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As urban and suburban areas expand, the problem of sewage disposal spreads as well. Inappropriate planning of a sewage management system could impair water quality, destroy habitat, and threaten public health. Simply building a sewage interceptor system along the urban river corridor to handle the wastewater effluents without regard to the impacts from combined-sewer overflows (CSOs) in the storm events cannot fulfill the ultimate goal of environmental restoration in the receiving water body. This study therefore carries out a system-based assessment to search for the optimal operating strategy of the interceptor facilities with respect to biocomplexity or biodiversity in an urban river system. In particular, it focuses on the richness of the fish community in the biological systems, the effect of stress on the fish community by storm events, and their capacity for adaptive behavior in response to the CSOs' impact in the Love River estuarine system, South Taiwan. By integrating the biological indicators in an environmental context, two simulation models describing the quality and quantity of storm water and their impact on the river water quality are calibrated and verified. The interactions of natural systems and engineered systems covering both spatial and temporal aspects can then be explored in terms of the predicted levels of dissoved oxygen (DO) along the river reaches so as to strengthen an ultimate optimal search for the best operational alternative for the interceptor system. In view of the inherent complexity of integrating simulation outputs at various scales to aid in building the optimization step, three regression submodels were derived beforehand. These submodels present a high potential for exhibiting, eliciting, and summarizing the nonlinear behavior between the CSO impacts and the DO levels in the river reaches. With the aid of such findings, this study finally applies a linear programming model to determine the optimal size of a constructed storage pond (i.e., a detention pond), based on several types of storm events in the study area. This is proved essential for minimizing the ecological risk in such a way so as to indirectly improve the biodiversity in the estuarine river system.

A: DGM, Dusty Gas Model.T N An experimental study was conducted to assess the rela ve contribu ons of molecular and Knudsen diff usions for gasphase transport in unsaturated silica fl our with an intrinsic permeability of 1 ? 2 × 10 −14 m 2 . Single-gas phase fl ow and binary diff usion experiments were performed on the same soils to determine the Knudsen diff usion and the eff ec ve gas-phase diff usion coeffi cients, respec vely. These results were further used to assess the diff usibility factor for Fick's law of diff usion and the obstruc on factor for the Dusty Gas Model theory. These factors were used to account for impedance to gas diff usion caused by the tortuous nature of soil pores. The Knudsen diff usion coeffi cient was found to be one to two orders of magnitude greater than the eff ec ve diff usion coeffi cient for silica fl our at water satura ons ranging from 53 to 75% (v/v), which suggested that the Knudsen eff ect has negligible impact on the eff ec ve diff usion coeffi cient for the unsaturated silica-fl our system at water satura ons lower than 75%. For unsaturated silica fl our with air-fi lled porosity <0.2, the diff usibility factor (or the obstruc on factor) value can be more than 10 mes smaller than the values es mated by other diff usibility correla ons published in the literature.