Probablistic analysis of runoff simulations in a small urban catchment

1997 ◽  
Vol 36 (8-9) ◽  
pp. 51-56
Author(s):  
F. Calomino ◽  
P. Veltri ◽  
P. Piro ◽  
J. Niemczynowicz
Keyword(s):  
Frequency Distribution ◽  
Basic Question ◽  
Rainfall Runoff ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Frequency Distributions ◽  
The Common ◽  
Runoff Events ◽  
Peak Discharges ◽  
Good Agreement

In Urban Hydrology, a basic question is whether or not the common methods involving the use of design storms bring to the the some results obtained by those methods that make use of real storms. In general, one can say that different design storms give good results when used with the appropriate model, or, conversely, that good results can be achieved through careful model calibration. On the basis of 51 rainfall-runoff recordings obtained from the experimental catchment of Luzzi (Cosenza, Italy), the frequency distribution of the observed peak discharges was initially computed. Then the runoff events were simulated using Wallrus, a well known simulation model, taking as input the observed precipitations. The frequency distribution of the simulated peak discharges was compared to that of the observed ones, with the aim of calibrating the model on a statistical basis. After that, the rainfall events were analysed, obtaining the frequency distributions of the observed intensities over several durations and developing IDF curves of given frequencies and, then, the Chicago design storms. The plotting positions of the peak discharges simulated by this way show a good agreement with the distribution of both the observed peak discharges and the peak discharges simulated through the real storms.

scholarly journals Curve Number Estimation for a Small Urban Catchment from Recorded Rainfall-Runoff Events

2014 ◽  
Vol 40 (3) ◽  
pp. 75-86 ◽  
Author(s):  
Kazimierz Banasik ◽  
Adam Krajewski ◽  
Anna Sikorska ◽  
Leszek Hejduk
Keyword(s):  
Urban Areas ◽  
Land Use Changes ◽  
Low Impact Development ◽  
Curve Number ◽  
Rainfall Runoff ◽  
Ungauged Catchments ◽  
Department Of Agriculture ◽  
Urban Catchment ◽  
Urban Catchments ◽  
Runoff Events

Abstract Runoff estimation is a key component in various hydrological considerations. Estimation of storm runoff is especially important for the effective design of hydraulic and road structures, for the flood flow management, as well as for the analysis of land use changes, i.e. urbanization or low impact development of urban areas. The curve number (CN) method, developed by Soil Conservation Service (SCS) of the U.S. Department of Agriculture for predicting the flood runoff depth from ungauged catchments, has been in continuous use for ca. 60 years. This method has not been extensively tested in Poland, especially in small urban catchments, because of lack of data. In this study, 39 rainfall-runoff events, collected during four years (2009–2012) in a small (A=28.7 km2), urban catchment of Służew Creek in southwest part of Warsaw were used, with the aim of determining the CNs and to check its applicability to ungauged urban areas. The parameters CN, estimated empirically, vary from 65.1 to 95.0, decreasing with rainfall size and, when sorted rainfall and runoff separately, reaching the value from 67 to 74 for large rainfall events.

scholarly journals Analysis of the runoff response of an Alpine catchment at different scales

2005 ◽  
Vol 2 (5) ◽  
pp. 1923-1960 ◽  
Author(s):  
B. Zillgens ◽  
B. Merz ◽  
R. Kirnbauer ◽  
N. Tilch
Keyword(s):  
Spatial Scales ◽  
Rainfall Runoff ◽  
Event Type ◽  
Catchment Scale ◽  
Small Catchment ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Micro Scale ◽  
Long Duration ◽  
Runoff Events

Abstract. To understand how hydrological processes are related across different spatial scales, 201 rainfall runoff events were examined in three nested catchments of the upper river Saalach in the Austrian Alps. The Saalach basin is a nested catchment covering different spatial scales, from the micro-scale (Limberg, 0.07 km2), to the small-catchment scale (Rammern, 15.5 km2), and the meso-scale (Viehhofen, 150 km2). At these three scales two different event types could clearly be identified, depending on rainfall characteristics and initial baseflow level: (1) a unimodal event type with a quick rising and falling hydrograph, responding to short duration rainfall, and (2) a bimodal event type with a double peak hydrograph at the micro-scale and substantially increased flow values at the larger basins Rammern and Viehhofen, responding to long duration rainfall events. In all cases where a bimodal event was identified at the microscale, the hydrographs at the larger scales exhibited significantly attenuated recession behavior, quantified by recession constants. At all scales, the bimodal events are associated with considerably higher runoff volumes than the unimodal events. From the investigations at the headwater Limberg we came to the conclusion that the higher amount of runoff of bimodal events is due to the mobilization of subsurface flow processes. The analysis shows that the occurrence of the two event types is consistent over three orders of magnitude in area. This link between the scales means that the runoff behavior of the headwater may be used as an indicator of the runoff behavior of much larger areas.

