scholarly journals Factors affecting the runoff coefficient

2012 ◽  
Vol 9 (4) ◽  
pp. 4919-4941 ◽  
Author(s):  
G. Del Giudice ◽  
R. Padulano ◽  
G. Rasulo
Keyword(s):  
Curve Number ◽  
Runoff Coefficient ◽  
Drainage Basins ◽  
Simple Analytical Expression ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Factors Affecting ◽  
Flood Peak ◽  
The Us

Abstract. The runoff coefficient φ is a crucial parameter for flood peak discharge estimate in ungauged drainage basins. Tables and graphs generally allow the determination of φ in a somewhat empirical way that can lead to inconsistency in application; therefore, it is important to identify other parameters that can be utilized to assess φ more directly. In the present paper, focusing on Southern Continental Italy, a simple analytical expression between runoff coefficient φ and soil potential maximum retention S is proposed; moreover, an improvement of this expression is provided by considering the pre-event moisture condition of the watershed through the use of a climatic factor. At this aim, the US Soil Conservation Service classification for soil permeability has been adopted, that allows the evaluation of S, according to its relationship with the runoff curve number CN, as a function of soil type, land use and antecedent soil moisture condition (AMC).

scholarly journals Formulation of Parsimonious Urban Flash Flood Predictive Model with Inferential Statistics

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 175
Author(s):  
Lloyd Ling ◽  
Sai Hin Lai ◽  
Zulkifli Yusop ◽  
Ren Jie Chin ◽  
Joan Lucille Ling
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Flash Flood ◽  
Curve Number ◽  
Runoff Coefficient ◽  
Rainfall Runoff ◽  
Inferential Statistics ◽  
Moisture Condition ◽  
Antecedent Moisture ◽  
Runoff Model

The curve number (CN) rainfall–runoff model is widely adopted. However, it had been reported to repeatedly fail in consistently predicting runoff results worldwide. Unlike the existing antecedent moisture condition concept, this study preserved its parsimonious model structure for calibration according to different ground saturation conditions under guidance from inferential statistics. The existing CN model was not statistically significant without calibration. The calibrated model did not rely on the return period data and included rainfall depths less than 25.4 mm to formulate statistically significant urban runoff predictive models, and it derived CN directly. Contrarily, the linear regression runoff model and the asymptotic fitting method failed to model hydrological conditions when runoff coefficient was greater than 50%. Although the land-use and land cover remained the same throughout this study, the calculated CN value of this urban watershed increased from 93.35 to 96.50 as the watershed became more saturated. On average, a 3.4% increase in CN value would affect runoff by 44% (178,000 m3). This proves that the CN value cannot be selected according to the land-use and land cover of the watershed only. Urban flash flood modelling should be formulated with rainfall–runoff data pairs with a runoff coefficient > 50%.

Synchronicity and drivers of river flooding

2020 ◽  
Author(s):  
Wouter Berghuijs ◽  
James Kirchner
Keyword(s):  
Soil Moisture ◽  
Heavy Precipitation ◽  
Flood Forecasting ◽  
Drainage Basins ◽  
Antecedent Soil Moisture ◽  
River Flooding ◽  
Flood Risks ◽  
The Us ◽  
Order Of Magnitude ◽  
Precipitation Events

<p>When rivers flood, surrounding rivers often flood at the same time. When large precipitation events occur, floods do not always occur. Here we explore the drivers and synchronicity of river flooding. Using flood data from thousands of European and US rivers, we demonstrate that the <em>flood synchrony scale</em>—the distance over which multiple rivers flood near synchronously—far exceeds the size of individual drainage basins and varies regionally by more than an order of magnitude. Regions of large flood synchrony scales are mostly uncorrelated with regions of large precipitation synchrony scales; across most of Europe and the US few floods are caused by the biggest rainfall peaks. Instead, most floods are caused by the concurrence of heavy precipitation with high antecedent soil moisture. Risk finance, flood forecasting, and interpretations of flood trends can benefit from accounting for what drives flooding and how flood risks extend beyond the borders of individual drainage basins.</p>

scholarly journals A comparative analysis of the effectiveness of flood management measures based on the concept of "retaining water in the landscape" in different European hydro-climatic regions

