Environmental Geology Lab Practical II Set

What is Groundwater?

Water stored below Earth's surface in soil, sediment, and rock.

What are Aquifers?

Underground reservoirs that store groundwater.

What makes good Aquifers?

Usually have high porosity and permeability.

What are some examples of materials that make good Aquifers?

Example: materials such as gravel, sand, sandstone, and some fractured or dissolved rocks.

What do Aquitards do?

Store small amounts of water but do not transmit it well.

What do Aquicludes do?

Do not store significant water and do not transmit it.

True or False: Clay, shale, and other non-porous rocks commonly act as aquitards or aquicludes.

True

Fractured rock and karst limestone can transmit large amounts of groundwater through what?

cracks and conduits

What is Porosity?

The amount of empty space that can hold fluids

What is Permeability?

How easily fluids move through a material

True or False: Impermeable materials allow little to no fluid flow.

True

High Porosity/High Permeability + Good Aquifer = what material?

Sandstone

Low Porosity/Low Permeability + Good aquitard or aquiclude = what material?

Clay or Shale

Variable/Very high along conduits + Can transmit water rapidly = what material?

Karst limestone

What is the Water Table?

The top of the saturated zone

Water-table depth changes with what?

Season, climate, and location

Groundwater flows in which direction?

flows from higher elevation (or pressure) towards lower elevation (or pressure)

What angle does Groundwater flow to water-table contours?

flow is perpendicular to water-table contours

How do Karst Form?

When slightly acidic water dissolves calcite in limestone

What are some features of Karst?

sinkholes, caves, springs, and disappearing streams

Groundwater and contaminants can move quickly through karst because?

Water travels through conduits instead of slowly through pore spaces

Change in elevation/Horizontal distance = which equation?

Hydraulic Gradient Equation

Distance/Time = which equation?

Velocity (or flow rate) Equation

What are Monitoring Wells used for?

Used to sample groundwater, measure water levels, detect contamination, and track plume migration.

What are Injection Wells used for?

Used to add fluids to groundwater systems, such as dye tracers, waster-water, brine, or other substances

What are Tracer Dye be used for?

Can be used to determine groundwater flow direction and speed

In the lab (groundwater II), what did contour lines represent?

Pollutant concentration instead of elevation

What is collected from monitoring wells through time and then transferred to well-field diagrams?

Concentration data

True or False: Multiple time intervals are conducted to show plume movement and concentration changes

True

Change in elevation/Distance = what equation?

Slope Equation

Velocity/Slope = which equation?

Hydraulic Conductivity Equation

Width x Height of aquifer layer = which equation?

Cross-Sectional Area Equation

Cross-Sectional Area x Velocity = which Equation?

Discharge Equation

What are Coastlines shaped by?

The interaction of land, ocean, and atmosphere

What resists erosion better than sand, clay, and loose sediment?

Hard rock

Sediment supply from rivers, currents, and local erosion helps determine what?

Wether coastlines grow, shrink, or stay stable

True or False: Wave energy, wind, currents, sea-level change, tectonics, storms, organisms, and human activity also affect coastlines.

True

What do Depositional Processes do?

Add and store sediment, causing coastlines to grow seaward (emergent)

What do Erosional Processes do?

Remove sediment and erode rock, causing coastlines to retreat landward (submergent)

Growth seaward = ?

Emergent Coastlines

Landward retreat (and flooding) = ?

Submergent Coastlines

Depositional Process + Gently sloping accumulation of sand or gravel =

Beach

Depositional Process + Fan-shaped sediment deposit at a river mouth =

Delta

Depositional Process + Long, narrow island parallel to the mainland =

Barrier Island

Depositional Process + Coral formation that runs parallel to a shoreline =

Reef

Erosional Process + cliff eroded by wave action =

Wave-cut Cliff

Erosional Process + Flat bench at sea level formed by wave erosion =

Wave-cut Platform

Erosional Process + Elevated wave-cut platform formed by uplift or regression =

Marine Terrace

What are Wetlands good for?

storing sediment, reducing wave energy, supporting coastal ecosystems

What is an Estuary?

