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Climate change leads to increasing intensity and frequency of extreme rainfalls, especially in Taiwan with steep slopes and rapid currents. Heavy rainfalls trigger serious erosion and landslides on hillslopes, which increase sand concentration in rivers, and thus affect the water quality of reservoirs and the ecohydrological functions of rivers. We take the Zhuoshui River basin as an example and applied the modified Soil Water Assessment Tool (SWAT) model, SWAT-Twn, to simulate sediment in the basin. In SWAT-Twn, estimation of sediment yield is carried out by integrating the Taiwan Universal Soil Loss Equation (TUSLE) and the landslide simulation. Results of daily streamflow simulation showed that the model performances were above the satisfactory level, while simulations of daily sediment loads showed that the SWAT-Twn model performed better than the official SWAT (SWAT664), in terms of PBIAS of − 46.6 to 16.0% (SWAT-Twn) and − 1.2 to − 107.0% (SWAT664). Two scenarios of land use/cover, scenario 1 with fixed land use/cover and scenario 2 with updated land use/cover in each year, were applied to simulate annual sediment in the river basin for investigating the effects of landslide area variation on sediments. Results of sediment simulation under the two scenarios showed that although updating landslide area may facilitate sediment yield simulation at the subbasin level, the sediment transport equation, Bagnold equation, does not reflect the variation in sediment loads in the watershed. With further modifications, SWAT-Twn is expected to be an effective tool for simulating the impacts of landslide on sediment loads in the watersheds with rainfall-induced landslide.
Li-Chi Chiang; Ci-Jyun Liao; Chih-Mei Lu; Yung-Chieh Wang. Applicability of modified SWAT model (SWAT-Twn) on simulation of watershed sediment yields under different land use/cover scenarios in Taiwan. Environmental Monitoring and Assessment 2021, 193, 1 -23.
AMA StyleLi-Chi Chiang, Ci-Jyun Liao, Chih-Mei Lu, Yung-Chieh Wang. Applicability of modified SWAT model (SWAT-Twn) on simulation of watershed sediment yields under different land use/cover scenarios in Taiwan. Environmental Monitoring and Assessment. 2021; 193 (8):1-23.
Chicago/Turabian StyleLi-Chi Chiang; Ci-Jyun Liao; Chih-Mei Lu; Yung-Chieh Wang. 2021. "Applicability of modified SWAT model (SWAT-Twn) on simulation of watershed sediment yields under different land use/cover scenarios in Taiwan." Environmental Monitoring and Assessment 193, no. 8: 1-23.
Change in water quality is seen as a reflection of change in terrestrial and aquatic ecosystems that are degraded by anthropogenic activities, including inappropriate land use management, deforestation, and urbanization. As the inter-correlations among landscape structure and ecological process have great influences on the hydrological process, energy flow, and nutrient cycles, it is important to evaluate the impact of landscape configuration on water quality for individual basins. Spatio-temporal variations of water quality and correlations among land use/land cover and water quality across Taiwan have not been thoroughly investigated. In this study, 48 water quality stations within 10 basins across Taiwan are investigated to identify the relationships among various water quality indices, land use/land cover, and landscape metrics at two different time periods. A total of 12 water quality parameters are included: water temperature, pH value, electrical conductivity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, total suspended sediment, total phosphorus, ammonia, nitrate, nitrite, and total nitrogen. Two years (1994 and 2007) of land use/land cover were characterized by using landscape metrics to quantify change in landscape configuration. The hypothesis is that individual basin has different characteristics resulting in different water quality – landscape metric relationships. The results showed that high degrees of landscape fragmentation and interspersion are correlated with degradation of water quality, in terms of high biological and chemical oxygen demands, and nitrogen loads, and such significant relationships are found in certain land use types as pollution sources. Only 3 out of 10 basins have strong or moderate impacts of landscape variation on water quality, indicating these findings could provide reference for developing an effective watershed planning and management with further investigations of landscape configuration at the class level.
