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A Comparative Study of Water Quality Characteristics at East Java River

IPTEK The Journal for Technology and Science Vol 21, No 4 (2010)
Publisher : Institut Teknologi Sepuluh Nopember

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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.

Evaluating Error of Temporal Disaggregation from Daily into Hourly Rainfall using Heytos Model at Sampean Catchments Area

IPTEK The Journal for Technology and Science Vol 21, No 1 (2010)
Publisher : Institut Teknologi Sepuluh Nopember

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Abstract

Developing a rainfall-runoff model sufficient to flood prediction hourly rainfall data. Lack of automatic rain gauge for high resolution rainfall in catchment area can be an obstacle for the modeling. Otherwise, the manual rain gauges may spread on all of catchments areas, providing daily rainfall. Daily rainfall disaggregation to hourly rainfall is an innovation to get higher temporal resolution of the rainfall. This paper attempts to evaluate the implementation of rainfall disaggregation model in Sampean Catchments Area using Heytos. The proposed parameter optimation use Moment Performance model that tested by calibrating it with available hourly data. The results of model indicated that only data within five months had good performance. The estimation result showed that relative error total of January, February, August, November, and December was less than one. In case of March, April, May, June, July, September, and October the model could not result respectively to generate model.

Dividing Streamline Formation Channel Confluences by Physical Modeling

IPTEK The Journal for Technology and Science Vol 21, No 1 (2010)
Publisher : Institut Teknologi Sepuluh Nopember

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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 30º. 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)

IPTEK The Journal for Technology and Science Vol 22, No 1 (2011)
Publisher : Institut Teknologi Sepuluh Nopember

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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.

IDENTIFIKASI KELEMAHAN METODE EARNED VALUE PADA PENGUKURAN KINERJA BIAYA DAN WAKTU PROYEK KONSTRUKSI

JOURNAL TEKNIK SIPIL DAN INFRASTRUKTUR Vol 3, No 2 (2013)
Publisher : JOURNAL TEKNIK SIPIL DAN INFRASTRUKTUR

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Abstract

Earned Value method (EV) has several weaknesses which makes it difficult to optimally apply in the construction projects. This study aims to identify the shortcomings of Earned Value related to the project cost and time performance. Literature study was conducted from the various sources related to the EV topic. The result shows that the main weakness of Earned Value method are: EV prediction method is assumed deterministic, linear, non-dynamic and does not accommodate uncertainty factors of time and cost of construction projects.   Keywords: construction  project, time and cost performance, earned value

STUDI EROS. DAN CIR H.DROLIKA ALiRAN DIPt:RMUKAAN LAHAN (Erosion Study and Hydroulic Row on Land Surface)

MAPETA Vol 4, No 13 (2002): MAPETA
Publisher : MAPETA

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Abstract

The purposed of the study is to identify of characteristics hydraulic flow and erosion as real picture on incipient motion-m sediment transport. The study is conducted in types of soil namely Alfisol and Entisol. They have a wide range utilization and a high erosion susceptibility. Simulation has been conducted by dropping eight different rain height to undisturbed soil block samples with 2.500 square em, width and 10 em thickness and with 9 % and 17 % land slopes. The results shows that surface run off not play in detachment of soil particle if equal with rain pellet and dispersion of water, but its transport sediment. Surface run off on plot standard in two kind of soil (Alfisol and Entisol) is laminar sub critics with Reynold number 140,2 and 136,2; Froude Number 0,940 and 0,980; drag force 9,02 and 4,44 Nm-2. Whereas 17% slope is super critics with Reynolrd Number 206,2 and 78,1; Froude number 1,219 and 1,286 and drag force 14,79 and 9,76 Nm-2.· Key Words: Erosion, hydraulic characteristic, sediment transport

IDENTIFIKASI RISIKO PADA KONTRAK BERBASIS KINERJA (KBK) PROYEK JALAN RAYA DI INDONESIA

Simposium II UNIID 2017 Vol 2 (2017)
Publisher : Simposium II UNIID 2017

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Abstract

Kontrak Berbasis Kinerja (KBK) merupakan kontrak terintegrasi sebagai salah satu upaya pemerintah agar jalan raya selalu dalam kondisi mantap. Sebelumnya, pemeliharaan jalan dilakukan dengan kontrak konvensional dimana perencana, pelaksana pekerjaan konstruksi dan masa layanan pemeliharaan dilakukan oleh penyedia jasa yang berbeda. Sedangkan kontrak berbasis kinerja ini menyerahkan semua tanggung jawab tersebut pada satu penyedia jasa (kontraktor) dan dibayar secara lump sum sesuai kinerja yang dihasilkan. KBK mendorong penyedia jasa untuk menyediakan pekerjaan bermutu jika tidak ingin mengalami kerugian lebih besar pada masa layanan pemeliharaan. KBK telah digunakan di negara maju dan negara berkembang serta berhasil memberi manfaat bagi otoritas jalan berupa penghematan biaya pemeliharaan dan peningkatan kondisi aset jalan yang dikontrakkan. Pada dasarnya kontrak berbasis kinerja merupakan usaha penempatan risiko kepada pihak penyebab risiko. Pada kontrak konvensional, risiko tersebut menjadi beban pihak pemerintah. Penelitian ini bertujuan untuk identifikasi risiko-risiko pada tahap persiapan kontrak berbasis kinerja yaitu tahap prebidding, bidding serta tahap perencanaan konstruksi, tahap pelaksanaan konstruksi dan masa layanan pemeliharaan. Tahap prebidding dan bidding merupakan lingkup pekerjaan pemilik proyek (owner) sedangkan tahap selanjutnya yaitu tahap perencanaan, pelaksanaan dan masa layanan pemeliharaan merupakan lingkup pekerjaan penyedia jasa