Partially enclosed coastal body of brackish water where freshwater mixes with seawater

What is a Tidal Flat?

A muddy or sandy area covered at high tide and exposed at low tide

What is a Salt Marsh?

A coastal marsh flooded by seawater during high tide

What is a Storm Surge?

An abnormal rise in seawater level during a storm or hurricane

What mainly causes a Storm Surge?

Winds pushing water onshore

When is a Storm Surge most hazardous?

When it occurs during high tide (which can cause severe coastal flooding)

What are Landfills?

Disposal sites for waste materials, especially municipal solid waste

What do modern sanitary landfills use to reduce environmental impacts?

covers, liners, monitoring systems

What is Leachate?

A highly contaminated liquid formed when water percolates through waste

What are some things Leachate contains?

Dissolved organic matter, metals, ions, and hazardous substances

True or False: Because leachate is rich in ions, it is a good conductor of electricity

True

What are important design features of Sanitary Landfills?

buffer zones, plastic liners, clay caps, and monitoring systems

When do leaks in Sanitary Landfills occur?

When the liner develops a hold and leachate escapes into soil or groundwater

Why is early detection important when leaks occur in Sanitary Landfills?

Because leaks can threaten nearby communities and water supplies

What is Resistivity?

A material's ability to resist the flow of electric current

What is the opposite of Resistivity?

Conductivity

True or False: A battery provides current to the ground and a voltmeter measures voltage differences

True

What can indicate leachate leakage?

Low resistance or high conductivity

What was closer to the leak location in the lab setup?

Higher voltage values

First step of the Leaky Landfill lab procedure:

Mapped a leak-free landfill to establish a relatively even electrical-potential pattern

Second step of the Leaky Landfill lab procedure:

Mapped the leaky-landfill and identify the zone with abnormal electrical behavior

Third step of the Leaky Landfill lab procedure:

Construct contour maps of electrical potential

Fourth step of the Leaky Landfill lab procedure:

Use contour lines and flow lines to infer the location of the leak and direction of current flow

What is the 3-Point Environmental Game?

Combines concepts from topographic maps, groundwater, and leaky landfills labs

What was the goal of the Environmental Game?

To delineate the direction and concentration of the pollution plume from the Meadowlands Landfill and identify which town will be affected

What were two components of the Environmental Game?

Each group acts as an environmental consulting company and the winning team finds the plume while spending the least amount of money.

What is a Contamination Plume?

A 3D zone of contaminated air, water, or soil spreading from a single source

What are some examples of Contamination Plumes?

leaking tanks, industrial discharge, and leaking landfills

What do Plumes form?

Form concentration gradients, with the highest concentration near the near the source which dissipate outwards

What do Structure Contours do?

Connect points of equal elevation (or depth) on a geologic surface

Structure Contours are similar to topographic contour lines, but?

They represent subsurface geologic surfaces (like faults, formations, or the water table)

Structure Contours show what?

Elevation or depth and help determine dip direction

What is a 3-point problem?

Used to determine the orientation of a planar subsurface surface (such as a fault or aquifer) from three well points

What is the process of the 3-point problem?

Plot and label the depths of three wells on the map. Draw a line between the deepest and shallowest points. Estimate where the same depth on that line matches the mid-depth well. Connect equal-depth points to create a structure contour line. The structure contour line gives the strike

Dip is "blank " to strike?

perpendicular and points toward lower elevations

Groundwater flow follows what direction?

direction follows the dip direction

True or False: Additional depth contours can be extrapolated from the second structure contour

False, depth contours can be extrapolated from the first structure contour

Game Rules in the Environmental Game:

Each team started with $20,000. Only one well was drilled per turn. Each well cost $1,000. Teams delineated all four plume concentrations while staying under budget.

What was a useful strategy for the Environmental Game?

To drill wells near the landfill in the direction of groundwater flow