 to 200L/h ), the removal of Chl-a, TP, TDP increased to a certain extent（Chl-a: from 63.63% to 67.66%; TP:from 76.15% to 85.13%;TDP:from 80.10% to 88.44%）,and that of TN,TDN and NO3-N decreased to different extents（TN: from 45.19% to 31.97%; TDN: from 42.81% to 28.77%; NO3-N: from 38.11% to –5.26%）, but that of NH4-N and PO4-P altered little(NH4-N：from 96.80% to 95.94%；PO4-P：from 85.38% to 87.02%). It will provide reference for recovery and re-contribution of destroyed Eco-system, and a new thought for treatment in eutrophical lakes.

A comparison of biofilm growth and water quality changes in sewers with anoxic and anaerobic (septic) conditions

1997 ◽  
Vol 36 (1) ◽  
pp. 303-310 ◽  
Author(s):  
Anette Æsøy ◽  
Målfrid Storfjell ◽  
Lovisa Mellgren ◽  
Herman Helness ◽  
Gøril Thorvaldsen ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Chemical Treatment ◽  
Suspended Solids ◽  
Pilot Scale ◽  
Water Velocity ◽  
Small Reduction ◽  
Biofilm Growth ◽  
Pre Treatment ◽  
High Concentrations

Changes in water quality in sewers may have significant effects on the performance of treatment plants. Experiments have been carried out in two pilot scale sewers for studies of biofilm growth and changes of water quality with anoxic (dosage of nitrate) and anaerobic (septic) conditions, respectively. The thickness of the biofilm in the anoxic sewer was 1-2 mm as compared to 0.3-0.6 mm in the septic sewer at a water velocity of 0.5 m/s. An increase in the water velocity from 0.002 m/s to 0.5 m/s gave thicker and denser biofilms. Sulphide formation was prevented in the anoxic sewer, and influent sulphide was efficiently removed. The denitrification rate in the anoxic sewer was 3.5-4.3 g NO3-N/m2d (15°C). This gave a considerable reduction in both organic matter and phosphorus and an increase in pH and alkalinity. The potential to remove organic matter in sewers may be exploited as a pre-treatment to mechanical and chemical treatment plants in order to meet more stringent effluent standards for organic matter discharge. Removal of readily biodegradable organic matter in the sewer may, however, be a disadvantage for treatment plants based on pre-denitrification. A reduced phosphate concentration may give a reduced metal coagulant dose at chemical treatment plants, whereas an increase in pH and alkalinity may give an increased dose. In the septic sewer, there was a small reduction in the organic matter, but no significant net change in total phosphorus, pH and alkalinity on average. The production rate of sulphide was in the range of 0.3-0.7 gS/m2d (15°C). On average there was no change in the concentration of suspended solids in either of the sewers. A sporadic large sloughing of biofilm was observed, particularly in situations with a very diluted wastewater. Sporadic high concentrations of suspended solids may cause separation problems at treatment plants.

scholarly journals Sedimentary fractions of phosphorus before and after drainage of an urban water body (Maltański Reservoir, Poland)

2015 ◽  
Vol 15 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Piotr Rzymski ◽  
Tadeusz Sobczyński ◽  
Piotr Klimaszyk ◽  
Przemysław Niedzielski
Keyword(s):  
Water Flow ◽  
Water Body ◽  
Simultaneous Increase ◽  
Urban Water ◽  
P Fractions ◽  
Residual P ◽  
P Content ◽  
Before And After ◽  
Recreational Use ◽  
Persistent Contaminants

Abstract Urban reservoirs can receive high loads of chemicals, including persistent contaminants and eutrophication-promoting nutrients. To maintain their economic and recreational use, implementation of various restoration methods is often required. The Maltański Reservoir (Poland, Europe), a small, shallow and dammed urban water body, undergoes complete draining every four years as part of its restoration procedure. Here, we investigated the phosphorus (P) content and its fractions just before the reservoir was drained and after it had been completely filled with water again. As demonstrated, the highest accumulation of P occurred at sites through which the main water flow is directed. Calcium-bound and residual P constituted the largest proportion of P fractions. A shift in P fractions after the reservoir was drained and sediments were left without water for at least 4 months was observed. A decrease in phytoplankton utilized NH4Cl-P, Fe-P and NaOH-P fractions was found and followed a simultaneous increase in nearly biologically inaccessible HCl-P and practically biologically inactive residual P fractions. Our study demonstrates that complete drainage of the Maltański Reservoir may additionally decrease the risk of internal P loading through shifts in its fractions.

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