scholarly journals AN ANALYSIS OF DESIGN FLOOD DISCHARGE IN PARANGJOHO WATERSHED USING THE METHODS OF SYNTHETIC UNIT HYDROGRAPH (SUH) AND SOIL CONVERSATION SERVICE (SCS)

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Ridwan Abadi Akbar ◽  
Adwitya Bhaskara

<p align="center"><strong>Abstract.</strong></p><p>Floods always come suddenly and unexpectedly, and lots of people living in the flood-prone area can be the victims. As happened on February 2, 2020, a number of rice fields, roads, and houses belonging to the residents in the Parangjoho watershed, Eromoko District, Wonogiri, with 9.8-km river length and 32.59-km<sup>2</sup> area, was flooded due to heavy rain for some time which flushed the Eromoko area, therefore, the river flow could not accommodate the volume of water that entered and overflowed. This was what motivated researchers to calculate the design flood discharge to be able to carry out the flood control.</p><p>The methods of calculating the design flood discharge in the Parangjoho watershed used the Nakayasu Synthetic Unit Hydrograph (SUH) Method and the Soil Conservation Service (SCS) Method, using the rainfall data from the Bengawan Solo Central River Region at Parangjoho Station. The rainfall data used were from 2000 to 2019.</p>

2020 ◽  
Vol 22 (2) ◽  
pp. 146-151
Author(s):  
Nadya Kintantrie Maulana ◽  
Yeri Sutopo

Abstract: Various kinds of buildings in civil engineering require careful planning. For example, in the planning of a water building needed a method to calculate the design flood discharge before starting to plan the dimensions of the building to meet the effectiveness of the water structure. Design flood discharge can be determined using several hydrograph methods that have been used in water building planning in Indonesia. One of the popular hydrograph method used is the Nakayasu Synthetic Unit Hydrograph method. In this case, the design flood discharge is located in the Garang watershed, precisely in Semarang City, province of Central Java, using rainfall data for the past 16 years. Hydrological analysis is carried out first before determining the design flood discharge with a return period of 2, 5, 10, 25, and 50 years. The results of the design flood discharge using Nakayasu method respectively were 305,522 m3/s, 390,742 m3/s, 447,783 m3/s, 520,560 m3/s, and 574,912 m3/s.


2018 ◽  
Vol 6 (1) ◽  
pp. 29-44
Author(s):  
Gustama Gustama ◽  
Fadillah Sabri ◽  
Donny Fransiskus Manalu

A widely used method for analyzing river flow for flood forecasts is hydrograph unit. The hydrograph unit is a direct runoff hydrograph that can be created when there are AWLR record data, debit measurements and rainfall data. Synthetic Unit Hydrograph (SUH) is a unit hydrograph derived based on river data in the same watershed or nearby watershed but has the same characteristics, ie HSS Gama I, HSS Nakayasu, Limasan HSS, HSS Snyder and HSS SCS. Of the two hydrographs, there will be suitability of the hydrograph form that is going to be made. Sub territory of Pedindang  River Basin has four flood incidents, namely, date 23-24 February 2016; March 2-3, 2016; March 3-4, 2016; and date 5-6 March 2016. In the analysis of each flood event, the peak discharge of synthetic unit hydrograph is very different from the peak discharge of the measured unit hydrograph. The average peak discharge of synthetic unit hydrograph occurs in the range of 2 or 3 hours, while the measured unit hydrograph of Pedindang River occurs in the range of 7 or 8 hours. In four flood events it is stated that, HSS Gama I approaches RMSE value (validation <10%) to HST form of Pedindang River with value: RMSE incidence I (23,601%); RMSE incidence II (16.315%); RMSE incidence III (50,400%); RMSE incidence IV (22.322%). With this result, it is stated that there is no synthetic unit hydrograph model that has compatibility with the measured unit hydrograph of Pedindang River.


2020 ◽  
Vol 3 (2) ◽  
pp. 115-128
Author(s):  
Asta Asta ◽  
Nurjaya Nurjaya

The Kayan Watershed in Bulungan Regency is the largest river in North Kalimantan which has the potential for flooding in several irrigated points. Kayan River is a flood-prone area and prioritized to be handled immediately because there is already a smooth life for the community. Potentially need to know the great potential of flooding in the Kayan River. To find out the relationship between flood discharge and flood time, the Synthetic Unit Hydrograph calculation method is used. The aim is to determine the shape and results of peak discharge in Synthetic Unit Hydrograph Y (SUH). This study uses a debit calculation in the Kayan watershed using Snyder HSS a nd Nakayasu HSS. From the calculation results obtained Snyder SUH peak discharge of 118.0 m3/ sec at 73.85 hours, and Nakayasu SUH has a peak discharge of 109.35 m3 / sec at 54.09 hours.


