Estimation of CN Parameter for Small Agricultural Watersheds Using Asymptotic Functions

Kowalik, Tomasz; Wałęga, Andrzej

doi:10.3390/w7030939

Cited by 48 publications

(37 citation statements)

References 37 publications

(48 reference statements)

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“…In most cases, the estimated CN fits quite well with the empirically-derived ones. These are subject to significant uncertainties, both because of the limited data sample, as well as the assumptions made when extracting them from observed flood data [64,65,74]. Clearer evidence of the good agreement of the proposed approach with the hydrological behavior of the examined catchments results from the high correlation of the estimated CNs with the observed average runoff coefficients; the latter are easily computed as the ratio of flood runoff to rainfall, and thus, they are not prone to arbitrary assumptions.…”

Section: Validation Based On Observed Flood Eventsmentioning

confidence: 95%

The Curve Number Concept as a Driver for Delineating Hydrological Response Units

Savvidou

Efstratiadis

Koussis

et al. 2018

Water

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Abstract:In this paper, a new methodology for delineating Hydrological Response Units (HRUs), based on the Curve Number (CN) concept, is presented. Initially, a semi-automatic procedure in a GIS environment is used to produce basin maps of distributed CN values as the product of the three classified layers, soil permeability, land use/land cover characteristics and drainage capacity. The map of CN values is used in the context of model parameterization, in order to identify the essential number and spatial extent of HRUs and, consequently, the number of control variables of the calibration problem. The new approach aims at reducing the subjectivity introduced by the definition of HRUs and providing parsimonious modelling schemes. In particular, the CN-based parameterization (1) allows the user to assign as many parameters as can be supported by the available hydrological information, (2) associates the model parameters with anticipated basin responses, as quantified in terms of CN classes across HRUs, and (3) reduces the effort for model calibration, simultaneously ensuring good predictive capacity. The advantages of the proposed approach are demonstrated in the hydrological simulation of the Nedontas River Basin, Greece, where parameterizations of different complexities are employed in a recently improved version of the HYDROGEIOS model. A modelling experiment with a varying number of HRUs, where the parameter estimation problem was handled through automatic optimization, showed that the parameterization with three HRUs, i.e., equal to the number of flow records, ensured the optimal performance. Similarly, tests with alternative HRU configurations confirmed that the optimal scores, both in calibration and validation, were achieved by the CN-based approach, also resulting in parameters values across the HRUs that were in agreement with their physical interpretation.

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Section: Validation Based On Observed Flood Eventsmentioning

confidence: 95%

The Curve Number Concept as a Driver for Delineating Hydrological Response Units

Savvidou

Efstratiadis

Koussis

et al. 2018

Water

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“…The wide use of this method is due to its applicability in different environments, its simplicity, and its dependence from soil types, land use, and antecedent moisture conditions [39].…”

Section: Hydraulic Modelingmentioning

confidence: 99%

Economic Risk Evaluation in Urban Flooding and Instability-Prone Areas: The Case Study of San Giovanni Rotondo (Southern Italy)

et al. 2018

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Abstract:Estimating economic losses caused on buildings and other civil engineering works due to flooding events is often a difficult task. The accuracy of the estimate is affected by the availability of detailed data regarding the return period of the flooding event, vulnerability of exposed assets, and type of economy run in the affected area. This paper aims to provide a quantitative methodology for the assessment of economic losses associated with flood scenarios. The proposed methodology was performed for an urban area in Southern Italy prone to hydrogeological instabilities. At first, the main physical characteristics of the area such as rainfall, land use, permeability, roughness, and slopes of the area under investigation were estimated in order to obtain input for flooding simulations. Afterwards, the analysis focused on the spatial variability incidence of the rainfall parameters in flood events. The hydraulic modeling provided different flood hazard scenarios. The risk curve obtained by plotting economic consequences vs. the return period for each hazard scenario can be a useful tool for local authorities to identify adequate risk mitigation measures and therefore prioritize the economic resources necessary for the implementation of such mitigation measures.

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“…The SCS-CN formula for the estimation of direct runoff depth is obtained as follows [18,[31][32][33]. Based on the water balance equation and on the fundamental assumption that the ratio of runoff to effective rainfall is the same as the ratio of actual retention to potential retention,…”

Section: Runoff Depth Estimationmentioning

confidence: 99%

Estimating the Effect of Urban Growth on Annual Runoff Volume Using GIS in the Erbil Sub-Basin of the Kurdistan Region of Iraq

Hameed

2017

Hydrology

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Abstract:The growth and spread of impervious surfaces within urbanizing catchment areas pose signiificant threats to the quality of natural and built-up environments. Impervious surfaces prevent water infiltration into the soil, resulting in increased runoff generation. The Erbil Sub-basin was selected because the impervious cover is increasing rapidly and is affecting the hydrological condition of the watershed. The overall aim of this study is to examine the impact of urban growth and other changes in land use on runoff response during the study period of 1984 to 2014. The study describes long-term hydrologic responses within the rapidly developing catchment area of Erbil city, in the Kurdistan Region of Iraq. Data from six rainfall stations in and around the Erbil Sub-basin were used. A Digital Elevation Model (DEM) was also used to extract the distribution of the drainage network. Historical levels of urban growth and the corresponding impervious areas, as well as land use/land cover changes were mapped from 1984 to 2014 using a temporal satellite image (Landsat) to determine land use/land cover changes. Land use/land cover was combined with a hydrological model (SCS-CN) to estimate the volume of runoff from the watershed. The study indicates that the urbanization of the watershed has increased the impervious land cover by 71% for the period from 1984 to 2004 and by 51% from 2004 to 2014. The volume of runoff was 85% higher in 2014 as compared to 1984 due to the increase in the impervious surface area; this is attributed to urban growth. The study also points out that the slope of the watershed in the Erbil sub-basin should be taken into account in surface runoff estimation as the upstream part of the watershed has a high gradient and the land is almost barren with very little vegetation cover; this causes an increase in the velocity of the flow and increases the risk of flooding in Erbil city.

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Estimation of CN Parameter for Small Agricultural Watersheds Using Asymptotic Functions

Cited by 48 publications

References 37 publications

The Curve Number Concept as a Driver for Delineating Hydrological Response Units

The Curve Number Concept as a Driver for Delineating Hydrological Response Units

Economic Risk Evaluation in Urban Flooding and Instability-Prone Areas: The Case Study of San Giovanni Rotondo (Southern Italy)

Estimating the Effect of Urban Growth on Annual Runoff Volume Using GIS in the Erbil Sub-Basin of the Kurdistan Region of Iraq

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