Lars Chr. Larsen, Arne Hurup Nielsen
The EAGLE project concerns the development of the environmental information and management support system for Øresund. The system has been developed for Øresundskonsortiet A/S, who are responsible for the construction of the fixed link between Denmark and Sweden.
In the construction phase, a large number of environmental issues concerning the marine environment have to be monitored and evaluated. The state of the ecosystem is one of the most important parameters in management decisions about the dredging and reclamation works. Data such as hydrographic parameters, sediment transport, eelgrass growth, mussel coverage, fish migration, water quality and bird life are taken into account. EAGLE contains information about the present state of the ecosystem and interacts with the forecast modelling system to evaluate various construction scenarios in order to achieve the most economic alternative, while still adhering to the environmental criteria.
The EAGLE system monitors a large variety of data on-line; it receives results from hindcast and forecast models and evaluates the results against a large number of environmental criteria. In the event that consents are violated, a series of actions is triggered. The events and actions are fully documented within the system for later analysis and as documentation for the authorities.
The information system part of EAGLE is used by the authorities and other interested parties to monitor the progress of the project and to follow the decisions and field observations closely. EAGLE is constructed using the geographical information system, ArcView, together with other programming tools. The main part of the system runs on PC-based hardware, employing both local and wide area network technology. EAGLE has been implemented in collaboration between Danish Hydraulic Institute and the Danish Water Quality Institute.
The project of constructing a fixed link between the two countries Denmark and Sweden, crossing the strait called the Sound, is a 3.7 bilion dollar project. The link will be a combination of a bridge and a tunnel carrying both rail and road traffic. Concern about the long term environmental effects of reducing the water flow between the North Sea and the Baltic has led to requirements concerning the blocking effect of the bridge - This in turn leads to the neccesity of marking extensive dredgings to compensate for the blocking effect of the bridge contruction. The need for such large dredging operations, may on the other hand, have severe impact upon the local environment. To avoid this, extensive requirements to the performance of the dredging have been made in the legislation accompanying the project. A complex monitoring and a control program has been established and, to support these programs and their administration, the EAGLE system described in this paper has been created.
During the construction the major environmental concerns are related to the local environment in the vicinity of the construction area. About 7 million cubic meters of mainly clay and chalk-based seabed is being dredged, resulting in extensive sediment plumes in the shallow water areas surrounding the construction site which may severely affect the environment.
An extensive environmental assessment concerning both the local and global effects of the link was carried out prior to the design of the bridge, but as such assessments need to be done using the conditions of a so-called 'normal year' there is nothing to ensure that the conditions simulated during the assessment will be similar to the actual conditions. This is particularly true for the construction phase which covers a four-year period only. Because of this uncertanty, intensive monitoring is needed to follow the development and an organization must be ready to evaluate the results and to take remedial action on a very short time scale in order to avoid permanent damage to the environment.
The more sensitive parts of the local environment concern the land-based fauna, the marine flora and the marine fauna of the area - the bridge will eventually border a major wildlife protection area.
The two governments involved and the corresponding EPDs expressed a number of fairly general conditions when authorizationg the work. One example of such a general criteria is the criteria expressing that the biomass in the area may not be reduced by more than 25% for reasons caused by the construction works.
Obviously such criteria cannot be controlled on a day-to-day basis and consequently the daily control has to be done on simpler and more exact criteria. These criteria are referred to as the operational criteria.
The operational criteria have been chosen in such a way that they are relatively easy to transform into the general criteria of the project. As an example, eelgrass has been chosen as a central plant to monitor as: 1) it is an important part of the ecosystem in the area and 2) it is easily affected by sediment concentrations in the water. In a similar fashion a large number of criteria have been established; criteria which may be evaluated on the basis of measurements and put into a monitoring program.
In order to control the environmental impact directly and provide sufficient information to support remedial actions at short notice a number of monitoring activities are performed on a routine basis. The project involves four different monitoring programs, all supplying data to the EAGLE system where results can be evaluated and compared:
Several of the monitoring activities are combined with modelling activities. The following models run on a routine basis in the system:
The modelling activities are mainly run on a 'hind-cast' basis, i.e. the known weather- and other boundary conditions for the previous period are used as input to the model. The results of the model can then be used to extrapolate the relatively sparse measurements into a total coverage of the project area.