Li-Chi Chiang; Yung-Chieh Wang; Yu-Kai Chen; Ci-Jyun Liao. Quantification of land use/land cover impacts on stream water quality across Taiwan. Journal of Cleaner Production 2021, 128443 .
AMA StyleLi-Chi Chiang, Yung-Chieh Wang, Yu-Kai Chen, Ci-Jyun Liao. Quantification of land use/land cover impacts on stream water quality across Taiwan. Journal of Cleaner Production. 2021; ():128443.
Chicago/Turabian StyleLi-Chi Chiang; Yung-Chieh Wang; Yu-Kai Chen; Ci-Jyun Liao. 2021. "Quantification of land use/land cover impacts on stream water quality across Taiwan." Journal of Cleaner Production , no. : 128443.
Grassed channels utilize the soil stabilization and water infiltration enhancement functions of grass in order to conserve soil and water in drainage systems. The construction processes and hydraulic mechanisms of grassed channels are more complicated, depending on the conditions of both soil and grass. As flow resistance is affected by grass characteristics, giving a single value of Manning’s n for a grass type under different flow conditions may lead to over-conservative designs or safety concerns. In this study, grassed flow experiments were carried out in a flume, with a bed of red soil covered by three grass species and with the flow conditions of three bed slopes. Average flow velocities were evaluated using five methods, including Manning’s equation and an analytical method. Comparison between the methods showed that Manning’s equation was unable to properly reflect the grass characteristic effects on the flow, but the analytical method performed better in estimating the average velocity and velocity profiles. The experimental results will be useful for the verification of mathematical methods, including analytical solutions and numerical models of grassed flow. For application, the relationships of average flow velocity against the grass layer relative height were proposed based on the analytical method as a reference for a hillslope drainage system design in Taiwan.
Ping-Cheng Hsieh; Yi-Cheng Lin; Yung-Chieh Wang. Comparison of Empirical and Analytical Solutions for Open-Channel Flow Velocity with Common Grass Species in Taiwan. Water 2021, 13, 1839 .
AMA StylePing-Cheng Hsieh, Yi-Cheng Lin, Yung-Chieh Wang. Comparison of Empirical and Analytical Solutions for Open-Channel Flow Velocity with Common Grass Species in Taiwan. Water. 2021; 13 (13):1839.
Chicago/Turabian StylePing-Cheng Hsieh; Yi-Cheng Lin; Yung-Chieh Wang. 2021. "Comparison of Empirical and Analytical Solutions for Open-Channel Flow Velocity with Common Grass Species in Taiwan." Water 13, no. 13: 1839.
Over the last five decades, there has been a decline of rural communities in Taiwan due to urbanization expansion. In the past 10 years, the central government has implemented the Rural Regeneration Project (RRP) aimed at revitalization and sustainable development in rural Taiwan. During the project’s implementation, communities have faced several disasters as a result of climate change-induced extreme rainfall events. Perceptions and adaptation practices of climate change-induced extreme events are critical to community sustainability and resilience. The gap between perceived and actual risks that communities experience creates challenges for policy-makers in achieving sustainability goals. This study aims to evaluate the perceived climate change-induced flooding hazard perceptions compared to the scientific projection and actual hazard events in 287 rural communities implementing the RRP. This study revealed consistency in risk perception, in that communities facing high potential exposure to extreme rainfall showed higher awareness of various impacts of climate change. However, when comparing climate actions, communities exposed to low-potential hazard areas had a relatively higher degree of recognition of the benefits of adaptation to climate change. Moreover, 59 rural communities with low awareness and exposed to high potentials of extreme events were widely distributed among hills of western, southern, and northern Taiwan, where compound disasters such as mudslides can occur. This research suggests that there is a need to integrate climate change planning and work with communities to bridge the gap between perceived and actual climate risks. In particular, capacity training, counseling services, and implementation of adaptation practices should be integrated into institutional planning and management for providing assistance in disaster prevention, relief, and post-event restoration; also, encouraging climate actions can directly improve community resilience toward climate change. While investing in the sustainable development of rural communities is largely based on revitalizing economic development, this study revealed the link to ensure resilience and social-ecological sustainability in rural communities under climate change impacts.
