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Response of dense granular media due to fluid injection is studied experimentally utilizing a radial Hele-Shaw cell filled with Ottawa F-110 sand and silica flour mixtures with aqueous glycerin solutions as the invading fluid. By varying the injection velocity, the invading fluid viscosity and the silica flour weight fraction, the fluid flow patterns show a transition from a simple radial flow pattern to a ramified morphology while the granular media behaviors change from that of rigid porous media to localized failure that lead to development of fluid channels inside the cell. The effect of velocity, viscosity and the granular media properties can be integrated into a dimensionless group that reflects the characteristic time scales of the injection and diffusion processes. Due to the quasi two-dimensional nature, these laboratory experiments offer excellent benchmark cases for multiphysics and multiscale numerical modeling.

Recent evidence suggests that, although their ultimate destination is the sea, juvenile salmonids also travel upstream to locate more desirable habitat and feeding areas. Since many culverts are impassible to juvenile salmonids, baffle systems are being evaluated that will facilitate greater upstream passage. A culvert test bed facility at Washington Department of Fish and Wildlife Skookumchuck Rearing Facility near Tenino, Washington was built to test fish passage success and study the hydrodynamic regimes induced by the baffles. The study involved installing baffles within a 40 foot long, 6 foot diameter corrugated culvert and recording 3-D velocities using an Acoustic Doppler Velocimeter (ADV). The purpose of these tests is to describe the hydrodynamics of the baffle flow and to evaluate how different hydraulic conditions may benefit or hinder fish passage. Baffle generated flow structures such as a jet on the low side of the baffle or a roller wave are identified. Using the 3-D velocity data and surface images, the flow structures are then characterized according to their intensity and size. A scaling equation is analyzed to relate the modification of flow features to the independent study parameters. This paper establishes hydraulic guidance that can help biologists and engineers to improve baffle design and configuration to aid juvenile salmon migration.

The problem of culverts that block fish from freely moving up and downstream is becoming a critical environmental issue. Agencies often retrofit culverts with baffles to aid in fish passage, but little is known about the detailed flow characteristics within a baffled culvert. During August and September, 2005, fine-scaled measurements were taken at the Skookumchuck hatchery near Tenino, WA on the flow field inside a 6-foot diameter corrugated metal culvert fitted with sloped-weir baffles. The culvert was 40 feet long and set at a 1.14% slope, and the data were collected for flow rates 1.5, 2.0, 3.0, 4.0, and 8.0 cubic feet per second. Flow field measurements were collected using a Sontek acoustic Doppler velocimeter at 50 Hz. Preliminary data were used to understand the turbulence characteristics of flow within a culvert fitted with baffles, and to compare the flow field caused by sloped-weir baffles to experiments of other baffle types recorded in literature. It has been found that the turbulent kinetic energy (TKE) dissipates as the flow moves downstream from a baffle. At flows less than 3.0 cfs, the sloped-weir baffles cause higher TKE values on the left side of the flow (looking upstream) due to plunging flow. As the flow rate increases, the TKE becomes equal on both sides of the culvert, and are higher on the edges due to shear stress caused by the culvert boundary. The flow is also described using dimensionless discharge, and data from this experiment are compared to dimensionless discharge equations given by previous researchers. This research provides new information on the turbulence characteristics of flows within culverts retrofitted with sloped-weir baffles, and will be useful in recognizing which areas of the flow field could be too turbulent for fish passage.

The Detroit District, Corps of Engineers is responsible for 95 navigation projects on the Great Lakes in the States of Michigan, Wisconsin, and Minnesota. The District has been using Confined Disposal Facilities (CDFs) for placement of contaminated dredged material since the 1970s. Several harbors are contaminated with heavy metals and PCBs and most of this material has been placed in the CDFs during that time. Continued dredging and lower contaminant loading into the waterway system has resulted in cleaner dredging material being placed in the upper layers of many CDFs more recently. In addition, the Detroit District is reviewing alternatives to enhance biodegradation , to optimize capping requirements and to reduce exposure pathways at several CDF sites.

