scholarly journals A Comparative Study on the Derivation of Unit Hydrograph for Dhadhar River Basin

2019 ◽  
pp. 36-43
Author(s):  
Prerna Sutariya
Keyword(s):  
River Basin ◽  
Gamma Distribution ◽  
Beta Distribution ◽  
Daily Rainfall ◽  
Distribution Functions ◽  
Unit Hydrograph ◽  
Model Study ◽  
Hourly Rainfall ◽  
The One ◽  
Two Parameter

Several techniques are available for the development of the unit hydrograph. But most of these traditional methods require manual fitting of the unit hydrograph through few points, which does not guarantee the area under the unit hydrograph to be unity. More over most of the stations are ungauged, due to which it becomes difficult to develop the unit hydrograph. So in order to overcome these problems, two methods have been considered in this study for the development of the unit hydrograph for Dhadhar river basin. They are the “two parameter Gamma distribution” and “three parameter Beta distribution”, both of which are based on Probability Distribution Functions (pdfs). The unit hydrograph developed by the two parameter Gamma distribution match well with the one developed by CWC method, but the unit hydrograph developed by the three parameter Beta distribution does not match well with the one developed by the CWC method. From the unit hydrograph, runoff hydrograph is convoluted for the year 2018. For this the hourly rainfall are generated from daily rainfall values by disaggregation. But on plotting, the simulated discharge hydrograph is found to be greater than the observed discharge. This may be due to non-incorporation of the inflow outflow processes of many hydraulic structures such as dams, irrigation schemes etc., existing in the basin in the model study.

Adequacy of two-parameter beta distribution for deriving the unit hydrograph

2008 ◽  
Vol 39 (3) ◽  
pp. 201-208 ◽  
Author(s):  
R. K. Rai ◽  
S. Sarkar ◽  
H. G. Gundekar
Keyword(s):  
Genetic Algorithm ◽  
Distribution Function ◽  
Gamma Distribution ◽  
Beta Distribution ◽  
Distribution Functions ◽  
Global Error ◽  
Unit Hydrograph ◽  
The Past ◽  
Two Parameter

In the past, to derive the unit hydrograph (UH) various distribution functions have been utilized so far, though they had their own limitations. In this study, the applicability of two-parameter beta distribution has been explored for the derivation of UH. The parameters of the distribution function were estimated using the Genetic Algorithm which facilitates the minimization of global error. The suitability of the derived UH resulting from the two-parameter beta distribution was verified by comparing the UH derived by the two-parameter gamma distribution. The results obtained from both the distributions were almost similar and close to the observed UHs, which confirmed the applicability of the two-parameter beta distribution as an alternate approach for the derivation of the UH.

scholarly journals Nine-Year Systematic Evaluation of the GPM and TRMM Precipitation Products in the Shuaishui River Basin in East-Central China

2020 ◽  
Vol 12 (6) ◽  
pp. 1042 ◽  
Author(s):  
Xiaoying Yang ◽  
Yang Lu ◽  
Mou Leong Tan ◽  
Xiaogang Li ◽  
Guoqing Wang ◽  
...  
Keyword(s):  
River Basin ◽  
Time Scales ◽  
Daily Rainfall ◽  
Central China ◽  
Spatiotemporal Resolution ◽  
Study Region ◽  
East Central ◽  
Hourly Rainfall ◽  
Rainfall Estimates ◽  
Different Time Scales

Owing to their advantages of wide coverage and high spatiotemporal resolution, satellite precipitation products (SPPs) have been increasingly used as surrogates for traditional ground observations. In this study, we have evaluated the accuracy of the latest five GPM IMERG V6 and TRMM 3B42 V7 precipitation products across the monthly, daily, and hourly scale in the hilly Shuaishui River Basin in East-Central China. For evaluation, a total of four continuous and three categorical metrics have been calculated based on SPP estimates and historical rainfall records at 13 stations over a period of 9 years from 2009 to 2017. One-way analysis of variance (ANOVA) and multiple posterior comparison tests are used to assess the significance of the difference in SPP rainfall estimates. Our evaluation results have revealed a wide-ranging performance among the SPPs in estimating rainfall at different time scales. Firstly, two post-time SPPs (IMERG_F and 3B42) perform considerably better in estimating monthly rainfall. Secondly, with IMERG_F performing the best, the GPM products generally produce better daily rainfall estimates than the TRMM products. Thirdly, with their correlation coefficients all falling below 0.6, neither GPM nor TRMM products could estimate hourly rainfall satisfactorily. In addition, topography tends to impose similar impact on the performance of SPPs across different time scales, with more estimation deviations at high altitude. In general, the post-time IMERG_F product may be considered as a reliable data source of monthly or daily rainfall in the study region. Effective bias-correction algorithms incorporating ground rainfall observations, however, are needed to further improve the hourly rainfall estimates of the SPPs to ensure the validity of their usage in real-world applications.

