Term
| Priorities for groundwater management |
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Definition
-sustainable long term yields from aquifers
-effective use of the large volume stored in aquifers
-preservation of water quality
-preservation of surface water bodies (i.e. avoid generation of losing streams, decreases in base flow) |
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Term
| What are some innovative approaches that contribute to groundwater sustainability? |
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Definition
-replace city storm water drains and pipes with vegetated swales
-removing curbs
-decreasing surface area of impermeable surfaces like driveways
-collecting roof run-off for garden use |
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Term
| What might be the most efficient, easiest, and most economical approach to maintaining sustainable aquifers? |
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Definition
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Term
| What are the effects of pumping on streams and rivers? |
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Definition
| Reversal of flow direction of aquifer |
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Term
| What are the advantages of groundwater of surface water? |
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Definition
-temperature
-protection against contamination, sediments provide a natural buffer, possibly better and more predictable water quality
-more abundant (in some areas) |
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Term
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Definition
-caused by overpumping of aquifers
-seawater is drawn into aquifers because the water table inland is lowered below sea level
-seawater eventually reaches pumping well
-water is no longer suitable for consumption
-need to design groundwater withdrawal such that only freshwater will be extracted |
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Term
| Groundwater contamination |
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Definition
-pollution of groundwater caused by human activities on and below ground surface
-water may no longer be suitable for use
Contaminants include:
-chlorinated solvents
-wood preservatives
-gasoline and oil
-metals
-agricultural contaminants
-radionuclides
-pharmaceuticals and household/beauty products |
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Term
| Location of contaminants in the subsurface |
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Definition
Fluid properties of certain contaminants can complicate finding their location in the subsurface and can complicate remediation techniques
-LNAPLs: LIGHT non-aqueaous phase liquids (petroleum products)
-DNAPLs: DENSE non-aqueaous phase liquids (chlorinated solvents, creosote) |
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Term
| Soil and Groundwater Remediation |
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Definition
Attempt to remove existing contamination from the subsurface
-source contaminants
-vapor phase
-plume zone: dissolved (mobile) contaminants
-deep accumulation zone |
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Term
| Source Contaminants Remediation |
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Definition
source removal: dig and dump
-removal of free phase liquids by pumping wells |
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Term
| Vapor Phase: Soil Vapor Extraction |
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Definition
| -apply vacuum and extract soil, air, and contaminant vapour |
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Term
| Vapor phase + dissolved phase: Air Sparging |
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Definition
-inject air or pure oxygen in the subsurface
-volatilize the contaminant into bubbles
-enhance biodegradation for contaminants |
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Term
| Plume treatment: Pump and Treat System |
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Definition
| Installation of pumping well in path of groundwater plume, withdrawal of contaminated water, treatment on surface |
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Term
| Plume treatment: Permeable Reactive Barriers |
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Definition
| Installation of reactive material in path of groundwater plume, treatment in subsurface (often called in-situ) |
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Term
| What are some radioactive waste storage proposals? |
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Definition
-burial under the ocean floor or in the Polar Ice caps
-Storing underground or "Deep Geological Disposal"
-shooting into space |
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Term
| What are some remediation challenges? |
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Definition
Often difficult to find contaminant
-better understanding of subsurface geology leads to better ability to find contaminant
Contaminants are often difficult to remove
-material that is present in low permeability zones slowly diffuses out over time |
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