scholarly journals Development of Temporal Rainfall Pattern for Southern Region of Sarawak

2012 ◽  
Vol 3 ◽  
pp. 17-23 ◽  
Author(s):  
Rosmina A. Bustami ◽  
Nor Azalina Rosli ◽  
Jethro Henry Adam ◽  
Kuan Pei Li
Keyword(s):  
Temporal Pattern ◽  
Rainfall Intensity ◽  
Peninsular Malaysia ◽  
Southern Region ◽  
Rainfall Pattern ◽  
Rainfall Duration ◽  
Design Rainfall ◽  
Average Rainfall ◽  
Urban Storm ◽  
Australian Rainfall

 In the process of a design rainfall, information on rainfall duration, average rainfall intensity and temporal rainfall pattern is important. This study focuses on developing a temporal rainfall pattern for the Southern region of Sarawak since temporal pattern for Sarawak is yet to be available in the Malaysian Urban Storm Water Management Manual (MSMA), which publishes temporal pattern for design storms only for Peninsular Malaysia. The recommended technique by the Australian Rainfall and Runoff (AR&R) known as the ‘Average Variability Method’ and method in Hydrological Procedure No.1-1982 are used to derive design rainfall temporal pattern for the study. Rainfall data of 5 minutes interval from year 1998 to year 2006 for 7 selected rainfall stations in the selected region is obtained from Department of Irrigation and Drainage (DID). The temporal rainfall patterns developed are for 10 minutes,15 minutes, 30 minutes, 60 minutes, 120 minutes, 180 minutes and 360 minutes duration. The results show that Southern region of Sarawak has an exclusive rainfall pattern, which is different from the pattern developed for Peninsular Malaysia.

scholarly journals Development of Temporal Rainfall Pattern for Segamat District

2015 ◽  
Vol 773-774 ◽  
pp. 1205-1209
Author(s):  
Noorfathiah Che Ali ◽  
Yuliarahmadila Erfen ◽  
Nurul Farehah Amat ◽  
Zawani Mohd Zahudi ◽  
Mohd Shalahuddin Adnan
Keyword(s):  
Survey Data ◽  
Temporal Pattern ◽  
Temporal Patterns ◽  
Rainfall Pattern ◽  
Intermediate Type ◽  
Design Rainfall ◽  
Minute Interval ◽  
Flood Estimation ◽  
Australian Rainfall

The designing of rainfall temporal pattern is very important in displaying the diversity and intensity of rainfall in addition to flood estimation and planning. The main purpose of this study was to develop a temporal rainfall pattern for Segamat District. Average Variability Method, AVM which had recommended by the Australian Rainfall and Runoff were used to derive design rainfall temporal patterns for this study. The survey data for 5 minute interval from 2003 to 2012 for 4 selected rainfall stations that obtained from the Drainage and Irrigation Department, DID have been selected. In this study, the temporal rainfall pattern is built for 10 minutes, 15 minutes, 30 minutes, 60 minutes, 120 minutes, 180 minutes, and 360 minutes. The results shows the actual rainfall on the field in the form of temporal rainfall pattern. Up to 75% of the temporal patterns in the region can be classified as intermediate type while the advance and delay type are 11% and 14%, respectively. From the temporal rainfall pattern, the duration of rainfall occurs can be predicted, therefore, the probability of the flooding during the period can be estimated.

scholarly journals Estimating urban flood risk – uncertainty in design criteria

2015 ◽  
Vol 370 ◽  
pp. 3-7 ◽  
Author(s):  
M. Newby ◽  
S. W. Franks ◽  
C. J. White
Keyword(s):  
Data Analysis ◽  
Flood Risk ◽  
Rainfall Intensity ◽  
Design Criteria ◽  
Climate Change Scenarios ◽  
Urban Flood ◽  
Frequency Distributions ◽  
Rainfall Variation ◽  
Design Rainfall ◽  
Australian Rainfall

Abstract. The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1 : 5 year ARI correlates with an 18.13% AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20% AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.

scholarly journals Prediction of factors affecting activation of soil erosion by mathematical modeling at pedon scale under laboratory conditions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Saeed Shojaei ◽  
Zahra Kalantari ◽  
Jesús Rodrigo-Comino
Keyword(s):  
Soil Loss ◽  
Rainfall Intensity ◽  
Quadratic Function ◽  
Interactive Effects ◽  
Soil Protection ◽  
Single Factor ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
The Impact ◽  
Runoff Production

