STATISTICAL ANALYSIS OF RAINFALL DATA AND ESTIMATION OF PEAK FLOOD DISCHARGE FOR UNGAUGED CATCHMENTS

Banjir merupakan salah satu bentuk bencana alam yang hingga saat ini masih belum dapat diselesaikan. Dampak banjir tidak hanya kerugian infrastruktur berupa jalan dan fasilitas umum akan tetapi kerugian materil menjadi bagian dari dampak yang merugikan bagi masyarakan. Padahal, bagi sebagian warga di Semarang dan Kabupaten Demak, banjir menjadi persoalan rutin pada musim penghujan. Daerah yang menjadi langganan banjir di Demak yaitu daerah Sayung, Karang Asem dan Mranggen. Banjir di daerah tersebut sulit diatasi bahkan semakin lama persoalan banjir tersebut semakin parah dan meluas. Dengan demikian penelitian ini bertujuan untuk mengetahui perbandingan perkiraan debit puncak banjir melalui dua metode yang berbeda. Berdasarkan pada hasil maka mitigasi bencana juga dapat ditingkatkan. Metode dalam penelitian ini menggunakan metode Nakayasu dan FSR Jawa Sumatera untuk mengukur debit puncak banjir dengan menggunakan rentang data curah hujan 10 tahun. Adapun hasil analisis menunjukkan bahwa debit banjir yang dianalisis dengan menggunakan metode Nakayasu menghasilkan debit banjir lebih besar daripada analisis debit banjir menggunakan FSR Jawa Sumatera. Hasil analisis dengan menggunakan metode Nakayasu diperoleh nilai terbesar untuk Sungai Penggaron 270,4 m3/detik. Sungai Dombo Sayung 296,4 m3/detik dan Sugai Dolok 332,2 m3/detik. Adapun, untuk Metode FSR Jawa Sumatera diperoleh nilai terbesar untuk Sungai Penggaron 112,7 m3/detik. Sungai Dombo Sayung 239,7 m3/detik dan Sugai Dolok 632,1 m3/detik.Kata kunci : debit banjir; dombo sayung; FSR Jawa Sumatera; nakayasu ABSTRACTFlooding is a form of natural disaster that has yet to be resolved. The impact of flooding is the loss of infrastructure in roads and public facilities, but a material loss is part of the community's detrimental impact. For some residents in Semarang and Demak Regency, flooding is a routine problem during the rainy season. Areas that are regularly flooded in Demak are Sayung, Karang Asem, and Mranggen. Floods in the area are challenging to overcome, even if flooding is getting worse and broader. Thus this study aims to determine the comparison of the estimated peak flood discharge through two different methods. Based on the results, disaster mitigation can also be improved. This study used Nakayasu and Java Sumatera FSR to measure the peak flood discharge using a ten-year rainfall data range. The analysis results show that the flood discharge analyzed using the Nakayasu method produces a more massive flood discharge than the flood discharge analysis using the Java Sumatra FSR. The analysis results using the Nakayasu method obtained the most significant value for the Penggaron River 270.4 m3/second. Sungai Dombo Sayung 296.4 m3/second and Sugai Dolok 332.2 m3/second. Meanwhile, for the Java Sumatra FSR Method, the most significant value was obtained for the Penggaron River 112.7 m3/second. Sungai Dombo Sayung 239.7 m3/second and Sugai Dolok 632.1 m3/second.

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Peak Flood Discharge Confidence Limits

Journal of the Hydraulics Division ◽

10.1061/jyceaj.0001932 ◽

1969 ◽

Vol 95 (1) ◽

pp. 161-174

Author(s):

Richard M. Shane ◽

Walter R. Lynn

Keyword(s):

Confidence Limits ◽

Flood Discharge ◽

Peak Flood

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Geospatial Modelling of Watershed Peak Flood Discharge in Selangor, Malaysia

Water ◽

10.3390/w11122490 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2490 ◽

Cited By ~ 1

Author(s):

Ryan Cheah ◽

Lawal Billa ◽

Andy Chan ◽

Fang Yenn Teo ◽

Biswajeet Pradhan ◽

...