BANGUNAN ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 1
Author(s):  
Gilang Id'fi

Abstrak:Permasalahan banjir seringkali melanda wilayah DAS Kali Ngotok setiap tahun. Masalah banjir pada umumnya disebabkan oleh perubahan tata guna lahan dan penurunan fungsi sungai yang ada di wilayah DAS Kali Ngotok serta sering terjadinya back water dari sungai-sungai yang bermuara di Kali Brantas pada saat mengalami debit maksimal. Untuk itu studi perbandingan debit puncak banjir perlu dilakukan karena belum adanya penelitian mengenai pengendalian banjir. Sehingga dilakukan penelitian mengenai analisis model hidrograf satuan sintetik. Metode hidrograf satuan sintetik yang digunakan adalah SCS, Snyder, dan Nakayasu. Data hujan yang digunakan adalah data hujan tahun 1998-2016 dari 14 stasiun hujan di wilayah DAS Kali Ngotok. Metode poligon Thiessen digunakan untuk mengetahui besaran hujan yang tersebar di wilayah DAS Kali Ngotok. Besaran hujan rata-rata yang turun di DAS Kali Ngotok dalam kurun waktu 1998-2016 sebesar 97.05 mm. Pada tahap pemodelan, pembagian sub catchment DAS dilakukan dengan membagi menjadi 5 sub DAS. Hasil pemodelan dengan metode SCS, Snyder, dan Nakayasu menunjukkan besaran debit untuk kala ulang 2 tahun, 5 tahun, 10 tahun, 20 tahun, 25 tahun, 50 tahun, 100 tahun, dan 200 tahun yang bervariasi. Data AWLR yang mendekati hasil pemodelan adalah data tahun 2014. Hasil kalibrasi hidrograf untuk metode SCS dengan kala ulang 25 tahun sebesar 0.88, untuk metode Snyder dengan kala ulang 25 tahun sebesar 0.74, dan untuk metode Nakayasu dengan kala ulang 25 tahun sebesar 0.43. Dengan demikian model hidrograf SCS dengan kala ulang 25 tahun mendekati dengan model hidrograf lapangan berdasarkan data AWLR yang ada serta sesuai dengan hasil pengamatan pada saat survey penduduk.Kata-kata kunci: DAS, Kali Ngotok, SCS, Snyder, NakayasuAbstract: Flood problems often hit the Ngotok River watershed every year. The problem of flooding is generally caused by changes in land use and a decrease in river functions in the Ngotok River watershed area as well as frequent back water from rivers which empties into Brantas River when experiencing maximum discharge. For that reason a comparative study of peak flood discharge needs to be done because there is no research on flood control. So that research is conducted on the analysis of synthetic unit hydrograph models. The synthetic unit hydrograph method used is SCS, Snyder, and Nakayasu. Rainfall data used is data from 1998-2016 from 14 rain stations in the Ngotok River watershed. The Thiessen polygon method is used to determine the amount of rain scattered in the Ngotok River watershed. The average rainfall in the Ngotok River watershed in the period 1998-2016 was 97.05 mm. In the modeling phase, the sub catchment division of the watershed is carried out by dividing it into 5 sub catchments. The modeling results using the SCS, Snyder, and Nakayasu methods show the amount of discharge for the return period of 2 years, 5 years, 10 years, 20 years, 25 years, 50 years, 100 years, and 200 years which varies. AWLR data approaching the modeling results are 2014 data. The hydrograph calibration results for the SCS method with a 25 year return period are 0.88, for the Snyder method with a 25 year return period of 0.74, and for the Nakayasu method with a 25 year return period of 0.43. Thus the SCS hydrograph model with a 25 year return period approaches the field hydrograph model based on the AWLR data that exists and is in accordance with the observations during the population survey.Keywords: Watershed, Ngotok River, SCS, Snyder, Nakayasu


2020 ◽  
Vol 4 (2) ◽  
pp. 126-137
Author(s):  
Aswar Amiruddin ◽  
Saparuddin Saparuddin ◽  
Triyanti Anasiru

Floods often occur in several regions in Indonesia. The problem is the flooding with its uncertain characteristics is one of the environmental problems that has not been handled optimally. The method of converting rain data into discharge data for flood analysis has been widely presented in previous studies. The methods used to analyze flood discharge also vary, starting from rational, empirical, statistical models to the unit hydrograph model. This research aims to determine the flood discharge design for return periods 2, 5, 10, 20, 25, 50, and 100 years in Tojo watershed, Tojo Una-una Regency using the synthetic unit hydrograph method of ITB-1. Research methods are data collection and data analysis. Data collection was carried out at several agencies and collecting from online sources. Results of this research design flood discharge that was analyzed by synthetic unit hydrograph of ITB-1 method. The maximum design flood discharge at Tojo watershed are 82.375m3/s for a 2-year, 98.21 m3/s for a 5-year, 104.77 m3/s for a 10-year, 111.83 m3/s for a 20-year, 113.3 m3/s for a 25-year, 118.87 m3/s for a 50-year, 123.86 m3/s for a 100-year return period