AbstractSoil degradation due to erosion is a significant worldwide problem at different spatial (from pedon to watershed) and temporal scales. All stages and factors in the erosion process must be detected and evaluated to reduce this environmental issue and protect existing fertile soils and natural ecosystems. Laboratory studies using rainfall simulators allow single factors and interactive effects to be investigated under controlled conditions during extreme rainfall events. In this study, three main factors (rainfall intensity, inclination, and rainfall duration) were assessed to obtain empirical data for modeling water erosion during single rainfall events. Each factor was divided into three levels (− 1, 0, + 1), which were applied in different combinations using a rainfall simulator on beds (6 × 1 m) filled with soil from a study plot located in the arid Sistan region, Iran. The rainfall duration levels tested were 3, 5, and 7 min, the rainfall intensity levels were 30, 60, and 90 mm/h, and the inclination levels were 5, 15, and 25%. The results showed that the highest rainfall intensity tested (90 mm/h) for the longest duration (7 min) caused the highest runoff (62 mm3/s) and soil loss (1580 g/m2/h). Based on the empirical results, a quadratic function was the best mathematical model (R2 = 0.90) for predicting runoff (Q) and soil loss. Single-factor analysis revealed that rainfall intensity was more influential for runoff production than changes in time and inclination, while rainfall duration was the most influential single factor for soil loss. Modeling and three-dimensional depictions of the data revealed that sediment production was high and runoff production lower at the beginning of the experiment, but this trend was reversed over time as the soil became saturated. These results indicate that avoiding the initial stage of erosion is critical, so all soil protection measures should be taken to reduce the impact at this stage. The final stages of erosion appeared too complicated to be modeled, because different factors showed differing effects on erosion.

scholarly journals Spatial Interpolation on Rainfall Data over Peninsular Malaysia Using Ordinary Kriging

2013 ◽  
Vol 63 (2) ◽  
Author(s):  
Suhaila Jamaludin ◽  
Hanisah Suhaimi
Keyword(s):  
Spatial Analysis ◽  
Ordinary Kriging ◽  
Spatial Interpolation ◽  
Rainfall Intensity ◽  
Peninsular Malaysia ◽  
Rainfall Data ◽  
Kriging Method ◽  
Intensity Index ◽  
Dry Conditions ◽  
Two Indices

This study presents the spatial analysis of the rainfall data over Peninsular Malaysia. 70 rainfall stations were utilized in this study. Due to the limited number of rainfall stations, the Ordinary Kriging method which is one of the techniques in Spatial Interpolation was used to estimate the values of the rainfall data and to map their spatial distribution. This spatial analysis was analysed according to the two indices that describe the wet events and another two indices that characterize dry conditions. Large areas at the east experienced high rainfall intensity compared to the areas in the west, northwest and southwest. The small value that has been obtained in Aridity Intensity Index (AII) reflects that the high amount of rainfall in the eastern areas is not contributed by low-intensity events (less than 25th percentile). In terms of number of consecutive dry days, Northwestern areas in Peninsular Malaysia recorded the highest value. This finding explains the occurrence of a large number of floods and soil erosions in the eastern areas.

scholarly journals Spatial Analysis of the Air Pollutant Index in the Southern Region of Peninsular Malaysia Using Environmetric Techniques

2013 ◽  
pp. 307-312 ◽  
Author(s):  
Azman Azid ◽  
Hafizan Juahir ◽  
Ahmad Zaharin Aris ◽  
Mohd Ekhwan Toriman ◽  
Mohd Talib Latif ◽  
...  
Keyword(s):  
Spatial Analysis ◽  
Peninsular Malaysia ◽  
Air Pollutant ◽  
Southern Region

scholarly journals Individual Rainfall Change Based on Observed Hourly Precipitation Records on the Chinese Loess Plateau from 1983 to 2012

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2268
Author(s):  
Wenbin Ding ◽  
Fei Wang ◽  
Kai Jin ◽  
Jianqiao Han ◽  
Qiang Yu ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Heavy Rainfall ◽  
Rainfall Intensity ◽  
Rainfall Amount ◽  
The Loess Plateau ◽  
Total Rainfall ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
Rainfall Frequency ◽  
Annual Total

The magnitude and spatiotemporal distribution of precipitation are the main drivers of hydrologic and agricultural processes in soil moisture, runoff generation, soil erosion, vegetation growth and agriculture activities on the Loess Plateau (LP). This study detects the spatiotemporal variations of individual rainfall events during a rainy season (RS) from May to September based on the hourly precipitation data measured at 87 stations on the LP from 1983 to 2012. The incidence and contribution rates were calculated for all classes of rainfall duration and intensity to identify the dominant contribution to the rainfall amount and frequency variations. The trend rates of regional mean annual total rainfall amount (ATR) and annual mean rainfall intensity (ARI) were 0.43 mm/year and 0.002 mm/h/year in the RS for 1983–2012, respectively. However, the regional mean annual total rainfall frequency (ARF) and rainfall events (ATE) were −0.27 h/year and −0.11 times/year, respectively. In terms of spatial patterns, an increase in ATR appeared in most areas except for the southwest, while the ARI increased throughout the study region, with particularly higher values in the northwest and southeast. Areas of decreasing ARF occurred mainly in the northwest and central south of the LP, while ATE was found in most areas except for the northeast. Short-duration (≤6 h) and light rainfall events occurred mostly on the LP, accounting for 69.89% and 72.48% of total rainfall events, respectively. Long-duration (≥7 h) and moderate rainfall events contributed to the total rainfall amount by 70.64% and 66.73% of the total rainfall amount, respectively. Rainfall frequency contributed the most to the variations of rainfall amount for light and moderate rainfall events, while rainfall intensity played an important role in heavy rainfall and rainstorms. The variation in rainfall frequency for moderate rainfall, heavy rainfall, and rainstorms is mainly affected by rainfall duration, while rainfall event was identified as a critical factor for light rainfall. The characteristics in rainfall variations on the Loess Plateau revealed in this study can provide useful information for sustainable water resources management and plans.

