Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

Albert Nkwasa; Celray James Chawanda; Annika Schlemm; Job Ekolu; Katja Frieler; Ann van Griensven

doi:10.1007/s10584-024-03702-9

Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

Albert Nkwasa
, Celray James Chawanda
, Annika Schlemm
, Job Ekolu
, Katja Frieler
, Ann van Griensven

Centre for Agroecology, Water and Resilience

Vrije Universiteit Brussel
International Institute for Applied Systems Analysis
Potsdam Institute for Climate Impact Research
IHE Delft Institute for Water Education

Research output: Contribution to journal › Article › peer-review

19 Citations (Scopus)

119 Downloads (Pure)

Abstract

The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.

Original language	English
Article number	42
Number of pages	21
Journal	Climatic Change
Volume	177
Early online date	26 Feb 2024
DOIs	https://doi.org/10.1007/s10584-024-03702-9
Publication status	E-pub ahead of print - 26 Feb 2024

Bibliographical note

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Funding

The authors thank the Research Foundation \u2013 Flanders (FWO) for funding the International Coordination Action (ICA) \u201COpen Water Network: Open Data and Software tools for water resources management\u201D (project code G0E2621N), the EU H2020 programme for funding \u201CWater-ForCE \u2013 Water scenarios For Copernicus Exploitation\u201D (grant agreement No. 101004186), the EU H2020-MSCA-ITN-2020 project InventWater \u201CInventive forecasting tools for adapting water quality management to a new climate\u201D (grant agreement 956623) and the King Baudouin Foundation for the Ernest du Bois Fund (agreement No. 2022-F2812650-228938).

Funders	Funder number
Fonds Wetenschappelijk Onderzoek
Horizon Europe	956623
King Baudouin Foundation	2022-F2812650-228938
Horizon Europe	101004186

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 13 Climate Action

Keywords

Impact attribution
Africa
Climate change
SWAT+

Access to Document

10.1007/s10584-024-03702-9Licence: CC BY

Ekolu2024BVorFinal published version, 6.47 MBLicence: CC BY

Cite this

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abstract = "The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.",

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AU - Schlemm, Annika

AU - Ekolu, Job

AU - Frieler, Katja

AU - van Griensven, Ann

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N2 - The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.

AB - The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.

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KW - Africa

KW - Climate change

KW - SWAT+

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DO - 10.1007/s10584-024-03702-9

M3 - Article

SN - 0165-0009

VL - 177

JO - Climatic Change

JF - Climatic Change

M1 - 42

ER -

Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

Abstract

Bibliographical note

Funding

UN SDGs

Keywords

Access to Document

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