2012 ◽  
Vol 12 (11) ◽  
pp. 3287-3306 ◽  
Author(s):  
S. Salazar ◽  
F. Francés ◽  
J. Komma ◽  
T. Blume ◽  
T. Francke ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Storage Capacity ◽  
Methodological Approach ◽  
Flood Management ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Climatic Regions ◽  
General Terms ◽  
Management Measures

Abstract. In this paper, we analyse the effectiveness of flood management measures based on the concept known as "retaining water in the landscape". The investigated measures include afforestation, micro-ponds and small-reservoirs. A comparative and model-based methodological approach has been developed and applied for three meso-scale catchments located in different European hydro-climatological regions: Poyo (184 km2) in the Spanish Mediterranean, Upper Iller (954 km2) in the German Alps and Kamp (621 km2) in Northeast-Austria representing the Continental hydro-climate. This comparative analysis has found general similarities in spite of the particular differences among studied areas. In general terms, the flood reduction through the concept of "retaining water in the landscape" depends on the following factors: the storage capacity increase in the catchment resulting from such measures, the characteristics of the rainfall event, the antecedent soil moisture condition and the spatial distribution of such flood management measures in the catchment. In general, our study has shown that, this concept is effective for small and medium events, but almost negligible for the largest and less frequent floods: this holds true for all different hydro-climatic regions, and with different land-use, soils and morphological settings.

scholarly journals Spatiotemporal impact of antecedent drought on hot extremes from the nonstationary risk perspective: A case study in eastern China

2021 ◽  
Author(s):  
Pengcheng Xu ◽  
Dong Wang ◽  
Yuankun Wang ◽  
Vijay Singh ◽  
Jianchun Qiu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Eastern China ◽  
Extreme Temperature ◽  
Dependence Structure ◽  
Sensitivity Index ◽  
Driving Mechanism ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition

Hot extremes may adversely impact human health and agricultural production. Owing to anthropogenic and climate changes, the close and dynamic interaction between drought and hot extremes in most areas of China need to be revisited from the perspective of nonstationarity. This study therefore proposes a time-varying Copula-based model to describe the nonstationary dependence structure of extreme temperature (ET) and antecedent soil moisture condition to quantify the dynamic risk of hot extremes conditioned on dry/wet condition. This study proposed a new approach to identify the soil moisture driving law over extreme temperature from the point view of tail monotonicity and nonstationary risk assessment. Owing to the LTI-RTD (left tail increasing and right tail decreasing) tail monotonicity for dependence structure of these two extremes derived from most areas, the driving laws of soil moisture over ET follows DDL1-WDL1 laws (DDL1: drier antecedent soil moisture condition would trigger a higher risk of ET; WDL1: wetter antecedent soil moisture condition would alleviate the occurrence risk of ET). Because of the spatiotemporal divergence of sensitivity index derived from tail monotonicity (SITM), we can conclude that the spatial and temporal heterogeneity of response degree of ET over the variations of antecedent dry/wet conditions is evident. Incorporation of nonstationarity and tail monotonicity helps identify the changes of driving mechanism (laws) between soil moisture and hot extremes. From the comparison of different kinds of nonstationary behaviours over the spatial distribution of conditional probability of ET (CP1), the dependence nonstationarity can impose greater variations on the spatial distribution of conditional risk of ET given antecedent dry condition (CP1).

