Environmental Impacts

1
Environmental Impacts

• Douglas Daley
• FEG 437
• Road and Highway Design

2
Environmental Legislation

• Identify involved agencies - single medium
• Mandatory consideration of impacts
• multiple permit requirements
• identify mitigation measures
• National Environmental Policy Act (NEPA) 1969
• New York State Environmental Quality Review Act
  (SEQRA)

3
SEQRA 6 NYCRR Part 617

• Incorporate environmental factors into planning,
  review and decision making processes at earliest
  possible time.
• Required for projects or decisions undertaken by
  public agency, funded with public money, or
  approved by agency.
• Lead Agency identification

4
Highway Environmental Impacts

• Noise
• Air Pollution
• NOX
• Wetlands
• Water Quality
• eutrophication
• sedimentation
• organic compounds

5
Determining Significance

• Substantial adverse change in existing air
  quality, ground or surface water quality or
  quantity, traffic or noise levels substantial
  increase in solid waste production substantial
  increase in potential for erosion, flooding,
  leaching or drainage problems.
• Removal of large quantities of vegetation
  substantial interference with migration of fish
  or wildlife impact on significant habitat area
  substantial adverse impacts on threatened or
  endangered species of animal or plant, or habitat
• Two related actions that singly do not have a
  significant impact, but cumulatively would.

6
Environmental Analyses

• Classes of Actions (NEPA)
• Class I significant impact
• EIS required
• specifically listed projects
• Class II no EIS or EA required
• repaving
• Class III Unclassified - requires Environmental
  Assessment

7
EIS Contents

• Description of Proposed Action
• Land Use Planning
• Probable Impact of Proposed Action
• Alternatives to Proposed Action
• Unavoidable adverse impacts
• Irreversible and irretrievable commitment of
  resources
• Historic and cultural impacts
• Public and minority involvement

8
Mitigating Measures

• Divert stormwater
• Build sound barriers
• Enclose road in a tunnel
• Elevate road
• Use alternative mode (ferry)
• Control erosion

9
Environmental Factors that Affect Design

• Topography
• Plant habitat
• Soils and geology
• Climate
• Water bodies
• Noise

• Land use
• Animal habitat
• Visual impact (aesthetics)
• Air quality
• Solid waste
• Wetlands

10
Activity

• Identify 5 potential environmental impacts of
  constructing a two lane asphalt paved road
  through 2 miles of forested, hilly terrain for
  the purpose of developing a residential
  subdivision on a lake.
• Describe 2 examples of data needed to assess each
  impact.
• Describe one mitigating measure for each impact
• Question Would your responses differ if you are
  the developer versus a member of the Sierra Club?

11
Geomorphic Effects

• Sedimentation and Landslides
• Chronic (long-term) effects of sedimentation
• Acute effects of slope failure
• Effects
• Alter channel morphology
• Degrade habitat
• Present risk to public safety and downstream
  structures

12
Mechanisms

• Accelerate erosion from road surface and prism
• Improper placement and construction of fills
• Poor road siting w.r.t. soils and streams
• Valley vs. midslope vs. ridge
• Cut banks, road surface and ditches
• Post-construction vs. long-term
• Direct effects on channel geometry and structure
• Alter surface flow paths
• Diversion onto unstable soils
• saturation
• Cause interactions amongst water sediment and
  woody debris at crossings
• Inadequate sizing for hydraulic and debris control

13
Highway Runoff

• Nonpoint Source - Watershed Controls
• Roads are linear features in a non-linear
  landscape
• channelizing and concentrating flow
• intercepting groundwater
• SedimentsThe annual total sediment loading
  ranged from 36,500 to 148,000 pound per acre of
  road surface
• Nutrients N, P
• Chemicals auto fluids, lubricants
• Airborne deposition lead other metals

14
Hydrologic Effects

• Central issue
• Roads function to
• Intercept rainfall and convey away from road
  surface
• Concentrate flow
• Divert or reroute flow paths
• Convey and discharge

15
Upland Habitat Fragmentation

• Findings Effects are broader than just road
  prism
• Road avoidance behavior black bears dont cross
  highways or heavily traveled roads
• Roads create edge habitat
• New habitat supports increased diversity in
  forest setting
• Competition with interior wildlife and habitats
• Invasive species

16
Fish Passage - Culvert Design Criteria

• State of Washington
• http//www.wa.gov/wdfw/hab/engineer/habeng.htm
• Chesapeake Bay
• http//www.chesapeakebay.net/fishpass.htm

17
Biological Invasions

• Invasion promoted by disturbance
• Ongoing maintenance (ditches, mowing, grading)
  present disturbance opportunities
• Dispersion by air and water, and human activity
• Road corridor for invasion, pathogens

18
Aquatic Habitat

• Multitude of impacts widespread and profound
• Sediment gt decreased fry production, reduced
  benthic organism and algal production
• Groundwater interception or shade loss gt change
  in temperature
• Change in stream flow, migration barriers
  (culverts)
• Road density effects

19
Terrestrial Vertebrates

• Effects are derived from direct (habitat loss)
  road use (avoidance or kill) and facilitation
  (hunting and trapping)
• 1 million vertebrates/day in US
• Forest roads small, slow-moving animals
• Scavengers also become road kill

20
Forest Ecosystem Management Assessment Team
(FEMAT, 1993)

• Pacific Northwest
• Spotted Owl habitat federally managed lands
• 180,000 km of roads, 250,000 stream crossings
  (1.25/km), most of which could not pass a 25 year
  storm
• February 1996 flood - 170 M damage over 70
  for road reconstruction

21
Sources of Phosphorous
22
Simple Method Pollutant Load