At regular intervals the same models are used in forecast mode to provide an updated environmental impact assessment (EIA) for the complete construction period, now using the measured data up to the start of the modelling period. This procedure will gradually decrease the uncertainty of the forecast and thus provide a still better foundation for decisions on remedial actions etc. in case there is danger of violating any of the consents given for the project.
All results from the modelling and the monitoring programs are compared to a set of operational criteria, i.e. the results show if a criteria is violated. In case of violation of a criteria a pre-defined action, or set of actions, is triggered and reported in the system. The criteria and the actions are organized in an escalating loop as shown below:
A triggered action (normally the first action is intensified monitoring) will always produce a new set of data which again can be checked against the criteria. This will continue until either the situation is proven to be normal, or in the event of serious danger to the environment remedial actions (ultimately stopping the construction work) has been taken.
As it can be seen from the above description, the procedure for environmental monitoring and the feedback procedures are very complex and involves a large number of data, not only in terms of quantity but also in terms of different types. To assist the environmental decision makers in achieving the necessary overview of the system, and to support the right decisions, the GIS based information system EAGLE was designed.
EAGLE will display the relevant data from modelling, monitoring and from the decision process itself. The basic data flow of EAGLE is illustrated below. A database based upon a Microsoft SQL-Server running under Windows-NT is constantly updated by the organizations responsible for the monitoring and modelling. Several organizations report their results to EAGLE. Following an initial QA/QC phase the data is released to the central server - essentially a copy of the first database - from this server the data are available to all users of EAGLE.
Users will access EAGLE from either the local area network or through a wide area network based upon ISDN connections. An automatic program update is incorporated in the system. Whenever a program file or other files residing locally on the users machine is updated, new files will automatically be transferred to the user machines without manual intervention.
EAGLE consists of a number of sub-systems which may be considered individually. These main modules are reflected in the main menu as shown below:
The feedback criteria submodule provides an easy and fast overview of all the different criteria involved in the evaluation process. This part of the system is designed to provide a standard report for every criteria, and it may easily be used by casual users for a quick, but still well documented overview of the status.
The overview menu for the feedback criteria evaluation
Every criteria is accompanied by a visual indicatior that shows the actual condition of every criteria and lights up red if a criteria is violated. When a red lamp is on, as in the above example the incident may be further investigated by viewing the data together with the relevant limits CLICK here and HERE to see the next two screens a user may typically call up in the above example.
In the incident database every violation of a criteria, or any other incident of environmental importance is tracked in a 'bookkeeping system'. The incident is logged, and from that point on, the registration is protected against deletion. For each incident a number of 'actions' may be documented.
Both incidents and actions may be annotated with various supporting data such as data files, pictures, reports etc. and everything is logged with a time stamp, and the initials of the responsible person. The incident database will provide the user with a complete overview of the history, not only of what incidents have occurred, but also with the history of remedial actions performed to rectify the situation.
In this section the users may have access to all data included in the system. This is not only data directly involved in the testing of criteria etc., but also to a huge amount of background data and historic data included in this section. The data are included in complete raw mode, i.e. the user is allowed to carry out a full environmental assessment by using the system and he is not forced to rely upon conclusion made by other experts. Individual interests and concerns may be investigated to a very detailed level. Samples of the various presentations which can be extracted in EAGLE are shown below click on the sample screen you want to see:.
A the major cause for environmental problems in this particular project is the spilling of sediment during dredging and reclamation, a separate part of EAGLE is devoted to reporting the direct monitoring of spill. This part of the system also reports the progress of the construction work itself. Reports are done on a daily basis and supplemented with weekly reports containing quality controlled numbers only.
The EAGLE system has proven that by using modern GIS techniques, together with well known computer technologies like Windows and PC's, it is possible to compose a technically very complex and sophisticated system and still achieve a level of user friendliness. This allows relatively unskilled and non computer litterate users to benefit from the system. Systems such as EAGLE may add a new dimension to the awareness and the effectiveness of public control with environmental issues in large projects, where reports may still be under preparation as damage is being done to the environment.
Together with techniques for environmental impact assessment, complete systems may be composed which can document large projects, from the early design phases, to the conclusion of the project and present the data in a comprehensible manner. After these first experiences, several of the tools may be developed to a generic level, in such a way that environmental evaluation, information, and decision support system, falls into a standard type system category of its own.
