Abstract:
The long term hydro-climatic changes influences
streamflow variability and the estimation of long term
persistence (LTP) may help to improve the accuracy of
hydrological modelling. This study first determined the strength
of LTP of streamflow of stations located in five major river
basins in India using the classical Rescaled range (R/S) analysis.
Subsequently, the standard Mann – Kendall (MK1) is used to
analyse the trends in streamflow data. Finally, the Mann-Kendall
test with variations accounting for long term persistence (MK2)
is employed for trend detection. It is found that standard MK test
(MK1) showed statistical significance in the data of 33.8%
stations, while MK2 test detected statistical significance in only
21.77 % stations. It is concluded that MK1 test overestimate the
inherent trend in the datasets due to the presence of long term
persistence in streamflow and the latter method is more reliable
estimate in long term water resources planning and management.
