Curve Number Estimation for a Small Urban Catchment from Recorded Rainfall-Runoff Events

• Published in: Archives of environmental protection Vol. 40; no. 3; pp. 75 - 86
• Main Authors: Banasik, Kazimierz, Adam Krajewski, Anna Sikorska, Leszek Hejduk
• Format: Journal Article
• Language: English
• Published: Warsaw De Gruyter Open 11.12.2014; Polish Academy of Sciences
• Subjects: CN method; Engineering; Hydrology; Land use; land use change; prediction; Rain; Retention; Runoff; Soil conservation; Storm water runoff; stormwater; streams; Urban areas; urban fl ood management; urban fl ood management; urbanization; USDA; Warsaw; watersheds; Poland; United States
• ISSN: 2083-4810; 2083-4772; 2083-4810
• DOI: 10.2478/aep-2014-0032

Runoff estimation is a key component in various hydrological considerations. Estimation of storm runoff is especially important for the effective design of hydraulic and road structures, for the flood flow management, as well as for the analysis of land use changes, i.e. urbanization or low impact development of urban areas. The curve number (CN) method, developed by Soil Conservation Service (SCS) of the U.S. Department of Agriculture for predicting the flood runoff depth from ungauged catchments, has been in continuous use for ca. 60 years. This method has not been extensively tested in Poland, especially in small urban catchments, because of lack of data. In this study, 39 rainfall-runoff events, collected during four years (2009–2012) in a small (A=28.7 km²), urban catchment of Służew Creek in southwest part of Warsaw were used, with the aim of determining the CNs and to check its applicability to ungauged urban areas. The parameters CN, estimated empirically, vary from 65.1 to 95.0, decreasing with rainfall size and, when sorted rainfall and runoff separately, reaching the value from 67 to 74 for large rainfall events.