Ching-Pin Tung

Application and development of a decision-support system for assessing water shortage and allocation with climate change

The assessment to vulnerability of the water supply system needs several modeling tools and cases to simulate. A decision-support tool which integrates the common procedures of impact assessment of climate change, downscaling, weather generation, hydrological model, and interface for linking system dynamics model is proposed here. In this study, the impact of climatic change and growing water demand to the water supply system in Touchien river basin in Taiwan was derived. The vulnerability for the current water supply system was estimated for present and future conditions. The result demonstrated that the water supply system could meet the water demand in Touchien river basin but might be subjected to serious water shortage due to climatic change and expanded water demand. Results are expected to give the authorized government sectors a hint for instituting water policy and implementing allocation measures for irrigational water.

Application of genetic programming to project climate change impacts on the population of Formosan Landlocked Salmon

This work presents a novel methodology, genetic programming (GP), for developing environmental response functions for Formosan Landlocked Salmon (Oncorhynchus masou formosanus); these functions are then applied to evaluate the impacts of climate changes. Average daily temperature and maximal flows between two sampling periods were adopted as principal factors for categorizing environmental conditions. The GP successfully identified the response functions for various environmental categories. The response functions were further applied to assess the impact of climate change. Fourteen future possible climate scenarios were derived based on the equilibrium and transition experiments by GCMs. Impact assessment results indicated that climate change may significantly influence populations of Formosan Landlocked Salmon due to more frequent higher temperatures. Adaptation strategies are required to mitigate the impact of global climate change as current conservation measures for Formosan Landlocked Salmon habitat only reduce local human-induced effects. In the situation of complicated relationships between fish population and environmental conditions, GP provides a useful tool to obtain some information from the limited data.

Improvement of a drainage system for flood management with assessment of the potential effects of climate change

Abstract Runoff discharge in the Tuku lowlands, Taiwan, has increased with land development. Frequent floods caused by extreme weather conditions have resulted in considerable economic and social losses in recent years. Currently, numerous infrastructures have been built in the lowland areas that are prone to inundation; the measures and solutions for flood mitigation focus mainly on engineering aspects. Public participation in the development of principles for future flood management has helped both stakeholders and engineers. An integrated drainage–inundation model, combining a drainage flow model with a two-dimensional overland-flow inundation model is used to evaluate the flood management approaches with damage loss estimation. The proposed approaches include increasing drainage capacity, using fishponds as retention ponds, constructing pumping stations, and building flood diversion culverts. To assess the effects on the drainage system of projected increase of rainfall due to climate change, for each approach simulations were performed to obtain potential inundation extent and depth in terms of damage losses. The results demonstrate the importance of assessing the impacts of climate change for implementing appropriate flood management approaches. Editor Z.W. Kundzewicz Citation Chang, H.-K., Tan, Y.-C., Lai, J.-S., Pan, T.-Y., Liu, T.-M., and Tung, C.-P., 2013. Improvement of a drainage system for flood management with assessment of the potential effects of climate change. Hydrological Sciences Journal, 58 (8), 1581–1597.

Optimal balance between land development and groundwater conservation in an uncertain coastal environment

An optimization problem for balancing land carrying capacity and groundwater consumption in Central Taiwan was solved using a problem-oriented grey linear programming (POGLP) algorithm. Satisfactory grey solutions were obtained through formulating and solving the proposed POGLP models. These models provide useful information to decision makers regarding the possible ranges of final alternatives when system parameters are highly uncertain. Results indicate that all transferable lands currently used for agriculture and fish cultivation should be converted into other usage. This would conserve the groundwater resources, thereby preventing further land subsidence in that area. Grey sensitivity analyses performed well in the decision-making process when a set of interval regions instead of trend curves were systematically generated without increasing the complexity of the mathematical models.

Application to Reservoir Operation Rule-Curves

Researches in reservoir operation rules had already been studied more than half a century but much still remains to be done. Besides, as a result of global climate change and many nature or human causes, make the frequency and intensity of a lot of hydrological events such as drought and flood change, the existing reservoir operation rules need to change. This paper aims at reservoir operation rule -curves in detail, and applies to the newly rising evolution alg orithms to optimize reservoir operation systematically. Furthermore, the study detects the drought events by the prediction data and water resource system model, optimizes the double -group rule-curves and makes the water resources more effectively. The LiYuTan reservoir in Taiwan, for example, establish, the up -to-date operation rule.

