Water Resources Engineering (Teknik Pengairan)

ABSTRAK Salah satu analisa penting dalam sebuah perencanaan, pengembangan, maupun pengendalian insfrastruktur keairan adalah analisa hidrologi. Ketepatan analisa hidrologi bergantung pada kualitas data hidrologi yang didapatkan dari pos hujan dan pos duga air dengan penempatan yang benar-benar mampu merepresentasikan keadaan daerah studi. Selain itu adanya pengaruh kejadian hujan terhadap debit, maka ketepatan analisa hidrologi seharusnya didukung dengan adanya hubungan yang berkaitan antara data pos hujan dan pos duga air. Pada studi ini evaluasi penempatan pos hujan dan pos duga air dilakukan berdasarkan pedoman WMO ( World Meteorological Organization ) dengan menghitung luasan kerapatan pengaruh setiap pos dengan poligon thiessen. Rasionalisasi dilakukan dengan pemodelan regresi metode Stepwise untuk mencari pos hujan yang memiliki korelasi tertinggi terhadap pos duga air. Hasil evaluasi dan rasionalisasi menunjukkan bahwa terdapat kombinasi dengan lima pos hujan yang memiliki ko...

In this research, the authors analyze the addition of bacterial producer of biological cement on sandy soil to increase its stability. Pseudomonas sp was injected into the soil to produce urease enzyme, which converts urea that reacted with water become ammonium and carbonate, causing calcite precipitation. Soil stability can be improved by the production of pore-filling materials and particle-binding materials through the calcite precipitation process. The aim of these applications is to improve the mechanical properties of soil that it will be more suitable for construction or environmental purposes. After bacterial inoculation, the experiment with variation of bacterial content concluded the best way to increase soil stability is inject 15% bacteria relative to total weight of soil. Highest permeability reduction is 73,73% and highest shear strength increation for cohesion is 6,84 with friction angle 44,46°. California Bearing Ratio test with 10 of hits generated that the treatment soil can proved a significant penetration stress changed. From Environmental Scanning Electron Microscopy test results of the inoculation sand test images and surface scan, the formed exopolysaccharide attached to the wall of the sand soil particles which expected will fill, patch, and close the pores between the sandy soil particles.

Untuk membawa air dari sumber air hingga ke petak-petak sawah diperlukan adanya saluran irigasi. Jika saluran irigasi yang telah ada belum memiliki tinggi muka air yang mencukupi untuk dialirkan ke saluran induk maka perlu adanya bangunan guna menaikkan tinggi muka air tersebut.

Spillway atau disebut dengan pelimpah merupakan bangunan air beserta instalasinya yang berfungsi untuk mengalirkan debit banjir yang masuk ke dalam waduk agar tidak membahayakan keamanaan bendungan terhadap overtopping dan gerusan di hilir. Dimana kapasitasnya ditentukan terutama berdasarkan debit banjir yang diperhitungkan akan melalui bangunan air. Pelimpah selain terdapat pada bendungan, dapat pula digunakan sebagai kelengkapan utama pada bendung, embung, kantong lahar, dan lain-lain. Dengan adanya pelimpah, elevasi muka air di hulu didesain tidak akan melampaui batas maksimum berkaitan dengan debit banjir rencana.

