Role of rainfall events and imperviousness parameters on urban runoff modelling

2013 ◽  
Vol 19 (3) ◽  
pp. 329-334 ◽  
Author(s):  
Sanat Nalini Sahoo ◽  
P. Sreeja
Keyword(s):  
Urban Runoff ◽  
Rainfall Events

scholarly journals Hillslope Contribution to the Clark Instantaneous Unit Hydrograph: Application to the Seolmacheon Basin, Korea

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1707
Author(s):  
Chulsang Yoo ◽  
Huy Phuong Doan ◽  
Changhyun Jun ◽  
Wooyoung Na
Keyword(s):  
Peak Flow ◽  
Peak Time ◽  
Rainfall Runoff ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Storage Coefficient ◽  
Channel Velocity ◽  
Linear Reservoir ◽  
Mountainous Basin

In this study, the time–area curve of an ellipse is analytically derived by considering flow velocities within both channel and hillslope. The Clark IUH is also derived analytically by solving the continuity equation with the input of the derived time–area curve to the linear reservoir. The derived Clark IUH is then evaluated by application to the Seolmacheon basin, a small mountainous basin in Korea. The findings in this study are summarized as follows. (1) The time–area curve of a basin can more realistically be derived by considering both the channel and hillslope velocities. The role of the hillslope velocity can also be easily confirmed by analyzing the derived time–area curve. (2) The analytically derived Clark IUH shows the relative roles of the hillslope velocity and the storage coefficient. Under the condition that the channel velocity remains unchanged, the hillslope velocity controls the runoff peak flow and the concentration time. On the other hand, the effect of the storage coefficient can be found in the runoff peak flow and peak time, as well as in the falling limb of the runoff hydrograph. These findings are also confirmed in the analysis of rainfall–runoff events of the Seolmacheon basin. (3) The effect of the hillslope velocity varies considerably depending on the rainfall events, which is also found to be mostly dependent upon the maximum rainfall intensity.

scholarly journals Extreme Rainfall in the Mediterranean: What Can We Learn from Observations?

2013 ◽  
Vol 14 (3) ◽  
pp. 906-922 ◽  
Author(s):  
N. Rebora ◽  
L. Molini ◽  
E. Casella ◽  
A. Comellas ◽  
E. Fiori ◽  
...  
Keyword(s):  
Extreme Rainfall ◽  
Flash Floods ◽  
Rain Gauge ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Life Threatening ◽  
The Mediterranean ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Ground Effects

Abstract Flash floods induced by extreme rainfall events represent one of the most life-threatening phenomena in the Mediterranean. While their catastrophic ground effects are well documented by postevent surveys, the extreme rainfall events that generate them are still difficult to observe properly. Being able to collect observations of such events will help scientists to better understand and model these phenomena. The recent flash floods that hit the Liguria region (Italy) between the end of October and beginning of November 2011 give us the opportunity to use the measurements available from a large number of sensors, both ground based and spaceborne, to characterize these events. In this paper, the authors analyze the role of the key ingredients (e.g., unstable air masses, moist low-level jets, steep orography, and a slow-evolving synoptic pattern) for severe rainfall processes over complex orography. For the two Ligurian events, this role has been analyzed through the available observations (e.g., Meteosat Second Generation, Moderate Resolution Imaging Spectroradiometer, the Italian Radar Network mosaic, and the Italian rain gauge network observations). The authors then address the possible role of sea–atmosphere interactions and propose a characterization of these events in terms of their predictability.

scholarly journals Rainfall and weather conditions inducing intense landslide activity in northern Spain (Deba, Guipúzcoa)

2020 ◽  
Author(s):  
Victoria Rivas ◽  
Juan Remondo ◽  
Jaime Bonachea ◽  
Javier Sánchez-Espeso
Keyword(s):  
Weather Conditions ◽  
Rainfall Threshold ◽  
Large Network ◽  
Antecedent Rainfall ◽  
Northern Spain ◽  
Rainfall Events ◽  
Landslide Activity ◽  
Long Time ◽  
Span 60

Abstract. The Deba area is intensely affected by frequent shallow landslides triggered by rainfall. Relationships between rainfall and landslides in northern Spain, particularly for rainfall events driving multiple movements simultaneously, have not been explored in depth so far. This contribution explores the role of rainfall in landslide activity during a quite long time span, (60 years), from a large network of rainfall gauges and a complete inventory of landslides, and utilizing three different strategies of analysis. 1,180 landslides have been inventoried, and 3,241 rainfall episodes automatically recognized and characterized in terms of rainfall amount, duration and intensity. Antecedent rainfall has also been considered. Six episodes of intense rainfall, which have produced multiple landslides (> 50 % of the recent past occurrences) have been identified. The analysis provides different results: the extraordinary character of the triggering rainfall has been assessed, the meteorological conditions associated to those extreme episodes have been recognized and empirical rainfall threshold producing multiple landslides has been found (I = 7.7D-0.428) and compared with others described in literature. Results show that multiple landslide occurrences are triggered by extreme convective rainfall, intense, short and with limited horizontal extent, as well as a marked summer-autumn seasonality, characteristic of Mediterranean climate.

