A Simulation-Based Approach for Evaluating Cost and Performance of a Sediment Removal and Processing System for the Lower Susquehanna River Dams

A series of three major dams and reservoirs located along the Lower Susquehanna River have historically acted as a system of sediment and nutrient pollution traps.  However, episodic pulses of these pollution loads are released following short-term extreme storm events, affecting subaquatic vegetation, benthic organisms, and the overall water quality in the Upper Chesapeake Bay.  In addition, all three reservoirs have reached a state of near maximum storage capacity termed as dynamic equilibrium.  Based on prior research, this study seeks to reduce the sediment buildup behind the dams through a sediment removal and processing operation, and thereby reduce the ecological impact of major storms.  A set of scour performance curves derived from a regression analysis, and a stochastic lifecycle cost model were used to evaluate the sediment scouring reduction and economic feasibility of three processing alternatives:  Plasma Vitrification, Cement-Lock, and Quarry/Landfill, and three removal amount cases:  Nominal, Moderate, and Maximum.  Since the scour performance curves treat the dams as static, a fluid system dynamics model was used to determine if the dynamic interaction between the capacitance of the dams during major scouring events is negligible or considerable.  A utility vs. cost analysis factoring in time, performance, and suitability of the alternatives indicates that a Cement-Lock processing plant at moderate dredging for the Safe Harbor and Conowingo Dams is the most cost-performance effective solution

Rapid Assessment of Intertidal Wetland Sediments

Urbanization of coastal areas poses a severe threat to ecologically valuable intertidal wetlands. This paper presents a pragmatic approach called Rapid Assessment for Intertidal Wetland Sediments (RAITWS) for evaluating the sediment quality of intertidal wetlands. RAITWS involves construction of reference groups, selection of a subset of environmental variables, matching of test sites to reference groups, prediction of the benthic fauna community structure (e. g. of macroinvertebrates) at test sites, evaluation of the Observation to Expectation ratio (O/E ratio), quantification of environmental variables with series of dynamic numerical models, and interpretation of the O/E findings. The proposed method extends the existing rapid biological assessment approach from static to dynamic applications. In particular, RAITWS provides a fast method of assessing intertidal wetland sites which are undergoing ecological change due to nearby coastal development.Environmental SciencesSCI(E)EI0ARTICLE5574-5852

Impacts of sediment flushing on channel evolution and morphological processes: Case study of the Kurobe River, Japan

River morphodynamics and sediment transportSedimentation in reservoir

How foundation species shape tidal flats

In this thesis, I described how foundation species contribute to the of shape tidal flats based on a variety of species, regions and species interactions. Based on these results, I can conclude that both biological and physical processes play an important role in shaping tidal flats. For instance, the foundation species affect their environment strongly by sediment bioturbation or accretion. On the other hand, physical forces play an important role in the species distribution or the effect of foundation species on the environment i.e., when physical forces are too strong, foundation species will not survive or change their surroundings. To conclude, it is valuable to focus on an integral approach implementing both physical and biological processes when studying tidal flats. With this thesis, I took some important steps toward understanding tidal flat formation by studying small-scale species interactions and translate them to landscape-scale functioning

Renovation of Existing Reservoir in Taiwan for Sustainability

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

SPH modeling of water-related natural hazards

This paper collects some recent smoothed particle hydrodynamic (SPH) applications in the field of natural hazards connected to rapidly varied flows of both water and dense granular mixtures including sediment erosion and bed load transport. The paper gathers together and outlines the basic aspects of some relevant works dealing with flooding on complex topography, sediment scouring, fast landslide dynamics, and induced surge wave. Additionally, the preliminary results of a new study regarding the post-failure dynamics of rainfall-induced shallow landslide are presented. The paper also shows the latest advances in the use of high performance computing (HPC) techniques to accelerate computational fluid dynamic (CFD) codes through the efficient use of current computational resources. This aspect is extremely important when simulating complex three-dimensional problems that require a high computational cost and are generally involved in the modeling of water-related natural hazards of practical interest. The paper provides an overview of some widespread SPH free open source software (FOSS) codes applied to multiphase problems of theoretical and practical interest in the field of hydraulic engineering. The paper aims to provide insight into the SPH modeling of some relevant physical aspects involved in water-related natural hazards (e.g., sediment erosion and non-Newtonian rheology). The future perspectives of SPH in this application field are finally pointed out

Observations of Deep-Reef Ichthyofauna from the Bahama and Cayman Islands, with Notes on Relative Abundance and Depth Distribution

Observations of fish species inhabiting vertical wall habitats were conducted in the Bahama and Cayman islands. Twenty-three species from 12 families were recorded from various sites during the study. Number of species and abundance of individuals decreased with depth on the escarpments observed. Gramma melacara was the only species found throughout the depth ranges on all escarpments observed. Information about these habitats is sparse and more investigations are warranted

Observations of Deep-Reef Ichthyofauna from the Bahama and Cayman Islands, with Notes on Relative Abundance and Depth Distribution

Observations of fish species inhabiting vertical wall habitats were conducted in the Bahama and Cayman islands. Twenty-three species from 12 families were recorded from various sites during the study. Number of species and abundance of individuals decreased with depth on the escarpments observed. Gramma melacara was the only species found throughout the depth ranges on all escarpments observed. Information about these habitats is sparse and more investigations are warranted