The rational method revisited

1984 ◽  
Vol 11 (4) ◽  
pp. 854-862 ◽  
Author(s):  
Alan A. Smith ◽  
Ken-Beck Lee
Keyword(s):  
Response Function ◽  
Design Tool ◽  
Rational Method ◽  
Rainfall Runoff ◽  
Computer Design ◽  
Convolution Process ◽  
Runoff Hydrographs ◽  
Impervious Areas ◽  
Runoff Events ◽  
Good Agreement

Despite the increasing availability of more-sophisticated methods for simulating rainfall–runoff events, the 'rational method' continues to be used as a design tool in many municipal engineering offices. This paper examines the basic assumptions of the method and shows how hydrographs from impervious areas can be accurately simulated by a simple convolution process using the rectangular response function implied in the rational method. The use of the dynamically varying response function appears to give improved results. Moreover, in the example illustrated, routing of the runoff through a hypothetical reservoir appears to be unnecessary.For pervious areas, a method is suggested whereby the runoff coefficient is varied as a function of the time-dependent storage potential in the soil. For events with modest rainfall abstractions, the method appears to give good agreement with observed runoff hydrographs, but inclusion of a routing process through a cascade of reservoirs seems to be necessary in this case. Key words: computer, design, hydrology, rainfall, rational, runoff.

scholarly journals Analysis of the runoff response of an alpine catchment at different scales

2007 ◽  
Vol 11 (4) ◽  
pp. 1441-1454 ◽  
Author(s):  
B. Zillgens ◽  
B. Merz ◽  
R. Kirnbauer ◽  
N. Tilch
Keyword(s):  
Spatial Scales ◽  
Rainfall Runoff ◽  
Event Type ◽  
Catchment Scale ◽  
Small Catchment ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Micro Scale ◽  
Long Duration ◽  
Runoff Events

Abstract. To understand how hydrological processes are related across different spatial scales, 201 rainfall runoff events were examined in three nested catchments of the upper river Saalach in the Austrian Alps. The Saalach basin is a nested catchment covering different spatial scales, from the micro-scale (Limberg, 0.07 km²), to the small-catchment scale (Rammern, 15.5 km²), and the meso-scale (Viehhofen, 150 km²). At these three scales two different event types could clearly be identified, depending on rainfall characteristics and initial baseflow level: (1) a unimodal event type with a quick rising and falling hydrograph, responding to short duration rainfall, and (2) a bimodal event type with a double peak hydrograph at the micro-scale and substantially increased flow values at the larger basins Rammern and Viehhofen, responding to long duration rainfall events. In all cases where a bimodal event was identified at the microscale, the hydrographs at the larger scales exhibited significantly attenuated recession behavior, quantified by recession constants. At all scales, the bimodal events are associated with considerably higher runoff volumes than the unimodal events. From the investigations at the headwater Limberg we came to the conclusion that the higher amount of runoff of bimodal events is due to the mobilization of subsurface flow processes. The analysis shows that the occurrence of the two event types is consistent over three orders of magnitude in area. This link between the scales means that the runoff behavior of the headwater may be used as an indicator of the runoff behavior of much larger areas.

High Resolution Measurements of Pollution Wash-Off from an Asphalt Surface

1992 ◽  
Vol 23 (4) ◽  
pp. 245-256 ◽  
Author(s):  
Å. Spångberg ◽  
J. Niemczynowicz
Keyword(s):  
Water Quality ◽  
High Resolution ◽  
Time Resolution ◽  
Quality Data ◽  
Rainfall Runoff ◽  
Water Quality Data ◽  
Urban Catchment ◽  
Complex Process ◽  
Surface Measurements ◽  
Fine Time

The paper describes a measurement project aiming at delivering water quality data with the very fine time resolution necessary to discover deterministic elements of the complex process of pollution wash-off from an urban surface. Measurements of rainfall, runoff, turbidity, pH, conductivity and temperature with 10 sec time resolution were performed on a simple urban catchment, i.e. a single impermeable 270 m2 surface drained by one inlet. The paper presents data collection and some preliminary results.

Origins and characteristics of urban wet weather pollution in combined sewer systems: the experimental urban catchment “Le Marais” in Paris

1998 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Marie-Christine Gromaire-Mertz ◽  
Ghassan Chebbo ◽  
Mohamed Saad
Keyword(s):  
Waste Water ◽  
Sewer System ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Sources Of Pollution ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow ◽  
Different Sources

An experimental urban catchment has been created in the centre of Paris, in order to obtain a description of the pollution of urban wet weather flows at different levels of the combined sewer system, and to estimate the contribution of runoff, waste water and sewer sediments to this pollution. Twenty-two rainfall events were studied from May to October 1996. Dry weather flow was monitored for one week. Roof, street and yard runoff, total flow at the catchment outlet and waste water were analysed for SS, VSS, COD and BOD5, on both total and dissolved fraction. Results show an evolution in the characteristics of wet weather flow from up to downstream: concentrations increase from the catchment entry to the outlet, as well as the proportion of particle-bound pollutants and the part of organic matter. A first evaluation of the different sources of pollution establishes that a major part of wet weather flow pollution originates from inside the combined sewer, probably through erosion of sewer sediments.

