Estimating Errors in Sizing LID Device and Overflow Prediction Using the Intensity-Duration-Frequency Method

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1853
Author(s):  
Tang ◽  
Xu ◽  
Jia ◽  
Luo ◽  
Shao
Keyword(s):  
Rainfall Intensity ◽  
Relative Difference ◽  
Absolute Difference ◽  
Storm Event ◽  
Process Data ◽  
Frequency Method ◽  
Average Rainfall ◽  
Standard Deviations ◽  
Intensity Duration Frequency ◽  
Design Depth

Low impact development (LID) devices or green infrastructures have been advocated for urban stormwater management worldwide. Currently, the design and evaluation of LID devices adopt the Intensity-Duration-Frequency (IDF) method, which employs the average rainfall intensity. However, due to variations of rainfall intensity during a storm event, using average rainfall intensity may generate certain errors when designing a LID device. This paper presents an analytical study to calculate the magnitude of such errors with respect to LID device design and associated device performance evaluation. The normal distribution rainfall (NDR) with different standard deviations was employed to represent realistic rainfall processes. Compared with NDR method, the error in sizing the LID device was determined using the IDF method. Moreover, the overflow difference calculated using the IDF method was evaluated. We employed a programmed hydrological model to simulate different design scenarios. Using storm data from 31 regions with different climatic conditions in continental China, the results showed that different rainfall distributions (as represented by standard deviations (σ) of 5, 3, and 2) have little influence on the design depth of LID devices in most regions. The relative difference in design depth using IDF method was less than 1.00% in humid areas, −0.61% to 3.97% in semi-humid areas, and the significant error was 46.13% in arid areas. The maximum absolute difference in design depth resulting from the IDF method was 2.8 cm. For a LID device designed for storms with a 2-year recurrence interval, when meeting for the 5-year storm, the relative differences in calculated overflow volume using IDF method ranged from 19.8% to 95.3%, while those for the 20-year storm ranged from 7.4% to 40.5%. The average relative difference of the estimated overflow volume was 29.9% under a 5-year storm, and 12.0% under a 20-year storm. The relative difference in calculated overflow volumes using IDF method showed a decreasing tendency from northwest to southeast. Findings from this study suggest that the existing IDF method is adequate for use in sizing LID devices when the design storm is not usually very intense. However, accurate rainfall process data are required to estimate the overflow volume under large storms.

scholarly journals On the correction of processed historical rainfall data of siphoned rainfall recorders

Időjárás ◽  
2021 ◽  
Vol 125 (3) ◽  
pp. 513-519
Author(s):  
Tibor Rácz
Keyword(s):  
Rainfall Intensity ◽  
Time Window ◽  
Rainfall Data ◽  
Physical Parameters ◽  
Time Interval ◽  
Data Correction ◽  
Counting Error ◽  
Measurement Results ◽  
Average Rainfall ◽  
Intensity Duration Frequency

Historical rainfall data registered by siphoned rainfall recorder (SRW) devices have been widely used for a long time in rainfall intensity investigations. A relatively known counting error of the SRW devices is the siphoning error, when the registration of rainfall is blocked temporarily, during the drainage of measure tank. This issue causes a systematic underestimation in the rainfall and rainfall intensity measurement results. To reduce its consequences, a data correction is crucial when SRW data are used, for example as a reference for climate comparison studies, or for proceeding of intensity-duration-frequency curves, etc. In this paper, a formula is presented to fix the siphonage error of SRW devices for historical rainfall data. The early measures were processed in a significant percentage of cases, and sometimes the original measurement results (registration ribbon) have been lost. An essential advantage of the presented formula is that it can be applied for these processed data, which show only the intensity of a known length time interval. For this correction, the average rainfall intensity and the length of the time window are needed, over the physical parameters of the SRW device. The data correction can provide a fixed value of the rainfall intensity, which is undoubtedly closer to the real average rainfall intensity. The importance of this formula is in the reprocessing and validation of the historical rainfall intensity data, measured by siphoned rainfall recorders.

scholarly journals Relationships between rainfall intensity, duration and suspended particle washoff from an urban road surface

2011 ◽  
Vol 42 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Ian M. Brodie ◽  
Prasanna Egodawatta
Keyword(s):  
Rainfall Intensity ◽  
Suspended Particle ◽  
Measured Data ◽  
Storm Event ◽  
Storm Events ◽  
Constant Intensity ◽  
Urban Road ◽  
Road Surfaces ◽  
Basic Understanding ◽  
Average Rainfall

