Development of a hydrogeological conceptual wetland model in the data-scarce north-eastern region of Kilombero Valley, Tanzania

Burghof, Sonja; Gabiri, Geofrey; Stumpp, Christine; Chesnaux, Romain; Reichert, Barbara

doi:10.1007/s10040-017-1649-2

Cited by 16 publications

(22 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Deductions in statistical performance can be attributed to overestimations of discharge in some years (1959,1961) and inaccuracies in simulating the discharge peaks [23]. During calibration, five out of the seven most sensitive parameters were related to groundwater [23], indicating the importance of groundwater contribution for the catchment, which was also highlighted by other researchers [21,64].…”

Section: Model Performance and Bias-correctionmentioning

confidence: 77%

Impact of Climate Change on Water Resources in the Kilombero Catchment in Tanzania

Näschen

Diekkrüger

Leemhuis³

et al. 2019

Water

View full text Add to dashboard Cite

This article illustrates the impact of potential future climate scenarios on water quantity in time and space for an East African floodplain catchment surrounded by mountainous areas. In East Africa, agricultural intensification is shifting from upland cultivation into the wetlands due to year-round water availability and fertile soils. These advantageous agricultural conditions might be hampered through climate change impacts. Additionally, water-related risks, like droughts and flooding events, are likely to increase. Hence, this study investigates future climate patterns and their impact on water resources in one production cluster in Tanzania. To account for these changes, a regional climate model ensemble of the Coordinated Regional Downscaling Experiment (CORDEX) Africa project was analyzed to investigate changes in climatic patterns until 2060, according to the RCP4.5 (representative concentration pathways) and RCP8.5 scenarios. The semi-distributed Soil and Water Assessment Tool (SWAT) was utilized to analyze the impacts on water resources according to all scenarios. Modeling results indicate increasing temperatures, especially in the hot dry season, intensifying the distinctive features of the dry and rainy season. This consequently aggravates hydrological extremes, such as more-pronounced flooding and decreasing low flows. Overall, annual averages of water yield and surface runoff increase up to 61.6% and 67.8%, respectively, within the bias-corrected scenario simulations, compared to the historical simulations. However, changes in precipitation among the analyzed scenarios vary between −8.3% and +22.5% of the annual averages. Hydrological modeling results also show heterogeneous spatial patterns inside the catchment. These spatio-temporal patterns indicate the possibility of an aggravation for severe floods in wet seasons, as well as an increasing drought risk in dry seasons across the scenario simulations. Apart from that, the discharge peak, which is crucial for the flood recession agriculture in the floodplain, is likely to shift from April to May from the 2020s onwards.

show abstract

Section: Model Performance and Bias-correctionmentioning

confidence: 77%

Impact of Climate Change on Water Resources in the Kilombero Catchment in Tanzania

Näschen

Diekkrüger

Leemhuis³

et al. 2019

Water

View full text Add to dashboard Cite

show abstract

“…However, more observation-driven research is needed on the relation of surface water and groundwater resources on this topic [87]. Moreover, data availability on the hydrogeology of the Kilombero Catchment is still poor to be modeled precisely, although some data and a local conceptual model exists [88,89]. Furthermore, the groundwater routines of the SWAT model are not sufficient for adequately modeling groundwater processes, because distributed parameters like the hydraulic conductivity and storage coefficients are disregarded in the linear reservoir approximations [90].…”

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

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

View full text Add to dashboard Cite

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...

show abstract

“…Yawson et al [24] applied lumped models and linear transfer approaches, while Lyon et al [25] investigated spatio-temporal drainage patterns. Subcatchments of the Kilombero Catchment were analyzed by Burghof et al [26], Koutsouris et al [27], and Daniel et al [28], by developing a conceptual model, setting up an HBV (Hydrologiska Byråns Vattenavdelning) light model [29] for two subcatchments and by analyzing soil hydrological properties in a floodplain transect. These studies investigated water-related relationships within the Kilombero Catchment, giving either a detailed insight into specific subcatchments without considering the entire catchment [25][26][27]-or the entire catchment was analyzed, but without considering the spatial heterogeneity [24].…”

Section: Introductionmentioning

confidence: 99%

Hydrological Modeling in Data-Scarce Catchments: The Kilombero Floodplain in Tanzania

Näschen

Diekkrüger

Leemhuis

et al. 2018

Water

View full text Add to dashboard Cite

Deterioration of upland soils, demographic growth, and climate change all lead to an increased utilization of wetlands in East Africa. This considerable pressure on wetland resources results in trade-offs between those resources and their related ecosystem services. Furthermore, relationships between catchment attributes and available wetland water resources are one of the key drivers that might lead to wetland degradation. To investigate the impacts of these developments on catchment-wetland water resources, the Soil and Water Assessment Tool (SWAT) was applied to the Kilombero Catchment in Tanzania, which is like many other East African catchments, as it is characterized by overall data scarcity. Due to the lack of recent discharge data, the model was calibrated for the period from 1958-1965 (R 2 = 0.86, NSE = 0.85, KGE = 0.93) and validated from 1966-1970 (R 2 = 0.80, NSE = 0.80, KGE = 0.89) with the sequential uncertainty fitting algorithm (SUFI-2) on a daily resolution. Results show the dependency of the wetland on baseflow contribution from the enclosing catchment, especially in dry season. Main contributions with regard to overall water yield arise from the northern mountains and the southeastern highlands, which are characterized by steep slopes and a high share of forest and savanna vegetation, respectively. Simulations of land use change effects, generated with Landsat images from the 1970s up to 2014, show severe shifts in the water balance components on the subcatchment scale due to anthropogenic activities. Sustainable management of the investigated catchment should therefore account for the catchment-wetland interaction concerning water resources, with a special emphasis on groundwater fluxes to ensure future food production as well as the preservation of the wetland ecosystem.

show abstract

Development of a hydrogeological conceptual wetland model in the data-scarce north-eastern region of Kilombero Valley, Tanzania

Cited by 16 publications

References 45 publications

Impact of Climate Change on Water Resources in the Kilombero Catchment in Tanzania

Impact of Climate Change on Water Resources in the Kilombero Catchment in Tanzania

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

Hydrological Modeling in Data-Scarce Catchments: The Kilombero Floodplain in Tanzania

Contact Info

Product

Resources

About