Innovative stormwater management (SWM) has as one of its central principles the recycling of increased runoff volumes back into groundwater aquifers, accomplishing both water quantity and water quality objectives. However, in areas underlain by limestone carbonate bedrock, this otherwise optimal infiltration strategy for stormwater can pose risks of subsidence, sinkhole formation, and groundwater contamination. Cahill Associates (CA), working with the Lehigh Valley Planning Commission (LVPC) in Allentown PA, has developed a SWM program for the 107.5 square-mile Little Lehigh Creek Watershed in southeastern Pennsylvania, designed to achieve the multiple benefits of infiltration, even as the limestone-related risks are minimized. The result is a new design manual, Technical Best Management Practice Manual and Infiltration Feasibility Report: Infiltration of Stormwater in Areas Underlain by Carbonate Bedrock in the Little Lehigh Creek Watershed.

Chester County, Pennsylvania is one of the fastest growing areas in the Country, and is experiencing significant environmental impacts due to "suburban sprawl". Northern Chester County is a relatively undeveloped area, but is rapidly experiencing the pressure of encroaching development. This scenic and historically significant area is dependent on ground water for water supply and is traversed by four high quality or exceptional value streams of great environmental and recreational importance to the region. In Pennsylvania, regulations regarding stormwater management and water resources are enacted at the local or municipal level. Municipal boundaries rarely coincide with watershed boundaries, making effective watershed plans difficult to implement. To overcome this difficulty, the municipalities are working together with Green Valleys Association to develop a "Sustainable Watershed Management Program". At the heart of this program is a "Water Balance Model", interactively linked to a detailed GIS developed in ArcInfo and ArcView. This tool allows the municipalities to play "what if" scenarios and determine if the sustainable watershed goals are attainable, or if changes are needed in municipal regulations. For example, if current zoning allows for a certain type of development on a given parcel, the municipality can examine the effects of that development on water withdrawals, stormwater runoff and non-point source pollution, groundwater nitrate levels, and baseflow in the streams. The model evaluates conditions on a watershed basis, but allows for interpretation on a municipal basis. If the sustainability criteria are not met, the municipality can then look at the effects of changes in ordinances, changes in zoning, transferdevelopment rights, etc. The visual component of the GIS allows the planners and municipal officials to quickly "see" the areas of concern, as well as the effects of regulatory changes. Most importantly, theinteractiveGIS/model helps non-technical residents and decision makers to understand the inter-relationship between land use and water resources, and to make educated policy decisions accordingly. Introduction Sustainable Watershed Management Sustainable Watershed Management (SWM) has been developed by the Green Valleys Association (GVA) to guide the management of the special land and water systems that comprise northern Chester County watersheds. The primary goal is to sustain the essential environmental qualities that distinguish this region, and the values held so strongly by the local community. It is the goal of GVA that when the wave of development pressures

The discrete element method (DEM) is ideal for modeling many problems not accessible to traditional continuum-based methods such as finite difference and finite elements (Homer et al., 2001). DEM has the advantage of inherently capturing large non-affine deformations and the fluid--solid phase changes so commonly found in granular media. The DEM appears to derive much of its power from the kinematic freedom for the particles such that seemingly simplistic micro-scale models can replicate realistic macro-scale behavior. With the advent of large-scale computing, by which simulations of several million particles are possible, the DEM will become an important tool for geotechnical and industrial applications within the next 20 years. The advances in DEM have and will continue to mirror advances in computer hardware. Several advances in DEM technology will accompany the improvements in computer technology. The constitutive response of the DEM medium depends on micro-scale laws that define the contact mechanisms, particle size and shape, and particle distribution. The success of the method requires a correlation between the phenomenology of the DEM medium and the micro-scale laws. Most of these advances will be accomplished through numerical experiments, which at present are a popular tool for understanding granular media as a continuum. Is it reasonable to foresee a day when a continuum view is unnecessary? In this paper, this question is discussed from the standpoint of scale effects that infect all numerical approximations

Stream ecosystems in three different locations in the United States were found to benefit in a similar fashion from retention of watershed forest and wetland cover and wide, continuous riparian buffers with mature, native vegetation. The findings can help guide comprehensive watershed management and application of these non- structural practices in low-impact urban design. Intensive study of structural best management practices (BMPs) in one location found that, even with a relatively high level of attention, a minority of the developed area is served by these BMPs. Those BMPs installed are capable of mitigating an even smaller share of urban impacts, primarily because of inadequacies in design standards. Even with these shortcomings, though, results showed that structural BMPs help to sustain aquatic biological communities, especially at moderately high urbanization levels, where space limits non-structural options.