A basic understanding of the relationships between rainfall intensity, duration of rainfall and the amount of suspended particles in stormwater runoff generated from road surfaces has been gained mainly from past washoff experiments using rainfall simulators. Simulated rainfall was generally applied at constant intensities, whereas rainfall temporal patterns during actual storms are typically highly variable. This paper discusses a rationale for the application of the constant-intensity washoff concepts to actual storm event runoff. The rationale is tested using suspended particle load data collected at a road site located in Toowoomba, Australia. Agreement between the washoff concepts and measured data is most consistent for intermediate-duration storms (duration <5 h and >1 h). Particle loads resulting from these storm events increase linearly with average rainfall intensity. Above a threshold intensity, there is evidence to suggest a constant or plateau particle load is reached. The inclusion of a peak discharge factor (maximum 6 min rainfall intensity) enhances the ability to predict particle loads.

scholarly journals Influence of Specific Contributing Area algorithms on slope failure prediction in landslide modeling

2007 ◽  
Vol 7 (6) ◽  
pp. 781-792 ◽  
Author(s):  
J.-C. Huang ◽  
S.-J. Kao ◽  
M.-L. Hsu ◽  
Y.-A. Liu
Keyword(s):  
Slope Failure ◽  
Rainfall Intensity ◽  
Engineering Application ◽  
Relative Difference ◽  
Absolute Difference ◽  
Model Parameters ◽  
Mountainous Catchment ◽  
Landslide Modeling ◽  
Relative Differences ◽  
Increasing Trends

Abstract. This study anatomized algorithm effects of specific contributing area (SCA) on soil wetness estimation, consequently landslide prediction, in SHALSTAB. A subtropical mountainous catchment during three typhoon invasions is targeted. The peak 2-day rainfall intensity of the three typhoons: Haitang, Mindulle and Herb are 144, 248 and 327 mm/day, respectively. We use modified success rate (MSR) to retrieve the most satisfying mean condition for model parameters in SHALSTAB at three rainfall intensities and respective pre-typhoon NDVI themes. Simulation indicates that algorithm affects the prediction of landslide susceptibility (i.e. FS, Factor of Safety) significantly. Based on fixed NDVI and the mean condition, we simulate by using full scale rainfall intensity from 0 to 1200 mm/day. Simulations show that predicted unstable area coverage increases non-linearly as rainfall intensity increases for all algorithms yet with different increasing trends. Compared to Dinf, D8 always gives lower coverage of predicted unstable area during three typhoons. By contrast, FD8 gives higher coverage areas. The absolute difference (compared to Dinf) in predicted unstable area ranges from ~−3% to +4% (percent watershed area). The relative difference (compared to Dinf) ranges from −15% to as high as +40%. The maximum absolute and relative differences in unstable area prediction occur around the condition of 100–300 mm/day, which is common in subtropical mountainous region. Theoretical relationship among slope, rainfall intensity, SCA and FS value was derived in which FS values are very sensitive to algorithms in the field of slope from 37 to 52degree. Results imply any comparison among SCA-related landslide models or engineering application of rainfall return period analysis must base on the same algorithm to obtain comparable results. This study clarifies the SCA algorithm effect on FS prediction and deepens our understanding on landslide modeling.

scholarly journals Universal Power Law for Relationship between Rainfall Kinetic Energy and Rainfall Intensity

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Seung Sook Shin ◽  
Sang Deog Park ◽  
Byoung Koo Choi
Keyword(s):  
Kinetic Energy ◽  
Power Law ◽  
Rainfall Intensity ◽  
Mathematical Expression ◽  
Power Laws ◽  
Relative Difference ◽  
Universal Power Law ◽  
Average Rainfall ◽  
Independent Variable ◽  
Logarithmic Functions

Rainfall kinetic energy has been linked to linear, exponential, logarithmic, and power-law functions using rainfall intensity as an independent variable. The power law is the most suitable mathematical expression used to relate rainfall kinetic energy and rainfall intensity. In evaluating the rainfall kinetic energy, the empirical power laws have shown a larger deviation than other functions. In this study, universal power law between rainfall kinetic energy and rainfall intensity was proposed based on the rainfall power theory under an ideal assumption that drop-size is uniformly distributed in constant rainfall intensity. An exponent of the proposed power law was 11/9 and coefficient was estimated at 10.3 from the empirical equations of the existing power-law relation. The rainfall kinetic energy calculated by universal power law showed >95% concordance rate in comparison to the average values calculated from exponential and logarithmic functions used in soil erosion model such as USLE, RUSLE, EUROSEM, and SEMMA and <5% relative difference as compared to the average rainfall kinetic energies calculated by other empirical functions. Therefore, it is expected that power law of ideal assumption may be utilized as a universal power law in evaluating rainfall kinetic energy.

scholarly journals Development of Rainfall Intensity-Duration-Frequency (IDF) Curve for Abuja, Nigeria

2021 ◽  
Vol 40 (1) ◽  
pp. 154-160
Author(s):  
M.A. Ahmed ◽  
A.T. Olowosulu ◽  
B.K. Adeogun ◽  
A.A. Murana ◽  
H.A. Ahmed ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Economic Problem ◽  
Rainfall Data ◽  
Water Drainage ◽  
Social Implication ◽  
Frequency Method ◽  
Analysis And Design ◽  
Intensity Duration Frequency ◽  
The Cost