Chun-Hsien Lai; Pi-Ching Liao; Szu-Hung Chen; Yung-Chieh Wang; Chingwen Cheng; Chen-Fa Wu. Risk Perception and Adaptation of Climate Change: An Assessment of Community Resilience in Rural Taiwan. Sustainability 2021, 13, 3651 .
AMA StyleChun-Hsien Lai, Pi-Ching Liao, Szu-Hung Chen, Yung-Chieh Wang, Chingwen Cheng, Chen-Fa Wu. Risk Perception and Adaptation of Climate Change: An Assessment of Community Resilience in Rural Taiwan. Sustainability. 2021; 13 (7):3651.
Chicago/Turabian StyleChun-Hsien Lai; Pi-Ching Liao; Szu-Hung Chen; Yung-Chieh Wang; Chingwen Cheng; Chen-Fa Wu. 2021. "Risk Perception and Adaptation of Climate Change: An Assessment of Community Resilience in Rural Taiwan." Sustainability 13, no. 7: 3651.
A forecasting model is developed using a hybrid approach of artificial neural network (ANN) and multiple regression analysis (MRA) to predict the total typhoon rainfall and groundwater-level change in the Zhuoshui River basin. We used information from the raingauge stations in eastern Taiwan and open source typhoon data to build the ANN model for forecasting the total rainfall and the groundwater level during a typhoon event; then we revised the predictive values using MRA. As a result, the average accuracy improved up to 80% when the hybrid model of ANN and MRA was applied, even where insufficient data were available for model training. The outcome of this research can be applied to forecasts of total rainfall and groundwater-level change before a typhoon event reaches the Zhuoshui River basin once the typhoon has made landfall on the east coast of Taiwan.
Ping-Cheng Hsieh; Wei-An Tong; Yung-Chieh Wang. A hybrid approach of artificial neural network and multiple regression to forecast typhoon rainfall and groundwater-level change. Hydrological Sciences Journal 2019, 64, 1793 -1802.
AMA StylePing-Cheng Hsieh, Wei-An Tong, Yung-Chieh Wang. A hybrid approach of artificial neural network and multiple regression to forecast typhoon rainfall and groundwater-level change. Hydrological Sciences Journal. 2019; 64 (14):1793-1802.
Chicago/Turabian StylePing-Cheng Hsieh; Wei-An Tong; Yung-Chieh Wang. 2019. "A hybrid approach of artificial neural network and multiple regression to forecast typhoon rainfall and groundwater-level change." Hydrological Sciences Journal 64, no. 14: 1793-1802.
Soil erosion and landslide triggered by heavy rainfall are serious problems that have threatened water resources in Taiwan watersheds. This study investigated the relationship among streamflow, sediment load, sediment concentration and typhoon characteristics (path and rainfall amount) during 2000–2017 for nine gauging stations in five basins (Tamshui River basin, Zhuoshui River basin, Zengwen River basin, Gaoping River basin, and Hualien River basin) representing the diverse geomorphologic conditions in Taiwan. The results showed that streamflow and sediment load were positively correlated, and the correlation was improved when the sediment load data were grouped by sediment concentration. Among these basins, the Zhuoshui River basin has the highest unit-discharge sediment load and unit-area sediment load. The soil in the upstream was more erodible than the downstream soil during the normal discharge conditions, indicating its unique geological characteristics and how typhoons magnified sediment export. The spatiotemporal variation in sediment loads from different watersheds was further categorized by typhoons of different paths. Although typhoon path types matter, the Zhuoshui and Hualien River basin were usually impacted by typhoons of any path type. The results indicated that sediment concentration, the watershed soil characteristics, and typhoons paths were the key factors for sediment loads. This study can be useful for developing strategies of soil and water conservation implementation for sustainable watershed management.
