An injection well is a device that places fluid deep underground into porous rock formations, such as sandstone or limestone, or into or below the shallow soil layer. Use IGW-NET to simulate the migration of the continuous tracer plume resulting from injection well (a continuous point source), and perform sensitivity analysis with respect to: pumping rate and injection rate; and the leakance of the river characterizing the stream aquifer connection.

Surface water migrates into the groundwater by infiltration through the soil, or by runoff into areas where the water table is above the surface of the ground. Develop a IGW-NET model representing a contamination plume originating from surface contamination zone represented in three different ways: "prescribed flux" with a specified concentration, representing a leaky waste water pond above the water table; "two way head dependent flux" with specified concentration, representing a polluted pond that is hydraulic connected with the aquifer; and "prescribed head", with a specified concentration, representing a polluted pond fully connected with the aquifer.

Surface water migrates into the groundwater by infiltration through the soil, or by runoff into areas where the water table is above the surface of the ground. Use IGW-NET to model the impact of a contaminated stream on a nearby drinking water well, and numerically experiment with the effect of stream leakage coefficient (or leakance) characterizing stream-aquifer connection.

A relatively long ditch cuts through an aquifer perpendicular to the direction of the flow. A nonreactive chemical waste is being continuously pored into the ditch. Plot the variation of C versus distance for 1,2,and 10 years after the start of the operation, and (2) determine how far downstream from the ditch a concentration of 0.1 ppm or more can be found after 10 years. Then develop a IGW-NET model to confirm your results using an analytical approach.

An organic contaminant is disposed of continuously in a long narrow trench that fully penetrates a shallow, semi-infinite aquifer. Use IGW-NET to simulate the contaminant migration and calculate concentration distribution after three years.

A number of subsurface contamination sources are called "continuous" subsurface sources, because the the contaminant is continuously released over time, e.g., leaky landfills or buried gas tanks. Continuous sources may have time-varying or constant chemical concentrations. Develop a IGW-NET model that can simulate the plume migration for different mathematical treatments of continuous sources.

Intermediate - Analytical and numerical sub-problems. Originally a network of sloughs, lakes and wetlands, a piece of land has been converted into an open-pit landfill to dispose of refuse of a nearby population center. Solid waste continues to pile up, creating a leachate mound in the landfill that serves as a driving force for vertical and lateral loading of contaminants into a sand and gravel aquifer and the sloughs, respectively. Local residents are concerned about the impact on the surface water (used for fishing and recreational purposes) and groundwater (used for drinking water supply).

A hazardous waste facility is to be constructed in a given area. The state requires a buffer zone between the trenches and the property boundary. Calculate the maximum concentration that might be expected (in terms of c0, the plume concentration at the waste boundary) once the plume arrives at the edge of the buffer zone. Then develop a IGW-NET model to confirm your results using an analytical approach.

In the case of subsurface disposal of radioactive wastes or highly toxic inorganic or organic compounds, diffusion can be an important process. Consider the following problem: High-level radioactive waste is buried in a cavern in unfractured shale at a depth of 1000 m below ground surface. The burial zone is separated from the nearest overlying aquifer by a vertical thickness of 100 m of shale. Is it reasonable to expect that radionuclides will remain entirely within the shale during the next 100,000 years?

While in most cases subsurface contamination sources can be represented as a continuous source, contamination caused by accidental events (e.g., accidental spills, rupture of a tank) can often be represented as an instantaneous 'pulse' sources. Develop a IGW-NET model to simulate the plume migration originating from accidental spills and perform a sensitivity analysis with respect to different ways of representing of the instantaneous source.

A recharge well receives a conservative contaminant in the effluent from a treatment plant. Recharge from the well is captured by a river located 500 m downgradient through an aquifer. Use IGW-NET to determine the contaminant influx (loading) to the river as a function of time. In particular, determine the maximum influx.

There are more than 680,000 underground waste and injection wells in the US, more than 150,000 of which shoot industrial fluids thousands of feet below the surface. Scientists and federal regulators acknowledge they do not know how many of the sites are leaking. Use IGW-NET to investigate the movement of contaminant introduced by a disposal well for specified conditions.

A river has a total dissolved solids (TDS) concentration that averages Cr = 1200 mg/l, while groundwater recharging the river has a TDS concentration Cg = 300 mg/l. We want to place a water well which will produce 20,000 cubic feet per day (100 gpm) as close to the river as possible and still meet a water quality limit of c = 500 mg/l TDS. Use IGW-NET to simulate the groundwater flow and the water quality dynamics in the mixing zone and use the result to identify the optimal well location.

A truck hauling liquid waste has overturned on the highway. The waste is not recovered at the time of the spill, and we are interested in the concentration reaching a small stream located at a distance 150 meters from the highway and running parallel with it. Use IGW-NET to determine the maximum concentration of waste reaching the stream, and plot the stream concentration that will be observed by downstream users of surface water from the stream.

An abandoned well located 400 m from a municipal water well was used by miss Magda of the Devil's Grail Enterprises, Inc. as an illegal hazardous waste disposal site. Map the drawdown distribution around the pumping well and determine the travel time from the abandoned well to the pumping well. Also, it was recommended that the municipal well should become an injection well. After some time, the contaminant would flow back to the abandoned well, where it would be neutralized. Will the plan work? Why or why not?

An industrial facility has a 2 acre on-site landfill for disposal of solid waste. A thick, sandy aquifer lies beneath the facility. A regulatory compliance well is located on the site boundary. Using the provided site information, develop a IGW-NET model to determine maximum landfill leachate concentration for a conservative species, and for a species with a retardation factor of 2 and a hydrolysis half life of 600 days.

Dry cleaner establishments are quite common in urban settings. And so is the contamination that is associated with dry cleaning activities. Such contamination may pose serious health risks due to its nature and resistance to environmental degradation. Use IGW-NET to simulate the migration of two TCE contamination plumes at a dry cleaner site.

As a result of the rupture of a storage tank, liquid waste containing dissolved arsenic rapidly infiltrated into a shallow, unconfined sandy aquifer in which the flow is horizontal. As the contaminated zone moves through the aquifer, the arsenic does not undergo significant adsorption or precipitation. Estimate the maximum arsenic concentration after the contaminant cloud has moved a distance of 500 m. What will be the approximate dimensions of the cloud? Then develop a IGW-NET model to confirm your results using an analytical approach.

This problem considers the movement of a benzene plume in a confined aquifer toward a lake used for recreation and drinking water supply. Using IGW-NET, asses the risk, or probability of the contaminant concentration exceeding the MCL at the aquifer-lake interface. Analyze and compare the following situations i) a homogeneous aquifer; ii) a stratified aquifer; and iii) a stochastically stratified aquifer.