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THE EFFECTIVENESS NUMBER OF BAFFLE BLOCKS TO REDUCE ENERGY IN TUKUTAHA TRANSITION CHANNELS Agustina Nababan; Nadjadji Anwar; Wasis Wardoyo
Journal of Civil Engineering Vol 36, No 2 (2021)
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20861206.v36i2.9428

Abstract

One of the causes of damage to the weir structure is scouring. Scouring may occur along the weir channel. Scouring occurs due to the high flow velocity and high specific energy. One of the methods used to reduce specific velocity and energy is by installing baffle blocks in parts that have high-velocity and energy. The addition of baffle blocks is carried out at a place that has a high-velocity, namely the transition channel. To see the effect of baffle block variation on velocity and energy, a study was conducted. The study was conducted with four baffle block type models. The type 0 model is a baffle block installation pattern based on the initial design. Type 1 model is designed based on the planning of The Colorado State University (CSU) rigid boundary basin. Type 2 model is designed by reducing the number of baffle blocks from the initial design of 102 baffles to as many as 75 baffles. while the 3 channel type model transitions without baffle blocks. Based on the analysis of % energy loss in the transition channel, the type 0 model produces the largest energy loss. The type 0 model at maximum discharge has a % energy loss 10.821% greater than the type 1 model, 14.889% greater than the type 2 model and 33.02 % greater than the type 3 model.
A Comparative Study of Water Quality Characteristics at East Java River Sri Wahyuningsih; Nadjadji Anwar; Edijatno Edijatno; Nieke Karnaningroem
IPTEK The Journal for Technology and Science Vol 21, No 4 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i4.91

Abstract

Water is the natural resources have the function of very importance for human life and also as authorized capital in development. Water will influence by the other component. Exploiting of water to support all human life must done with wise action to management so that not result damage at water resource. As place relocation of water hence river have the selected capacities that able to change because natural activity and antropogenik. This research was conducted in nine major rivers in East Java. The objectives of this study were: 1) Identifying the characteristics and concestration range of water quality parameter, 2) Comparison the level of pollution in rivers in East Java. The results of this study indicated that the characteristic of water quality parameter of rivers in East Java were generally physical, chemical and biological. The comparison result of water quality parameter basically showed that in general the pH was still under threshold that had been determined, that was pH from 6 to 9. In general, DO concentration ranged from 0.5 mg/l to 7 mg/l, BOD concentration ranged from 3 mg/l to 11 mg/l and the COD concentration ranged between 0.5 mg/liter to 35 mg/l.
Dividing Streamline Formation Channel Confluences by Physical Modeling Minarni Nur Trilita; Nadjadji Anwar; Djoko Legono; Basuki Widodo
IPTEK The Journal for Technology and Science Vol 21, No 1 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i1.23

Abstract

Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline). In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30ยบ. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.
Generating Hourly Rainfall Model using Bayesian Time Series Model (A Case Study at Sentral Station, Bondowoso) Entin Hidayah; Nur Iriawan; Nadjadji Anwar; Edijatno Edijatno
IPTEK The Journal for Technology and Science Vol 22, No 1 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i1.57

Abstract

Disaggregation of hourly rainfall data is very important to fulfil the input of continual rainfall-runoff model, when the availability of automatic rainfall records are limited. Continual rainfall-runoff modeling requires rainfall data in form of series of hourly. Such specification can be obtained by temporal disaggregation in single site. The paper attempts to generate single-site rainfall model based upon time series (AR1) model by adjusting and establishing dummy procedure. Estimated with Bayesian Markov Chain Monte Carlo (MCMC) the objective variable is hourly rainfall depth. Performance of model has been evaluated by comparison of history data and model prediction. The result shows that the model has a good performance for dry interval periods. The performance of the model good represented by smaller number of MAE by 0.21 respectively.
A STUDY OF SEDIMENT DELIVERY RATIO USING AVSWAT-X IN THE CATCHMENT AREA OF PACAL RESERVOIR OF BOJONEGORO Bambang Sarwono; Nadjadji Anwar; Zulis Erwanto
Journal of Civil Engineering Vol. 30 No. 2 (2010)
Publisher : Institut Teknologi Sepuluh Nopember (ITS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20861206.v30i2.7535

Abstract

Recently, the flood intensity that brought by tributary rivers in the catchment area of Pacal reservoir has increased, both in the quantity of runoff and sediment volume. The research aims to set up erosion rate modeling and find the formulation of the Sediment Delivery Ratio (SDR) at Pacal reservoir. The research used USLE and MUSLE methods as comparator to find sediment yield accuracy at Pacal reservoir, by applying ArcView SWAT-X software. Total average annual erosion rate in the catchment area of Pacal reservoir which has area 82 Km2 calculated using USLE and MUSLE methods are 159,31 ton/ha/yr and 582 ton/ha/yr respectively. MUSLE method resulted SDR which is most closely to SDRobservation if it is compared to USLE method. In this research, MUSLE - Sediment-Discharge Rating Curve method has evaluation values MSE = 0,08; RMSE = 0,29; and Nash = 0,75. Furthermore, Sediment Delivery Ratio at catchment area of Pacal reservoir can be formulated as 0,29 3,83. DAS Waduk Pacal SDR A with value of SDRZulis = 0,27 and sediment yield obtained from MUSLE method equal to 157,40 ton/ha/yr, while from USLE method equal to 43,09 ton/ha/yr. Evaluate sediment yield of MUSLE from SDRZulis to formulation of SDR of former researcher was value of Nash = 0,89; MAE = 0,01. Based on the research result, it is expected that the institution which has responsibility in managing the catchment area of Pacal reservoir would pay high attention to zonation map of erosion risk level and can overcome sedimentation in Pacal reservoir.
THE EFFECTIVENESS NUMBER OF BAFFLE BLOCKS TO REDUCE ENERGY IN TUKUTAHA TRANSITION CHANNELS Agustina Nababan; Nadjadji Anwar; Wasis Wardoyo
Journal of Civil Engineering Vol. 36 No. 2 (2021)
Publisher : Institut Teknologi Sepuluh Nopember (ITS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20861206.v36i2.7633

Abstract

One of the causes of damage to the weir structure is scouring that can accur along the weir channel. Scouring occurs due to the high flow velocity and high specific energy. One of the methods used to reduce specific velocity and energy is by installing baffle blocks in parts that have high velocity and energy. The addition of baffle blocks is carried out at a place that has a high velocity, namely the transition channel. To see the effect of baffle block variation on velocity and energy, a study was conducted. The study was conducted with four baffle block models type. Model type 0 is a model with the same assumptions as of the existing one. model type 1 is designed based on the planning of The Colorado State University (CSU) rigid boundary basin. Model type 2 is designed by reducing the number of baffle blocks from the initial design of 102 baffles to as many as 75 baffles. while the 3 channel model type transitions without baffle blocks. Based on the percentage of energy loss analysis in the transition channel, Model type 0 can reduce energy greater than others models. At maximum discharge, the model type 0 has an energy loss of 10.821% greater than the model type 1, 14,889% greater than the model type 2, and 33.02% greater than the model type 3.