Assessing the Effects of Climate Change on Stream Flow and Water Quality in Watersheds-A Case Study of Fei-Tsui Reservoir Watershed
Date Issued
2010
Date
2010
Author(s)
Chang, Chih-Kuo
Abstract
Understanding the potential impact of discharge and water quality of watershed under climate change is a critical assignment for watershed management. In this study, HSPF (Hydrological Simulation Program-Fortran) and CAT (climate assessment tools) within BASINS (Better Assessment Science Integrating point & Non-point Sources) which is developed by U.S. EPA are used for investigating the impact caused by climate change.
Fei-Tsui Reservoir Watershed (303 Km2) which is the second largest reservoir of Taiwan is chosen for a case study. The upstream of reservoir is divided into three regions based on different basins, Pei-shih (110.3 Km2), Tai-yu-chueh (78.1 Km2) and Ching-kua-liao (24.6 Km2). And each region is divided into small sub-regions base on topography by model.
Discharge (daily) and water quality (monthly) data of 2008 are used for calibration. In this study, two climate scenarios are made based on AR4 (the Fourth Assessment Report) of IPCC(Intergovernmental Panel on Climate Change), A1F1 (2100, CO2=970 ppm, 26.9 ℃) and B1(2100, CO2=550 ppm, 21.6 ℃).Different precipitation variances(0 %, ±10 % and ±20 % ) are modeled to execute impact analysis for two scenarios and compared with baseline scenario (2008, CO2=385 ppm, 20.5 ℃).
The correlation coefficient between simulated and observed data are 0.90、0.96 and 0.91 respectively of three regions in hydrological simulation. Though water quality data are not actually sufficient for calibration, output of SS and TP are acceptable.
In A1F1 and B1 scenario, stream flow decreases by 1.51 % and 0.17 % respectively, SS increases by 41.12 % and 1.12 % respectively, and TP decreases by 1.57 % and increases by 0.06 % respectively. Precipitation variance by ±10 % and ±20 % generally changes discharge, SS and TP by -23.67 %~+21.88 %, -14.21 %~+84.48 % and -20.28 %~+16.97 % respectively in three regions.
These results show that rising temperature and precipitation variance cause critical impact on predicted discharge and water quality. The impact caused by precipitation variance is larger than the impact caused by rising temperature and the mechanisms are simpler. In addition, the impact caused by temperature is more sensitive to parameter settings
Subjects
climate change
HSPF
impact analysis
stream flow
suspended solid
total phosphorus
SDGs
Type
thesis
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