scholarly journals A determination of the synthetic hyetograph parameters for flow capacity assessment concerning stormwater systems

2018 ◽  
Vol 45 ◽  
pp. 00053
Author(s):  
Karolina Mazurkiewicz ◽  
Marcin Skotnicki
Keyword(s):  
Rainfall Intensity ◽  
Flow Time ◽  
Capacity Assessment ◽  
Rainfall Duration ◽  
Total Runoff ◽  
Flow Capacity ◽  
Flood Volume ◽  
Urban Catchments ◽  
Peak Location

The paper presents the results of an analysis of the influence of synthetic rainfall duration and location of rainfall intensity peak on the rate of the flood volume in surcharged storm sewers. The analyzed rainfalls had durations from 15 minutes to 180 minutes. It was assumed, that the rainfall peak location would change between the beginning and the end of the rainfall with increments of 10% of the rainfall duration. Outflow simulations were performed with the use of SWMM5.1.012 for three models of real urban catchments with surfaces from 1.6 km2 to 6.7 km2. An assessment of the influence of rainfall parameters was made on the basis of the flood volume rates. Short rainfalls with peaks located at the beginning of rainfall duration do not generate flooding. For other rainfalls it was found that for a specified rainfall duration the flood volume increases with the increase of time of the rainfall peak location. The maximum flood volume varied from 5% to 12% of the total runoff volume, depending on the catchment area, and is generated by the rainfall, whose intensity peak occurs right after the time corresponding to the flow time through the catchment.

scholarly journals Karst bare slope soil erosion and soil quality: a simulation case study

Solid Earth ◽  
2015 ◽  
Vol 6 (3) ◽  
pp. 985-995 ◽  
Author(s):  
Q. Dai ◽  
Z. Liu ◽  
H. Shao ◽  
Z. Yang
Keyword(s):  
Soil Erosion ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Infiltration Rate ◽  
Soil Infiltration ◽  
Seepage Rate ◽  
Rainfall Duration ◽  
Sediment Production ◽  
Correlation Degree ◽  
Slope Runoff

Abstract. The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1), no bottom load loss is produced on the surface, and surface runoff, underground runoff and sediment production are increased with the increasing of rainfall intensity. Secondly, surface runoff and sediment production reduced with increased underground pore fissure degree, while underground runoff and sediment production increased. Thirdly, raindrops hit the surface, forming a crust with rainfall duration. The formation of crusts increases surface runoff erosion and reduces soil infiltration rate. This formation also increases surface-runoff-erosion-damaged crust and increased soil seepage rate. Raindrops continued to hit the surface, leading the formation of crust. Soil permeability showed volatility which was from reduction to increases, reduction, and so on. Surface and subsurface runoff were volatile with rainfall duration. Fourthly, when rock bareness ratio is 50 % and rainfall intensities are 30 and 50 mm h−1, runoff is not produced on the surface, and the slope runoff and sediment production present a fluctuating change with increased rock bareness ratio. Fifthly, the correlation degree between the slope runoff and sediment production and all factors are as follows: rainfall intensity-rainfall duration-underground pore fissure degree–bedrock bareness ratio.

scholarly journals Spatial Interpolation of Historical Seasonal Rainfall Indices over Peninsular Malaysia

2018 ◽  
Vol 34 ◽  
pp. 02048
Author(s):  
Zulkarnain Hassan ◽  
Ahmad Haidir ◽  
Farah Naemah Mohd Saad ◽  
Afizah Ayob ◽  
Mustaqqim Abdul Rahim ◽  
...  
Keyword(s):  
Spatial Interpolation ◽  
Rainfall Intensity ◽  
Southwest Monsoon ◽  
Peninsular Malaysia ◽  
Seasonal Rainfall ◽  
Seasonal Patterns ◽  
Northeast Monsoon ◽  
Rainfall Characteristics ◽  
Distance Weighted ◽  
Inverse Distance

The inconsistency in inter-seasonal rainfall due to climate change will cause a different pattern in the rainfall characteristics and distribution. Peninsular Malaysia is not an exception for this inconsistency, in which it is resulting extreme events such as flood and water scarcity. This study evaluates the seasonal patterns in rainfall indices such as total amount of rainfall, the frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity in Peninsular Malaysia. 40 years (1975-2015) data records have been interpolated using Inverse Distance Weighted method. The results show that the formation of rainfall characteristics are significance during the Northeast monsoon (NEM), as compared to Southwest monsoon (SWM). Also, there is a high rainfall intensity and frequency related to extreme over eastern coasts of Peninsula during the NEM season.

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