Multiscale assessments of hydroclimatic modelling uncertainties under a changing climate

Abstract

Since the 1970s, climate change has led to decreasing water resources in the Sahel. To cope with climate change, reliable modelling of future hydroclimatic evolutions is required. This study uses multiclimate and hydrological modelling approaches to access past and future (1951–2100) hydroclimatic trends on nine headwater catchments of the Niger River Basin. Eight global climate models (GCMs) dynamically downscaled under the CORDEX CMIP5 project were used. The GCM data were bias-corrected with quantile–quantile mapping. Three rainfall–runoff models (IHACRES-CMD, IHACRES-CWI and Sacramento) were calibrated and validated with observed data and used to simulate runoff. The projected future runoff trend from 2061 to2090 was compared across the three hydrological models to assess uncertainties from hydrological models. Results show that the bias correction positively enhanced the quality of eight GCMs across the nine catchments. An average Nash–Sutcliffe Efficiency (NSE) across the nine catchments was improved from 0.53 to 0.68 and the Kling–Gupta Efficiency (KGE) was enhanced from 0.65 to0.83. The three hydrological models were calibrated and validated appropriately on the nine catchments. Despite this, high hydrological modelling uncertainties were witnessed with contrasting projected future runoff patterns by the three models. We recommended the use of ensembles of both climate and hydrological models to provide reliable hydroclimatic modelling.

Daily Simulation of the Rainfall–Runoff Relationship in the Sirba River Basin in West Africa: Insights from the HEC-HMS Model

“…Refs. [36,38] used the lumped and catchment scale Identification of Unit Hydrographs and Component Flows from Rainfall, Evaporation and Streamflow (IHACRES) model for rainfall-runoff modeling and the assessment of hydroclimatic uncertainties under climate change. Ref.…”

“…Hydrological modeling offers an interesting framework for large-scale analysis and assessment of the rainfall-runoff relationship [25][26][27][28][29], especially in the context of the SRB. Several hydrological modeling studies have been conducted in the SRB in West Africa, focusing on various aspects such as land surface modeling [30], statistical discharge time series analysis [31][32][33], hydrological rainfall-runoff assessments [21,23,[34][35][36][37][38] and the development of flood early warning systems [39]. Although these studies shed light on the understanding of hydroclimatic behavior and variability in the region, little work has been carried out on the possible contribution of the SRB to the onset of fluvial floods downstream of the SRB, in Niamey urban city.…”