| Summary: | 博士 === 國立臺灣海洋大學 === 河海工程學系 === 99 === The purpose of this paper is to establish an estimation model for regional renewable water resources and a comprehensive assessment model under climate change conditions, to analyze the impact of climate change on water resources in Taiwan, and provide relevant administration agencies with reference points for adaptive strategies for long term planning.
According to the downscaling rainfall data simulated by five GCM models(CCCma/CGCM3-T47、CNRM/CM3、CSIRO/MK3.5、GFDL/ CM2.0、LASG/ FGOALS-g1.0) under SRES-A1B condition, combination of historical (1979~1998) observations data to correct the modeling data by use of the Quadrant Transformation Method (QTM). And use the current situation (2002~2009) the integrity of hydrological and meteorological data for the validation of Thornthwaite method potential evapotranspiration application by Penman-Monteith/FAO56 method, and establish a regional evapotranspiration adjustment factor, which can be multiplied by potential evapotranspiration to obtain evapotranspiration, and use of Genetic Algorithm method for the adjustment factor parameter optimization. Finally, the corrected future precipitation, less future evapotranspiration returns the future (2080-2099) volume of regional renewable water resources in Taiwan.
We then conduct a water resources system simulation based on estimates of future water needs, regional reservoir effective capacity and renewable water resource volume. This paper uses three water resource assessment indicators: the annual water utilization ratio indicator, the water shortage indicator and the extreme event occurrence indicator. Through fuzzy comprehensive assessment, we divide the evaluation set into five levels: very good (L1), good (L2), fair (L3), poor (L4) and very poor (L5).
This study focuses on Taiwan’s four water resource regions, the results indicate that future (2080~2099) average annual renewable water resource volume for Northern Taiwan will drop by 19.1% from 161.4×108m3 to 130.7×108m3 (represented by the average of five modeling data) as compared with the historical (1979~1998) value, and the wet/dry distributions will be worse slightly from (59.8%/40.2%) to (64.2%/ 35.8%)；in the Central region, increasing by 4.4% from 161.4×108m3 to 168.5×108m3, but the wet/dry distributions will deteriorate obviously from (72.6%/27.4%) to (86.1%/13.9%)；in the South region, increasing obviously by 79.1% from 167.1×108m3 to 299.2×108m3 , but the wet/dry distributions will deteriorate to extremely uneven (98.4%/1.6%) from (92.4%/7.6%)；in the East region, increasing by 10.8% from 151.7×108m3 to 168.1×108m3, the wet/dry distributions will be worse slightly from (73.7%/26.3%) to (79.4%/20.6%).
The results of the analysis on Taiwan's water resource comprehensive condition show that, the future (2080~2099) water resource comprehensive condition for Northern Taiwan will be worse slightly than the historical (1979~1998) situation, but remained the same with the history of the fair (L3) level, which is affected by the increase of water demand approaches the impact of climate change；in the Central region, the comprehensive condition will deteriorate from the poor (L4) level to the very poor (L5) level, affected by the increase of water demand is slightly higher than the impact of climate change；in the South region, the comprehensive condition will deteriorate obviously from the fair (L3) level to the very poor (L5) level, affected by the increase of water demand is also slightly higher than the impact of climate change；in the East region, the comprehensive condition will be slightly better than the historical situation, remained the same with the history of the good (L2) level, its effect by increasing water demand for the slight negative impact, but the impact of climate change for the positive of the effect. In this paper, we also propose the adaptation strategies for Central and South region to provide relevant administration agencies with reference points for adaptive strategies for long term planning.
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