Groundwater Chemistry and Hydrochemistry Quiz

GEOL 350 Hydrology and Hydrogeology

• Course offered at SAIT (Southern Alberta Institute of Technology)
• Course title: Hydrology and Hydrogeology
• Course code: GEOL 350
• Winter 2025 session

Aquifers

• Aquifers are underground geological formations that hold groundwater.
• Groundwater flow paths vary in length, depth, and time.
• Flow paths can be localized (shallow, shorter), intermediate, or regional (deeper, longer).
• Flow paths through different geological layers affect groundwater chemistry.

Groundwater Flow Paths

• Recharge areas are where water enters the aquifer.
• Discharge areas are where water exits the aquifer.
• Groundwater flow paths vary greatly in length, depth, and travel time.
• Flow paths take groundwater through different geological layers.
• This influences groundwater chemistry.

Groundwater Flow (Local and Regional)

• Local flow takes place over short distances and time spans.
• Regional flow takes place over long distances and time spans, and is deeper.

Water Table

• The water table is the upper surface of the saturated zone, where groundwater occurs.
• It is connected to surface water bodies (ponds, lakes, streams).
• The water table elevation and surface water elevation are dynamic.

Types of Streams

• Gaining streams receive water from groundwater.
• Losing streams lose water to groundwater.
• Flow direction affects groundwater levels and chemistry.

Interactions between Stream and GW

• Stream stage increases can cause continuous re-adjustment between streams and adjacent shallow aquifers.
• Bank storage influences water exchange between streams and aquifers.
• Groundwater pumping near streams can alter water exchange and possibly deplete streamflow.

Importance of the Hyporheic Zone

• The hyporheic zone is an interface environment where groundwater and surface water interact.
• This zone has enhanced microbial activity and chemical transformations.
• High oxygen concentrations in the hyporheic zone support diverse aquatic life.

GW Contribution to Streamflow

• Baseflow is the groundwater contribution to streamflow.
• Baseflow is relatively stable compared to surface runoff.
• Baseflow fluctuates based on precipitation.

Measuring Baseflow in Streams

• Measuring data from stream-gauging stations is used.
• Data is plotted on a hydrograph (flow volume vs. time).
• Baseflow is typically 30% of total surface drainage.
• Runoff is the rest of the surface drainage.

Groundwater and Aquifers

• Overview of groundwater resources.

The Energy Resources Conservation Board/Alberta Geological Survey (ERCB/AGS)

• Organisation that provides information on groundwater.

Major River Basins (Watersheds)

• Alberta's river basins are nested systems, from small to larger ones.
• Major rivers and their associated drainage basins are defined and mapped.

Paskapoo Outcrop

• Outcrop of Paskapoo Formation displays differences between sandstone types due to cementation.
• Uncemented sandstone has high groundwater potential.

Groundwater Movement in Aquifers

• Groundwater movement is driven by changes in hydraulic head.
• Groundwater flows from higher to lower hydraulic head areas to equalize pressure.
• Factors like drought, flooding, pumping or land alterations influence this flow.

Xsection

• Diagram illustrating groundwater flow directions and layers.
• This section defines various aquifers (confined and unconfined),
• and how groundwater flows vertically and horizontally.

Geo Data Sources

• Logging core, measuring outcrop and groundwater sampling provide valuable data.
• Groundwater Atlas provides valuable information.

Data from Airborne Geophysical Surveys

• Airborne resistivity and electromagnetic surveys are used to map sediment types and water characteristics and water properties in subsurface.
• Interpretation of data helps map underground sediment types, characterization of water, and groundwater flow.

Bedrock Geology of Alberta

• Detailed map of the bedrock geology of Alberta is provided.

Permeability of Sediments

• Permeability of sediments above bedrock is illustrated and characterized by hydraulic conductivity.
• Aquifers and aquitards are illustrated based on high and low permeability.

Bedrock Topography map

• Bedrock topography shows the boundary between bedrock and unconsolidated sediments.
• Chemical weathering and glacial periods impact bedrock topography.

Buried Valley Aquifers

• Map showing the area of high sediment permeability related to buried valleys.
• Geophysics helps identify and map coarse-grained materials.

Great Online Resource

• The Groundwater Project website (https://gw-project.org/) is a valuable online resource.
• Ebooks, exercises, videos, animations, and models are available.
• Interactive tools for water table recharge, GW divide, well capture are described.

References

• List of sources (articles, reports, etc.) consulted for the information.

Extra Slides

• Additional slides related to the course content.

Contamination of GW

• Groundwater can transport contamination originating from point sources (e.g., waste sites) into the river system.
• Contaminant plume movement from a waste site is illustrated.

Types of Springs

• Groundwater springs are characterized by preferred paths of flow in highly permeable sediments.
• Diagram illustrating subsurface water flow leading to spring formation.

Effect of a Pumping Well near a Stream

• Effects of pumping wells on groundwater divide. Impacts on the stream's discharge from aquifer.
• Diagram showing groundwater movement modifications near the vicinity of pumping wells.