scholarly journals Oddziaływanie przepustu na warunki hydrauliczne przepływu wody w głównym rowie systemu odwadniającego stopnia wodnego Łączany

2017 ◽  
Vol 26 (1) ◽  
pp. 28-37
Author(s):  
Agata Majerczyk ◽  
Bogusław Michalec

The aim of the study is to analyze the impact of the culvert on the hydraulic conditions of water flow in the “R” ditch. The culvert was located on the main ditch in drainage system of Łączany barrage on the Vistula river. The research on ditch’s capacity in analyzed cross-section showed that the capacity decreased. The changes of cross-section caused by construction of the culvert substantially affect the flow conditions of water in the channel. The calculations showed that the existing dimension of culvert is not enough to pass the reliable discharge. The reliable flow was set for catchment area of 3.32 km2, not 0.67 km2, which is bigger than catchment area estimated in drainage project. It includes watercourses leading water to ditch with surrounds Kasztelan Pond, and then to “R” ditch. Discharges larger than 2.27 m3·s–1, particularly reliable flow, reach banks of the ditch “R” and flows out the channel. Discharges larger than the reliable discharge do not fit into the analyzed cross-section causing pouring out the water from the channel. On the basis of information taken from the locals and serving the system it is known that such a phenomenon occurs during the periods of heavy rains and floods.

2003 ◽  
Vol 48 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Nevenka Djurovic ◽  
Ruzica Stricevic

Dagan?s method as well as Kirkham?s one belong to the group of methods for drain spacing determination in steady state water flow conditions. Both methods are based on the assumption that drainage spacing (L) is linear function of water table depth and drainage discharge (h/q). The only difference can be distinguished in the values of coefficients. To dry out eugley type of soil, drain spacing is better determined by Dagan?s method in all treatments, as compared with Kirkham?s one. Advantage of this method is especially marked on the drainage system with narrower drain spacing.


2019 ◽  
Vol 100 ◽  
pp. 00087
Author(s):  
Krzysztof Wolski

The paper presents the results of numerical research on the impact of seasonal changes in vegetation on the hydraulic conditions prevailing in the bed of overgrowing lowland river on the example of Ślęza River (Poland). Hydrological characterization of the analyzed section of the river was made on the basis of data from the years 2006–2017 from the Ślęza water gauge. Based on them, the growing season and characteristic flows for modelling were determined. A two-dimensional hydrodynamic model (2HD) was built in two scenarios corresponding to the beginning and the end of the vegetation period for an about 50 m long section of the river. The bathymetric data of the bed and the plant distribution were measured in the field for both scenarios. The models were calibrated using a coefficient of roughness based on the velocities and surface elevations measured directly in the field. Various characteristic flows were then tested on calibrated and verified models for both scenarios. Changes in hydraulic conditions in both scenarios were compared by means of velocities and shear stress occurring in the riverbed. The obtained results indicate a significant impact of plants on the hydraulic conditions in the riverbed. The existence of plants causes the accumulation of backwater and change of local velocity distributions while maintaining medium and maximum velocities in the riverbed.


Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1826 ◽  
Author(s):  
Mariusz Starzec ◽  
Józef Dziopak ◽  
Daniel Słyś ◽  
Kamil Pochwat ◽  
Sabina Kordana

This article is aimed at defining the impact of the direction and velocity of waves of rainfall as they pass over interconnected stormwater detention tank systems. The simulations were conducted for a real urban catchment area as part of the Storm Water Management Model (SWMM) 5.1 programme. The results permit us to conclude that the direction and velocity of a moving wave of rainfall have a significant influence on the required volumes of interconnected stormwater detention tank systems. By comparing the modelling test results for stationary rainfall and rainfall moving over the urban catchment area, it has been demonstrated that differences in the required volume of the detention tank located at the terminal section of a stormwater drainage system are inversely proportional to the adopted value of the diameter of the outfall channel for upstream storage reservoirs. In extreme cases, the differences may be up to several dozen percentage points. Furthermore, it has been proven that the arrangement of the stormwater detention tanks in relation to one another and the adopted diameter of the outfall channel are key factors in identifying the degree to which the detention tanks are hydraulically dependent on one another.


ASTONJADRO ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 322
Author(s):  
Mohammad Imam Imamuddin ◽  
Laraswati Laraswati

The problem of flooding in Aneka Elok, which is located in the city of East Jakarta, is still a matter of concern, because every rainy season it is always routinely flooded. The catchment area in this study is 0,75 km<sup>2</sup> has a primary waterway that flow along the Aneka Elok area which flows northward to the reservoir and pump house. The reservoir in Aneka Elok area is located on an area of 32.000m<sup>2</sup>, is able to accommodate a flood debit of 225m<sup>3</sup> with an average depth of 4m. And has a pump capacity of 1000 liters/second as much as 2 units. With the current capacity of the reservoir and pump capacity, it is still not able to overcome the debit flood existing. This study aims to determine the existing debit in Aneka Elok area according to the return period of 5 years and 25 years, the debit flood existing in the research area, so that it can analyze the required waterway cross section and ideal pump capacity. With a return period of 5 years, the rainfall insensity of I<sub>5</sub> is 91,95 mm/hour to calculate the debit flood due the rain and compared to the debit existing flood, it is found that thecapacity of the existing waterway at C1-C2, C4-C9 and C11 is not sufficient to accommodate the current debit flood, so it is necessary to modify the waterway dimension. With a return period of 25 years, the rainfall insensity I<sub>25</sub> is 169,66 mm/hour to calculate the pump capacity, it is found that current capacity is still not sufficient so that it is necessary to increase the pump capacity from 2 m<sup>3</sup>/s to 3,5 m<sup>3</sup>/s to accelerate water flow.