Spatial prediction of the runoff coefficient in Southern Peninsular Italy for the index flood estimation

2013 ◽  
Vol 45 (2) ◽  
pp. 263-281 ◽  
Author(s):  
G. Del Giudice ◽  
R. Padulano ◽  
G. Rasulo
Keyword(s):  
Spatial Prediction ◽  
Mean Value ◽  
Transformation Model ◽  
Runoff Coefficient ◽  
Moisture Condition ◽  
Flood Peak ◽  
Antecedent Moisture ◽  
Index Flood ◽  
Flood Estimation ◽  
Direct Measures

The runoff coefficient φ is a crucial parameter for the estimation of the mean value of annual maximum flood peak discharges in ungauged watersheds, where no direct measures are available. If the rational method is applied as a rainfall–runoff transformation model, the runoff coefficient accounts for all the hydrological losses, and it can be conceptually defined as the fraction of the total rainfall contributing to the flood peak response. In the present paper, focusing on Southern Peninsular Italy, a regression model is proposed to improve the prediction of the above defined runoff coefficient as a function of several parameters describing both morphological and mean annual climatic watershed characteristics. Morphological features are described by using the Soil Conservation Service permeability classification and the related variable S, referred to an average antecedent moisture condition. Different climatic indices enable a subsequent enhancement of S in order to account for the specific mean annual moisture condition of each watershed.

PENGARUH KONDISI AWAL KELENGASAN TANAH TERHADAP DEBIT PUNCAK HIDROGRAF SATUAN

2017 ◽  
Vol 13 (3) ◽  
pp. 228
Author(s):  
Sasmito Sasmito ◽  
Bambang Triatmodjo ◽  
Joko Sujono ◽  
Sri Harto, Br
Keyword(s):  
Soil Moisture ◽  
Storage Capacity ◽  
Soil Moisture Deficit ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Moisture Deficit

Abstrak: Hidrograf satuan adalah salah satu cara untuk memperkirakan besarnya banjir di sungai akibat hujan pada suatu DAS. Hidrograf satuan sangat populer dan dipakai secara luas di dunia. Metode ini mempunyai fleksibilitas yang rendah terhadap hujan yang berbeda, sehingga hidrograf yang dihasilkan berbeda-beda pada setiap hujan. Hal ini diduga disebabkan antara lain karena teori hidrograf satuan mengabaikan pengaruh kondisi awal kelengasan tanah (antecedent soil moisture condition, AMC) pada proses penurunan hidrograf satuan. Tulisan ini menyajikan hasil penelitian tentang pengaruh AMC terhadap debit puncak hidrograf satuan observasi (qp-obs). Dalam penelitian ini variabel AMC didekati dengan besaran defisit kelengasan tanah (soil moisture deficit, SMD) yang mempunyai makna berlawanan dengan AMC. SMD direpresentasikan dengan variabel Sc (storage capacity) yakni volume udara di dalam pori tanah yang ditinggalkan air karena terevapotranspirasi keluar. Penelitian dilaksanakan dengan menggunakan data hidrologi (hujan, debit aliran, dan evaporasi) yang dikumpulkan dari 3 DAS hulu (upper catchment) di kawasan Gunung Merapi. Percobaan penelitian dilakukan dengan cara menurunkan hidrograf satuan dengan dua cara, yakni cara konvensional (Collins) menghasilkan hidrograf satuan observasi (HSosb), dan cara simulasi menggunakan model tangki menghasilkan hidrograf satuan simulasi (HSsim). Analisis pengaruh Sc dilakukan terhadap debit puncak HSosb dan debit puncak HSsim. Penelitian menghasilkan temuan yang dapat disimpulkan sebagai berikut: (1) Hubungan Sc dan debit puncak hidrograf satuan, menunjukkan semakin besar Sc (semakin kecil AMC) debit puncak HSobs semakin kecil, (2) Formula koreksi yang didapat berbentuk fungsi eksponensial (qp-obs)/(qp-obs-kor)=1,104 e-0,012Sc, dengan qp-obs-kor adalah debit puncak hidrograf satuan observasi terkoreksi, (3)  HS observasi terkoreksi rerata mempunyai debit puncak puncak paling tinggi dibanding debit puncak HSS Nakayasu dan debit puncak HSS Gama 1.

