ABSTRACT
The impact of climate change is now posing a greater threat
on the hydrological cycle leading to drought and water stress in small basins.
Matters of climate change have now become a primary concern to most nations due
to the implication on society and humanity. The study used 17 ensemble climate
model from the Coupled Model Intercompersion Project Phase 5 (CMIP5) to estimate
the future climatic condition for the 2050s (2035 to 2065) under Representative
Concentration Pathways (RCP) 4.5 and 8.5. The Soil and Water Assessment Tool
(Arc SWAT) model was used in assessing the effect of the generated climate
change on the hydrological processes (rainfall, water yield, soil water storage
and evapotranspiration) in the Densu River Basin (DRB). After calibration and
validation of the SWAT model, there was a strong correlation between the
simulated and the observed stream discharge with a coefficient of determination
(R2) of 0.84 for the calibration and 0.77 (validation). The CMIP5
estimated an annual mean increase of 2.7 oC and 1.3 oC
for maximum and minimum temperature respectively and 20.1 mm in rainfall by
2050s. Simulation from ArcSWAT predicted an increase of 60% in actual
evapotranspiration and 80 mm increase in soil water storage and a sharp decline
of 23 mm in water yield by 2050s. The condition predicted in the future gives
an indication that dry condition will occur at the DRB since increase in
temperature and soil water aid increased evapotranspiration causing an acute
decline in water yield which contribute to stream flow at the basin.
CHAPTER ONE
INTRODUCTION
Climate change in recent years has
gained centre stage of attention in the world, due to its effects on many other
natural and human systems. The changes in climatic condition have shown
significant impact on the hydrological cycle and it is leading to droughts,
floods, changes in rainfall, temperature and water stress. According to the
Inter-Governmental Panel on Climate Change (IPCC, 2014a), the changing climate
will be intensive in sub-Saharan Africa (SSA).
Climate change refers to increase
in the average global surface temperatures caused mainly by an anthropogenic
increase in the concentration of greenhouse gases, particularly carbon dioxide
(CO2) in the earth’s atmosphere (Kankam-Yeboah, Amisigio, & Obuobi, 2010).
Historically, there has been a
variation in the earth’s climate which is mainly by natural and anthropogenic
causes. The natural causes slow climate variations and it takes a longer period
to occur unlike the anthropogenic. The Fourth Assessment report of the (IPCC,
2007) confirms that since the mid-20th century, the global climate change is
directly proportional to anthropogenic drives. The effect of these climate
changes has manifested in agricultural and forestry management, human health,
industry, settlement and society and water resources.
Water is a requirement for all
aspects of human life. Availability and assess to clear, fresh and safe
drinking water is considered a basic human right (Gleick, 2009). Availability
of water resource in sub-Saharan Africa is important in economic growth and
social development particularly in the livelihood of the poor in the Sub-region
(Vörösmarty, Douglas, Green, & Revenga, 2005). The economy of Ghana depends
on water resource for economic and social activities such as water supply and
sanitation, agriculture, industry, urban development, hydropower generation,
inland fisheries, transportation and recreation. Water resources (both quantity
and quality) and its management are affected by climate change and most
importantly by human activities such as population growth and economic
activities.
water resources, population growth
and settlement around the banks of water resources present a global concern for
the availability and consumption of water (Pereira, Cordery, & Iacovides,
2002). Climate change and its impact on water resources availability in space
and time have posed further challenges to the sub-Saharan African (SSA)
countries in their aspiration to harness the water and improve food security.
In Ghana, all observed and
projected climate change in the 21st century predicts a rise in temperature but
that of rainfall is uncertain(Asante & Amuakwa-Mensah, 2014). From the
historical records, the temperatures for the coastal savannah regions have
increased by 2.35 OC with an anticipated increase of 1.68 OC to 2.54 OC by 2050
(Stanturf et al., 2011). The rainfall pattern along the coastal region has not
seen that much changes from the past decades while projected reports
show both an increase and decrease pattern by 2050 (Stanturf et al.,). The
changes in temperature and rainfall for the past decade have had significant
impact on water resources and it has reflected in the area of domestic water
supply, hydropower generation (Amisigo, McCluskey, & Swanson, 2015) and
crop production (Arndt, Asante, Thurlow, & Rosen, 2015).
The impact of the changing climate
has been assessed in some of the major basins in Ghana, notable among than are
the Volta and the Pra basins which researcher project an increase in
temperature, reduction in rainfall and stream flow by 2050 (Kankam-Yeboah et
al., 2010; Kankam-Yeboah et al., 2013; Amisigo et al., 2015). Globally, more
attention has been given to the impact of climate change on small basins, not
much of these assessments has been reported across the country. All these
assessments are essential and help decision makers in formulating policies.
The study intended to focus on how
Climate Change affects the hydrological system of the Densu River Basin (DRB)
using Soil and Water Assessment Tool (SWAT) model.
For more Environmental Science Projects Click here
===================================================================Item Type: Ghanaian Topic | Size: 94 pages | Chapters: 1-5
Format: MS Word | Delivery: Within 30Mins.
===================================================================
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.