2021 ◽  
Author(s):  
Sorosh Esmaelizadeh ◽  
Babak Lashkar-Ara

Abstract Floods are an important hazard throughout the world. The origins of some floods are a dam failure, hydraulic structure failure as well as an improper performance of the spillway. Among these, shaft spillways are known as a flood drainage system in dams, which is submerged by increasing the level of the reservoir, so that reduces the spillway efficiency and causes over topping. Investigations show that using deflector and aeration in shaft spillways will cause the flow pattern to improve. In this study, it has been tried to experiment on the impact of a deflector located in the throat and inlet geometry of the crest on the improvement of the hydraulic performance of the shaft spillway, and decrease to some extent the hazard induced by lack of timely drainage of floods in dam reservoirs. In order to investigate the deflector effect, three constriction specimens in shaft throat with constriction area to shaft area ratio (Ad/Ai) of respectively 0.75, 0.5 and 0.25 were considered as scenarios. In each scenario, the conditions of the flow passing through 12 different specimens of spillway with Crown Wheel inlets were tested and the results were compared with the flow conditions in crown wheel spillways without deflector (reference model). The results showed that the use of deflector has an important role in reducing vortex flows and stabilizing changes in the water level of the reservoir, and also increases the discharge coefficient of the flow. The studies on reference models also showed that Crown Wheel inlets (C.W.) improved shaft spillway performance, with C.W. spillways having an average discharge coefficient of 32% higher than shaft spillways. Finally, considering optimal deflector factors and C.W. geometry, an optimal model was proposed for flood reservoir conditions.


2020 ◽  
Vol 1 (1) ◽  
pp. 36-44
Author(s):  
Vitta Pratiwi ◽  
Tri Rahajoeningroem

ABSTRACT The effort to countermeasure flood and puddle in DKI Jakarta is one of the priority programs implemented by the Government in order to create Jakarta as the capital of the Republic of Indonesia that is comfortable to carry out social, cultural and economic activities, thus giving a positive impact to the economy of DKI Jakarta and Indonesia. In the effort to handle the puddle and flood problems above the need of infrastructure planning and flood control means especially in central Jakarta, so as to reduce the points of the puddle and flooding and the impact caused. With this activity is expected to produce a design of infrastructure development and a means of quality flood control that means that the development can be felt by all components of the community. This activity is conducted in two areas namely Petamburan (Jati Pinggir) and Kalibaru Timur. This methodology of implementation of activities consist of preparation and preliminary stages, field survey and data analysis as well as the formulation of channel design concept as well as simulated of drainage system and flood control modeling. The analysis of precipitation frequencies of the plan uses a 5-year anniversary with the Gumbell type 1 method. The problems in the Petamburan region are the basic elevation of the irregular channels, the number of basins in the middle of the channel, the capacity of channels that have been unable to receive debit plans and elevation of the land is generally lower than the elevation of the disposal channel Broad catchment area of 21.50 Ha, assuming the flow coefficient of 0.85 and the rainfall intensity is used at 5 years of 225.7 mm, resulting in flood discharge calculation of Q = 5.73 m3/second and plus existing pump 0.75 m3/sec. Handling of normalization with base tilt to 0.0028. Redimensioning is changed to uniform i.e. B = 1.20 m; H = 1.20 m. As for East Kalibaru region the thing that concern is the narrowing of the channel in the downstream. The Tc value is 121.26 minutes, I of 38.67 mm/h and Q = 8.47 m3/sec. Specification of the pump used is a submersible type axial flow with a capacity of 2 m3/sec. Key words: Flood, rainfall, discharge, intensity, pump   ABSTRAK Upaya penanggulangan banjir dan genangan di wilayah DKI Jakarta merupakan salah satu program prioritas yang dilaksanakan pemerintah dalam rangka menciptakan Jakarta sebagai ibukota Negara Republik Indonesia yang nyaman untuk melaksanakan kegiatan sosial, budaya maupun ekonomi, sehingga memberi dampak yang positif bagi perekonomian Provinsi DKI Jakarta maupun Indonesia. Dalam upaya penanganan permasalahan genangan dan banjir di atas dibutuhkan perencanaan prasarana dan sarana pengendali banjir khususnya di Jakarta Pusat, sehingga dapat mengurangi titik-titik genangan dan banjir serta dampak yang ditimbulkan. Dengan adanya kegiatan ini diharapkan dapat menghasilkan suatu desain pembangunan prasarana dan sarana pengendali banjir yang berkualitas yaitu yang bermakna bahwa pembangunan tersebut dapat dirasakan oleh seluruh komponen masyarakat. Pada kegiatan ini dilakukan di dua wilayah yaitu Petamburan (Jati Pinggir) dan Kalibaru Timur. Metodologi pelaksanaan kegiatan ini terdiri atas tahap persiapan dan pendahuluan, survey lapangan dan analisis data serta penyusunan konsep desain saluran serta simulasi pemodelan sistem drainase dan pengendalian banjir. Analisis frekuensi curah hujan rencana menggunakan kala ulang 5 tahun dengan metode Gumbell tipe 1. Permasalahan di wilayah Petamburan adalah elevasi dasar saluran tidak beraturan, banyaknya cekungan di tengah saluran, kapasitas saluran yang sudah tidak mampu menerima debit rencana dan elevasi lahan umumnya lebih rendah daripada elevasi saluran pembuang. Luas catchment area seluas 21.50 Ha, dengan asumsi koefisien pengaliran sebesar 0.85 dan intensitas curah hujan digunakan kala ulang 5 tahun sebesar 225.7 mm, sehingga didapat perhitungan debit banjir sebesar Q = 5.73 m3/detik dan ditambah pompa eksisting 0.75 m3/detik. Dilakukan penanganan normalisasi dengan kemiringan dasar menjadi 0.0028. Redimensi diubah menjadi seragam yaitu B = 1.20 m; H = 1.20 m. Sedangkan untuk wilayah Kalibaru Timur hal yang menjadi perhatian adalah penyempitan saluran di hilir. Nilai Tc adalah 121.26 menit, I sebesar 38.67 mm/jam dan Q = 8.47 m3/detik. Spesifikasi pompa yang dipergunakan merupakan tipe submersible axial flow dengan kapasitas 2 m3/detik. Kata kunci: Banjir, curah hujan, debit, intensitas, pompa


Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 826
Author(s):  
Xiaoli Hao ◽  
Jie Mu ◽  
Hongjian Shi

Storm drainage inlets transport urban runoff and discharge to underground sewer systems. If the inlet structure is blocked, the urban drainage system is hampered, leading to urban flooding. To quantitatively analyze the influence of clogging conditions on inlet discharge capacity, laboratory experiments were conducted to address the impact of different inlet clogging conditions on inlet discharge capacity under different upstream discharge conditions. These were based on a two-layer platform that mimicked a complete inlet structure including a drainage grate, a rainwater well, and a connecting pipe. The results show that the water flow near the inlet was similar to weir flow when the rainwater well was not full, whereas the water flow state near the inlet behaved similarly to orifice flow after becoming full. In addition, it was found that the clogging extent and position can significantly influence the comprehensive discharge capacity of the street inlet. The experimental dataset was used to calculate the inlet discharge coefficients of the weir and orifice flow states under different clogging conditions. The results are applicable to research addressing the formation mechanisms of urban floods. Additionally, this study is of practical significance for early warning systems and emergency response support during heavy rainfall.


1997 ◽  
Vol 24 ◽  
pp. 288-292 ◽  
Author(s):  
Andrew P. Barrett ◽  
David N. Collins

Combined measurements of meltwater discharge from the portal and of water level in a borehole drilled to the bed of Findelengletscher, Switzerland, were obtained during the later part of the 1993 ablation season. A severe storm, lasting from 22 through 24 September, produced at least 130 mm of precipitation over the glacier, largely as rain. The combined hydrological records indicate periods during which the basal drainage system became constricted and water storage in the glacier increased, as well as phases of channel growth. During the storm, water pressure generally increased as water backed up in the drainage network. Abrupt, temporary falls in borehole water level were accompanied by pulses in portal discharge. On 24 September, whilst borehole water level continued to rise, water started to escape under pressure with a resultant increase in discharge. As the drainage network expanded, a large amount of debris was flushed from a wide area of the bed. Progressive growth in channel capacity as discharge increased enabled stored water to drain and borehole water level to fall rapidly. Possible relationships between observed borehole water levels and water pressures in subglacial channels are influenced by hydraulic conditions at the base of the hole, distance between the hole and a channel, and the nature of the substrate.


1996 ◽  
Vol 33 (9) ◽  
pp. 9-16 ◽  
Author(s):  
John A. Swaffield ◽  
John A. McDougall

The transient flow conditions within a building drainage system may be simulated by the numerical solution of the defining equations of momentum and continuity, coupled to a knowledge of the boundary conditions representing either appliances discharging to the network or particular network terminations. While the fundamental mathematics has long been available, it is the availability of fast, affordable and accessible computing that has allowed the development of the simulations presented in this paper. A drainage system model for unsteady partially filled pipeflow will be presented in this paper. The model is capable of predicting flow depth and rate, and solid velocity, throughout a complex network. The ability of such models to assist in the decision making and design processes will be shown, particularly in such areas as appliance design and water conservation.


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