Li-Chi Chiang; Yung-Chieh Wang; Ci-Jyun Liao. Spatiotemporal Variation of Sediment Export from Multiple Taiwan Watersheds. International Journal of Environmental Research and Public Health 2019, 16, 1610 .
AMA StyleLi-Chi Chiang, Yung-Chieh Wang, Ci-Jyun Liao. Spatiotemporal Variation of Sediment Export from Multiple Taiwan Watersheds. International Journal of Environmental Research and Public Health. 2019; 16 (9):1610.
Chicago/Turabian StyleLi-Chi Chiang; Yung-Chieh Wang; Ci-Jyun Liao. 2019. "Spatiotemporal Variation of Sediment Export from Multiple Taiwan Watersheds." International Journal of Environmental Research and Public Health 16, no. 9: 1610.
Topographies during the erosion process obtained from the single-stripe laser-scanning method may provide an accurate, but affordable, soil loss estimation based on high-precision digital elevation model (DEM) data. In this study, we used laboratory erosion experiments with a sloping flume, a rainfall simulator, and a stripe laser apparatus to evaluate topographic changes of soil surface and the erosion process. In the experiments, six slope gradients of the flume (5° to 30° with an increment of 5°) were used and the rainfall simulator generated a 30-min rainfall with the kinetic energy equivalent to 80 mm/h on average. The laser-scanned topography and sediment yield were collected every 5 min in each test. The difference between the DEMs from laser scans of different time steps was used to obtain the eroded soil volumes and the corresponding estimates of soil loss in mass. The results suggest that the collected sediment yield and eroded soil volume increased with rainfall duration and slope, and quantified equations are proposed for soil loss prediction using rainfall duration and slope. This study shows the applicability of the stripe laser-scanning method in soil loss prediction and erosion evaluation in a laboratory case study.
Yung-Chieh Wang; Chun-Chen Lai. Evaluating the Erosion Process from a Single-Stripe Laser-Scanned Topography: A Laboratory Case Study. Water 2018, 10, 956 .
AMA StyleYung-Chieh Wang, Chun-Chen Lai. Evaluating the Erosion Process from a Single-Stripe Laser-Scanned Topography: A Laboratory Case Study. Water. 2018; 10 (7):956.
Chicago/Turabian StyleYung-Chieh Wang; Chun-Chen Lai. 2018. "Evaluating the Erosion Process from a Single-Stripe Laser-Scanned Topography: A Laboratory Case Study." Water 10, no. 7: 956.
Systematic conservation planning (SCP) deals with a delicate interplay of competing interests and has far-reaching impacts for all stakeholders and systems involved. While SCP has traditionally attempted to conserve ecosystem services that benefit ecological systems, public perceptions of conservation initiatives influence their ultimate feasibility and sustainability. In an attempt to balance ecological integrity, social utility, and urban development, this study develops a framework that applies four popular models to represent these competing factors, including two ecosystem services models—InVEST (Integrated Valuation of Environmental Services and Tradeoffs) for biophysical services (BpS), and SolVES (Social Values for Ecosystem Services) for social values (SV); a land use and land cover (LULC) suitability model; and Zonation for delimiting high priority areas. We also analyze a number of conservation scenarios that consider varying levels of urban development. While BpS are distributed with considerable spatial variability, SV spatially overlap. Approximately 6% of the area was identified as having both high BpS and SV, whereas a further 24.5% of the area was identified as either high BpS low SV or vise-versa. Urban development scenarios affected the conservation area selection drastically. These results indicate tradeoffs and potential synergies between development, SV, and BpS. Our findings suggest that the information provided by the proposed framework can assist in finding solutions to social-ecological planning complexities that serve multiple stakeholders.
