| Summary: | 碩士 === 國立中央大學 === 國際永續發展碩士在職專班 === 101 === Water serves as the fundamental link between the climate system, human society and the environment. Climate change is severely impacting the hydrological cycle and consequently, water management. This will in turn have significant effects on human development and security. St.Vincent and the Grenadines (SVG), one of the many islands located in the Caribbean region is projected to be highly affected by climate change, its water resource being no exception. The island depends on streams to meet its daily water demand. Climate change coupled with land use changes within the watersheds can potentially have irreversible impacts on the main source of water for the communities St. Vincent. Owing to the fact that streams are the main water resources of this island and the impact of climate change and poor land use management, this project assesses the effects of climate and land use change on streamflow in the Montreal watershed. As an end result an integrated and sustainable management plan was proposed for the watershed.
Taiwan Water Resources Assessment Programme (TaiWAP) was the main tool used to assist with the simulations and probable projections for the impacts of climate and land use change on streamflow. It includes climate change scenarios, weather generator and a hydrological model, the Generalized Watershed Loading Function (GWLF). Four Global Climate Models (GCMs) (GFDL-CM2.0, GFDL-CM2.1, MPIM-ECHAM5, and UKMO-HadCM3) were used under the SRES A2, A1B and B1. These scenarios were used to assess climate change for two periods 2050s (2040-2069) and 2080s (2070-2099). For the assessment of the effects of probable land use changes on streamflow two GCMs (GFDL-CM2.0 and MPIM-ECHAM5) under the SRES A2, A1B and B1. Three different modifications were assumed in the watershed (Expansion of urban lands, expansion of forest cover and expansion of agricultural lands) and compared with the present land use practice. Each modification was assumed to have increased by 15% for the period 2050s. This was done for both the dry season and wet season.
The results projected for the effects of climate change on the streamflow indicate an increasing trend in annual temperature from both the 2050s and 2080s period which ranged from 0.77oC to 3.28oC. The projections for rainfall fluctuated within the different models. However a significant decrease in annual rainfall is expected for both periods was noted. The annual rainfall ranges from 46.09% to -74.8%. Annual stream flow is anticipated to decrease for both periods, ranging from 38.59% to -99.89%
The results projected for land use change on streamflow based on the different modifications for the different seasons of the year (dry and wet) showed a similar trend. The results projects the expansion of urban lands and agricultural land to have a higher percentage streamflow when compared with the present land use while the expansion of forest cover will project a lower percentage streamflow in comparison to the present land use practice.
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