| Title: | Hydrological modeling in data-scarce catchments: The Kilombero Floodplain in Tanzania |
| Authors: | Näschen, K., B. Diekkrüger, C. Leemhuis, S. Steinbach, L.S. Seregina, F. Thonfeld and R. van der Linden |
| Year: | 2018 |
| Journal: | Water |
| Volume (Issue): | 10(5) |
| Pages: | |
| Article ID: | 399 |
| DOI: | 10.3390/w10050599 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | hydrologic assessment |
| Secondary Application Category: | land use change assessment |
| Watershed Description: | 34,000 km^2 Kilombero River, located in south central Tanzania. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | 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 (R2 = 0.86, NSE = 0.85, KGE = 0.93) and validated from
1966–1970 (R2 = 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. |
| Language: | English |
| Keywords: | SWAT model; hydrological modeling; East Africa; land use changes; water balance; wetlands |