GMAA: A DSS Based on the Decision Analysis Methodology - Application Survey and Further Developments - Efficient Decision Support Systems: Practice and Challenges from Current to Future - page 267

Throughout these projects, a synthetic, flexible and user-friendly computerized decision
support system, MOIRA, was implemented and tested on several real scenarios. The system
included a multi-attribute analyses module for the global assessment of the effectiveness of
the intervention strategies. This module was the origin of the GMAA system, which was
finally built into the last versions of the MOIRA system.
The selection of intervention strategies was based on environmental models for predicting
the migration of radionuclides through freshwater and coastal ecosystems and the effects of
feasible countermeasures on contamination levels. Moreover, other social and economic
criteria were taken into account.
Several real scenarios contaminated as a consequence of the Chernobyl accident were
analysed, like lake Øvre Heimdalsvatn (Jiménez et al., 2003), located in Oppland county
(Norway), lake Kozhanovskoe (Ríos Insua et al., 2004), located in the region of Bryansk
(Russia), and lake Svyatoye in Belarus (Ríos Insua et al. 2006).
Lake Svyatoye is located 237km from the Chernobyl nuclear power plant and 30km
southeast of Kostyukovichy (Belarus), and the 137 Cs contamination in the area was over 1480
kBq/m 2 . It is a collapse (karst) type lake. The maximum depth, at the center of the lake, is
5.2 m. It has both precipitation and subsurface water supply and the water balance is
controlled by evaporation and subsurface runoff.
According to the DA cycle, we started to build an objective hierarchy including all the key
aspects to be considered in the problem, see Fig. 1.
Environmental Impact (Environ. Imp) is one of the main objectives of the decision analysis. It
was divided into Lake Ecosystem Index (L.E.I.), a simple and rational approach for measuring
the ecological status of a lake, and Radiation Dose to Biota (Dose to Fish). Social Impact (Social
Imp.) was handled by two sub-objectives: minimizing impact on health (Dose to Man) and
Living Restrictions (Living restr).
Regarding dose to man, we focused on the Dose to Critical Individuals (Dose Crit In), who
should never receive radiation levels above thresholds for early health effects, and
Collective Dose (Coll. Dose), which was linearly related to the increase in the risk of
developing serious latent effects, mainly cancers. As regards living restrictions, other
impacts were taken into consideration. These include countermeasures affecting the direct
consumption of fish for food or its processing in the food industry, drinking water and
water used by the food industry, the use of water for crops irrigation and the recreational
uses of water bodies. For all these objectives, the attributes were the amount of fish
affected by restrictions (Amount fish), as well as the duration of such restrictions (Ban
Duration).
Finally, Economic Impact (Economic Im) was divided into Direct Effects (Direct Eff.), more
amenable to quantification, and Intangible Effects (Intang. Eff.), like loss-of-image and
adverse market reactions for the concerned area, which could also be subjectively valued by
the user. The direct effects include the costs generated by the different bans or restrictions to
normal living conditions, which can be sub-divided into Costs to the Economy (Cost to econ)
and the more subjective costs of lost recreation, and Application Costs (Applic. Cost), i.e.,
costs of chemical and physical remedial countermeasures.
Taking into account expert knowledge and opinions, a set of seven intervention strategies
were proposed for analysis, combining chemical countermeasures with fishing bans so as to
reduce the radiological and environmental impact:
 No action (natural evolution of the situation without intervention).

 Potassium (15 tonnes of potassium chloride added to the lake in April 1987).