Perubahan alih fungsi lahan dari lahan hijau menjadi lahan pemukiman pada menyebabkan terjadinya limpasan permukaan di beberapa lokasi di Kota Sumenep. Kondisi eksisting saluran membutuhkan perubahan dimensi yang mampu menyalurkan limpasan yang terjadi. Penelitian ini bertujuan untuk mengetahui kapasitas saluran drainase yang ada (eksisting) terhadap curah hujan dengan debit rencana kala ulang 5 tahun dan menentukan pengendalian banjir yang dapat dilakukan di Kota Sumenep. Pemodelan dengan SWMM membandingkan kondisi jaringan drainase sebelum dan sesudah penerapan rehabilitasi saluran. Pada perhitungan kalibrasi model diperoleh nilai RMSE sebesar 0,139. Nilai tersebut menunjukkan bahwa nilai parameter yang digunakan dalam pemodelan mendekati variasi nilai observasi. Dari hasil perhitungan diperoleh kapasitas outlet 1 = 3,53 m3/dt; outlet 2 = 2,75 m3/dt; outlet 3 = 2,52 m3/dt; outlet 4 = 1,21 m3/dt; outlet 5 = 4,65 m3/dt; outlet 6 = 6,20 m3/dt; outlet 7 = 1,47 m3/dt; outlet 8 = 0,60 m3/dt; outlet 9 = 4,49 m3/dt. Jaringan drainase sekunder outlet 3 dan 7 mampu menampung limpasan curah hujan, sedangkan untuk jaringan drainase sekunder outlet 1, 2, 4, 5, 6 dan 8 tidak mampu menampung curah hujan dengan debit rencana kala ulang 5 tahun. Untuk mengurangi genangan tersebut, dibutuhkan rencana rehabilitasi saluran drainase sekunder pada masing-masing outlet dan alternatif pengalihan debit limpasan. Berdasarkan perbandingan antara tinggi muka air Sungai Marengan dan outlet saluran, outlet 4, 5, dan 6 mengalami arus balik (backwater) dari Sungai Marengan. Dimensi saluran baru yang telah direncanakan tidak hanya mampu menampung limpasan air hujan, tapi juga mampu menampung limpasan debit akibat dari pengaruh arus balik. Kata kunci: debit limpasan hujan, kapasitas saluran drainasi, SWMM ABSTRACT : A change in land use of green land into residential land in recent years has caused a runoff in several locations in the Sumenep city. Existing conditions require changes in dimensional channel which is capable of channeling the runoff that has occurred. This study aims to determine the capacity of the existing drainage channels towards the rainfall with 5-year flood discharge plan and determine the flood control that can be performed in the Sumenep city. Modeling using SWMM instrument by comparing the drainage channel conditions before and after the implementation of channel rehabilitation. From the model calibration calculation, the RMSE value obtained is at 0,139. This value indicates that the value of the parameters used in the modeling approaches the observed values variation. From the calculation it is obtained that

Land use changing in Sumenep city in recent years has caused runoff in several locations. Therefore, rehabilitations of existing channel to suit the surface runoff are needed. This paper presents capacity determination of existing drainage channels subjected to rainfall with 5-year flood discharge plan and consideration of sea tides effect to Marengan River which crossed Sumenep city. The proposed flood control methods in Sumenep city area was also discussed. The catchment of specified rural area was modelled using SWMM instrument to compare channel conditions before and after rehabilitation. Channel size and height of water level in channel due to rainfall together with the effect of backwater occurred in Marengan River caused by the sea tides was observed during the time. From the analysis, it was found that most of existing secondary drainage channels are uncapable to accommodate rainfall with 5-year flood discharge plan. From the available eight secondary drainage channels outlets, the last three outlets were subjected to reverse flows effect in Marengan River due to sea tides. In order to reduce the occurance of surface runoff inundation, secondary drainage channel rehabilitation was planned at each outlet, and these proven capable to accommodate rainwater runoff and reverse flow as well.

Dispersive clays have been identified as soils which highly erosive because they have a higher percentage of dissolve sodium in their pore water than ordinary clays. The dominant sodium ions increase the thickness of the diffused double water layer surrounding the individual clay particles. This causes the repulsive forces to exceed the attractive forces so that the individual clay particles go into suspension in the presence of water. Their detrimental effect on the performance of dams, canals has been recognized. Piping in earth dams which lead to the failure of dams due to the presence of dispersive clays has been identified in Australia, United States, South Africa and many countries throughout the world. This research presented the tests using various available methods to identify the degree of dispersive of embankment material for Duriangkang dam, the first estuary dam in Indonesia. Analyses to the results were also discussed. The decision not to include the suspected dispersive and moderate dispersive clays in the embankment of Duriangkang dam was taken in order to minimize the risk of eroded and piping progress in the dam body.

This study evaluated 100 raw milk samples for bacterial contamination. Milk samples were collected from 10 main regions of District Lahore and tested for total plate count (TPC), total coliforms and faecal coliforms, Escherichia coli, Staphylococcus aureus, Lactobacilli and Salmonella. The bacterial counts (cfu mL -1 ) were 2.

Spyware is one of the biggest emerging threats that can target both home users and organisations simultaneously. Lots of Anti-Spyware products are available in the market which can protect from Spyware threat. Existing research shows that Spyware causes financial loss and efforts are being made to test Spyware to propose the best Anti-Spyware products to the end users. This research focuses on different aspects of Anti-Spyware testing that the test should be conducted in real life environment in which the users operate. Anti-Spyware programs are selected by carefully researching through existing test result s conducted by different internet security companies. The products are evaluated and tested to propose the suitable products to the end users. Some recommendations are also proposed on the basis of this research to help end user to increase their Spyware security.