Analysis of space–time patterns of rainfall events during 1996–2008 in Yilan County (Taiwan)

Understanding local precipitation patterns is essential to water resource management and flood mitigation. Precipitation patterns can vary in space and time depending on factors from different spatial scales such as local topographical changes and macroscopic atmospheric circulation. This study applied the two-stage classification method to distinguish the space–time patterns of local precipitations in the two identified distinct synoptic conditions, i.e. summer and autumn, from 24 gauges during 1996–2008 in Yilan County, Taiwan. The proposed method classifies the synoptic and local conditions for the space–time rainfall patterns by using K-means coupled with empirical orthogonal function analysis, and hierarchical ascending clustering method respectively. The proposed two-stage classification method considers not only the magnitude and the space–time distribution of rainfall events, but also the associated synoptic conditions. The results identified three primary patterns of extreme and two patterns of normal events in both seasons. Regarding the extreme events from typhoons, wind directions and the frontal accompanied effect are major contributors to the magnitude and spatial distribution of rainfall events in the summer and autumn, respectively. Spatiotemporal covariance structures are used to characterize the variability of normal events, showing the increasing frequency of wide spatial and temporal ranges from the summer to autumn. In summary, the proposed classification analysis provides patterns associated with distinct underlying physical mechanisms and space–time characteristics. The general characteristics of rainfall patterns can provide insights for the hydrological modeling of local catchments under different climatic scenarios.

The development of stream temperature model in a mountainous river of Taiwan

Formosan landlocked salmon is an endangered species and is very sensitive to stream temperature change. This study attempts to improve a former stream temperature model (STM) which was developed for the salmon’s habitat to simulate stream temperature more realistically. Two modules, solar radiation modification (SRM) and surface/subsurface runoff mixing (RM), were incorporated to overcome the limitation of STM designed only for clear-sky conditions. It was found that daily temperature difference is related to cloud cover and can be used to adjust the effects of cloud cover on incident solar radiation to the ground level. The modified model (STM + SRM) improved the simulation during a baseflow period in both winter and summer with the Nash-Sutcliffe efficiency coefficient improved from 0.37 (by STM only) to 0.71 for the winter and from −0.18 to 0.70 for the summer. On the days with surface/subsurface runoff, the incorporation of the two new modules together (STM + SRM + RM) improved the Nash-Sutcliffe efficiency coefficient from 0.00 to 0.65 and from 0.29 to 0.83 in the winter and the summer, respectively. Meanwhile, the contributions of major thermal sources to stream temperature changes were identified. Groundwater is a major controlling factor for regulating seasonal changes of stream temperature while solar radiation is the primary factor controlling daily stream temperature variations. This study advanced our understanding on short-term stream temperature variation, which could be useful for the authorities to restore the salmon’s habitat.

Interval number fuzzy linear programming for climate change impact assessments of reservoir active storage

The major uncertainty in the climate change impact study inherits from applying the predictions of General Circulation Models (GCMs). Different results might be obtained by using various GCMs’ predictions, which causes difficulties on the decision making of water resources management. This study proposed an integrated hydrological simulations and optimization framework, consisting of a fuzzy linear programming model with interval numbers, a streamflow simulation model, and agricultural water demand projections, to evaluate the impacts of climate change on reservoir active storage. The reservoir inflows are simulated by the WatBal model, while agricultural water demands are predicted based on the projected change of potential evapotranspiration. Inflows and water demands are used to formulate an interval number fuzzy linear programming model. Fuzzy relationships are used to describe tolerable deficits of water resources, and the interval number is employed to indicate ranges of possible inflows and water demands. This systematic framework is applied to study the Tsengwen reservoir watershed to provide an optimal interval of active storage. The results further indicate the higher tolerable deficit, the smaller difference between superior and inferior active storage.

PAWEES 2008 international conference on benefit of paddy to sustainable development: first announcement

The conference will bring together leading players, in the relevant fields, representing academia and international authorities including experienced engineers. Our international view will be enriched by: presentations of the latest study results and information exchange; pulling out future priority subjects in the field of paddy and water environment; discussing the future direction of international research; deliberating on several methodologies for application of past research achievements to the current and real world; and exploring strategies for food security, eradication of poverty and hunger in developing countries, and the development of agricultural communities.

The Relationship between Boussinesq Equation and Non-Linear Storage of Baseflow Simulation

There are several approaches for the analysis of baseflow which include different kind of conceptual models and theoretical analysis. The concepts of linear and nonlinear storage are often used in modeling the baseflow and the nonlinear relationship between baseflow (Q) and moisture storage (S) can be described as S = aQ b . Boussinesq equation is used to predict the baseflow, and the results are as good as the estimation by nonlinear storage. The purpose of this paper is to discuss the relationship between nonlinear storage concept and the Boussinesq Equation. The parameters a in nonlinear storage modeling will be discussed. By using the observed streamflow data in Taiwan, the physical properties of parameter a will be identified. The present study concentrated on the structure of baseflow modeling and their parameters.