The Curve Number’s Initial Abstraction and Physical Hydrology: ASCE-EWRI CN Hydrology Committee Synthesis

The curve number method for estimating rainfall runoff has continually evolved since its creation in the mid-20th century. Because it is inherently an empirical model that is broadly applied to many hydrological applications, the rationales for its parameters have become removed from physical interpretation over its evolution. The ASCE EWRI CN-Hydrology Committee, i.e., some of the foremost experts on this methodology, often finds itself internally at odds regarding many aspects of CN-hydrology. Here, the committee has synthesized its member’s perspectives on the physical interpretations of one CN-method parameter, the initial abstraction (Ia). This note provides insights into how the Ia concept has evolved and offers some context into reasons behind its evolution. This note also synthesized different interpretations of Ia within the framework of different hydrological settings, applications, and spatial scales. Broadly speaking, the committee suggests that Ia might need to be interpreted on a case-by-case basis although this note places reasonable boundaries on Ia for most applications.

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Publication Details

Journal
Journal of Irrigation and Drainage Engineering
Published
2025-05-14
DOI
https://doi.org/10.1061/jidedh.ireng-10449
Citations
4
Primary Topic
Hydrology and Watershed Management Studies
Type
article
Field-Weighted Citation Impact
3.27
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article

The Curve Number’s Initial Abstraction and Physical Hydrology: ASCE-EWRI CN Hydrology Committee Synthesis

Rocky Talchabhadel, Paulo Tarso Sanches de Oliveira, Glenn E. Moglen, Michael S. Johnson et al.
4 citations
Journal of Irrigation and Drainage Engineering
Hydrology and Watershed Management Studies
3.27
article

The Curve Number’s Initial Abstraction and Physical Hydrology: ASCE-EWRI CN Hydrology Committee Synthesis

Rocky Talchabhadel, Paulo Tarso Sanches de Oliveira, Glenn E. Moglen, Michael S. Johnson, Ernest William Tollner, J. V. Bonta, William P Minervini, John Jairo Ramirez-Avila, Tim J. Ward, Suresh Sharma, Tahneen Jahan Neelam, David A. Chin, Donald E. Woodward, Jim Miller, M. Todd Walter
article en
4 citations

Abstract

The curve number method for estimating rainfall runoff has continually evolved since its creation in the mid-20th century. Because it is inherently an empirical model that is broadly applied to many hydrological applications, the rationales for its parameters have become removed from physical interpretation over its evolution. The ASCE EWRI CN-Hydrology Committee, i.e., some of the foremost experts on this methodology, often finds itself internally at odds regarding many aspects of CN-hydrology. Here, the committee has synthesized its member’s perspectives on the physical interpretations of one CN-method parameter, the initial abstraction (Ia). This note provides insights into how the Ia concept has evolved and offers some context into reasons behind its evolution. This note also synthesized different interpretations of Ia within the framework of different hydrological settings, applications, and spatial scales. Broadly speaking, the committee suggests that Ia might need to be interpreted on a case-by-case basis although this note places reasonable boundaries on Ia for most applications.

Journal of Irrigation and Drainage EngineeringVol. 151(4)
University of North Carolina at Charlotte (US), New Jersey Department of Environmental Protection (US), Seinan Jo Gakuin University (JP), Universidade Federal de Mato Grosso do Sul (BR), Natural Resources Conservation Service (US), University of Miami (US), Youngstown State University (US), University of Georgia (US), Cornell University (US), National Sedimentation Laboratory (US), Desert Research Institute (US), Jackson State University (US), Mississippi State University (US)
Climate action
Openalex Percentile: Top 9%
Hydrology and Watershed Management Studies
3.27
DOISourceOpenAlex
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