VALIDATION OF DISHARGE DATA CASE STUDY: UPPER CITARUM RIVER BASIN

• Main Author: WINDATININGSIH , DESI
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/26514
• Institution: Institut Teknologi Bandung

Data validation is an examination process to ensure that hydrological data appropriate with the specified criteria and it is part of quality control. Validation technique will be designed to detect common errors that may occur and validation results will be designed to show the reason why the data values are flagged. The problem is the condition of availability of hydrological data, especially the discharge data is generally still low. The quality of discharge data can be classified as a low quality data caused by random errors, inhomogeneous data or missing data or incomplete data. Inhomogeneous data can be occur due to the equipment malfunction, error during recording data, hydrological phenomena which occurs due to natural changes and human activities (like land use change, water utilization, etc). Therefore it is necessary to take the validation test to the discharge data. <br /> <br /> This study aimed to analyze the homogeneity and trend methods, to detect trend of the data, to provide the information about the data quality conditions with category. The methods used in this study were collected and selected the discharge data by length > 30 years, checking the temporal data with visual, calculation of Base Flow Index (BFI), homogeneity test with Pettitt and T methods at the significance level of 5%, trend test with Mann Kendall and Spearman methods at the significance level of 5%, evaluation of comparison of the validation test results, conclusions and recommendations of the data validation test results with the criteria. <br /> <br /> Validation test of the discharge data in Upper Citarum river basin was choosen for 4 selected water level stations, there are Citarum-Nanjung, Cigulung-Maribaya, Ckapundung-Maribaya and Cikapundung-Gandok. The results of homogeneity test with Pettitt and T method at the significance level of 5% show that Pettitt method is better applied in this study since its data was not normally distributed, where the advantage of Pettit method that can be examine the data without assumptions to be normally distributed. The results of trend test with Mann Kendall and Spearman methods at the significance level of 5% show the result of the significance of both methods is relatively similar, because the two trend tests have non parametric statistical methods, the power of these tests are relatively similar depend on the significance level, size of data sample, and distribution type. <br /> <br /> About the data conditions in the Upper Citarum River Basin, the results test show that the Citarum-Nanjung station has the good data in homogeneity and trend, therefore the data condition of Citarum-Nanjung station is categorized as Good. Cigulung-Maribaya station has the bad data ini homogeneity, so it cannot be evaluated for the trend test, need to take the specific study for repair the data in that station to increase the quality of data, therefore the data condition of Cigulung-Maribaya station is categorized as Bad. Cikapundung-Maribaya station has the moderate data in homogeneity, and has an increased trend of discharge during the 1980s also decrease trend of BFI in the period of 1990-2013, this indicates that the effect of land use change at that period. Cikapundung-Gandok station has the moderate data in homogeneity and has an increased trend of discharge in the period of 2000-2013 and has neutral trend (no trend) of BFI, this indicates that the effect of land use change. Therefore the data conditions of Cikapundung-Maribaya and Cikapundung-Gandok stations are categorized as Moderate. <br /> <br /> The analyzed result in this study indicated that both homogeneity and trend of discharge data at Upper Citarum river basin were not uniform. The trend of discharge at the Cikapundung sub basin increased significantly in the 1980s and decreased for the trend of BFI at the Cikapundung-Maribaya station in the period of 1990-2013. This indicated that occur the effect of land use change at Cikapundung sub basin.