10 Fixed Link·Projects in Denmark and Ecological Monitoring of the IIIresund Fixed Link
111
which includes a hydrodynamic model, a wave model, two dispersion models for calculating spilled sediment and an ecological model for calculating effects on eelgrass,
phytoplankton and macroalgae.
0resundskonsortiet has also set up so-called operational environmental criteria for
sediment, eelgrass and common mussels which are stricter and more specific that those
of the authorities. This enables corrections to be made for any developments which
might otherwise result in an infringement of the authorities' criteria, as well as making
it possible to document compliance with those criteria.
10.5.8
Effect Monitoring
.AJ; part of their supervision of the construction work the environmental authorities
are running a general programme with a view to assessing whether the observed effects of the construction work lie within the frameworks of the expected effects decribed
in the Environmental Impact .AJ;sessment (0resundskonsortiet 1995). The programme
includes monitoring within the following areas of the 0resund's environment: water
quality, benthic vegetation and benthic fauna, fish, birds, bathing water quality and
coastal morphology (Ministry of Transport and Ministry of Environment and Energy
1995).
The effect monitoring is long term and is primarily aimed at identifying effects and
changes in the environment which are caused by the construction work. In this way the
monitoring will form the basis for an assessment of the need for adjustments to the
construction work in the longer term. The monitoring also addresses a broader crosssection of the ecosystem than the feedback monitoring, which focuses on fewer variables and the local area around the dredging operations.
10.5.8.1
Water Quality
The monitoring prograntme is being carried out at four stations in the north, middle
and south of the 0resund (Semac 1997a). Each sample is analysed for salinity, temperature and visibility (Secchi) depth, and for concentrations of oxygen, chlorophyll and
nutrients, as supporting parameters to help interpret the other sub-prograntmes. When
assessing the oxygen content of the water, oxygen depletion is regarded as beginning at
concentrations ofless than 2.8 ml ° 2 1- 1 (corresponding to 4 mg ° 2 1- 1 ). Fish will leave
areas with such a low oxygen content. Acute oxygen depletion with values below 104 ml
° 2 1- 1 (corresponding to 2 mg 0 2 1- 1 ) over an extended period can harm benthic fauna
so seriously that it will die out (Danish Ministry of the Environment and Energy, Danish Ministry of Transport, KSO 1997a).
10.5.8.2
Benthic Flora and Fauna
The programme for benthic fauna includes monitoring of the shallow-water fauna and
deep-water fauna together with a separate programme for common mussel. Shallowwater fauna is collected at a small number of transects and stations during the spring,
111
which includes a hydrodynamic model, a wave model, two dispersion models for calculating spilled sediment and an ecological model for calculating effects on eelgrass,
phytoplankton and macroalgae.
0resundskonsortiet has also set up so-called operational environmental criteria for
sediment, eelgrass and common mussels which are stricter and more specific that those
of the authorities. This enables corrections to be made for any developments which
might otherwise result in an infringement of the authorities' criteria, as well as making
it possible to document compliance with those criteria.
10.5.8
Effect Monitoring
.AJ; part of their supervision of the construction work the environmental authorities
are running a general programme with a view to assessing whether the observed effects of the construction work lie within the frameworks of the expected effects decribed
in the Environmental Impact .AJ;sessment (0resundskonsortiet 1995). The programme
includes monitoring within the following areas of the 0resund's environment: water
quality, benthic vegetation and benthic fauna, fish, birds, bathing water quality and
coastal morphology (Ministry of Transport and Ministry of Environment and Energy
1995).
The effect monitoring is long term and is primarily aimed at identifying effects and
changes in the environment which are caused by the construction work. In this way the
monitoring will form the basis for an assessment of the need for adjustments to the
construction work in the longer term. The monitoring also addresses a broader crosssection of the ecosystem than the feedback monitoring, which focuses on fewer variables and the local area around the dredging operations.
10.5.8.1
Water Quality
The monitoring prograntme is being carried out at four stations in the north, middle
and south of the 0resund (Semac 1997a). Each sample is analysed for salinity, temperature and visibility (Secchi) depth, and for concentrations of oxygen, chlorophyll and
nutrients, as supporting parameters to help interpret the other sub-prograntmes. When
assessing the oxygen content of the water, oxygen depletion is regarded as beginning at
concentrations ofless than 2.8 ml ° 2 1- 1 (corresponding to 4 mg ° 2 1- 1 ). Fish will leave
areas with such a low oxygen content. Acute oxygen depletion with values below 104 ml
° 2 1- 1 (corresponding to 2 mg 0 2 1- 1 ) over an extended period can harm benthic fauna
so seriously that it will die out (Danish Ministry of the Environment and Energy, Danish Ministry of Transport, KSO 1997a).
10.5.8.2
Benthic Flora and Fauna
The programme for benthic fauna includes monitoring of the shallow-water fauna and
deep-water fauna together with a separate programme for common mussel. Shallowwater fauna is collected at a small number of transects and stations during the spring,