Developing of Total Suspended Sediment Model Using Landsat-8 Satellite Image and In-Situ Data at The Surabaya Coast, East Java, Indonesia

Indonesian Journal of Geography Vol 49, No 1 (2017): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

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Abstract

The decrease of coastal-water quality in the Surabaya coastal region can be recognized from the conceentration of Total Suspended Sediment(TSS ) . As a result we need a system for monitoring sediment concentration in the coastal region of Surabaya which regularly measures TSS. The principle to model and monitor TSSconcentration using remote sensing methods is by the integration of Landsat-8OLI satellites image processing using some ofTSS-models then those are analyzed for looking its suitability with TSS value direcly measured in the field ( in-situ measurement). The TSS value modeled from all algorithms validated usingcorrelation analysis and linear regression . The result shows that TSS model with the highest correlation value is TSS algorithm by Budiman (2004)with r value 0.991. Hence this algorithm can be used to investigate TSS-distribution which represent the coastal water quality of Surabaya with TSS value between 75 mg/L to 125 mg/L.

Analysis of Waikelo Port Breakwater Failure through 2D Wave Model

Civil and Environmental Science Journal Vol 1, No 2 (2018)
Publisher : Fakultas Teknik UB

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Abstract

Waikelo Port is located in South West Sumba of East Nusa Tenggara. The port facilities are protected by breakwater with a vertical wall construction and it was built in a relatively deep ocean at -15m of Low Water Sea Level (LWS). On 21 of January 2012, an earthquake with magnitude of 6.3 Richter scale occurred around Sumba Island and it caused cracking in the concrete wall of breakwater. Then, 4 days after on 25 st January 2012, a heavy wind of 20–23 knots generated a high wave around 4.0–5.0m in Sumba strait. These high waves caused a critical damage on the west part of the breakwater. The damage of port facilities were getting worse when a storm called Lua hit on March 2012. This study was conducted to observe the effect of the extreme event in the failure of breakwater. The result of two-dimensional (2D) wave model shows that the wave heights in the area of breakwater are varied 3.80 to 4.0m. It is quite greater than the wave design of 50 years return period (= 2.00m) which was used in breakwater design and calculation. This observable fact confirms that the failure of breakwater was caused by the continuous extreme events that exceed the design criteria

APLIKASI METODE CURVE NUMBER UNTUK MEMPRESENTASIKAN HUBUNGAN CURAH HUJAN DAN ALIRAN PERMUKAAN DI DAS CILIWUNG HULU – JAWA BARAT

Jurnal Teknologi Lingkungan Vol 13, No 1 (2012)
Publisher : Center for Environmental Technology - Agency for Assessment and Application of Technology

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Abstract

Aliran permukaan/limpasan (run off) merupakan salah satu variabel hidrologi yang sangat penting di dalam menunjang kegiatan pengembangan sumber daya air. Metode prediksi yang handal untuk menghitung jumlah dan laju limpasan yang berasal dari permukaan tanah dan bergerak menuju sungai di suatu DAS yang tidak dilengkapi alat ukur (ungaged watershed) adalah suatu pekerjaan yang sangat sulit dan memerlukanwaktu yang banyak. Penelitian ini dilakukan di DAS Ciliwung Hulu, yang merupakan daerah penting dalam kotribusi banjir di Jakarta. Untuk mengetahaui run off  yang terjadi, digunakan data curah hujan dan debit Tahun 2007-2009. Sebagai model, untuk mengetahui run off menggunakan peta penggunaan lahan, peta jenis tanah, dan topografi. Peta-peta tersebut diolah dengan menggunakan Arcview, sehingga didapatkannilai CN. Berdasarkan analisis perhitungan, besarnya debit mendekati 50% dari tebal hujan. Kondisi ini mengindikasikan bahwa kondisi DAS Ciliwung Hulu sudah tidak mampu lagi menyerap curah hujan dengan baik. Korelasi antara hasil prediksi run off model yang menggunakan CN dengan perhitungan run off observasi cukup baik. Hal ini menunjukkan bahwa metode Curve Number cukup dapat mepresentaskan hubungancurah hujan dengan aliran permukaan (run off). kata kunci : Run off observasi, run off model, curve number AbstractRun off (surface flow) is one of the most important hydrological variable in supporting the activities of water resources development. A reliable prediction method to calculate the amount and rate of runoff from the land surface caused by the rain that falls in a watershed that is not equipped with measuring devices (un gauge watershed) is a verydifficult job and requires a lot of time. The research was conducted in the watershed Ciliwung Hulu, which is an important area in relation to the incidence of flooding in Jakarta. Curve Number (CN) method can be used to predict the amount of runoff from a watershed. This model required input of rainfall; land cover maps; soil type maps,and topography. The maps are processed using Arc View software, so we get the value of CN. In this study, we used of rainfall and discharge data 2007-2009. Based on the analysis of calculation, known that amount of surface flow approaching 50% of rainfall depth. This condition indicates that the Ciliwung Hulu watershed conditions were not ableand proper to absorb of rainfall. The correlation between the results of run-off prediction models using CN with run-off observation was quite good. This indicated that the Curve Number method could be able to represent the relationship of rainfall with surface flow (run off) and also to predict runoff key words: Run off observation, run-off model, curve number