Ching-Ho Chen

A simulation model for investigating the effects of rice paddy fields on the runoff system

Rice production in Taiwan is likely to decrease because of two major threats: an increase in the industrial demand on water resources and cheaper imported rice resulting from the free trade policy which will be enforced when Taiwan joins the World Trade Organization. A shrinkage in rice paddy acreage raises environmental concerns, especially in relation to water conservation. Besides rice production, the existence of paddy fields promotes groundwater recharge and remediates floods. Unlike rice production, the value of the environmental conservation is difficult to quantify. In this study, the effects of paddy fields on groundwater recharge and flood remediation have been investigated. To assess the long-term significance of these effects, the study team developed a model based on hydrologic equilibrium. This model describes the performance of water recharge and detention. According to a case study, the amount of runoff from a rice paddy field is about 27% of the amount of the precipitation. This percentage is significantly lower than that of the runoff from a dry farming field, which is normally as high as 55% of the precipitation. In this case, the amount of evapotranspiration from a rice paddy field and that from a dry farming field are 56% and 31%, respectively. In this case, the amount of recharge from a rice paddy field, 17%, is higher than that from a dry farming field, which is 14%. Clearly, a significant increase in runoff and a decrease in groundwater recharge can be expected when a rice paddy field is converted to other uses. The second analysis includes an event-based simulation study regarding the effects of rice paddy fields on the flood peak. Attributed to its superior detention capacity, a paddy field typically has a much lower flood peak, about one third of a dry farm field. These positive effects of rice paddy fields on runoff should be considered in making decisions about the reduction of rice cultivation.

Development of a system dynamics model for sustainable land use management

Abstract The current land use management framework considers economic, social, and environmental influences individually, making it difficult to achieve sustainable development. Therefore, this study aims to develop a system dynamics model to help decision makers to integrally and systematically consider the components and interactions in land use management. Based on the concept of sustainable development, this study uses systems thinking to develop dynamics of sustainable land use management in a river basin, which considers human activities, land resources, water resources, and air resources integrally. Furthermore, this study uses the concept of driving forcestate‐response to establish a conceptual dynamics framework for sustainable land use management. Because of the complicated interactions among the above components and iterative decision‐making procedures, this study uses Vensim software and the concept of object‐oriented programming to develop a sustainable land use management system dynamics model (SLUMSD model) based on the conceptual dynamics framework. The Nankan river basin is used as a case study to illustrate the capability of the SLUMSD model. The case study indicates that the interactions among the components in sustainable land use management can be effectively identified in the SLUMSD model. While planning strategies for sustainable land use management, decision‐makers can use the SLUMSD model to understand how the components vary with different alternatives. Using the SLUMSD model to iteratively modify alternatives can ensure appropriate decision‐making in sustainable land use management.

Development of a Methodology for Strategic Environmental Assessment: Application to the Assessment of Golf Course Installation Policy in Taiwan

Some countries, including Taiwan, have adopted strategic environmental assessment (SEA) to assess and modify proposed policies, plans, and programs (PPPs) in the planning phase for pursuing sustainable development. However, there were only some sketchy steps focusing on policy assessment in the system of Taiwan. This study aims to develop a methodology for SEA in Taiwan to enhance the effectiveness associated with PPPs. The proposed methodology comprises an SEA procedure involving PPP management and assessment in various phases, a sustainable assessment framework, and an SEA management system. The SEA procedure is devised based on the theoretical considerations by systems thinking and the regulative requirements in Taiwan. The positive and negative impacts on ecology, society, and economy are simultaneously considered in the planning (including policy generation and evaluation), implementation, and control phases of the procedure. This study used the analytic hierarchy process, Delphi technique, and systems analysis to develop a sustainable assessment framework. An SEA management system was built based on geographic information system software to process spatial, attribute, and satellite image data during the assessment procedure. The proposed methodology was applied in the SEA of golf course installation policy in 2001 as a case study, which was the first SEA in Taiwan. Most of the 82 existing golf courses in 2001 were installed on slope lands and caused a serious ecological impact. Assessment results indicated that 15 future golf courses installed on marginal lands (including buffer zones, remedied lands, and wastelands) were acceptable because the comprehensive environmental (ecological, social, and economic) assessment value was better based on environmental characteristics and management regulations of Taiwan. The SEA procedure in the planning phase for this policy was completed but the implementation phase of this policy was not begun because the related legislation procedure could not be arranged due to a few senators’ resistance. A self-review of the control phase was carried out in 2006 using this methodology. Installation permits for 12 courses on slope lands were terminated after 2001 and then 27 future courses could be installed on marginal lands. The assessment value of this policy using the data on ecological, social, and economic conditions from 2006 was higher than that using the data from 2001. The analytical results illustrate that the proposed methodology can be used to effectively and efficiently assist the related authorities for SEA.

Simulation model for investigating effect of reservoir operation on water quality

Abstract This paper investigates the effect of reservoir operation on downstream water quality. This is accomplished by the following procedures. An automated channel network extracting system, C-NES, is used to extract channel network from Digital Elevation Model and a distributed rainfall-runoff model is adopted to estimate the streamflows. The relationship between water quality and streamflows is established. Subsequently, a reservoir water quality model, WASP, is employed to predict water quality under several sedimentation conditions and operation policies. Different reservoir operation rules are simulated to address the possibility of maintaining water quality through proper operation. The watershed of Ta-Chi Reservoir in Taiwan is chosen as a case study. The simulation results show that an appropriate operation rule can improve outlet water quality by releasing water from a certain depth in the reservoir. This is because the flow field that influences the bio-chemical reactions is altered. It is suggested that careful consideration of the outlet positions should be included in the future design and operation of a reservoir.