Keyword(s):

Hydrological Modeling ◽

Estimation Methods ◽

Coefficient Of Determination ◽

Storm Event ◽

Storm Events ◽

Unit Hydrograph ◽

Runoff Simulation ◽

Flood Discharge ◽

Geospatial Modelling ◽

Peak Flood

Conservative peak flood discharge estimation methods such as the rational method do not take into account the soil infiltration of the precipitation, thus leading to inaccurate estimations of peak discharges during storm events. The accuracy of estimated peak flood discharge is crucial in designing a drainage system that has the capacity to channel runoffs during a storm event, especially cloudbursts and in the analysis of flood prevention and mitigation. The aim of this study was to model the peak flood discharges of each sub-watershed in Selangor using a geographic information system (GIS). The geospatial modelling integrated the watershed terrain model, the developed Soil Conservation Service Curve Cumber (SCS-CN) and precipitation to develop an equation for estimation of peak flood discharge. Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS) was used again to simulate the rainfall-runoff based on the Clark-unit hydrograph to validate the modelled estimation of peak flood discharge. The estimated peak flood discharge showed a coefficient of determination, r2 of 0.9445, when compared with the runoff simulation of the Clark-unit hydrograph. Both the results of the geospatial modelling and the developed equation suggest that the peak flood discharge of a sub-watershed during a storm event has a positive relationship with the watershed area, precipitation and Curve Number (CN), which takes into account the soil bulk density and land-use of the studied area, Selangor in Malaysia. The findings of the study present a comparable and holistic approach to the estimation of peak flood discharge in a watershed which can be in the absence of a hydrodynamic simulation model.

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Quantifying the contribution of flood intensity indicators with the projection pursuit model

Hydrology Research ◽

10.2166/nh.2017.038 ◽

2017 ◽

Vol 49 (1) ◽

pp. 60-71 ◽

Cited By ~ 2

Author(s):

Lina Wang ◽

Yanqing Lian ◽

Xiaohong Chen

Keyword(s):

Southern China ◽

Projection Pursuit ◽

Flood Events ◽

Flood Duration ◽

Flood Discharge ◽

Wujiang River ◽

Flood Volume ◽

Projection Pursuit Model ◽

Flood Intensity ◽

Peak Flood

Abstract Identifying the various factors that affect the intensity of a flood event, such as its duration and volume, is essential for strategic planning and flood management. Further, quantifying the impacts of these major factors on flood intensity using the contribution rate is essential, but technically challenging. In this study, the authors have adopted the projection pursuit model to quantify the contribution rates of peak flood stage and peak flood discharge, flood duration, and total flood volume (the maximum 12-, 24-, and 72-hour flood volumes) in the Wujiang River in Southern China. This study showed that peak flood discharge and total flood volume were the two dominant factors impacting flood intensity. Although flood duration can be a major factor for some flood events, it contributed the least to flood intensity for most of the historic flood events studied. Likewise, the maximum 24-hour and 72-hour flood volumes contributed little to flood intensity. Findings from this study not only demonstrated the successful adoption of the projection pursuit model for contribution rates, but also provided critical information for planning and managing the regional hydraulic resources in the Wujiang River.

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Assessment of droughts and their linkage to environmental flow conditions over a large Indian river basin

10.5194/egusphere-egu2020-1048 ◽

2020 ◽

Author(s):

Sabyasachi Swain ◽

Surendra Kumar Mishra ◽

Ashish Pandey

Keyword(s):