scholarly journals The role of conidia in the dispersal of Ascochyta rabiei

2020 ◽  
Author(s):  
Ihsanul Khaliq ◽  
Joshua Fanning ◽  
Paul Melloy ◽  
Jean Galloway ◽  
Kevin Moore ◽  
...  
Keyword(s):  
Additive Model ◽  
Sprinkler Irrigation ◽  
Ascochyta Rabiei ◽  
Strong Wind ◽  
Generalised Additive Model ◽  
Rainfall Events ◽  
Plant Parts ◽  
Trap Plants ◽  
Further Development

AbstractAscochyta rabiei asexual spores (conidia) were assumed to spread over short distances (∼10 m) in a combination of rain and strong wind. The potential distance of conidial spread was investigated in three rainfall and three sprinkler irrigation events. Chickpea trap plants were distributed at the distances of 0, 10, 25, 50 and 75 m from infected chickpea plots before scheduled irrigation and forecast rainfall events. Trap plants were transferred to a controlled temperature room (20 °C) for 48 h (100% humidity) after being exposed in the field for 2–6 days for rainfall events, and for one day for irrigation events. After a 48 h incubation period, trap plants were transferred to a glasshouse (20 °C) to allow lesion development. Lesions on all plant parts were counted after two weeks, which gave an estimate of the number of conidia released and the distance travelled. Trap plants at all distances were infected in all sprinkler irrigation and rainfall events. The highest number of lesions on trap plants were recorded closest to the infected plots – the numbers decreased as the distance from the infected plots increased. There was a positive relationship between the amount of rainfall and the number of lesions recorded. A generalised additive model was developed that efficiently described spatial patterns of conidial spread. With further development, the model can be used to predict the spread of A. rabiei. This is the first systematic study to show that conidia distribute A. rabiei over longer distances than previously reported.

Collection and Analysis of Urban Runoff Data in Finland

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1175-1185 ◽  
Author(s):  
M. J. Melanen
Keyword(s):  
Waste Water Treatment ◽  
Urban Runoff ◽  
Waste Waters ◽  
Runoff Water ◽  
Rainfall Events ◽  
Water Treatment Plants ◽  
The City ◽  
City Centres ◽  
Sewer Networks

An extensive three-year urban hydrology programme was carried out in Finland. Data were collected and analysed on the quantity and quality of precipitation and runoff water at seven urban test catchments. During rainfall events, on the average, the proportion of surfaces generating direct runoff was found to account for 50-80 per cent of the proportion of paved surfaces in the residential catchments, and for 80-90 per cent in the city centres. Under Finnish conditions, the pollutant loads discharged to recipients with untreated runoff waters are relatively minor in comparison to those of purified waste waters, regarding organic matter and nutrients. Further measures in the Finnish sewage works should thus be focused on other factors, such as increasing the effectiveness of the existing waste water treatment plants, and decreasing the amount of leakage inflows to sewer networks.

scholarly journals Intense Precipitation Events Associated with Landfalling Tropical Cyclones in Response to a Warmer Climate and Increased CO2

2014 ◽  
Vol 27 (12) ◽  
pp. 4642-4654 ◽  
Author(s):  
Enrico Scoccimarro ◽  
Silvio Gualdi ◽  
Gabriele Villarini ◽  
Gabriel A. Vecchi ◽  
Ming Zhao ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Atmospheric Carbon Dioxide ◽  
Sea Surface ◽  
Special Focus ◽  
Relative Role ◽  
Rainfall Events ◽  
Landfalling Tropical Cyclones ◽  
Precipitation Changes ◽  
Precipitation Events

Abstract In this work the authors investigate possible changes in the intensity of rainfall events associated with tropical cyclones (TCs) under idealized forcing scenarios, including a uniformly warmer climate, with a special focus on landfalling storms. A new set of experiments designed within the U.S. Climate Variability and Predictability (CLIVAR) Hurricane Working Group allows disentangling the relative role of changes in atmospheric carbon dioxide from that played by sea surface temperature (SST) in changing the amount of precipitation associated with TCs in a warmer world. Compared to the present-day simulation, an increase in TC precipitation was found under the scenarios involving SST increases. On the other hand, in a CO2-doubling-only scenario, the changes in TC rainfall are small and it was found that, on average, TC rainfall tends to decrease compared to the present-day climate. The results of this study highlight the contribution of landfalling TCs to the projected increase in the precipitation changes affecting the tropical coastal regions.

