CGER Reports


Development of Process-based NICE Model and Simulation of Ecosystem Dynamics in the Catchment of East Asia (Part III)


It is very important to assess and predict ecosystem functions quantitatively and make scientifically sound policy recommendations for sustainable development concerning the degradation of environmental resources, including water resources, through human activities on a global scale. In particular, there are diverse and complex water-resources problems in combination with rapid economic growth and serious environmental degradation in East Asia (Fig. 1).

This monograph (Part III) succeeds Reports Vol. 11 (Part I, CGER-I063-2006) and Vol. 14 (Part II, CGER-I083-2008) published previously. Environmental pollution has recently come to be synonymous with degradation of water and thermal environments and contamination in urban areas. The development of the National Integrated Catchment-based Eco-hydrology (NICE) model combined with ground-based observation network and satellite data (Fig. 2), and simulation of ecosystem dynamics in catchments are therefore very important not only for the solution of these intertwined environmental degradations but also for the quantitative evaluation of catchments.

In this monograph the author reviews some examples of the model application to urban areas in Japan and China. For example, the author introduces some results on the clarification of water degradation by over-exploitation of water resources in the North China Plain (NCP) (Fig. 3), on the environmental assessment of ecosystem degradation in catchments accompanied by economic growth in urban areas (Fig. 4), and on the prediction of the mitigation of heat island by the effective management of water resources in the Tokyo metropolitan area (Fig. 5).

Though water resources are vital for human activity, their over-exploitation causes serious hydrologic change and ecosystem degradation in catchments. However, effective management of water resources is powerful for achieving a win-win solution to intertwined pollution problems in eco-conscious societies.

Fig. 1. Evaluation of ecosystem degradation by cyclic changes in water, heat, and mass.
Fig. 2. Process-based NICE (National Integrated Catchment-based Eco-hydrology) model. NICE simulates the water–heat budget, mass transport, and vegetation succession processes iteratively.
Fig. 3. Groundwater degradation by over-exploitation in the NCP. NICE included complex and diverse water systems and clarified the spatial distribution of groundwater degradation over the last half century. The model also evaluated quantitative relationships between crop productivity, hydrologic cycle, and available water resources.
Fig. 4. Relation between the increase in water consumption in Dalian and environmental degradation in Biliu River catchment. The statistical analysis of a decoupling indicator based on the simulated water carrying capacity and on the satellite data of vegetation index indicated that water-related stress in Dalian had increased in accordance with the environmental degradation after the completion of the reservoir.
Fig. 5. Prediction of hydrothermal changes to recover a sound hydrologic cycle and thermal environment in the Kawasaki urban area. NICE indicated that an effective water resources management including groundwater is powerful for recovering a sound hydrologic cycle from the imbalance such as ground subsidence and inundated areas, caused by human over-exploitation, and for reducing thermal pollution accompanied by heat island.