Constructed wetlands are promising engineering technique that reproduce the conditions of the natural wetlands [1]. They have high water treatment capacity because of the intensive “work” of the plants and the microorganisms. Depending on the conditions various types of plants are growing: common reed (Phragmites australis), rush (Typha latifolia), iris, etc. (Fig. 1). These plants are stable t...

Selecting the proper primary variables is a critical step in efficiently modeling the highly nonlinear problem of multiphase subsurface flow in a heterogeneous porous-fractured media. Current simulation and ground modeling techniques consist of (1) spatial discretization of mass and/or heat conservation equations using finite difference or finite element methods; (2) fully implicit time discret...

The Azores and St. Helena currents (AzC and StHC, respectively, the latter also known as Tristan da Cunha current), in the North and South Subtropical Atlantic Ocean, have been subject of a few studies using in situ data, that pointed towards a number of similarities between them regarding intensity, depth penetration and volume transport, and the latitudes at which their main cores are found (...

[1] Numerous studies show a relationship between radar backscattering and surface roughness. While estimating the statistical properties of small-scale topography is of particular interest for geologic analysis of Cassini radar data, there is no analytic description of radar scattering over a wide range of incidence angles and roughness. This paper presents an empirical function that links the ...

Natural reservoirs exhibit high degree of spatial variability in their properties in multiple length scales. It has been established that such variability has a strong impact in determining fluid flow patterns in subsurface formations. Direct measurements of reservoir properties are only available at a small number of locations. Without an adequate description of the formation properties, such ...

The fate of hydrocarbons in the subsurface near Bemidji, Minnesota, has been investigated by a multidisciplinary group of scientists for over a quarter century. Research at Bemidji has involved extensive investigations of multiphase flow and transport, volatilization, dissolution, geochemical interactions, microbial populations, and biodegradation with the goal of providing an improved understa...

[1] We present a general framework for probabilistic risk assessment (PRA) of subsurface contamination. PRA provides a natural venue for the rigorous quantification of structural (model) and parametric uncertainties inherent in predictions of subsurface flow and transport. A typical PRA starts by identifying relevant components of a subsurface system (e.g., a buried solid-waste tank, an aquitar...

The hydraulics of steep mountain streams differ from lower gradient rivers due to shallow and rough flows, energetic subsurface flow, and macro-scale form drag from immobile boulders and channel and bed forms. Heightened flow resistance and reduced sediment transport rates in steep streams are commonly attributed to macro-scale form drag; however, little work has explored steep river hydrodynam...