scholarly journals Application of the SCS–CN Method to the Hancheon Basin on the Volcanic Jeju Island, Korea

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3350
Author(s):  
Minseok Kang ◽  
Chulsang Yoo
Keyword(s):  
Negative Correlation ◽  
The Other ◽  
Jeju Island ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Rainfall Events ◽  
Initial Abstraction ◽  
Other Hand ◽  
Scs Cn

This study investigates three issues regarding the application of the SCS–CN (Soil Conservation Service–Curve Number) method to a basin on the volcanic Jeju Island, Korea. The first issue is the possible relation between the initial abstraction and the maximum potential retention. The second is the determination of the maximum potential retention, which is also closely related to the estimation of CN. The third issue is the effect of the antecedent soil moisture condition (AMC) on the initial abstraction, maximum potential retention and CN. All of these issues are dealt with based on the analysis of several rainfall events observed in the Hancheon basin, a typical basin on Jeju Island. In summary, the results are that, firstly, estimates of initial abstraction, ratio λ, maximum potential retention, and CN were all found to be consistent with the SCS–CN model structure. That is, CN and the maximum potential retention showed a strong negative correlation, and the ratio λ and the maximum potential retention also showed a rather weak negative correlation. On the other hand, a significant positive correlation was found between CN and the ratio λ. Second, in the case where the accumulated number of days is four or five, the effect of antecedent precipitation amount is clear. The antecedent five-day rainfall amount for the AMC-III condition is higher than 400 mm, compared to the AMC-I condition of less than 100 mm. Third, an inverse proportional relationship is found between the AMC and the maximum potential retention. On the other hand, a clear linear proportional relation is found between the AMC and CN. Finally, the maximum potential retention for the Hancheon basin is around 200 mm, with the corresponding CN being around 65. The ratio between the initial abstraction and the maximum potential retention is around 0.3. Even though these results are derived by analyzing a limited number of rainfall events, they are believed to properly consider the soil characteristics of Jeju Island.

Soil Moisture and Streamflow Relationship in Forested Hillslope: A Perspective on their Hysteretic Behavior.

2021 ◽  
Author(s):  
Bassey Bassey Friday ◽  
Eunhyung Lee ◽  
Sanghyun Kim
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Meteorological Data ◽  
Hysteretic Behavior ◽  
Bivariate Analysis ◽  
Storm Event ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
General Response

<p>The hysteretic behavior between soil moisture and streamflow has received only little attention in the context of hillslope hydrological processes, despite the overarching role it plays in the understanding of the temporal and spatial dynamics of hillslope responses. In this study, hydro-meteorological data were collected daily on bi-hourly basis from 2009 to 2013 over 56 soil moisture measuring points at various depths (10, 30, and 60 cm) with 147 distinct storm events chosen for investigation. A bivariate analysis approach was implemented to characterize 8,232 hysteretic behaviors between streamflow and soil moisture with a view to exploring its patterns and uniformities using data obtained in the following timescale - the whole period of campaign, seasonally and storm event. In addition, hydrological control features such as antecedent soil moisture, rainfall intensity and duration, soil depth and hillslope positions were examined to establish the degree of control it poses on hillslope responses. Our investigation showed three dominant responses – clockwise, counter-clockwise and no response. Clockwise response which implied that streamflow peaked before soil moisture, governed the entire period of campaign with the frequency of responses significantly decreasing as depth increases, except for some downslope points located around the riparian zone. Furthermore, distinct variation in the hysteretic behavior of the hillslope under seasonal timescale was observed, with clockwise responses dominating summer and fall season whereas counter clockwise responses prevailed in the spring season. Our findings further reveals that antecedent soil moisture condition and soil depth were the major drivers that influenced the general response of the hillslope.</p>

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