The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences

The NCRS-curve number equation allows calculating the storm runoff from a rainfall event for specific types of land use. It was based on an analysis of direct runoff data using baseflow corrected hydrographs and rainfall. Given this basis, the curve number equation can be derived assuming a constant...

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Main Author: Klaas Metselaar
Format: Article
Language:English
Published: Elsevier 2023-05-01
Series:Journal of Hydrology X
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2589915523000044
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author Klaas Metselaar
author_facet Klaas Metselaar
author_sort Klaas Metselaar
collection DOAJ
description The NCRS-curve number equation allows calculating the storm runoff from a rainfall event for specific types of land use. It was based on an analysis of direct runoff data using baseflow corrected hydrographs and rainfall. Given this basis, the curve number equation can be derived assuming a constant effective rainfall intensity and a cubic reciprocal function as the instantaneous unit hydrograph. The instantaneous unit hydrograph and the resulting curve number equation are further generalized by adding a lag time. The equation for a curve number related hydrograph is presented, allowing to fit this curve number-based hydrograph to event data. The curve number itself is shown be a function of a catchment response time and the average event rainfall intensity. As the catchment response time is linked to the time of concentration the curve number equation and the storage index can be linked to catchment- and flow type characteristics. First results suggest that including the rainfall intensity duration frequency function in the curve number equation may explain systematic deviations observed when fitting the NCRS curve number equation to measured data.
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spelling doaj.art-88eb8c9595d94880bedfc8b84fe01d182023-05-01T04:07:12ZengElsevierJournal of Hydrology X2589-91552023-05-0119100151The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequencesKlaas Metselaar0Wageningen University, Chairgroup Soil Physics and Land Management, Droevendaalsesteeg 3, 6708 PB Wageningen, NetherlandsThe NCRS-curve number equation allows calculating the storm runoff from a rainfall event for specific types of land use. It was based on an analysis of direct runoff data using baseflow corrected hydrographs and rainfall. Given this basis, the curve number equation can be derived assuming a constant effective rainfall intensity and a cubic reciprocal function as the instantaneous unit hydrograph. The instantaneous unit hydrograph and the resulting curve number equation are further generalized by adding a lag time. The equation for a curve number related hydrograph is presented, allowing to fit this curve number-based hydrograph to event data. The curve number itself is shown be a function of a catchment response time and the average event rainfall intensity. As the catchment response time is linked to the time of concentration the curve number equation and the storage index can be linked to catchment- and flow type characteristics. First results suggest that including the rainfall intensity duration frequency function in the curve number equation may explain systematic deviations observed when fitting the NCRS curve number equation to measured data.http://www.sciencedirect.com/science/article/pii/S2589915523000044Linear reservoirS-curveRainfall-runoffBiasComplacentViolent
spellingShingle Klaas Metselaar
The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
Journal of Hydrology X
Linear reservoir
S-curve
Rainfall-runoff
Bias
Complacent
Violent
title The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
title_full The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
title_fullStr The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
title_full_unstemmed The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
title_short The NRCS curve number equation derived from an instantaneous unit hydrograph: Some consequences
title_sort nrcs curve number equation derived from an instantaneous unit hydrograph some consequences
topic Linear reservoir
S-curve
Rainfall-runoff
Bias
Complacent
Violent
url http://www.sciencedirect.com/science/article/pii/S2589915523000044
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