ENVI 485 2/6/07
•Introduction to Environmental Geology (cont.)
•Land use planning
•Introduction to soils
Fundamental Concepts of Environmental Geology
• Population growth• Sustainability• The earth system• Uniformitarianism• Hazardous earth
processes
• Geology as a basic environmental science
Fundamental Concepts-Geology as a basic environmental science
Geology is a factor in every person’s life:
“Civilization exists by geological consent…subject to change without notice”--Will Durant
Fundamental Concepts-Geology as a basic environmental science
Branches of Environmental Geology: Geomorphology (Geologic Landforms and
Processes) Hydrogeology (Water and soil / rock interactions) Pedology (Soils) Economic geology Engineering geology Classical geology
Fundamental Concepts-Geology as a basic environmental science
Environmental problems are interdisciplinary Physical
Geography, geologic processes, hydrology, rock types, soil types, climate
Biological Plants, animals, biologic conditions, spatial analysis of
biologic information
Human interest/useLand use, economics, aesthetics, environmental law,
hazards, historical/archaeological value
Environmental Geology and Land-Use Planning• There is a limited supply of landWe strive to plan so that suitable land
is available for specific uses for this generation and those that follow
Comprehensive plan – designed for long-range local development based on an environmental inventory of resources and hazards
Landscape EvaluationLandscape EvaluationEnvironmental geologists provide geologic
information and analysis to assist in planning, design, and construction
Former and present land usePhysical and chemical properties of earth materials– Pollutants– Engineering Properties of soil and rock
Natural hazardsGroundwater characteristics
Site SelectionSite SelectionCost-Benefits Analysis – Assumes all
relevant costs and benefits can be determined
Examples: Building a shopping mall in a flood zone; Drilling oil wells in National Parks?
Physiographic Determination-applying ecological principals to planning
Considers physical, social, and aesthetic dataLet natural characteristics determine the choice of a site
Environmental Impact AnalysisEnvironmental Impact Analysis1969- National Environmental Policy Act
(NEPA)All major federal actions which could affect the quality of the human environment must be preceded by an evaluation of the project and the potential impact to the environmentEnvironmental Impact Statements (EIS)– Discussion of the environmental consequences of the proposed
project and of the alternatives
State Environmental Impact LegislationState Environmental Policy Acts (SEPAs)– California Environmental Quality Act (CEQA)
What do Environmental Geologists do?
Mostly Site Assessments (ESAs) and Brownfields Studies
What are “Brownfields”?
brownfield site
– “real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.”
Sampling/Analysis –Sampling Methods
Conventional– borings/excavation
– groundwater monitoring wells
– decontamination/plugging/abandonment/waste disposal
– crude field-screening
– off-site analysis
Accelerated– geophysical surveys
– direct-push probes
– field labs/test kits
– off-site analytical confirmation
– electronic data archiving/interpretation
What are ESAs?
Identify/evaluate:– environmental concerns– Magnitude and extent of contamination– Cleanup goals– Remediation options– Future land use
Phase I ESA
Identify potential environmental concerns All Appropriate Inquiry
– Records review – Site reconnaissance– Interviews– Report
Phase II ESA
Evaluates potential concerns from Phase I Tailored to site-specific needs
Limited sampling/analysis» Confirm/rule out concerns
Expanded sampling/analysis» Amount and extent of contamination
Recommended cleanup goals/optionsIncr
easi
ng C
osts
Phase III ESA
Corrective actions for environmental concerns
What are ESAs? – Summary
Land Uses
Contaminants & Related Risk
Site Improvements
Focus on:
Past, Present & Future
Sampling/Analysis – Sampling Methods
Conventional drilling/sampling technology
Sampling/Analysis – Sampling Methods
Screening/field-based methods - Direct-push methods
Sampling/Analysis – Sampling Methods
Geophysical MethodsElectromagnetic Conductivity
& Magnetic Surveys
Ground-Penetrating Radar
Soils Crucial to land use planning Waste disposal Evaluation of natural hazards
Flooding LandslidesEarthquakes
Evaluation building construction
Soils as a natural resource
“The thin layer of soil covering the Earth’s surface represents the difference between survival and
extinction of most terrestrial life”
Soil: Definition
Soil Scientist:Solid earth material that can support rooted
plant life Engineer / Geologist:
Earth material that can be removed without blasting (any earth material that is ripable)
What sphere of the earth system includes soil?
What is soil made of?
Components of soil:1. Minerals
• inorganic materials derived from weathering rocks
• extremely variable in size.
• Provide nutrients to plants
• Basis for soil classification
Components of soil:2. Air
• Pore spaces filled with air or water comprise 1/2 the volume.
• The amount and composition of air in a soil are determined by the water content of the soil.
• Metabolic activity of roots, microbes and fauna change the composition of soil air. (Carbon dioxide greater than atmosphere).
Components of soil: 3. Water
• Water is the major transport agent in soil– Within the soil– To groundwater
• participates in geochemical cycles – weathering geological substrates– leaching materials to groundwater – moving ions and particles through the soil profile.
• Organisms alter the suite of solutes in percolating water
Components of soil:4. Organic Material
• includes: – living organisms (soil biomass)
– remains of organisms
– decomposed organic compounds
What is soil?
• Open, dynamic, natural bodies in the landscape.• exchange water and air with the atmosphere, and
ions and minerals with the lithosphere • Plants introduce reduced carbon to support a
heterotropic biomass • Decomposition of these substrates results in the
cycling of nutrients
Controls on soil formation
• Climate
• Topography
• Parent material
• Time
• Organic Processes
Soils
• Soil forming process produce distinctive layers (horizons) defined by the processes that form them– Leaching– Oxidation– Accumulation of minerals