Environmental impact assessment

Environmental impact assessment is a technique or a process by which information about the environmental effects of a project is collected, both by the developer and from other sources, and taken into account by the relevant decision making body before a decision is given on whether the development should go ahead.

Impacts and sources

Potential environmental impacts include:

Water

Surface water hydrology/hydraulics

Changed surface water run-off

Changed flow velocities

Changed magnitude of flooding

Changed frequency of flooding

Changed duration of flooding

Convergence/divergence of flow

Changed hydraulic roughness

Regulated flow

Low flows

Wave generation

Reduced tidal flow/flushing/mixing

Riparian drainage

Changed flow regime

Groundwater resources and hydraulics

Changed flow

Changed infiltration

Changed direction of flow

Change in water table (level)

Barrier to flow

Change in pressure potential

Changed storage capacity

Changed flow capacity

Groundwater quality

Movement of contaminated water

Change in quality

Saline intrusion

Chemical pollution

Organic pollution

Microbial contamination

Changed dilution capacity

Change in conductivity/ pH/acidification

Change in oxygen content

Change in temperature

Mobilisation of contaminants

Channel morphology/sediments

Changed bank/bed stability

Degradation/erosion of beds or banks

Deposition/siltation

Change of bed slope

Change of platform/pattern

Disturbance to bed forms (pools, riffles)

Downstream erosion

Changed channel size

Changed suspended sediment load

Changed bed load

Contaminated sediment

Surface-water quality

Altered salinity

Change in quality

Chemical pollution

Eutrophication

Changed turbidity

Microbial contamination

Stratification

Re-suspension of contaminated sediments

Changed dilution capacity

Organic pollution

Change in residence/flushing time

Change in oxygen content

Change in conductivity/ pH/acidification

Change in temperature

Air and climatic factors Regional and global climate

Changes in air moisture

Reduction in sunlight

Acid deposition

Carbon dioxide levels

Methane levels

Ozone levels

Sulphur dioxide levels

Nitrogen dioxide levels

Local air quality and local climate

Ponding of cold air

Alteration to airflow

Changes in air moisture

Changes in local air quality parameters (NOx, SOx, O3, etc.)

Other gaseous pollutants (CO, VOCs,)

Release of metal pollutants

Release of chemical pollutants

Release of toxic organic micro- pollutants (e.g. dioxins, PAHs, PCBs)

Release of particulates (dust, smoke, PM10)

Ionising radiation (including naturally occurring radon)

Land Geology

Removal of bedrock

Removal of drift deposits

Loss of mineral deposits

Loss of non-renewable resources

Sterilisation of minerals or resources

Damage to Regionally Important

Geological Sites (RIGS) Land use and designations

Change to existing use of site

Conflict with use of adjacent land

Changed landscape character including: function as a resource, its scenic quality, degree to which it is unspoilt, sense of place that it engenders, its conservation interests

Visual intrusion

Change in amenity value

Arable intensification

Change in grade of agricultural land

Increase in urban land

Deforestation

Afforestation

Change in riparian land

Development of floodplain

Development of coastal zone

Effects on future developments

Effects on designated sites and other locally important sites

Soils

Altered soil structure, texture, organic component, mineral component, biotic component, water content of soil

Changed soil chemistry

Changed soil fertility

Changed soil density and compaction tolerances

Changed soil profile and classification

Soil erosion (by wind or water)

Change in ability of soil to support proposed end uses

Physical damage to soil systems through management practices

Off-site impacts through deposition of atmospheric pollutants leading to: – Acidification of soils through deposition of SOx, NOx and ammonia – Eutrophication of soils in semi- natural habitats from deposition of NOx and ammonia

Accumulation of heavy metals and persistent organic pollutants

Build-up of heavy metals, such as Zn, Cd, Cu, Hg, Ni, and Pb from the application of organic materials on agricultural land

Accumulation of organic compounds, e.g. PCBs

PAHs, from the application of contaminated wastes

Build-up of phosphorus in soils that receive regular applications of sewage sludge and/or livestock manure in addition to phosphorus fertiliser

Accumulation of pesticides in soils and potential impacts on soil biodiversity

Ecology and biodiversity Aquatic ecology

Altered habitat

Changed fish biomass

Changed invertebrate biomass

Changed plant biomass

Changed species diversity

Changed fish behaviour

Change in fish community

Barrier to fish migration

Fish kill

Changes in spawning

Disturbance of sensitive species

Loss of rheophilic flora and fauna

Barrier to mammals

Loss of sensitive species

Effects on designated sites and other locally important sites

Introduction of alien species

Changes to population dynamics, distribution and abundance of key species, rare species and endemics

