Details
| Original language | English |
|---|---|
| Pages (from-to) | 867-883 |
| Number of pages | 17 |
| Journal | Land Degradation and Development |
| Volume | 35 |
| Issue number | 2 |
| Publication status | Published - 30 Jan 2024 |
| Externally published | Yes |
Abstract
Deltas, being areas where river sediments accumulate, are sensitive to changes in climate and anthropogenic processes that affect sediment generation. The Omo Delta, on the Ethiopia–Kenya border, is constantly changing due to fluctuating lake levels, a variable climate, and rapidly changing land use. Due to field data scarcity and the region's limited accessibility, we relied on remote sensing (RS) data to investigate delta extent between 1990 and 2018 and attempted to disentangle the effect of climatic from anthropogenic variables. We obtained a time series of delta extent from Landsat imagery using Random Forest (RF) classification. Using parametric and non-parametric regression techniques, we regressed the delta extent on Lake Turkana levels, Omo River discharges, Omo-Gibe Basin rainfall, tree cover loss, and irrigation extent. The RF algorithm distinguished water from land with high (>90%) accuracies and revealed Omo Delta extent fluctuations ranging from 949 km2 in 1993 to 651 km2 in 2000. Lake water level, which depends on the rainfall over the Omo-Turkana Basin, emerged as the best predictor of delta extent. However, the annual rainfall over the Omo-Gibe Basin showed no correlation with delta extent. The regression models further show a connection between delta extent, irrigation extent, and tree cover loss. We conclude that rainfall indirectly influences delta extent across the Omo-Turkana Basin. Regression models indicate additional cumulative effects of human activity in the Omo-Gibe Basin but fall short in explaining delta dynamics.
Keywords
- climate change, irrigation, Landsat images, multiple linear regression, Omo-Turkana, Random Forest
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Chemistry
- Social Sciences(all)
- Development
- Environmental Science(all)
- Agricultural and Biological Sciences(all)
- Soil Science
Sustainable Development Goals
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In: Land Degradation and Development, Vol. 35, No. 2, 30.01.2024, p. 867-883.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Variation of the Omo Delta between 1990 and 2018
T2 - What remote sensing data reveal and models explain
AU - Kangi, Gladys
AU - Dondeyne, Stefaan
AU - Kleinschroth, Fritz
AU - Van Orshoven, Jos
N1 - Publisher Copyright: © 2023 John Wiley & Sons Ltd.
PY - 2024/1/30
Y1 - 2024/1/30
N2 - Deltas, being areas where river sediments accumulate, are sensitive to changes in climate and anthropogenic processes that affect sediment generation. The Omo Delta, on the Ethiopia–Kenya border, is constantly changing due to fluctuating lake levels, a variable climate, and rapidly changing land use. Due to field data scarcity and the region's limited accessibility, we relied on remote sensing (RS) data to investigate delta extent between 1990 and 2018 and attempted to disentangle the effect of climatic from anthropogenic variables. We obtained a time series of delta extent from Landsat imagery using Random Forest (RF) classification. Using parametric and non-parametric regression techniques, we regressed the delta extent on Lake Turkana levels, Omo River discharges, Omo-Gibe Basin rainfall, tree cover loss, and irrigation extent. The RF algorithm distinguished water from land with high (>90%) accuracies and revealed Omo Delta extent fluctuations ranging from 949 km2 in 1993 to 651 km2 in 2000. Lake water level, which depends on the rainfall over the Omo-Turkana Basin, emerged as the best predictor of delta extent. However, the annual rainfall over the Omo-Gibe Basin showed no correlation with delta extent. The regression models further show a connection between delta extent, irrigation extent, and tree cover loss. We conclude that rainfall indirectly influences delta extent across the Omo-Turkana Basin. Regression models indicate additional cumulative effects of human activity in the Omo-Gibe Basin but fall short in explaining delta dynamics.
AB - Deltas, being areas where river sediments accumulate, are sensitive to changes in climate and anthropogenic processes that affect sediment generation. The Omo Delta, on the Ethiopia–Kenya border, is constantly changing due to fluctuating lake levels, a variable climate, and rapidly changing land use. Due to field data scarcity and the region's limited accessibility, we relied on remote sensing (RS) data to investigate delta extent between 1990 and 2018 and attempted to disentangle the effect of climatic from anthropogenic variables. We obtained a time series of delta extent from Landsat imagery using Random Forest (RF) classification. Using parametric and non-parametric regression techniques, we regressed the delta extent on Lake Turkana levels, Omo River discharges, Omo-Gibe Basin rainfall, tree cover loss, and irrigation extent. The RF algorithm distinguished water from land with high (>90%) accuracies and revealed Omo Delta extent fluctuations ranging from 949 km2 in 1993 to 651 km2 in 2000. Lake water level, which depends on the rainfall over the Omo-Turkana Basin, emerged as the best predictor of delta extent. However, the annual rainfall over the Omo-Gibe Basin showed no correlation with delta extent. The regression models further show a connection between delta extent, irrigation extent, and tree cover loss. We conclude that rainfall indirectly influences delta extent across the Omo-Turkana Basin. Regression models indicate additional cumulative effects of human activity in the Omo-Gibe Basin but fall short in explaining delta dynamics.
KW - climate change
KW - irrigation
KW - Landsat images
KW - multiple linear regression
KW - Omo-Turkana
KW - Random Forest
UR - http://www.scopus.com/inward/record.url?scp=85174566262&partnerID=8YFLogxK
U2 - 10.1002/ldr.4958
DO - 10.1002/ldr.4958
M3 - Article
AN - SCOPUS:85174566262
VL - 35
SP - 867
EP - 883
JO - Land Degradation and Development
JF - Land Degradation and Development
SN - 1085-3278
IS - 2
ER -