Standardized Precipitation Index ◽

Environmental Flow ◽

Rainfall Data ◽

Severe Drought ◽

Ungauged Catchments ◽

Mk Test ◽

Entire Duration ◽

Increased Risk ◽

Indian River ◽

Meteorological Droughts

<p>A robust characterization and risk assessment of meteorological droughts is the need of the hour considering its pervasiveness and consequences; however, their precise physical quantification is a difficult geophysical endeavor. This becomes a serious issue for India, having 18% of the world&#8217;s population and 4% of global freshwater, out of which 83% is used in agriculture. In this study, a detailed spatiotemporal assessment of the meteorological droughts characterized by standardized precipitation index (SPI) at annual scale is carried out over the Narmada Basin, India using the monthly rainfall data from 24 stations for 63 years (1951- 2013). The entire duration was divided into two epochs of 31 years (i.e. 1951-1981 and 1982-2012) for a comparative assessment of drought characteristics. The non- parametric Mann- Kendall (MK) test is applied to investigate the trend of droughts. Further, to predict the environmental Flow (EF) conditions from rainfall data only, the linkage of SPI with the average annual flow (%AAF) is examined over four sub-catchments (Mohegaon, Hridaynagar, Manot, and Sher) of the basin. The results reveal that the Narmada basin is prone to droughts with a frequency of once in 3 to 5 years. The frequency and severity of droughts have significantly increased in 1982-2012 as compared to 1951-1981. The severity of recent droughts shows a more widespread aerial extent in the region. The MK test results indicate an increasing trend in the droughts over most of the stations. An exquisite agreement between SPI and %AAF (used to describe the EF condition) is observed with R<sup>2</sup> ranging from 0.757 to 0.988, which shows that coupling SPI with %AAF can be effective for ungauged catchments. This study suggests that appropriate measures must be taken for better management of the water resources in the basin, and also for mitigation droughts, considering the increased risk of the severe drought events in recent decades.</p>

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Statistical Analysis of the Flood Discharge of the Shinano River Flow Discharge and Evaluation of the Yokota-Gire Flood Flow

JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES ◽

10.3178/jjshwr.18.362 ◽

2005 ◽

Vol 18 (4) ◽

pp. 362-369

Author(s):

Kazuo TAKASHIMA ◽

Fumito MURATA ◽

Norio HAYAKAWA

Keyword(s):

Statistical Analysis ◽

River Flow ◽

Flow Discharge ◽

Flood Discharge ◽

Flood Flow

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Features of the Maximum Water Flows of the Arpa River Under Modern Conditions

E3S Web of Conferences ◽

10.1051/e3sconf/202133302006 ◽

2021 ◽

Vol 333 ◽

pp. 02006

Author(s):

Varduhi Margaryan ◽

Levon Azizyan ◽

Amalya Misakyan ◽

Ekaterina Gaidukova ◽

Gennady Tsibul’skii ◽

...

Keyword(s):

Actual Data ◽

Water Flows ◽

Flood Discharge ◽

Maximum Water ◽

Monitoring Center ◽

The Republic ◽

Discharge Distribution ◽

Peak Flood

The paper discusses the main regularities of the peak flood discharge distribution in modern conditions, using actual data of Hydrometeorology and Monitoring Center SNCO with Ministry of Environment of the Republic of Armenia on the peak flood discharge of the river Arpa.

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Increasing Effectiveness of The Urban Artificial Reservoir Trough Cross Section Improvement

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/945/1/012046 ◽

2021 ◽

Vol 945 (1) ◽

pp. 012046

Author(s):

Rizka Arbaningrum ◽

Marelianda Al Dianty ◽

Frederik Josef Putuhena ◽

Rifki Priyambodo ◽

Budianto Ontowirjo

Keyword(s):

Land Use ◽

Surface Area ◽

Cross Section ◽

Return Period ◽

Rainfall Data ◽

Flood Mitigation ◽

Maximum Rainfall ◽

Artificial Reservoir ◽

Flood Discharge ◽

Main Factor

Abstract Situ Ciledug is an artificial reservoir located at Tangerang Selatan, Indonesia. In 1950 known as one of the largest lakes with total area of 32.806 hectares. As time goes by, due to the construction of housing and land use around the area, the catcahment area was reduced about 19.3 hectares in 2013 and by the end of 2020 the surface area was become 16.2 hectares. Urbanization is the main factor that makes the area of Situ Ciledug’s narrower. The second impact was flooding, as a result, the flood inundates the cities around the reservoir. This study aims to increase the storage capacities by normalizing the reservoir using SWMM 5.1 software. Hydrological analysis was carried out in the first stage to find the maximum rainfall using a 100-year return period. Then result intensity of rainfall used to analyze the hyetograph as input for rainfall data in SWMM 5.1. The modeling uses a maximum of rainfall about 107 mm with a reservoir depth of 1.3 meters. The large inflow that enters the reservoir is 87.504 m3/second aand the volume is 30.145 m3/second. Therefore, it is necessary to normalize the reservoir by increasing the depth of the reservoir by 0.7 meters. Normalization is carried out to accommodate flood discharge as a solution to flood mitigation due to the overflow.

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