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