Multi-century flow reconstruction of the Lhasa River, China

• Published in: Journal of hydrology. Regional studies 2024-06, Vol.53, p.101795, Article 101795
• Main Authors: Zeng, Jue, Yu, Bofu, Fu, Xudong, Hu, Hongchang
• Format: Article
• Language: English
• Subjects: Catchment hydrological modelling; Daily flow reconstruction; Greater natural variability; Representability of observed flows; Water management
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2024.101795

Lhasa River Basin Multi-century records are needed to characterize flow variability including the magnitude and frequency of occurrence of extreme events. Such long records are not available without integrating well-calibrated hydrological models and climate proxies. To test whether 50–70 years of observations represent the long-term flow variability for water resources management, daily flows (1472–2000) were reconstructed by integrating the Variable Infiltration Capacity (VIC) model with proxy-based precipitation and temperature data for Lhasa River. VIC performed well during calibration and validation for 3 gauging stations with the Nash-Sutcliffe coefficient of efficiency (NSE) exceeding 0.52. Proxy-based precipitation, temperature, and reconstructed flow are broadly stationary over the past 529 years, while recent decades show detectable local trends. The inter-annual/decadal variability is aligned with long-term variations in sea surface temperatures and the intensity of south Asian summer monsoon. Moreover, higher long-term average, greater variabilities, and persistent periods of above/below-average flows are detected. The maximum daily flows with small annual recurrence intervals (ARIs) less than 60 years would be overestimated based on observations, and underestimated for ARIs > 60 years. It is the first time to have reconstructed long-term daily flows using hydrological models coupled with proxy-based climate data, and this approach offers invaluable insights into the pre-instrumental flow responses to changing climate conditions in Lhasa River basin. [Display omitted] •Integrate VIC model & proxy-based climate to generate pre-instrumental daily flow.•Trends in climate and flow post-1960 are part of natural variability.•Periods with persistent above- or below-average are detected over the 529 years.•Recent decades (1961–2000) are relatively dry compared to long-term averages.•Maximum daily flow will be underestimated for ARI>60 based on instrumental records.