Methodology of disaster risk assessment for debris flows in a river basin

Abstract“Disaster risk assessment” is important in the planning of risk management strategies that reduce societal losses. However, governmental agencies in Taiwan generally assess risks that emerge from debris flows without adequately considering risk management and taking a systems approach. This work proposes an approach to thoroughly consider the interactive influence mechanism of debris flow disaster risk. Additionally, a systematic method for assessing disaster risks is developed. This proposed method can be used in the current risk assessment and as a basis for management strategy planning. Based on systems thinking, the components and attributes of a conceptual system of disaster risk management associated with debris flows in a river basin are identified. Subsequently, a conceptual mitigation–hazard–exposure–resistance framework and an indicator system for assessing the debris flow disaster risks in a river basin are identified. The disaster risks for each exposed community in each drainage zone can be systematically calculated based on the current status or plans of prevention and evacuation measures using the proposed indicator system. A case study of implementing the proposed methodology that involves the Chishan River Basin is presented, in which disaster risk according to the current status of prevention and evacuation measures is assessed. Drainage zones and communities with a significant debris flow disaster risk are located; this risk is associated with a lack of adequate prevention and evacuation measures that have been planned of government agencies. Analytical results indicate that the proposed methodology can systematically and effectively assess the disaster risks of a river basin. The proposed methodology provides a valuable reference for governmental agencies that must manage disaster risk associated with debris flows.

Development of an air pollution evaluation system by linking air pollution total quantity control and land use management

Abstract This study considers air pollution total quantity control and land use management to establish a methodology for estimating unit emission loads of land use types. An air pollution evaluation system (APES) is developed, based on air pollution evaluation theory and procedure by linking air pollution total quantity control and land use management. The APES consists of an information management subsystem, a model management subsystem, and an evaluation subsystem. The Nankan urban area, located in northern Taiwan, is used to illustrate the capability of the APES. The analysis results indicate that the integration of GIS technology, a spreadsheet application, and an air pollution simulation model into APES has made it an effective system for facilitating the examination of a set of alternatives and generating a sustainable land use management strategy.

Reuse Resource of Food Processing Sludge-Derived Fuel Incinerated Ash

The heat value of food processing sludge is similar to that of bituminous coal, thus is suitable as biofuel; however, the problem of incinerated ash disposal after combustion should be address. This study evaluated the applicability of food processing sludge-derived fuel incinerated ash (FA) to pozzolanic material and soil improvement, and proposed reuse strategies. When applied to pozzolanic material, the addition of FA reduced the hydration heat of fresh incinerated ash cement paste (FACP) significantly (85.96~91.23%), and prolonged the initial setting times (87.88~134.85%) and final setting times (87.88~134.85%) of FACP significantly. When the FA addition was 10% and 20% respectively, the pozzolanic strength activity index (SAI) was greater than 75% until the hardened FACP was cured for 28 days and 90 days respectively. When applied in soil improvement, the final seed germination of Chinese cabbage and water spinach in the original soil (ash content 0%) and improved soil (ash content 20%) was 98% and 90% respectively. There was no significant effect on the growth rate of Chinese cabbage and water spinach.

Predicting Hardness of Four Groundwater Monitoring Stations in Kaohsiung City of Taiwan Using Seven Types of GM (1, 1) Model

In this study, seven types of first-order and one-variable grey differential equation model (abbreviated as GM (1, 1) model) were used to predict the hardness of four groundwater monitoring stations in Kaohsiung City of Taiwan. The mean absolute percentage error (MAPE) was used to evaluate the predicting performance. The results indicated the minimum MAPE of 4.71 %, 3.15 %, 2.66 %, and 16.63 % could be achieved when predicting hardness of Fonsi, Datung, Shaukang, and Chihsien stations, respectively. According to the results, it revealed that GM (1, 1) was an efficiently early warning tool for providing groundwater quality information to the competent authority.

Integrated Management Methodology for Sustainability and Land Use of a River Basin

Sustainability assessment of a river basin is usually performed separately from the planning of land uses within the basin. This work develops a methodology for simultaneously considering environmental, social, and economic sustainability for land use planning in a river basin. Systems thinking, managing for results (MFRs), and the driving force-pressure-state-impact- response (DPSIR) framework are firstly used to develop a management framework and an indicator system, which is integrated into an optimization model to simultaneously maximize the sustainability of the river basin. Moreover, a prototype of integrated management system for sustainability and land use for a river basin (IMSSLU) is established to obtain the optimal strategy. The Shetzu River Basin in Taiwan is used as case study. The sustainability of this river basin can be increased as the land use plan is developed. The optimal land use strategies for the Shetzu River Basin and its land divisions can both be generated. The total quantities of pollution discharges and resource uses of each drainage zone are also obtained. Analytical results indicate that the proposed methodology and IMSSLU system can be used to help the authorities to devise the optimal land use plan for a river basin while simultaneously pursuing its optimal sustainability.

Development of the systematic object event data model for integrated point source pollution management

Previous works on database integration focused mainly on the creation of transformation interfaces between incompatible databases built up by different departments of the Taiwan Environmental Protection Administration, ignoring the demands of systematically and flexibly integrated information for advanced pollution control of point sources. To provide a systematic framework for flexible integration of distributed data, this paper presents a general model as the systematic object event data model based on systems thinking, to improve the integration capability of databases. The conceptual database framework for integrated pollution control was proposed as a result of the application of the systematic object event data model. The fundamental part of the systematic object event data model, creation of the object registry database, was put into practice from the year 2008. The object database of pollution source is available to factories in 2009, which helps factories to create and Taiwan environmental protection administration to maintain the consistent object data through the electronic application processes of permits. To construct various event databases that systematically connect to object database would be the following step to more efficiently provide systematic information from systematic data integration.