Cough airflow dynamics have been previously studied using a variety of experimental methods. In this study, real-time, noninvasive shadowgraph imaging was applied to obtain additional analyses of cough airflows produced by healthy volunteers. Twenty healthy volunteers (10 women, mean age 32.2612.9 years; 10 men, mean age 25.362.5 years) were asked to cough freely, then into their sleeves (as per current US CDC recommendations) in this study to analyze cough airflow dynamics. For the 10 females (cases 1-10), their maximum detectable cough propagation distances ranged from 0.16-0.55 m, with maximum derived velocities of 2.2-5.0 m/s, and their maximum detectable 2-D projected areas ranged from 0.010-0.11 m 2 , with maximum derived expansion rates of 0.15-0.55 m 2 /s. For the 10 males (cases 11-20), their maximum detectable cough propagation distances ranged from 0.31-0.64 m, with maximum derived velocities of 3.2-14 m/s, and their maximum detectable 2-D projected areas ranged from 0.04-0.14 m 2 , with maximum derived expansion rates of 0.25-1.4 m 2 /s. These peak velocities were measured when the visibility of the exhaled airflows was optimal and compare favorably with those reported previously using other methods, and may be seen as a validation of these previous approaches in a more natural setting. However, the propagation distances can only represent a lower limit due to the inability of the shadowgraph method to visualize these cough airflows once their temperature cools to that of the ambient air, which is an important limitation of this methodology. The qualitative high-speed video footage of these volunteers coughing into their sleeves demonstrates that although this method rarely completely blocks the cough airflow, it decelerates, splits and redirects the airflow, eventually reducing its propagation. The effectiveness of this intervention depends on optimum positioning of the arm over the nose and mouth during coughing, though unsightly stains on sleeves may make it unacceptable to some.

Resistivitas listrik dapat digunakan untuk mengidentifikasikan parameter geoteknik seperti kadar air, batas cair, batas plastis dan berat volume tanah. Telah diketahui bahwa nilai konduktivitas hidrolik dapat diprediksi berdasarkan nilai sifat fisik tanah, maka seharusnya nilai konduktivitas hidrolik tanah juga dapat ditentukan melalui pengujian resistivitas. Beberapa peneliti menjelaskan bahwa konduktivitas hidrolik tanah tidak jenuh berkorelasi dengan kurva karakteristik air-tanah (soil-water characteristic curve, SWCC), sehingga perkiraan nilai konduktivitas hidrolik menggunakan uji resistivitas sangat penting untuk dikembangkan dengan mengamati perilaku tanah. Penelitian ini mengkaji perubahan konduktivitas hidrolik tanah tidak jenuh berdasarkan pengujian resistivitas laboratorium. Hasil pengujian dibandingkan dengan metode empiris ) dan Campbel (1973. Hasil yang diperoleh menunjukkan bahwa nilai konduktivitas hidrolik tanah tidak jenuh berkorelasi cukup baik dengan kedua metode empiris yang digunakan.

In Kemuning Lor village -Jember regency -East Java, The local site of geology and topographic on ground motion during earthquake induced landslide were investigated using Horizontal to Vertical Spectra Ratio (HVSR). The microtremor measurements were performed at the landslide area on 82 free-field measurement having 20 x 20 m dense grid. The amplification factor (A m ) in 2-7 range and the soil natural frequency (f o ) in 1-3 Hz were obtained from the HVSR analysis. The f o value had changed with the topographic pattern. The bedrock surface might be estimated using the f o value. The A m highest value was found at the main scarp landslide and at the slope area having high topographic gradient. Variations of f o and Am parameters were indicated as surface soil parameter's variations. In general, the local geology effects is more dominant than the topography effect. The level of soil damage due to the local site effects at the landslide location was indicated by the vulnerability index (kg) and the effective shear strain (). Generaly, vulnerability index (kg) varied from 2.6 to 34.6 and the  values varied from 500 x10 -6 to 6700 x 10 -6 . This paper illustrates how the vulnerability index and the effective shear strain could be used to make preliminary assessment of the main scarp area failed during the earthquake.