Assessment of impacts of climate change on surface water availability using coupled SWAT and WEAP models: case of upper Pangani River Basin, Tanzania
Peter Kishiwa Joel Nobert Victor Kongo Preksedis Ndomba
Abstract. This study was designed to investigate the dynamics of current and future
surface water availability for different water users in the upper Pangani
River Basin under changing climate. A multi-tier modeling technique was used
in the study, by coupling the Soil and Water Assessment Tool (SWAT) and Water
Evaluation And Planning (WEAP) models, to simulate streamflows under climate
change and assess scenarios of future water availability to different
socio-economic activities by year 2060. Six common Global Circulation Models
(GCMs) from WCRP-CMIP3 with emissions Scenario A2 were selected. These are
HadCM3, HadGEM1, ECHAM5, MIROC3.2MED, GFDLCM2.1 and CSIROMK3. They were
downscaled by using LARS-WG to station scale. The SWAT model was calibrated
with observed data and utilized the LARS-WG outputs to generate future
streamflows before being used as input to WEAP model to assess future water
availability to different socio-economic activities. GCMs results show future
rainfall increase in upper Pangani River Basin between 16–18 % in 2050s
relative to 1980–1999 periods. Temperature is projected to increase by an
average of 2 ∘C in 2050s, relative to baseline period. Long-term
mean streamflows is expected to increase by approximately 10 %. However,
future peak flows are estimated to be lower than the prevailing average peak
flows. Nevertheless, the overall annual water demand in Pangani basin will
increase from 1879.73 Mm3 at present (2011) to 3249.69 Mm3 in the
future (2060s), resulting to unmet demand of 1673.8 Mm3 (51.5 %).
The impact of future shortage will be more severe in irrigation where
71.12 % of its future demand will be unmet. Future water demands of
Hydropower and Livestock will be unmet by 27.47 and 1.41 % respectively.
However, future domestic water use will have no shortage. This calls for
planning of current and future surface water use in the upper Pangani River
Basin.
CC BY 029 мая 2018
Тип материала: Статья
Тематика: WATER RESOURCES
Язык: EN
Ранее опубликовано
Copernicus GmbH
UNDERSTANDING SPATIO-TEMPORAL VARIABILITY OF WATER RESOURCES AND THE IMPLICATIONS FOR IWRM IN SEMI-ARID EASTERN AND SOUTHERN AFRICA, VOL 378