Modelling the impact of land use management on water resources in a tropical inland valley catchment of central Uganda, East Africa

Gabiri, Geofrey; Leemhuis, Constanze; Diekkrüger, Bernd; Näschen, Kristian; Steinbach, Stefanie; Thonfeld, Frank

doi:10.1016/j.scitotenv.2018.10.430

Cited by 28 publications

(36 citation statements)

References 62 publications

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“…Overall, analyses on subcatchment scale (Figures 10 and 12) show that the conversion into cropland leads to increasing surface runoff and overall water yield (Figure 10a,b), whereas a more diverse picture is shown for the rice setups (Figure 10d,e), due to the differences in LULC in the setups ( Figure 5) and the aforementioned water demand of rice plants [29]. Average annual evapotranspiration is decreasing in both agricultural setups in most of the subcatchments, especially where natural systems are converted into agricultural production zones, which is in line with other studies from the tropics [3,6,7]. Still, there are studies that report increasing evapotranspiration due to conversion of forests to cropland [91].…”

Section: Land Use/cover and Climate Change Impact Assessment On Watersupporting

confidence: 87%

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The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

et al. 2019

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Many parts of sub-Saharan Africa (SSA) are prone to land use and land cover change (LULCC). In many cases, natural systems are converted into agricultural land to feed the growing population. However, despite climate change being a major focus nowadays, the impacts of these conversions on water resources, which are essential for agricultural production, is still often neglected, jeopardizing the sustainability of the socio-ecological system. This study investigates historic land use/land cover (LULC) patterns as well as potential future LULCC and its effect on water quantities in a complex tropical catchment in Tanzania. It then compares the results using two climate change scenarios. The Land Change Modeler (LCM) is used to analyze and to project LULC patterns until 2030 and the Soil and Water Assessment Tool (SWAT) is utilized to simulate the water balance under various LULC conditions. Results show decreasing low flows by 6-8% for the LULC scenarios, whereas high flows increase by up to 84% for the combined LULC and climate change scenarios. The effect of climate change is stronger compared to the effect of LULCC, but also contains higher uncertainties. The effects of LULCC are more distinct, although crop specific effects show diverging effects on water balance components. This study develops a methodology for quantifying the impact of land use and climate change and therefore contributes to the sustainable management of the investigated catchment, as it shows the impact of environmental change on hydrological extremes (low flow and floods) and determines hot spots, which are critical for environmental development.Sustainability 2019, 11, 7083 2 of 28 increased agricultural outputs such as food and timber production [9,13]. Several water-related targets of the Sustainable Development Goals (SDGs) are at risk due to land conversions into arable land, especially with regard to SDG 6 (Clean Water and Sanitation) and SDG 15 (Life on Land) [13,14].Several studies investigated the impact of LULCC and climate change on water resources separately [3,15] or simultaneously [16,17]. The results of the studies differ due to several reasons e.g., the type of LULCC, the regional focus, or the time period and model chosen to simulate climate change. However, many studies indicate an increased exposure to hydro-climatic extremes in Eastern Africa [18][19][20][21]. This study exemplarily analyzes LULCC compared to climate change in the Kilombero Catchment in Tanzania and how these affect water resources. The catchment itself is subject to aforementioned LULCC [1,13] and pressure on land resources in the valley is fostered by government plans to implement the Southern Agricultural Growth Corridor of Tanzania (SAGCOT) [22], which is accompanied by a growing population and migration of pastoralists into the valley [23]. SAGCOT follows a green growth approach covering three development clusters in Kilombero, Ihemi, and Mbarali, comprising one third of the mainland of Tanzania [1,24,25]. On the one hand the key clusters are charac...

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Section: Land Use/cover and Climate Change Impact Assessment On Watersupporting

confidence: 87%

“…Recent developments in sub-Saharan Africa (SSA) show an increasing trend of conversion of natural land cover into arable land [1][2][3][4][5][6][7][8][9][10][11]. Drivers of change are manifold and can be directly linked to human activities such as population growth, economic development, and globalization [11,12].…”

Section: Introductionmentioning

confidence: 99%

The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

et al. 2019

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“…The major hydrological processes in the catchment are evapotranspiration and runoff (Hortonian surface runoff and lateral flow). The runoff is due to Land use/Land cover (LULC), soil properties, and slope gradients, where steep slopes are observed along the fringes and uplands of the catchment [31]. The native vegetation in the inland valley is papyrus (Cyperus papyrus L.) and tropical rainforests, although these are significantly being converted into subsistence agriculture, with a mosaic of land uses and drainage and settlement [34].…”