2021 ◽  
Vol 8 (2) ◽  
pp. 141
Author(s):  
Muhammad Rifaldi Mustamin ◽  
Farouk Maricar ◽  
Riswal Karamma

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


2021 ◽  
Vol 331 ◽  
pp. 07015
Author(s):  
Dian Pratiwi ◽  
Arniza Fitri ◽  
Arlina Phelia ◽  
Nabila Annisa Amara Adma ◽  
Kastamto

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.


2019 ◽  
Vol 8 (4) ◽  
pp. 5509-5514

The lacks of hydrograph data in the field has become the drawback of the hydraulic structure planning. However, such a conditional deficiency in particular, has urgently placed the Synthetic Unit Hydrograph (SUH) models to be very great utility. The Synthetic Unit Hydrograph (SUH) is a popular model that is used in many water resources designs especially in design flood analysis in ungagged watershed. One of the SUH that is usually used in Indonesia is Nakayasu SUH. This model is depended on the α parameter that is influencing the unit hydrograph ordinate and time base. This research intends to build a model of α parameter that is as the characteristic factor of part of watersheds in Indonesia. The methodology consists of observed unit hydrograph analysis for obtaining the α parameter in each watershed, to collect the characteristic data in each watershed, and then to formulate the α parameter model that is as the function of watershed characteristic. The result is formulation model of α that can be used to analyze the design flood in the watershed in Indonesia


2015 ◽  
Vol 1 (1) ◽  
pp. 15-28
Author(s):  
Ichsan Syahputra

Krueng Langsa  is a river crossing Langsa City the position is in the middle of residential and potentially catastrophic spills seasonal flooding. Krueng Langsa River watershed has an area of 126 km2, with a rainfall of 2300 mm / year and includes areas with relatively high rainfall. In the upper part of the river flow characteristics along the hills, while the central part of the narrowing of the river in the extreme. Hydrologic simulation based on rainfall data using HEC-HMS software obtained flood discharge of 59.30 m³ / sec. Passing the analysis of flood discharge capacity obtained on existing cross-section of 60.07 m³ / sec which is almost close to the value of the existing flood discharge based on the model HEC-HMS. HEC-RAS analysis results with simulation input Q2 years, to 140 pieces of the cross section illustrates that almost all river basins experienced flooding conditions (overflow), and only a few parts that are not experiencing flooding conditions. This is because the flood water level exceeds the elevation of the bank. Scenario flood control is done by normalizing the river, which enlarge the dimensions of the existing river with a wide cross-section of the river on average 20 m to 60 m and planning at the river levee embankment crest elevation +2.00 m and surveillance (freeboard) 0.50 m of surface water flooding . At the mouth of the river, starting from the point STA.0 + 000 to STA.2+ 000  planned use of the river revetment rock pile (Dump Stone). Both scenarios flood control can be recommended to reduce the flooding that occurred in the Krueng Langsa river.


Author(s):  
S. Samatan

Design flood discharge is one of the important parameters in the management of water resources, especially water resources utilization structures and water damage control structures. This parameter serves to determine the dimensions and capacity of the planned water structures. As an important reference, this design flood discharge must be carefully determined so that the planned building is effective and financially functional and economically efficient. This study aims to determine the design flood discharge using rainfall data which will be recommended as a reference for the design of a micro-hydro power plant building in Kaliwadas River, Pekalongan Regency, Central Java Province. The results of the analysis based on rainfall data are compared with estimates using discharge data to determine deviations resulting from the use of rainfall data. Frequency analysis is applied to both types of rainfall and maximum daily discharge data. Chi-Square and Kolmogorov-Smirnov tests were performed to test four distribution methods: Normal, Normal Log, Pearson Log III and Gumbel. Transformation of design rainfall into design discharge is done using the Snyder Synthetic Unit Hydrograph Method, by first optimizing the hydrograph parameter. The analysis shows that the design flood discharge using rainfall data is relatively lower than using discharge data with an average deviation of more than 15%. This deviation is expected to occur when the transformation of rainfall into discharge is influenced by various very complex parameters, especially changes in land cover and rainfall distribution that have not been fully accommodated. However, for watersheds with very limited discharge data, the use of rain data can be an option for establishing a design flood discharge.


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