Disentangling the role of subsurface storage in the propagation of drought through the hydrological cycle. (November 2022)

• Record Type: Journal Article
• Authors: Bruno, Giulia; Avanzi, Francesco; Gabellani, Simone; Ferraris, Luca; Cremonese, Edoardo; Galvagno, Marta; Massari, Christian
• Is Part Of: Advances in water resources. Volume 169(2022)
• Publication Date: 2022-11
• Subjects: Hydrological drought -- Water balance -- Subsurface storage -- Drought propagation -- Large-sample analysis; Hydrology -- Periodicals; Hydrodynamics -- Periodicals; Hydraulic engineering -- Periodicals; 551.48
• DOI: 10.1016/j.advwatres.2022.104305
• Languages: English
• ISSNs: 0309-1708

Abstract

Abstract: Subsurface storage changes ( Δ S) represent a key modulator of drought propagation through the hydrological cycle, but their contribution to the annual water balance, and to drought propagation and recovery has rarely been explicitly assessed across catchments and climates. To expand on previous work on this matter, here we performed a large-sample analysis of precipitation, discharge, actual evapotranspiration (ET), and Δ S for 10 hydrological years and 102 catchments across various hydro-climatological regimes in Italy. We found that Δ S cannot be neglected in the annual water balance. Storage depletion leads to the attenuation of hydrological drought compared to meteorological drought, meaning that subsurface storage actively supports discharge during drought. We also found that storage generally recovers from precipitation deficits over time scales similar to the discharge recovery time, while recovery times for ET are longer. These findings show that subsurface storage drives drought propagation and recovery, regardless of climatic and catchment characteristics, and are thus relevant to properly inform water managers about surface- and ground-water availability in a changing climate. Highlights: Large-sample analysis of water balance components to study drought propagation and recovery. Subsurface storage changes account on average for the 11% of long-term mean annual precipitation across the catchments. Subsurface storage depletion sustains discharge during drought and the following recovery period. A water balance approach is needed to better understand drought propagation and recovery.