MATHEMATICAL MODELING OF RICE FIELDS AS RETENTION POND FOR REDUCTION OF PEAK FLOOD DISCHARGES

• Main Author: Plenita Agnindhira, Gracia
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/80621
• Institution: Institut Teknologi Bandung

Ricefield is one of many types of artificial wetlands which have high popularity in Indonesia culture, judging from the distribution of numbers in the main islands and high populated area across the country. In the other hand, the intensity characteristic of Indonesia rainfall is generally high which can cause the increase of surface runoff overflow or flooding probability. Based on its characteristic, ricefields can be assumed as an alternative form of retention ponds applied in sustainable urban drainage system. The purpose of this study is to perform mathematical modeling of ricefiled ability to reduce peak flood discharge and also to see the effectiveness of the reducing ability under the influence of several variables such as the variation of rainfall intensity, ricefield wetted area, as well as the structure of the ricefield. The modeling was done with level pool routing procedure by utilizing finite difference method to solve the differential equation of storage and outflow variable. Program used to run the model is MO – EXCEL completed by several visual basic application function. The inputs needed to run the model include water elevation in each outlet of ricefields and meteorological parameter within certain period of time with the dimension and soil characteristic of the ricefield. The output of the model will be displayed in the form of a graph which shows the difference between inflow and outflow hydrograph. The result of several scenarios run in the model suggest that the greater the intensity of the rainfall is, the reduction of peak flood discharge will become smaller. The wider the rice field dimensions are used, the capacity of flood peak discharge will be greater. While the structure of the composition of ricefield terraces will not significantly affects the effectiveness of ricefield ability to reduce peak flood discharge.