Effect of age and rainfall pH on contaminant yields from metal roofs

2014 ◽  
Vol 69 (10) ◽  
pp. 2166-2173 ◽  
Author(s):  
Daniel Wicke ◽  
Thomas A. Cochrane ◽  
Aisling D. O'Sullivan ◽  
Simon Cave ◽  
Mark Derksen
Keyword(s):  
Urban Runoff ◽  
Weather Conditions ◽  
Urban Streams ◽  
Galvanized Steel ◽  
Combined Effects ◽  
Metal Mobilization ◽  
Runoff Water ◽  
Roof Runoff ◽  
Rainfall Events ◽  
Effect Of Age

Metal roofs are recognized for conveying significant metal loads to urban streams through stormwater runoff. Metal concentrations in urban runoff depend on roof types and prevailing weather conditions but the combined effects of roof age and rainfall pH on metal mobilization are not well understood. To investigate these effects on roof runoff, water quality was analysed from galvanized iron and copper roofs following rainfall events and also from simulating runoff using a rainfall simulator on specially constructed roof modules. Zinc and copper yields under different pH regimes were investigated for two roof materials and two different ages. Metal mobilization from older roofs was greater than new roofs with 55-year-old galvanized roof surfaces yielding more Zn, on average increasing by 45% and 30% under a rainfall pH of 4 and 8, respectively. Predominantly dissolved (85–95%) Zn and Cu concentrations in runoff exponentially increased as the rainfall pH decreased. Results also confirmed that copper guttering and downpipes associated with galvanized steel roof systems can substantially increase copper levels in roof runoff. Understanding the dynamics of roof surfaces as a function of weathering and rainfall pH regimes can help developers with making better choices about roof types and materials for stormwater improvement.

The role of monsoon low-level jet in modulating heavy rainfall events

2017 ◽  
Vol 38 ◽  
pp. e569-e576 ◽  
Author(s):  
Anu Xavier ◽  
Ajil Kottayil ◽  
K. Mohanakumar ◽  
Prince K. Xavier
Keyword(s):  
Heavy Rainfall ◽  
Rainfall Events ◽  
Low Level ◽  
Low Level Jet ◽  
Heavy Rainfall Events

scholarly journals Assessing methods for the estimation of response times of stream discharge: the role of rainfall duration

2019 ◽  
Vol 67 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Jaime G. Cuevas ◽  
José L. Arumí ◽  
José Dörner
Keyword(s):  
Response Times ◽  
Stream Velocity ◽  
Middle Point ◽  
Rainfall Events ◽  
Average Value ◽  
Stream Discharge ◽  
Rainfall Duration ◽  
Watershed Dynamics ◽  
The Mean

Abstract Lagtimes and times of concentration are frequently determined parameters in hydrological design and greatly aid in understanding natural watershed dynamics. In unmonitored catchments, they are usually calculated using empirical or semiempirical equations developed in other studies, without critically considering where those equations were obtained and what basic assumptions they entailed. In this study, we determined the lagtimes (LT) between the middle point of rainfall events and the discharge peaks in a watershed characterized by volcanic soils and swamp forests in southern Chile. Our results were compared with calculations from 24 equations found in the literature. The mean LT for 100 episodes was 20 hours (ranging between 0.6–58.5 hours). Most formulae that only included physiographic predictors severely underestimated the mean LT, while those including the rainfall intensity or stream velocity showed better agreement with the average value. The duration of the rainfall events related significantly and positively with LTs. Thus, we accounted for varying LTs within the same watershed by including the rainfall duration in the equations that showed the best results, consequently improving our predictions. Izzard and velocity methods are recommended, and we suggest that lagtimes and times of concentration must be locally determined with hyetograph-hydrograph analyses, in addition to explicitly considering precipitation patterns.

scholarly journals The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines

2021 ◽  
Vol 21 (5) ◽  
pp. 1531-1550
Author(s):  
Clàudia Abancó ◽  
Georgina L. Bennett ◽  
Adrian J. Matthews ◽  
Mark Anthony M. Matera ◽  
Fibor J. Tan
Keyword(s):  
Soil Moisture ◽  
High Intensity ◽  
The Philippines ◽  
Saturation Point ◽  
Rainfall Events ◽  
Precipitation Measurement ◽  
Global Precipitation Measurement ◽  
Global Precipitation ◽  
First Time

Abstract. In 2018 Typhoon Mangkhut (locally known as Typhoon Ompong) triggered thousands of landslides in the Itogon region of the Philippines. A landslide inventory of the affected region is compiled for the first time, comprising 1101 landslides over a 570 km2 area. The inventory is used to study the geomorphological characteristics and land cover more prone to landsliding as well as the hydrometeorological conditions that led to widespread failure. The results showed that landslides mostly occurred on grassland and wooded slopes of clay superficial geology, predominantly facing east-southeast. Rainfall (Integrated Multi-satellitE Retrievals for Global Precipitation Measurement, IMERG GPM) associated with Typhoon Mangkhut is compared with 33 high-intensity rainfall events that did not trigger regional landslide events in 2018. Results show that landslides occurred during high-intensity rainfall that coincided with the highest soil moisture values (estimated clays saturation point), according to Soil Moisture Active Passive level 4 (SMAP-L4) data. Our results demonstrate the potential of SMAP-L4 and GPM IMERG data for landslide hazard assessment and early warning where ground-based data are scarce. However, other rainfall events in the months leading up to Typhoon Mangkhut that had similar or higher rainfall intensities and also occurred when soils were saturated did not trigger widespread landsliding, highlighting the need for further research into the conditions that trigger landslides in typhoons.

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