Comparison of stochastic models of rainfall processes in mountainous climatic conditions

2010 ◽  
Vol 1 (2) ◽  
pp. 135-146
Author(s):  
J. Y. Lee ◽  
M. Y. Han ◽  
D. K. Kim ◽  
W. H. Ji
Keyword(s):  
Exponential Distribution ◽  
Gamma Distribution ◽  
Rainwater Harvesting ◽  
Daily Rainfall ◽  
Percentage Error ◽  
Parameter Distribution ◽  
Mountainous Region ◽  
Simpler Algorithm ◽  
Two Parameter ◽  
Mixed Exponential Distribution

The main objective of this work was to find a stochastic simulation model that was suitable for designing a rainwater harvesting system for agricultural water utilization and irrigation water in a mountainous region. Several models were applied using daily rainfall data from two sites (Gangneung and Daekwanreung) to assess the accuracy and suitability of the model for simulating the daily rainfall. The amount of rainfall for the mountainous region was well described by a two-parameter gamma distribution and performed better than other distributions. However, validation tests revealed that the annual mean absolute percentage error (MAPE) was more than 10% at both locations. This result was different from some previous research in which a three-parameter mixed-exponential distribution was well described. In addition, although the exponential distribution was also well described by a second-order expression, the use of a one-parameter distribution had a simpler algorithm than the two-parameter gamma distribution and the three-parameter mixed-exponential distribution.

scholarly journals The within-day behaviour of 6 minute rainfall intensity in Australia

2011 ◽  
Vol 15 (8) ◽  
pp. 2561-2579 ◽  
Author(s):  
A. W. Western ◽  
B. Anderson ◽  
L. Siriwardena ◽  
F. H. S. Chiew ◽  
A. Seed ◽  
...  
Keyword(s):  
Goodness Of Fit ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Distribution Functions ◽  
Average Intensity ◽  
Fit Statistics ◽  
Australian Continent ◽  
Generation Mechanisms ◽  
Parameter Values ◽  
Two Parameter

Abstract. The statistical behaviour and distribution of high-resolution (6 min) rainfall intensity within the wet part of rainy days (total rainfall depth >10 mm) is investigated for 42 stations across Australia. This paper compares nine theoretical distribution functions (TDFs) in representing these data. Two goodness-of-fit statistics are reported: the Root Mean Square Error (RMSE) between the fitted and observed within-day distribution; and the coefficient of efficiency for the fit to the highest rainfall intensities (average intensity of the 5 highest intensity intervals) across all days at a site. The three-parameter Generalised Pareto distribution was clearly the best performer. Good results were also obtained from Exponential, Gamma, and two-parameter Generalized Pareto distributions, each of which are two parameter functions, which may be advantageous when predicting parameter values. Results of different fitting methods are compared for different estimation techniques. The behaviour of the statistical properties of the within-day intensity distributions was also investigated and trends with latitude, Köppen climate zone (strongly related to latitude) and daily rainfall amount were identified. The latitudinal trends are likely related to a changing mix of rainfall generation mechanisms across the Australian continent.

scholarly journals The within-day behaviour of 6 minute rainfall intensity in Australia

2011 ◽  
Vol 8 (2) ◽  
pp. 3189-3231
Author(s):  
A. W. Western ◽  
B. Anderson ◽  
L. Siriwardena ◽  
F. H. S. Chiew ◽  
A. Seed ◽  
...  
Keyword(s):  
Goodness Of Fit ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Distribution Functions ◽  
Average Intensity ◽  
Fit Statistics ◽  
Australian Continent ◽  
Generation Mechanisms ◽  
Parameter Values ◽  
Two Parameter

Abstract. The statistical behaviour and distribution of high-resolution (6 min) rainfall intensity within the wet part of rainy days (total rainfall depth >10 mm) is investigated for 42 stations across Australia. This paper compares nine theoretical distribution functions (TDFs) in representing these data. Two goodness-of-fit statistics are reported: the Root Mean Square Error (RMSE) between the fitted and observed within-day distribution; and the efficiency of prediction of the highest rainfall intensities (average intensity of the 5 highest intensity intervals). The three-parameter Generalised Pareto distribution was clearly the best performer. Good results were also obtained from Exponential, Gamma, and two-parameter Generalized Pareto distributions, each of which are two parameter functions, which may be advantageous when predicting parameter values. Results of different fitting methods are compared for different estimation techniques. The behaviour of the statistical properties of the within-day intensity distributions was also investigated and trends with latitude, Köppen climate zone (strongly related to latitude) and daily rainfall amount were identified. The latitudinal trends are likely related to a changing mix of rainfall generation mechanisms across the Australian continent.

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