Improving runoff estimation by raster‐based Natural Resources Conservation Service‐Curve Number adjustment for a new initial abstraction ratio in semi‐arid climates

2021 ◽  
Author(s):  
Abolghasem Akbari ◽  
Farshid Daryabor ◽  
Azizan Abu Samah ◽  
Zahra Shirmohammadi Aliakbarkhani
Keyword(s):  
Natural Resources ◽  
Curve Number ◽  
Initial Abstraction ◽  
Resources Conservation ◽  
Service Curve ◽  
Semi Arid

scholarly journals Variability of the Initial Abstraction Ratio in an Urban and an Agroforested Catchment

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 415 ◽  
Author(s):  
Adam Krajewski ◽  
Anna E. Sikorska-Senoner ◽  
Agnieszka Hejduk ◽  
Leszek Hejduk
Keyword(s):  
Land Use ◽  
Curve Number ◽  
Threshold Value ◽  
Storm Events ◽  
Direct Runoff ◽  
Initial Abstraction ◽  
Land Use Types ◽  
Rainfall Depth ◽  
Storm Rainfall ◽  
Service Curve

The Curve Number method is one of the most commonly applied methods to describe the relationship between the direct runoff and storm rainfall depth. Due to its popularity and simplicity, it has been studied extensively. Less attention has been given to the dimensionless initial abstraction ratio, which is crucial for an accurate direct runoff estimation with the Curve Number. This ratio is most often assumed to be equal to 0.20, which was originally proposed by the method’s developers. In this work, storm events recorded in the years 2009–2017 in two small Polish catchments of different land use types (urban and agroforested) were analyzed for variability in the initial abstraction ratio across events, seasons, and land use type. Our results showed that: (i) estimated initial abstraction ratios varied between storm events and seasons, and were most often lower than the original value of 0.20; (ii) for large events, the initial abstraction ratio in the catchment approaches a constant value after the rainfall depth exceeds a certain threshold value. Thus, when using the Soil Conservation Service-Curve Number (SCS-CN) method, the initial abstraction ratio should be locally verified, and the conditions for the application of the suggested value of 0.20 should be established.

scholarly journals Evaluation of Sediment Yield and Risk Management of Sediment Disaster With the Natural Resources Conservation Service-Curve Number Method

2021 ◽  
Author(s):  
Wen-Yan Zhang
Keyword(s):  
Sediment Yield ◽  
Curve Number ◽  
Cumulative Number ◽  
Rating Curve ◽  
Resources Conservation ◽  
Service Curve ◽  
Sediment Disaster ◽  
The Relationship ◽  
Potential Maximum

Subtropical areas are often struck by typhoons. The sediment disasters that accompany typhoons severely affect the environment. However, sediment yield (SY) data usually lack integrity. This study used long-term daily river discharge and SY data to establish a runoff–SY rating curve (Q–Qs rating curve) and used it to estimate the SY of typhoon events. In addition, based on the curve number, this study analyzed the relationship between the potential maximum retention (S) and SY; the results showed that different amounts of cumulative rainfall correspond to different S–SY functions; thus, the potential maximum erosion (A) of the catchment area could be estimated using this characteristic. For a sediment management strategy, this study took subdivisions as a unit and incorporated the potential maximum erosion (A) and slope to establish a map indicating the spatial distribution of sediment disaster risks. To determine the priority areas for management, the relationship between the cumulative number of subdivisions and landslide rate could be used to determine the areas with high potential, which can serve as a reference for related management research.

Determination of SCS-CN initial abstraction ratio in a catchment prone to flash floods

2020 ◽  
Vol 15 (1) ◽  
pp. 112-123 ◽  
Author(s):  
Martin Caletka ◽  
Monika Šulc Michalková
Keyword(s):  
Surface Runoff ◽  
Soil Conservation ◽  
Curve Number ◽  
Flash Floods ◽  
Soil Conservation Service ◽  
Initial Abstraction ◽  
Service Curve ◽  
Scs Cn ◽  
Proper Setting

Abstract The soil conservation service - curve number method is a globally used approach to simulations of surface runoff for its simplicity and applicability. Nevertheless, relevant simulations require proper setting of the model's components. This work focuses on optimization of initial abstraction ratio λ in the Husí potok sub-catchments in Czech Republic. Due to favorable morphology, the watershed is prone to flash floods and accurate modeling of surface runoff is of high interest. The analysis was conducted using pairs of discharge and rainfall measurements. The results outline that the traditional value λ= 0.2 is too high in this watershed and should be reduced.

scholarly journals Método Curve Number – pesquisas e discussões dos parâmetros valor CN e abstração inicial

2021 ◽  
Vol 25 ◽  
pp. e31
Author(s):  
Fabio Carvalho ◽  
Silvio Carlos Rodrigues
Keyword(s):  
Natural Resources ◽  
Curve Number ◽  
Resources Conservation

O estudo de condições de resposta ao processo de precipitação e geração de escoamento é um dos desafios em estudos hidrogeomorfológicos. Entre estudos existentes, o Método CN tornou-se importante devido à sua facilidade de aplicação a partir da utilização de parâmetros físicos, de uso e ocupação da terra e de dados de chuva, estimando o escoamento superficial e o armazenamento potencial de bacias hidrográficas, fornecendo informações hidrológicas para a tomada de decisões. Este trabalho objetiva apresentar aspectos históricos e de desenvolvimento do Método CN, bem como pesquisas e discussões do parâmetro principal da metodologia conhecido como valor CN e da abstração inicial (Ia), segundo revisão de literatura. Os valores CN contidos em tabelas e gráficos do Natural Resources Conservation Service (NRCS) consideram o índice de Ia=0,2, todavia, pesquisas indicam variações nos índices de Ia. Valores CN e índices de Ia podem ser conseguidos mediante dados de precipitação e de escoamento superficial obtidos em bacias hidrográficas e por experimentos com chuvas artificiais em parcelas experimentais, fornecendo informações locais. Abordagens utilizando pesquisas e experimentos regionais demonstram que podem melhorar os parâmetros do Método CN para algumas regiões, gerando melhor estimativa do escoamento superficial. Os índices de abstração inicial alteram o escoamento superficial estimado pela metodologia, e pesquisas indicam que o índice de Ia=0,2 ser elevado para algumas condições edafoclimáticas.

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.

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