Abstract:
The Niger basin has experienced historical drought episodes and floods in recent times. Reliable hydrological modelling has
been hampered by missing values in daily river discharge data. We assessed the potential of using the Multivariate Imputation
by Chained Equations (MICE) to estimate both continuous and discontinuous daily missing data across different spatial scales in
the Niger basin. The study was conducted on 22 discharge stations that have missing data ranging from 2% to 70%. Four efficiency
metrics were used to determine the effectiveness of MICE. The flow duration curves (FDC) of observed and filled data
were compared to determine how MICE captured the discharge patterns. Mann-Kendall, Modified Mann-Kendall, Pettit and
Sen’s Slope were used to assess the complete discharge trends using the gap-filled data. Results shows that MICE near perfectly
filled the missing discharge data with Nash-Sutcliffe Efficiency (NSE) range of 0.94–0.99 for the calibration (1992–1994)
period. Good fits were obtained between FDC of observed and gap-filled data in all considered stations. All the catchments
showed significantly increasing discharge trend since 1990s after gap filling. Consequently, the use of MICE in handling missing
data challenges across spatial scales in the Niger basin was proposed.
