scholarly journals Forecasting annual maximum water level for the Negro River at Manaus

Author(s):  
Amulya Chevuturi ◽  
Nicholas P. Klingaman ◽  
Conrado M. Rudorff ◽  
Caio A. S. Coelho ◽  
Jochen Schöngart
2021 ◽  
Author(s):  
Amulya Chevuturi ◽  
Nicholas P. Klingaman ◽  
Steven J. Woolnough ◽  
Conrado M. Rudorff ◽  
Caio A. S. Coelho ◽  
...  

<p>Variations in water levels of the Negro River, that flows through the Port of Manaus, can cause considerable regional environmental and socio-economic losses. It is therefore critical to advance predictions for water levels, especially flood levels, to provide more effective and earlier warnings to safeguard lives and livelihoods. Variations in water levels in free-flowing river systems, like the Negro follow large-scale precipitation anomalies, which offers an opportunity to predict maximum water levels using observed antecedent rainfall. This study aims to improve the performance and extend the lead time of statistical forecasts for annual maximum water level of the Negro River at Manaus, relative to operational forecasts. Multiple linear regression methods are applied to develop forecast models, that can be issued in March, February and January, with the best possible combinations potential predictors: observed antecedent catchment rainfall and water levels, large-scale modes of climate variability and the linear trend in water levels. Our statistical models gain one month of lead time against existing models, but are only moderately better than existing models at similar lead time. Using European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal reforecast data with our statistical models, further gains an additional month of lead time of skilful performance. Our models lose performance at longer lead times, as expected. Our forecast models can issue skilful operational forecasts in March or earlier and have been successfully tested for operational forecast of 2020. This method can be applied to develop statistical models for annual maximum water level over other free-flowing rivers in the Amazon basin with intact catchments and historical water level record.</p>


2019 ◽  
Vol 27 (1) ◽  
pp. 344-353
Author(s):  
Abdul-Hassan K. Al-Shukur ◽  
Ranya Badea’ Mahmoud

One of the most common type of embankment dam failure is the dam-break due to overtopping. In this study, the finite elements method has been used to analyze seepage and limit equilibrium method to study stability of the body of an earthfill dam during the flood condition. For this purpose, the software Geostudio 2012 is used through its subprograms SEEP/W and SLOPE/W. Al-Adhaim dam in Iraq has been chosen to analysis the 5 days of flood. It was found that the water flux of seepage during the flood reaches about 8.772*10-5. m3/sec when the water level 146.5 m at 2nd day. Seepage through the embankment at maximum water level increased by 55.1 % from maximum water level. It was concluded that the factor of safety against sliding in downstream side decrease with increasing water level and vice versa. It was also concluded that the deposits are getting more critical stability during the conditions of flood when the factor of safety value reaches 1.219 at 2nd day.


2021 ◽  
Vol 10 (1) ◽  
pp. 1-8
Author(s):  
Dyah Pratiwi Kusumastuti ◽  
Husna Alghoida

Abstract Dams have many benefits such as irrigation, flood prevention, power generation and even tourism, especially in areas where the dam is located. So that the benefits received can last a long time, in the planning, it must be analyzed for stability, seepage discharge that occurs and the safety of the piping. The piping hazard safety figures in this study were calculated using the Harza method for maximum water level conditions, normal water levels, fast receding and empty dams at sta 0 + 150, sta 0 + 200, sta 0 + 250 and sta 0 + 300. Based on the calculation results, it is found that the safety of piping hazards without filters with the grouting method do not meet the requirements safety factor, especially in conditions of maximum water level, normal water level and fast receding. In order for the safety of piping hazard in order to meet the requirements, a filter is applied under the dams. The filter is applied so that the piping hazard safety figure meets the requirements of all water level conditions and all station is 80 cm deep.   Keywords: safety factor, piping, Harza method, filter   ABSTRAK Bendungan memiliki banyak manfaat seperti irigasi, pencegah banjir, pembangkit listrik bahkan pariwisata khususnya pada wilayah dimana bendungan tersebut berada. Agar manfaat yang diterima dapat berlangsung lama maka dalam perencanaannya wajib dianalisis terhadap stabilitas, debit rembesan yang terjadi maupun keamanan dari piping. Angka keamanan bahaya piping pada penelitian ini dihitung dengan menggunakan metode Harza untuk kondisi muka air maksimum, muka air normal, surut cepat dan bendungan kosong di sta 0+150, sta 0+200, sta 0+250 serta sta 0+300. Berdasarkan hasil perhitungan didapatkan bahwa angka keamanan bahaya piping tanpa penggunaan filter dengan metode grouting tidak memenuhi persyaratan angka keamanan khususnya pada kondisi muka air maksimum, muka air normal dan surut cepat. Agar angka keamanan bahaya piping memenuhi persyaratan maka diaplikasikan filter dibawah tubuh bendungan. Filter yang diaplikasikan agar angka keamanan bahaya piping memenuhi persyaratan diseluruh kondisi muka air dan seluruh sta adalah dengan kedalaman 80 cm.   Kata kunci: angka keamanan, piping, metode Harza, filter Abstract Dams have many benefits such as irrigation, flood prevention, power generation and even tourism, especially in areas where the dam is located. So that the benefits received can last a long time, in the planning, it must be analyzed for stability, seepage discharge that occurs and the safety of the piping. The piping hazard safety figures in this study were calculated using the Harza method for maximum water level conditions, normal water levels, fast receding and empty dams at sta 0 + 150, sta 0 + 200, sta 0 + 250 and sta 0 + 300. Based on the calculation results, it is found that the safety of piping hazards without filters with the grouting method do not meet the requirements safety factor, especially in conditions of maximum water level, normal water level and fast receding. In order for the safety of piping hazard in order to meet the requirements, a filter is applied under the dams. The filter is applied so that the piping hazard safety figure meets the requirements of all water level conditions and all station is 80 cm deep.   Keywords: safety factor, piping, Harza method, filter   ABSTRAK Bendungan memiliki banyak manfaat seperti irigasi, pencegah banjir, pembangkit listrik bahkan pariwisata khususnya pada wilayah dimana bendungan tersebut berada. Agar manfaat yang diterima dapat berlangsung lama maka dalam perencanaannya wajib dianalisis terhadap stabilitas, debit rembesan yang terjadi maupun keamanan dari piping. Angka keamanan bahaya piping pada penelitian ini dihitung dengan menggunakan metode Harza untuk kondisi muka air maksimum, muka air normal, surut cepat dan bendungan kosong di sta 0+150, sta 0+200, sta 0+250 serta sta 0+300. Berdasarkan hasil perhitungan didapatkan bahwa angka keamanan bahaya piping tanpa penggunaan filter dengan metode grouting tidak memenuhi persyaratan angka keamanan khususnya pada kondisi muka air maksimum, muka air normal dan surut cepat. Agar angka keamanan bahaya piping memenuhi persyaratan maka diaplikasikan filter dibawah tubuh bendungan. Filter yang diaplikasikan agar angka keamanan bahaya piping memenuhi persyaratan diseluruh kondisi muka air dan seluruh sta adalah dengan kedalaman 80 cm.   Kata kunci: angka keamanan, piping, metode Harza, filter