scholarly journals Multi-Objective Model-Based Assessment of Green-Grey Infrastructures for Urban Flood Mitigation

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 110
Author(s):  
Carlos Martínez ◽  
Zoran Vojinovic ◽  
Arlex Sanchez
Keyword(s):  
Green Infrastructure ◽  
Overland Flow ◽  
Flood Damage ◽  
Optimal Number ◽  
Rainfall Runoff ◽  
Urban Catchment ◽  
Model Based ◽  
Model Domain ◽  
Infiltration Processes ◽  
2D Model

This paper presents the performance quantification of different green-grey infrastructures, including rainfall-runoff and infiltration processes, on the overland flow and its connection with a sewer system. The present study suggests three main components to form the structure of the proposed model-based assessment. The first two components provide the optimal number of green infrastructure (GI) practices allocated in an urban catchment and optimal grey infrastructures, such as pipe and storage tank sizing. The third component evaluates selected combined green-grey infrastructures based on rainfall-runoff and infiltration computation in a 2D model domain. This framework was applied in an urban catchment in Dhaka City (Bangladesh) where different green-grey infrastructures were evaluated in relation to flood damage and investment costs. These practices implemented separately have an impact on the reduction of damage and investment costs. However, their combination has been shown to be the best action to follow. Finally, it was proved that including rainfall-runoff and infiltration processes, along with the representation of GI within a 2D model domain, enhances the analysis of the optimal combination of infrastructures, which in turn allows the drainage system to be assessed holistically.

Tunable balanced to balanced filtering power divider with high common-mode suppression

Frequenz ◽  
2020 ◽  
Vol 74 (7-8) ◽  
pp. 263-270
Author(s):  
Cao Zeng ◽  
Xue Han Hu ◽  
Feng Wei ◽  
Xiao Wei Shi
Keyword(s):  
Return Loss ◽  
High Selectivity ◽  
Power Divider ◽  
Center Frequency ◽  
Differential Mode ◽  
Common Mode ◽  
Mode Suppression ◽  
The Common ◽  
Equal Power ◽  
Good Agreement

AbstractIn this paper, a tunable balanced-to-balanced in-phase filtering power divider (FPD) is designed, which can realize a two-way equal power division with high selectivity and isolation. A differential-mode (DM) passband with a steep filtering performance is realized by applying microstrip stub-loaded resonators (SLRs). Meanwhile, six varactors are loaded to the SLRs to achieve the center frequency (CF) and bandwidth adjustment, respectively. U-type microstrip lines integrated with stepped impedance slotline resonators are utilized as the differential feedlines, which suppress the common-mode (CM) intrinsically, making the DM responses independent of the CM ones. A tuning center frequency from 3.2 to 3.75 GHz and a fractional bandwidth (12.1–17.6%) with more than 10 dB return loss and less than 2.3 dB insertion loss can be achieved by changing the voltage across the varactors. A good agreement between the simulated and measured results is observed. To the best of authors' knowledge, the proposed balanced-to-balanced tunable FPD is first ever reported.

scholarly journals Initial abstraction ratio and Curve Number estimation using rainfall and runoff data from a tropical watershed

RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Luiz Claudio Galvão do Valle Junior ◽  
Dulce Buchala Bicca Rodrigues ◽  
Paulo Tarso Sanches de Oliveira
Keyword(s):  
Conversion Factor ◽  
Poor Performance ◽  
Curve Number ◽  
Storm Events ◽  
Rainfall Runoff ◽  
Initial Abstraction ◽  
Rainfall Depth ◽  
Standard Value ◽  
Tropical Watershed ◽  
Runoff Events

ABSTRACT The Curve Number (CN) method is extensively used for predict surface runoff from storm events. However, remain some uncertainties in the method, such as in the use of an initial abstraction (λ) standard value of 0.2 and on the choice of the most suitable CN values. Here, we compute λ and CN values using rainfall and runoff data to a rural basin located in Midwestern Brazil. We used 30 observed rainfall-runoff events with rainfall depth greater than 25 mm to derive associated CN values using five statistical methods. We noted λ values ranging from 0.005 to 0.455, with a median of 0.045, suggesting the use of λ = 0.05 instead of 0.2. We found a S0.2 to S0.05 conversion factor of 2.865. We also found negative values of Nash-Sutcliffe Efficiency (to the estimated and observed runoff). Therefore, our findings indicated that the CN method was not suitable to estimate runoff in the studied basin. This poor performance suggests that the runoff mechanisms in the studied area are dominated by subsurface stormflow.

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.

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