Hydrological Analysis In Selecting Flood Discharge Method In Watershed Of Kelara River

For Engineers involved in planning and construction of water resources building, hydrology becomes very important data. In terms of planning stage in water resources especially waterworks, it is known that design flood discharge closed to field realistic conditions is often needed in order that a planned construction is able to control flood discharge. Several previous researches in choosing flood discharge selection method have diverse depending on observed watershed. One method in determining selected flood discharge by verification using Creager diagram, by comparing discharge calculation results of several Synthetic Unit Hydrograph (SUH) with infrastructure flood discharge (AWLR result) in observation point. This research aims to obtain the most suitable synthetic unit hydrograph and close to analysis result of measured discharge frequency, and Creager diagram in Kelara watershed (DAS). Based on the calculation of design flood discharge according to rainfall data using synthetic unit hydrograph of Nakayasu, ITB I, ITB II, and SCS (HEC-HMS) as well as the calculation of design flood discharge according to collected data, it is concluded that the synthetic unit hydrograph method closest to design flood discharge with measured discharge rate and Q1000 rate of Creager diagram is SCS. Flood discharge rate obtained according to HSS SCS method using HEC-HMS 4.8 application in period of 2 years is 658,40 m3/s, 25 years is 682,70 m3/s, 50 years is 787,00 m3/s, 100 years is 885,70 m3/det, and 1000 years is 1202,60 m3/s

Assessment of the empirical methods for the development of the synthetic unit hydrograph: a case study of a semi-arid river basin

This study aims to assess various empirical synthetic unit hydrograph (SUH) methods and find the best method. Ideally, each river should have a definite rain gauge station (RGS) to get sufficient rainfall data that is available for carrying out meaningful analysis. The provisions of Indian Standard (IS) 4987:1994 determined the optimum number of RGS. In the absence of RGS, the SUH is recommended. SUHs have been developed using various methods such as Snyder's, Taylor and Schwarz, Soil Conservation Service, Mitchell's and Central Water Commission (CWC). In the present study, the Rel River Basin (RRB) is considered as the study area which has two existing RGS. IS 4987:1994 suggested that four RGS are required for more reliable rainfall data. Various efficiency criteria such as Correlation Coefficient, Pearson Coefficient, Nash Sutcliffe Efficiency, Index of Agreement, Normalized Root Mean Square Error, Mean Absolute Error, Root Mean Square Error and Kling-Gupta Efficiency have been used to compare SUH methods. The ranking of SUH methods was reported based on the compound factor (CF) through efficiency criteria. The 1.125 CF was observed as the minimum for the CWC method and recommended for determining peak discharge and timing for the study area.

Analysis of Cross-Sectional Capacity of the Jambi River in the Muaro Jambi Temple About Various Times of Flooding Using HEC-RAS Software

Jambi River is one of the rivers located in the Muaro Jambi Temple Complex Area, Muaro Jambi Regency, Jambi Province. Muaro Jambi Temple is one of the tourist attractions in Jambi Province. This study aims to find the capacity of Jambi River tested by planned flood discharge utilizing (synthetic unit hydrograph) HSS Nakayasu method for a return period of two, five, ten, twenty-five, fifty and hundred years. HEC-RAS software used to analyse the water level in the Jambi River towards the flood potential that causes the submerging of the Kedaton Temple building. This research used the log Pearson type III method to calculate the planned rain return period and used the Nakayasu synthetic unit method to calculate the planned flood discharge. The analysis showed that the Jambi River could not load the flood discharge in the five, ten, twenty-five, fifty, and one hundred years return period at several measurement points: river sta-1, river sta-2 and river sta-5. The floodwater level did not cause the Kedaton Temple building to be flooded from the simulation result

Analisis Hidrograf DAS Poso dengan Metode Hidrograf Satuan Sintetis Snyder dan Hidrograf Satuan Sintetis Soil Conversation Service (SCS)