2018 ◽  
Vol 18 (5) ◽  
pp. 1852-1860 ◽  
Author(s):  
Yuqin Gao ◽  
Yu Yuan ◽  
Huaizhi Wang ◽  
Zhenxing Zhang ◽  
Liu Ye

Abstract Flood control with polders is prevalent in East China. Their impact on flood processes is critically important for flood control, but has not been well documented. The Qinhuai River Basin was selected as the study area. A Hydrologic Engineering Center – River Analysis System (HEC-RAS) hydraulic model was developed to simulate and predict storm flood processes and the associated impact of polders. The study shows that the HEC-RAS model is capable of simulating the impact of polders on flood processes in the Qinhuai River Basin. The polders increased the water level outside of the polders. The polders in upstream watersheds have a greater impact on the water level than polders close to basin outlets when individually distributed. The maximum water level at Dongshan section shows an increasing trend for different sized flood with the increasing number of polders in the basin, and a linear increasing trend associated with urbanization. The smaller the flood scale is, the greater the maximum water level changes.


Author(s):  
I G. Suryadinata P ◽  
I N. Norken ◽  
I G. B. Sila Dharma

Tukad Mati is one of the rivers in the province of Bali that unfolds and flows in Badung regency and Denpasar. Inundation due to flooding is a problem that often occurs in this region during the rainy season. In an effort to overcome problems of flooding have been many studies carried out so as to produce flood control alternatives such as normalization, diversion channels and retarding basins. Retarding basin is one of flood control alternative that has not been much studied. In this study conducted a simulation of flood prevention alternative with retarding basin at Tukad Mati, by the hydrology approach method and hydraulics using HEC-RAS 4.0 program applications. Simulations performed on the current river flow conditions (existing condition) and to the existing conditions with the retarding basin, according to the detail design of retarding basin in the city of Denpasar and evaluate the effectiveness of the retarding basin in the river basin flood control of Tukad Mati. Flood control by retarding basin based on simulations with the 2 (two) years flood return period, resulting in a reduction of water level by an average of 0.42 meters or an average of 12% of the maximum water level in the conditions without retarding basin, which occurred in along the grooves on the lower reaches of the retarding basin and inundation waters still occur in some places, particularly in the downstream of Umadui Dam. Economic analysis of both the analysis of Benefits/Cost produces a parameter of BCR, NPV and IRR are not meet the feasibility requirements. The effective retention of retarding basin based on simulation results are 282,630.00 m3 with the ability to flood accommodate for 3-4 hours. In terms of economic development retarding basin is not feasible in terms of comparative costs and benefits


2012 ◽  
Vol 7 (5) ◽  
pp. 867-877 ◽  
Author(s):  
Vida Žiliukienė ◽  
Valdemaras Žiliukas

AbstractThe aim of the study was to describe the peculiarities of pike spawning in mesotrophic Lake Rubikiai, to determine the spawning population structure and evaluate the influence of some environmental factors on year-class strength formation. The data were collected in April and May (1994–2011). A total of 1586 individuals were caught. The age of pike ranged from 1 to 12 years; 2–5-yearold males (96.0%) and 3–8-year-old females (89.1%) prevailed. The overall sex ratio of females to males was 1:4.1. One-year-old spawning males (26.5–28.5 cm) and two-year-old spawning females (31.5–35.5 cm) constituted 2.1% and 2.6%, respectively. Water temperature during the spawning period was relatively stable, between 4 and 6°C, during March and increased slightly towards 10°C in the middle of April. No correlation was observed between female length and spawning date. Year-class strength did not correlate with the last day of ice presence and the minimal water level at the end of spawning (WLmin), but statistically significantly negatively correlated with the maximum water level at the beginning of spawning (WLmax) and the difference between WLmax and WLmin. The mean annual survival rate for pike (aged ≥2) was 0.74 and the mean annual instantaneous mortality rate was 0.45.


2013 ◽  
Vol 304 ◽  
pp. 85-94 ◽  
Author(s):  
Yixing Yin ◽  
Ying Chen ◽  
Shutong Yu ◽  
Wucheng Xu ◽  
Wen Wang ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document