Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World
Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 105–110.
Regionalization of flow duration curves
IRINA KRASOVSKAIA1, LARS GOTTSCHALK1, ETIENNE LEBLOIS2 & ALEXIA PACHECO3
1 Department of Geosciences, University of Oslo, PO Box 1047 Blindern, N-0316 Oslo, Norway
irina.gottschalk@geo.uio.no
2 Cemagref, 3 bis quai Chauveau, CP
220, F-69336 Lyon Cedex 09, France
3 Instituto
Costarricense de Electricidad, PO Box 10032-1000, San José, Costa Rica
Abstract A method for estimating the
flow duration curve (FDC) in an ungauged basin (i.e. regionalization of FDCs)
is developed. An FDC can be described by the mean value and the coefficient of
variation either in terms of empirically determined regional FDCs or as fitted
theoretical regional curves. The development of these two first order moments
of the FDC along the river network and with the spatial scale, i.e. the basin
area, is analysed and a scheme for their interpolation along the river network
is elaborated. Daily runoff data records from Costa Rica are used to
demonstrate the findings. The estimation errors are highest in relative terms
(~30%) for the durations longer than 85%, somewhat smaller for durations less
than 20% (~10%) and small for central parts of the FDC (~8%). Differences
between the empirical and theoretical curves are minor, although the latter
give systematically better results especially in central parts of the FDC.
Key words flow duration curve;
regionalization; Costa Rica