Siltation of gravel spawning areas

Terrestrial and coastal ecology

Altered habitat quality

Altered habitat diversity

Habitat severance

Habitat fragmentation

Loss of habitat

Tree removal

Wetland changes, including incoming and outgoing water flows

Changed riparian habitat

Change in plant biomass

Change in animal biomass

Disturbance of sensitive species

Changed species diversity

Effects on designated sites and other locally important sites

Introduction of alien species

Changes to population dynamics, distribution and abundance of key species, rare species and endemics

Human environment Socio-economic (inc. planning gain)

Population movement

Changes in population size

Changes in population characteristics (age range, family size, socio- economic groups, etc.)

Altered settlement patterns

Altered housing tenure types

Change in house prices

Change in demand for public or private housing

Increase in homelessness

Change in local economy

Change in local and non-local employment

Change in characteristics of employment

Changed labour supply

Change in demand for local education, health, social and emergency services

Community structure and institutional arrangements

Introduction of divergent views

Individual and family level impacts

Altered crime and perceptions of crime rate

Enhanced opportunities for planning gain

Need for temporary accommodation during construction

Nuisance

Odour

Vibration

Noise

Flood discharges, flow of contaminated water

Soil erosion onto roads, properties, etc

Light pollution

Architectural and archaeological heritage

Threat to known sites

Threat to other sites

Threat to archaeological sites, monuments and features, above ground

Threat to archaeological sites and features below ground

Threat to settings of archaeological sites, monuments and features

Threat to human artefacts, including historic buildings and sites (e.g. listed buildings), cemeteries and burial grounds, parks, gardens, village greens, bridges and canals and conservation areas

Threat to designated and locally important sites and features

Threat to other buildings and features of architectural merit

Threat to other buildings and features of planning merit

Threat to other buildings and features of social or economic importance

Threat to other buildings and features that show technological innovation or virtuosity

Threat to other buildings and features taken together as having group value

Local transport

Altered volume of traffic

Altered traffic profile (vehicle types and weights)

Changed rates of flow

Changed times of flow

Changed waiting times

Change in traffic speed

Change in accident rate

Change in access to parking

Change in turning movements

Effects on multi-modal transport profile (cars, buses, trams, trains, walking, cycling)

Severance

Effects on ecology

Effects on pedestrians

Effects on cyclists

Effects on car users

Effects on commercial vehicles

Effects on frontage land uses

Health and safety

Changed flood risk

Loss of property

Change in air pollution

Change in water pollution

Change in land contamination

Change in noise levels

Change in vehicles

Change in equipment

Change in emergency situations

Amenity, access, leisure and recreation facilities

Change in access

Altered facilities

Altered use

Effects on users of land-, water- and air-based facilities

Pests/vermin

Birds

Invertebrates

Rodents

Other mammals

Micro-organisms

Visual impact

Altered aesthetic value, including proportion, scale, enclosure, texture, colour, views

Change in landscape

Change in townscape

Visual intrusion

Procedures

John Glasson, Riki Therivel et. al. suggest the following procedures for the environmental impact assessment (EIA) process, which is developed from their earlier book originally published in 1994.

Department of the Environment, Transport and the Regions, a now-dissolved UK governmental agency in charge of environmental affairs, also provides with a checklist of matters that may be considered for inclusion in an EIA. This checklist is often used as a guidance to ensure that all the possible significant effects of the development are considered.

The environmental effects of a development during its construction and commissioning phases should be considered separately from the effects arising while it is operational. Where the operational life of a development is expected to be limited, the effects of decommissioning or reinstating the land should also be considered separately.

Section 1: Information describing the project

1.1 Purpose and physical characteristics of the project, including details of proposed access and transport arrangements, and of numbers to be employed and where they will come from.

1.2 Land-use requirements and other physical features of the project: • during construction; • when operational; • after use has ceased (where appropriate).

1.3 Production processes and operational features of the project:

• type and quantities of raw materials, energy and other resources consumed; • residues and emissions by type, quantity, composition and strength including: discharges to water; emissions to air; noise; vibration; light; heat; radiation; deposits/residues to land and soil; others.

1.4 Main alternative sites and processes considered, where appropriate, and reasons for final choice.

Section 2: Information describing the site and its environment

Physical features

2.1 Population - proximity and numbers.

2.2 Flora and fauna (including both habitats and species) - in particular, protected species and their habitats.

2.3 Soil: agricultural quality, geology and geomorphology.

2.4 Water: aquifers, watercourses, shoreline, including the type, quantity, composition and strength of any existing discharges.

