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Journal : TEKNIK

PENYELIDIKAN POLA ALIRAN EMBUNG SAMIRAN DENGAN UJI MODEL HIDROLIK FISIK Ari Wulandari, Dyah; Kirno, Kirno
TEKNIK Volume 31, Nomor 1, Tahun 2010
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2869.163 KB) | DOI: 10.14710/teknik.v31i1.1753

Abstract

Samiran Dam is located in Grawah river, Boyolali Regency, Central Java Province. The aim of Samiran Damis for service water supply. The hydraulic model test are conducted for clarifying the appropriateness ofhydraulic design, to perfect and optimize the hydraulic design of the spillway. One of the main objective is tostudy the flow pattern approaching spillway, at spillway, stilling bazin and river in the downstream of thestilling bazin.The detail model is made as three dimensional model, covering the part of reservoir, spillway, stilling bazin andriver in the downstream of spillway. The hydraulic model test was carried out in The Hydraulic Laboratory ofExperimental Station for River in Surakarta.Base on the study result then there are necessary to modified design of the stilling bazin and to add groundsillconstruction at the river in the downstream of the stilling bazin
Keakuratan Prediksi Inflow Waduk Dengan Neraca Air Waduk Wulandari, Dyah Ari; Budieny, Hary; Kurniani, Dwi
TEKNIK Vol 37, No 2 (2016): (Desember 2016)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (287.872 KB) | DOI: 10.14710/teknik.v37i2.12613

Abstract

Dalam perhitungan inflow waduk sering digunakan persamaan neraca air waduk yang menggunakan data seri laporan harian operasi waduk, evaporasi dan curah hujan diwaduk, dan lengkung H-V-A waduk. Pada pengamatan data series laporan harian operasi waduk dan pengukuran kapasitas tampungan waduk, dapat terjadi kesalahan yang disebabkan karena kesalahan faktor manusia maupun faktor alat, hal ini akan menyebabkan kesalahan pula pada besarnya inflow waduk yang dihasilkan. Lebih lanjut di dalam perencanaan, data series inflow waduk ini diperlukan sebagai input pada pemodelan optimasi operasi waduk dan sedimentasi waduk, sehingga keakuratan datanya sangat diperlukan. Tujuan penelitian ini adalah untuk mengevaluasi tingkat akurasi penggunaan neraca air waduk dalam memprediksi inflow waduk. Untuk mengetahui tingkat akurasi dilakukan dengan membandingkan antara inflow waduk dari anak sungai hasil pengukuran dan hasil hitungan dengan persamaan neraca air waduk. Kemudian dilakukan variasi periode pengukuran dan kurva H- V-A yang digunakan. Berdasarkan penelitian yang dilakukan maka pada periode perhitungan yang lebih lama menghasilkan tingkat error yang lebih kecil. Pemakaian kurva waduk yang berbeda menghasilkan inflow yang berbeda. Tingkat error yang didapat masih cukup besar, diatas 30 %, sehingga perhitungan inflow waduk dari anak sungai dengan menggunakan metode neraca air waduk kurang akurat. [Title: Accuracy of Reservoir Inflow Prediction Using Reservoir Water Balance] In the calculation of reservoir inflow often used reservoir water balance equation using the data series of daily reports reservoir operation, evaporation and precipitation, and H-V-A curve. In observation of the data series of daily reports of reservoir operation and measurement of reservoir storage capacity, the errors may occur due to human error factor and factor appliance. This will cause an error on the reservoir inflow generated. Further, in the planning, this series data of reservoir inflow is required as input to the modeling of reservoir operation optimization and reservoir sedimentation, so the accuracy of the data are required. The purpose of this study was to evaluate the use of the reservoir water balance accuracy rate in predicting inflow. To determine the level of accuracy, the effort is done by comparing the inflow tributary reservoirs of measurement and the count with the reservoir water balance. Then perform variations of the measurement period and curves H-V-A is used. Based on the research conducted in the period longer calculation produces a smaller error. The different H-V-A curve results in the different inflow. Error rate obtained is still quite large, above 30%, so the calculation of tributary inflow reservoirs using reservoir water balance method is less accurate.  
Analysis of Initial Impoundment Using the F.J. Mock Flow Discharge Model at Pamukkulu Dam Nugraha, Hendy Adiyat; Wulandari, Dyah Ari; Suharyanto, Suharyanto
TEKNIK Vol 46, No 2 (2025) April 2025
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v46i2.67500