Urban flooding is a major social and economic problem of any nation. The social implication is attributed to loss of lives and property, unwanted displacement and emotional disturbance attached. While that of economic problem is the cost of mitigation of flood and the aftermath solution. Thus, storm water drainage is part of essential modern city infrastructure. The need for proper analysis and design of drainages and other road water facilities cannot be overemphasized. To achieve this, critical analysis of available rainfall data, which is a key input, is required. A 35 years daily rainfall data were obtained from NIMET, from which the analysis was carried out using frequency method. The output generated are presented in graphical forms and model. Ultimately, an IDF curve generated, depicts Abuja rainfall pattern from which a 3-parameter model equation, I = 37Tr0.2 (t + 0.1)−0.9 was formulated. This is site or location specific. The curve and/or the formulated model can be adopted to determine rainfall intensity of Abuja city if the rainfall duration and return period are predictable.

scholarly journals Estimation of the G2P Design Storm from a Rainfall Convectivity Index

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1943
Author(s):  
Rosario Balbastre-Soldevila ◽  
Rafael García-Bartual ◽  
Ignacio Andrés-Doménech
Keyword(s):  
Shape Parameter ◽  
Rainfall Intensity ◽  
Analytical Relationship ◽  
Urban Drainage ◽  
Practical Application ◽  
Resolution Time ◽  
Simple Method ◽  
Design Storm ◽  
Intensity Duration Frequency ◽  
Two Parameter

The two-parameter gamma function (G2P) design storm is a recent methodology used to obtain synthetic hyetographs especially developed for urban hydrology applications. Further analytical developments on the G2P design storm are presented herein, linking the rainfall convectivity n-index with the shape parameter of the design storm. This step can provide a useful basis for future easy-to-handle rainfall inputs in the context of regional urban drainage studies. A practical application is presented herein for the case of Valencia (Spain), based on high-resolution time series of rainfall intensity. The resulting design storm captures certain internal statistics and features observed in the fine-scale rainfall intensity historical records. On the other hand, a direct, simple method is formulated to derivate the design storm from the intensity–duration–frequency (IDF) curves, making use of the analytical relationship with the n-index.

Development of Rainfall Intensity-Duration-Frequency Curves Based on Dynamically Downscaled Climate Data: Arizona Case Study

2021 ◽  
Vol 26 (5) ◽  
pp. 05021005
Author(s):  
Amin Mohebbi ◽  
Simin Akbariyeh ◽  
Montasir Maruf ◽  
Ziyan Wu ◽  
Juan Carlos Acuna ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Climate Data ◽  
Intensity Duration Frequency ◽  
Frequency Curves

Response to Motion in Extrastriate Area MSTl: Disparity Sensitivity

1999 ◽  
Vol 82 (5) ◽  
pp. 2462-2475 ◽  
Author(s):  
Satoshi Eifuku ◽  
Robert H. Wurtz
Keyword(s):  
Receptive Field ◽  
Tuning Curve ◽  
Receptive Fields ◽  
Relative Difference ◽  
Moving Object ◽  
Absolute Difference ◽  
Stimulus Motion ◽  
Temporal Area ◽  
Moving Stimuli ◽  
Medial Superior Temporal

Many neurons in the lateral-ventral region of the medial superior temporal area (MSTl) have a clear center surround separation in their receptive fields. Either moving or stationary stimuli in the surround modulates the response to moving stimuli in the center, and this modulation could facilitate the perceptual segmentation of a moving object from its background. Another mechanism that could facilitate such segmentation would be sensitivity to binocular disparity in the center and surround regions of the receptive fields of these neurons. We therefore investigated the sensitivity of these MSTl neurons to disparity ranging from three degrees crossed disparity (near) to three degrees uncrossed disparity (far) applied to both the center and the surround regions. Many neurons showed clear disparity sensitivity to stimulus motion in the center of the receptive field. About [Formula: see text] of 104 neurons had a clear peak in their response, whereas another [Formula: see text] had broader tuning. Monocular stimulation abolished the tuning. The prevalence of cells broadly tuned to near and far disparity and the reversal of preferred directions at different disparities observed in MSTd were not found in MSTl. A stationary surround at zero disparity simply modulated up or down the response to moving stimuli at different disparities in the receptive field (RF) center but did not alter the disparity tuning curve. When the RF center motion was held at zero disparity and the disparity of the stationary surround was varied, some surround disparities produced greater modulation of MSTl neuron response than did others. Some neurons with different disparity preferences in center and surround responded best to the relative disparity differences between center and surround, whereas others were related to the absolute difference between center and surround. The combination of modulatory surrounds and the sensitivity to relative difference between center and surround disparity make these MSTl neurons particularly well suited for the segmentation of a moving object from the background.

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