Section: Description Of Study Areamentioning

confidence: 99%

“…The native vegetation in the inland valley is papyrus (Cyperus papyrus L.) and tropical rainforests, although these are significantly being converted into subsistence agriculture, with a mosaic of land uses and drainage and settlement [34]. The predominant LULC in the catchment is agriculture with an area coverage of 64.8% of the total catchment, followed by mixed forests (tropical forests) and planted eucalyptus ( Figure 2) [31]. Along the valley slopes are mainly settlements and agriculture characterized by upland crops such as maize (Zea mays L.), beans (Phaseolus vulgaris L.), and sweet potatoes (Ipomoea batatas L.).…”

Section: Description Of Study Areamentioning

confidence: 99%

“…There exist limited studies [28][29][30][31][32] that have demonstrated the impact of climate and land use change on the hydrological processes in the wetland-catchment nexus in East Africa. Yet, this information is vital to evaluate the possible vulnerability and resilience of these ecosystems to climate change, in particular the impacts of low predictability of precipitation.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Climate and Land Use/Land Cover Change on the Water Resources of a Tropical Inland Valley Catchment in Uganda, East Africa

Gabiri

Diekkrüger

Näschen

et al. 2020

Climate

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The impact of climate and land use/land cover (LULC) change continues to threaten water resources availability for the agriculturally used inland valley wetlands and their catchments in East Africa. This study assessed climate and LULC change impacts on the hydrological processes of a tropical headwater inland valley catchment in Uganda. The hydrological model Soil and Water Assessment Tool (SWAT) was applied to analyze climate and LULC change impacts on the hydrological processes. An ensemble of six regional climate models (RCMs) from the Coordinated Regional Downscaling Experiment for two Representative Concentration Pathways (RCPs), RCP4.5 and RCP8.5, were used for climate change assessment for historical (1976–2005) and future climate (2021–2050). Four LULC scenarios defined as exploitation, total conservation, slope conservation, and protection of headwater catchment were considered. The results indicate an increase in precipitation by 7.4% and 21.8% of the annual averages in the future under RCP4.5 and RCP8.5, respectively. Future wet conditions are more pronounced in the short rainy season than in the long rainy season. Flooding intensity is likely to increase during the rainy season with low flows more pronounced in the dry season. Increases in future annual averages of water yield (29.0% and 42.7% under RCP4.5 and RCP8.5, respectively) and surface runoff (37.6% and 51.8% under RCP4.5 and RCP8.5, respectively) relative to the historical simulations are projected. LULC and climate change individually will cause changes in the inland valley hydrological processes, but more pronounced changes are expected if the drivers are combined, although LULC changes will have a dominant influence. Adoption of total conservation, slope conservation and protection of headwater catchment LULC scenarios will significantly reduce climate change impacts on water resources in the inland valley. Thus, if sustainable climate-smart management practices are adopted, the availability of water resources for human consumption and agricultural production will increase.

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Climatic impacts on water resources in a tropical catchment in Uganda and adaptation measures proposed by resident stakeholders

2021

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The Ruhezamyenda catchment in Uganda includes a unique lake, Lake Bunyonyi, and is threatened by increasing social and environmental pressures. The COSERO hydrological model was used to assess the impact of climate change on future surface runoff and evapotranspiration in the Lake Bunyonyi catchment (381 km2). The model was forced with an ensemble of CMIP5 global climate model (GCM) simulations for the mid-term future (2041–2070) and for the far future (2071–2100), each with RCP4.5 and RCP8.5. In the Ruhezamyenda catchment, compared to 1971–2000, the median of all GCMs (for both RCPs) showed the mean monthly air temperature to increase by approximately 1.5 to 3.0 °C in the mid-term future and by roughly 2.0 to 4.5 °C in the far future. The mean annual precipitation is generally projected to increase, with future changes between − 25 and + 75% (RCP8.5). AET in the Lake Bunyonyi catchment was simulated to increase for the future by approximately + 8 mm/month in the median of all GCMs for RCP8.5 for the far future. The runoff for future periods showed much uncertainty, but with an overall increasing trend. A combination of no-regrets adaptation options in the five categories of: governance; communication and capacity development; water, soil, land management and livelihoods improvement; data management; and research, was identified and validated with stakeholders, who also identified additional adaptation actions based on the model results. This study contributes to improving scientific knowledge on the impacts of climate change on water resources in Uganda with the purpose to support adaptation.

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Modelling the impact of land use management on water resources in a tropical inland valley catchment of central Uganda, East Africa

Cited by 28 publications

References 62 publications

The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

Impact of Climate and Land Use/Land Cover Change on the Water Resources of a Tropical Inland Valley Catchment in Uganda, East Africa

Climatic impacts on water resources in a tropical catchment in Uganda and adaptation measures proposed by resident stakeholders

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