Assessment of the impacts of climate variability on highly engineered watersheds: A case study from the Tigris Euphrates watershed
Abstract
Understanding the impacts of the climate change, particularly precipitation intensity, duration, and frequency, on the hydrological systems, and whether these systems can buffer these impacts has been, and continues to be among the most critical environmental concerns. More intense and prolonged floods and droughts are being reported from many basins across the globe. While these events could introduce devastating socioeconomic impacts on many of the worlds river basins and their populations, highly engineered systems can buffer these projected impacts. The impacts of projected increase in frequency and intensity of extreme rainfall and drought events in the 21st century due to global warming were assessed over highly engineered river systems using the Tigris Euphrates Watershed (TEW) as a test site. Extreme drought and wet periods were identified from temporal (1920-2020) precipitation data (GPCC) and their impact on monthly signals of GRACE and GRACE-FO Terrestrial Water Storage (GRACETWS), Surface Water Storage (SWSALT; 13 main reservoirs/lakes), and Ground Water Storage were evaluated. Findings include: (1) during the past two decades, the TEW witnessed (2007-2018) a prolonged and intense drought (AAP < 400 km3) with no parallels in the past 100 years (AAP in 1920-2020: 528 km3); the drought was preceded by a wet period (Phase I: 2003-2007) characterized by positive and near-steady GRACETWS values (average GRACETWS: 91 km3); (2) a sharp decline and significant losses in GRACETWS (144km3/1.8yrs) signaled the onset (Phase II: 2007-2009) of the drought that transitioned into a period (Phase III: 2009 to 2014) of negative and near-steady GRACETWS values (average: 26 km3), followed (Phase IV: 2014 to 2018) by a second decline and additional losses in GRACETWS values (63km3/4.2yrs); (3) an impressive recovery (113 km3, > 43 km3 of which, captured in reservoirs and lakes) amounting to 50% of losses endured in Phases II - IV was brought to an end by a 1 in 100 year extreme precipitation event (726 km3) in 2019 probably signaling the beginning of a wetter period (Phase V: 2018-2020). Findings demonstrate that the TEW and similar highly engineered watersheds worldwide are better prepared for modulating the projected climatic variabilities of the 21st century and reducing hazards associated with flooding events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H21A..02S