2.5 Air: climatic factors, air quality, etc.

2.6 Architectural and historic heritage, archaeological sites and features, and other material assets.

2.7 Landscape and topography.

2.8 Recreational uses.

2.9 Any other relevant environmental features.

The policy framework

2.10 Where applicable, the information considered under this section should include all relevant statutory designations such as national nature reserves, sites of special scientific interest, national parks, areas of outstanding natural beauty, heritage coasts, regional parks, country parks and designated green belt, local nature reserves, areas affected by tree preservation orders, water protection zones, conservation areas, listed buildings, scheduled ancient monuments and designated areas of archaeological importance. It should also include references to relevant national policies (including Planning Policy Guidance (P P G ) notes) and to regional and local plans and policies (including approved or emerging development plans).

2.11 Reference should also be made to international designations, e.g. those under the EC ‘Wild Birds’ or ‘Habitats' Directives, the Biodiversity Convention and the Ramsar Convention.

Section 3: Assessment of effects

Including direct and indirect, secondary, cumulative, short-, medium- and long-term, permanent and temporary, positive and negative effects of the project.

Effects on human beings, buildings and man-made features

3.1 Change in population arising from the development, and consequential environment effects.

3.2 Visual effects of the development on the surrounding area and landscape.

3.3 Levels and effects of emissions from the development during normal operation.

3.4 Levels and effects of noise from the development.

3.5 Effects of the development on local roads and transport.

3.6 Effects of the development on buildings, the architectural and historic heritage, archaeological features and other human artefacts, e.g. through pollutants, visual intrusion, vibration.

Effects on flora, fauna and geology

3.7 Loss of, and damage to, habitats and plant and animal species.

3.8 Loss of, and damage to, geological, palaeontological and physiographic features.

3.9 Other ecological consequences

Effects on land

3.10 Physical effects of the development, e.g. change in local topography, effect of earth-moving on stability, soil erosion, etc.

3.11 Effects of chemical emissions and deposits on soil of site and surrounding land.

3.12 Land-use/resource effects:

• quality and quantity of agricultural land to be taken; • sterilization of mineral resources; • other alternative uses of the site, including the ‘do nothing1option; • effect on surrounding land uses including agriculture; • waste disposal.

Effects on water

3.13 Effects of development on drainage pattern in the area.

3.14 Changes to other hydrographic characteristics, e.g. groundwater level, watercourses, flow of underground water.

3.15 Effects on coastal or estuarine hydrology.

3.16 Effects of pollutants, waste, etc. on water quality.

Effects on air and climate

3.17 Level and concentration of chemical emissions and their environmental effects.

3.18 Particulate matter.

3.19 Offensive odours.

3.20 Any other climatic effects.

Other indirect and secondary effects associated with the project

3.21 Effects from traffic (road, rail, air, water) related to the development.

3.22 Effects arising from the extraction and consumption of materials, water, energy or other resources bythe development.

3.23 Effects of other development associated with the project, e.g. new roads, sewers, housing, power lines, pipelines, telecommunications, etc.

3.24 Effects of association of the development with other existing or proposed development.

3.25 Secondary effects resulting from the interaction of separate direct effects listed above.

Section 4: Mitigating measures

4.1 Where significant adverse effects are identified, a description of the measures to be taken to avoid, reduce or remedy those effects, e.g.:

(a) site planning;

(b) technical measures, e.g.:

• process selection; • recycling; • pollution control and treatment; • containment (e.g. bunding of storage vessels). (c) aesthetic and ecological measures, e.g.:

• mounding; • design, colour, etc.; • landscaping; • tree plantings; • measures to preserve particular habitats or create alternative habitats; • recording of archaeological sites; • measures to safeguard historic buildings or sites.

4.2 Assessment of the likely effectiveness of mitigating measures.

Section 5: Risk of accidents and hazardous development

5.1 Risk of accidents as such is not covered in the EIA Directive or, consequently, in the implementing Regulations. However, when the proposed development involves materials that could be harmful to the environment (including people) in the event of an accident, the environmental statement should include an indication of the preventive measures that will be adopted so that such an occurrence is not likely to have a significant effect. This could, where appropriate, include reference to compliance with Health and Safety legislation.

5.2 There are separate arrangements in force relating to the keeping or use of hazardous substances and the H S E provides local planning authorities with expert advice about risk assessment on any planning application involving a hazardous installation.

5.3 Nevertheless, it is desirable that, wherever possible, the risk of accidents and the general environmental effects of developments should be considered together, and developers and planning authorities should bear this in mind.