The Poso River is a river located in Poso Regency, Central Sulawesi Province, which has a length of 74.58 km, and watershed area of 1092.810 km2. Energy in the Poso River is used for hydroelectric power plant (PLTA). With the construction of the Poso hydropower plant, maximum flood discharge data is needed for the prevention of Poso hydro power plant safety. In calculating the flood discharge, the method used is a synthetic unit hydrograph. Synthetic unit hydrograph is a graph of the relationship between flow rate (Q) and time (t). In this study, the method used to calculate the designed flood discharge is the Snyder synthetic unit hydrograph method and the Soil Conversation Service (SCS) synthetic unit hydrograph. The aims of this study are to determine the largest flood discharge value and to determine the hydrograph shapes of the two methods. The parameters that will be obtained from both methods are peak time (Tp), base time (Tb) and peak discharge (Qp). From the analysis it can be found that in the Snyder SUH method, the peak time (Tp) is 12.616 hours, the base time (Tb) is 67.276 hours with a peak discharge (Qp) of 21.672 m3sec. Whereas in the SCS SUH method, the peak time (Tp) is 10.954 hours, the base time (Tb) is 57.268 hours with a peak discharge (Qp) of 20.751 m3/sec. The result demonstrates the result that the largest flood discharge has occurred in the Snyder SUH method.

ANALISIS DEBIT PUNCAK PADA DAS AIR MANNA BAGIAN HILIR MENGGUNAKAN PENDEKATAN METODE HIDROGRAF SATUAN SINTETIS (HSS) SNYDER DAN HEC-RAS 5.0.7

Floods is a disaster which is one of the causes of failure of watershed managemen. High rainfall is also a factor in flooding. As a result the river cross section is not able to accommodate the flow of water and cause the river to overflow. This research was conducted to determine the amount of peak discharge Sub-DAS Air Manna Bagian Hilir and identify areas prone to flooding. This study uses a synthetic unit hydrograph (HSS) Snyder and HEC-RAS 5.0.7. Hydrological analysis results obtained from the peak discharge at Sub-DAS Rindu Hati using HSS Snyder for a return period of 2, 5, 10, 25, 50 and 100 yearsthat is 743,627 m3/sec, 839,491 m3/sec, 897,761 m3/sec, 962,599 m3/sec, 1008,717 m3/sec, and 1052,800 m3/sec with a peak time of 5,915 hours. After analysis using software HEC-RAS 5.0.7, DAS Air Manna no longer able to accommodate flow rates occur.

PEAK DEBIT ANALYSIS USING SYNTHETIC UNIT HYDOGRAPHIC METHOD ITB 1 AND HEC-RAS VERSION 5.0.7 (Case Study of Manna Downstream watershed)

Flooding is a natural disaster caused by the discharge or volume of water that flows in a river exceeds its stream capacity. One of the causes of the flood is high rainfall. The discharge of a river flow depends on the rainfall that falls in a watershed. The purpose of this study was to determine the peak discharge due to the intensity of rainfall in the downstream of Air Manna Watershed and determine the point that will undergo runoff on the Air Manna river flow. This study used Synthetic Unit Hydrograph (HSS) ITB 1 method and analyzed used HEC-RAS 5.0.7. From the result of hydrological analysis used the HSS ITB 1 method, it was found out the peak discharge in the downstream of Air Manna Watershed for return periods 2, 5, 10, 25, 50 and 100 years was 1322.21 m3/s, 1492.94 m3 /s, 1594 12 m3 /s, 1712.20 m3/s, 1794.33 m3 /s, and 1872.85 m3/s. After analyzing used HEC-RAS 5.0.7 software, Air Manna river was unable to accommodate the flow rate that occurred and undergo runoff along the flow.

Analysis of urban flood using synthetic unit hydrograph (SUH) and flood mitigation strategies along way Halim River: a case study on Seroja street, Tanjung Senang District

In the urban area, flooding becomes the most common disaster that has not been resolved until today. The utilization of river border area into housing and lack of absorption area becomes the trigger factor of urban flooding, as what is happening around Way Halim River on Seroja street. In this area, floods often happen during the rainy season, with the latest events recorded on January 21st, 2021. Analysis of flood intensities and discharges can be parameters for the decision-making of flood mitigation strategies. This study aims to analyze the flood discharges along Way Halim River, Seroja street by comparing the flood discharges resulting from three analysis methods of Synthetic Unit Hydrograph (SUH) including Gama I SUH, Nakayasu SUH, and Snyder SUH. Finally, suitable flood mitigation strategies were also proposed in this study based on the flood discharges and rain intensities. The results showed that Nakayasu SUH had the highest peak flood discharge than Snyder SUH and Gama I SUH. Based on the results of the investigation of land suitability; and analysis of rainfall intensities and flood discharges, the proposed flood mitigation in Seroja street is by installing biopore infiltration holes along Seroja street for storing water and reducing the risk of flooding in the area.