Abstract

The construction of a dam consists of several stages, including construction preparation, construction planning, construction execution, and initial reservoir impoundment. This study aims to determine the duration of the initial impoundment of the Pamukkulu Reservoir during dry, normal, and wet years using the F.J. Mock water availability method. Water losses in this study include reservoir water release through the bottom outlet to meet irrigation water demand at a rate of 0.3 m³/s and reservoir evaporation. The calculation of the impoundment duration is based on the monthly accumulation of volume until reaching the total storage volume of 82.57 million m³ at a normal water level elevation of +126.00 meters. The analysis results indicate that the duration of the initial impoundment of the Pamukkulu Reservoir is 11.16 months (335 days) in a dry year with an inflow reliability of 31.81%, 8.66 months (260 days) in a normal year with an inflow reliability of 63.63%, and 7.63 months (229 days) in a wet year with an inflow reliability of 77.27%. The study concludes that the Pamukkulu Dam will reach its normal water level storage volume in December (first period) during a wet year classification.
Analysis of Water Availability at Margatiga Dam Setyawanto, Ega Rizky; Wulandari, Dyah Ari
TEKNIK Vol 46, No 2 (2025) April 2025
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v46i2.67856

Abstract

A dam is a structural construction built to retain or store water and serves to distribute water for raw water supply, irrigation, and hydroelectric power generation. Margatiga Dam is the third and most downstream dam in the Sekampung River Cascade Dam System in Lampung Province. It functions to supply irrigation and raw water as well as to control floods. To meet water demand, an analysis of water availability is necessary to determine the difference between water availability and demand. This study aims to determine the water availability discharge during wet, normal, and dry years at Margatiga Dam. The study uses satellite rainfall data calibrated with ground station rainfall data from 2001 to 2023. The methods used include satellite rainfall data correction, potential evapotranspiration analysis using the modified Penman method, flow discharge analysis using the F.J. Mock method, and reliable discharge analysis using the Weibull method. The results show that the water availability discharge at Margatiga Dam is 13.96 m³/s in a wet year, 10.34 m³/s in a normal year, and 8.13 m³/s in a dry year.
Evaluation of Soil Water Assessment Tool (SWAT) Model Accuracy in Estimating Erosion and Sedimentation Rates in the Sutami Reservoir Watershed Wijaya, Hendri; Wulandari, Dyah Ari; Suripin, Suripin
TEKNIK Vol 46, No 2 (2025) April 2025
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v46i2.67929

Abstract

The storage capacity of the reservoir is affected by poor management of the Watershed (DTA), which in turn influences erosion and sedimentation levels. In 1972, the erosion rate at Sutami Reservoir was 0,18 mm/year, rising to 1.44 mm/year by 2022. This data reflects a significant increase in the erosion rate within the Sutami Reservoir watershed, highlighting the need for effective watershed management modeling. The Soil and Water Assessment Tool (SWAT) is commonly used for watershed management assessment. This study aims to predict erosion and sedimentation rates using SWAT and evaluate the accuracy of its simulations through calibration and validation. The simulation results from SWAT show that the total erosion rate is 5,280.45 tons/ha/year, with a total sedimentation of 11,662,851.94 tons/year. Additionally, These results were compared with an analysis using the USLE method, which indicated an erosion rate of 5,178.98 tons/ha/year and sedimentation of 11,060,798.14 tons/year. The comparison of both methods showed similar outcomes, suggesting that the SWAT model provides reasonably accurate predictions. The calibration process, using observed discharge data from 2022 and SWAT-simulated discharge, yielded an NSE value of 0.778, classified as 'very good.' On the other hand, validation using discharge data from 2023 and SWAT-simulated discharge yielded an NSE value of 0.660, classified as "good." Based on these results, the SWAT simulation offers a reliable representation of calibration and validation, making it an appropriate model for this study.