10 Fixed Link Projects in Denmark and Ecological Monitoring of the IIlresund Fixed Link
109
10.5.4
Monitoring Strategy
The Danish and Swedish environmental authorities and 0resundskonsortiet have developed control and monitoring programmes to ensure that the spillage limits are not
exceeded and the quality objectives are not violated. The control and monitoring programmes are conducted at three different levels:
• The contractor is contractually obliged to ensure that total spillage limits are not
exceeded, and that the requirements for spillage intensity in time and space are fulfilled. The spillage monitoring conducted by the contractor is supervised by
0resundskonsortiet and the environmental authorities in Denmark and Sweden.
• 0resundskonsortiet is responsible for a feedback monitoring programme in order ,to ensure that timely measures are taken to avoid any risk of violation of any of the authorities' requirements both to the marine environment and to the execution of the work.
• The authorities independently carry out monitoring and control of the environmental impact on water quality, bottom fauna, bottom vegetation, coastal morphology, herring migration, birds and bathing water quality.
The authorities in Denmark and Sweden have to report the results of the ecological
control and monitoring programmes semi-anually to the governments.
10.5.5
The Contractors' Spill Monitoring Programme
Spillage measurements are carried out while sailing across the sediment plumes and in
profIles in the sediment plumes themselves. In 1996 the measuring was done on a 24-h
basis, but during the autumn of 1996 a special method was developed for determining
spillage from dredging work done by dredgers equipped with a bucket. The new method
determines the spillage percentage using a combination of concrete measurements and
model calculations based on the experience gained so far. The aim is to limit measuring activities and so utilize the resources of the measuring vessels more effectively
while satisfying the uncertainty requirements with regard to determining the spillage
percentage. The new method for determining spillage was put into operation in spring
1997 (0resundskonsortiet 1996a).
Monitoring of the bed load transport of sediment from dredging operations has
been carried out in two stages. The first stage consists of visual observation of the
seabed in and around the various dredging areas, and the second stage of more detailed investigation if spilled sediment in thicknesses in excess of 10 cm is found (0resundskonsortiet 1996b). The non-quality-assured spill data shall within 48 h be stored
in an Environmental Information System to which the authorities have direct access.
On a weekly basis the contractor has to prepare a report with quality-assured spill data
within 3 weeks from the end of the report period.
By the end of 1996 the overall average spillage percentage for all dredging operations was calculated as approx. 234 000 tons or approx. 4.4% of the total dredged amount
(approx. 5300000 tons (Fig. 10.2); (Danish Ministry of the Environment and Energy,
Danish Ministry of Transport, KSO 1997a)
109
10.5.4
Monitoring Strategy
The Danish and Swedish environmental authorities and 0resundskonsortiet have developed control and monitoring programmes to ensure that the spillage limits are not
exceeded and the quality objectives are not violated. The control and monitoring programmes are conducted at three different levels:
• The contractor is contractually obliged to ensure that total spillage limits are not
exceeded, and that the requirements for spillage intensity in time and space are fulfilled. The spillage monitoring conducted by the contractor is supervised by
0resundskonsortiet and the environmental authorities in Denmark and Sweden.
• 0resundskonsortiet is responsible for a feedback monitoring programme in order ,to ensure that timely measures are taken to avoid any risk of violation of any of the authorities' requirements both to the marine environment and to the execution of the work.
• The authorities independently carry out monitoring and control of the environmental impact on water quality, bottom fauna, bottom vegetation, coastal morphology, herring migration, birds and bathing water quality.
The authorities in Denmark and Sweden have to report the results of the ecological
control and monitoring programmes semi-anually to the governments.
10.5.5
The Contractors' Spill Monitoring Programme
Spillage measurements are carried out while sailing across the sediment plumes and in
profIles in the sediment plumes themselves. In 1996 the measuring was done on a 24-h
basis, but during the autumn of 1996 a special method was developed for determining
spillage from dredging work done by dredgers equipped with a bucket. The new method
determines the spillage percentage using a combination of concrete measurements and
model calculations based on the experience gained so far. The aim is to limit measuring activities and so utilize the resources of the measuring vessels more effectively
while satisfying the uncertainty requirements with regard to determining the spillage
percentage. The new method for determining spillage was put into operation in spring
1997 (0resundskonsortiet 1996a).
Monitoring of the bed load transport of sediment from dredging operations has
been carried out in two stages. The first stage consists of visual observation of the
seabed in and around the various dredging areas, and the second stage of more detailed investigation if spilled sediment in thicknesses in excess of 10 cm is found (0resundskonsortiet 1996b). The non-quality-assured spill data shall within 48 h be stored
in an Environmental Information System to which the authorities have direct access.
On a weekly basis the contractor has to prepare a report with quality-assured spill data
within 3 weeks from the end of the report period.
By the end of 1996 the overall average spillage percentage for all dredging operations was calculated as approx. 234 000 tons or approx. 4.4% of the total dredged amount
(approx. 5300000 tons (Fig. 10.2); (Danish Ministry of the Environment and Energy,
Danish Ministry of Transport, KSO 1997a)