Rainfall-Runoff Simulation Using HEC-HMS Model in the Benanain Watershed, Timor Island

Abstract

Floods in a watershed area are caused by reduced water recharge due to changes in land use, increasing their discharge volume. Benanain watershed is an extensive area with many tributaries. Watershed morphometrics provides initial information about the hydrological behavior and the hydrograph shape of flooding in these areas. Furthermore, rainfall-runoff modeling uses as a unit to approach the hydrological values of the flooding process. This study determines the physical characteristics of the Benanain watershed based on curve number (CN) values, land cover, peak discharge, and peak time. It was conducted on the Benanain watershed with 29 sub-watersheds covering 3,181.521 km2. Data were collected on the rainfall experienced for 13 years from 1996 to 2008 and analyzed using the Log Pearson Type III method, while the HEC HMS model was used for flood discharge analysis. HEC-HMS model must calibrate by adjusting the model parameter values until the model results match historical data such as initial abstraction, lag time, recession, baseflow values, and curve number. The results show that the curve number values range from 56.55 - 73.90, comprising secondary dryland forest and shrubs. Moreover, the rock lithology in the Benanain watershed is dominated by scaly clay and other rock blocks. This means the area has low to very low permeability, which affects the volume of runoff. The return period of a 1000-year flood discharge obtained a peak of 5,794.50 m3/s, with a peak time of ± 14 hours. Morphometry of the Temef watershed with large catchment, radial shape pattern, an average of steep slope river, and meandering affects the peak of flood discharge hydrograph and the peak time of the flood.

Analyzing Green Building of Appropriate Site Development Requirements in High Rise Building

“…The term "site landscape" refers to the physical features and characteristics of a specific site or location, including topography, vegetation, land use, and other natural or human-made features. It encompasses all visual and functional aspects of the area, as well as ecological and aesthetic characteristics (Bunganaen et al, 2021). Analyzed by measuring the area of soft landscape area with vegetation type in accordance with Ministerial Regulation PU.5/PRT/M/2008 and the use of cultivated local vegetation.…”

Pengaruh Distribusi Hujan Terhadap Perhitungan Debit Banjir Pada Daerah Rawa Das Martapura

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Calibration Analysis of Rain Discharge Modeling in the Kalibodo Watershed Using Hec-HMS

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