Paper No. JAWRA-12-0194-P of the Journal of the American Water Resources Association (JAWRA).
Curve Number Derivation for Watersheds Draining Two Headwater Streams in Lower Coastal Plain South Carolina, USA†
Version of Record online: 28 JUN 2013
© 2013 American Water Resources Association
JAWRA Journal of the American Water Resources Association
Volume 49, Issue 6, pages 1284–1295, December 2013
How to Cite
2013. Curve Number Derivation for Watersheds Draining Two Headwater Streams in Lower Coastal Plain South Carolina, USA. Journal of the American Water Resources Association (JAWRA) 49(6):1284-1295. DOI: 10.1111/jawr.12084, , , , , .
Discussions are open until six months from print publication.
- Issue online: 2 DEC 2013
- Version of Record online: 28 JUN 2013
- Manuscript Accepted: 1 MAR 2013
- Manuscript Received: 27 AUG 2012
- South Carolina Sea Grant Consortium. Grant Number: NA10OAR4I70073
- Clemson University Public Service Activities
- NIFA/USDA. Grant Number: SC-1700443
- surface water/groundwater interactions;
- stormwater management;
- watershed management;
- curve number method;
- first-order streams
The objective of this study was to assess curve number (CN) values derived for two forested headwater catchments in the Lower Coastal Plain (LCP) of South Carolina using a three-year period of storm event rainfall and runoff data in comparison with results obtained from CN method calculations. Derived CNs from rainfall/runoff pairs ranged from 46 to 90 for the Upper Debidue Creek (UDC) watershed and from 42 to 89 for the Watershed 80 (WS80). However, runoff generation from storm events was strongly related to water table elevation, where seasonally variable evapotranspirative wet and dry moisture conditions persist. Seasonal water table fluctuation is independent of, but can be compounded by, wet conditions that occur as a result of prior storm events, further complicating flow prediction. Runoff predictions for LCP first-order watersheds do not compare closely to measured flow under the average moisture condition normally associated with the CN method. In this study, however, results show improvement in flow predictions using CNs adjusted for antecedent runoff conditions and based on water table position. These results indicate that adaptations of CN model parameters are required for reliable flow predictions for these LCP catchments with shallow water tables. Low gradient topography and shallow water table characteristics of LCP watersheds allow for unique hydrologic conditions that must be assessed and managed differently than higher gradient watersheds.