Yu-Pin Lin; Wei-Chih Lin; Hsin-Yi Li; Yung-Chieh Wang; Chih-Chen Hsu; Wan-Yu Lien; Johnathen Anthony; Joy R. Petway. Integrating Social Values and Ecosystem Services in Systematic Conservation Planning: A Case Study in Datuan Watershed. Sustainability 2017, 9, 718 .
AMA StyleYu-Pin Lin, Wei-Chih Lin, Hsin-Yi Li, Yung-Chieh Wang, Chih-Chen Hsu, Wan-Yu Lien, Johnathen Anthony, Joy R. Petway. Integrating Social Values and Ecosystem Services in Systematic Conservation Planning: A Case Study in Datuan Watershed. Sustainability. 2017; 9 (5):718.
Chicago/Turabian StyleYu-Pin Lin; Wei-Chih Lin; Hsin-Yi Li; Yung-Chieh Wang; Chih-Chen Hsu; Wan-Yu Lien; Johnathen Anthony; Joy R. Petway. 2017. "Integrating Social Values and Ecosystem Services in Systematic Conservation Planning: A Case Study in Datuan Watershed." Sustainability 9, no. 5: 718.
Tree species in mountainous areas are expected to shift their distribution upward in elevation in response to climate change, calling for a potential redesign of existing protected areas. This study aims to predict whether or not the distributions of two high-mountain tree species, Abies (Abies kawakamii) and Tsuga (Tsuga chinensis var. formosana), will significantly shift upward due to temperature change, and whether current protected areas will be suitable for conserving these species. Future temperature change was projected for 15 different future scenarios produced from five global climate models. Shifts in Abies and Tsuga distributions were then predicted through the use of species distribution models (SDMs) which included occurrence data of Abies and Tsuga, as well as seasonal temperature, and elevation. The 25 km × 25 km downscaled General Circulation Model (GCMs) data for 2020–2039 produced by the Taiwan Climate Change Projection and Information Platform was adopted in this study. Habitat suitability in the study area was calculated using maximum entropy model under different climatic scenarios. A bootstrap method was applied to assess the parameter uncertainty of the maximum entropy model. In comparison to the baseline projection, we found that there are significant differences in suitable habitat distributions for Abies and Tsuga under seven of the 15 scenarios. The results suggest that mountainous ecosystems will be substantially impacted by climate change. We also found that the uncertainty originating from GCMs and the parameters of the SDM contribute most to the overall level of variability in species distributions. Finally, based on the uncertainty analysis and the shift in habitat suitability, we applied systematic conservation planning approaches to identify suitable areas to add to Taiwan’s protected area network.
Wei-Chih Lin; Yu-Pin Lin; Wan-Yu Lien; Yung-Chieh Wang; Cheng-Tao Lin; Chyi-Rong Chiou; Johnathen Anthony; Neville D. Crossman. Expansion of Protected Areas under Climate Change: An Example of Mountainous Tree Species in Taiwan. Forests 2014, 5, 2882 -2904.
AMA StyleWei-Chih Lin, Yu-Pin Lin, Wan-Yu Lien, Yung-Chieh Wang, Cheng-Tao Lin, Chyi-Rong Chiou, Johnathen Anthony, Neville D. Crossman. Expansion of Protected Areas under Climate Change: An Example of Mountainous Tree Species in Taiwan. Forests. 2014; 5 (11):2882-2904.
Chicago/Turabian StyleWei-Chih Lin; Yu-Pin Lin; Wan-Yu Lien; Yung-Chieh Wang; Cheng-Tao Lin; Chyi-Rong Chiou; Johnathen Anthony; Neville D. Crossman. 2014. "Expansion of Protected Areas under Climate Change: An Example of Mountainous Tree Species in Taiwan." Forests 5, no. 11: 2882-2904.