Why, how, and how far should microbiological contamination in a coastal zone be mitigated? An application of the systems approach to the Thau lagoon (France)

Abstract

This paper describes the building of an integrated simulation tool based on a systems approach, and its contribution to local political discussion of the mitigation of microbiological contamination of the water in a coastal area. Local management schemes view water quality as a high-priority environmental objective. In practice, how far this objective is achieved depends on trade-offs between the costs of improved water treatment facilities and the acceptable impacts of water contamination. An in-the-field experiment in collaboration with local managers was carried out in the Thau lagoon on the French Mediterranean coast during the SPICOSA (Science and Policy Integration for Coastal System Assessment) project, from 2007 through 2011. It consisted of building a modeling platform and an integrated assessment framework for simulating exploratory scenarios. The modeling platform combines a dynamic contamination model, which represents the sources of microbiological contamination, wastewater treatment facilities, and physical mechanisms of lagoon contamination, with a prospective economic model, which estimates the patterns of development of economic activities in the area through a holistic approach. Exploratory scenarios are used to assess the risk of water contamination and the efficiency of management measures, under various assumptions about the evolution of the system. The contamination simulations suggest that the work currently planned by local authorities will be inadequate for preventing increased water pollution, and that additional but fairly inexpensive management measures for maintaining the current level of water quality should be considered. The integrated assessment framework estimates the ecological and socio-economic impacts of the various pollution mitigation policies in the broader context of possible local development patterns. The results illustrate how the systems approach may aid in the design of an applicable water policy based on operational objectives and feasible technical options.

Mapping distribution and habitats of Aurelia sp. polyps in Thau lagoon, north-western Mediterranean Sea (France)

“…support of small pontoons and oyster-production rafts, which alone occupy ca. 20 % of the lagoon surface; Mongruel et al 2013) and were the most common artificial substrate identified in the lagoon, even when excluding oyster-production rafts. Therefore, the elevated colonization of metal structures appears to be associated with their high accessibility.…”

“…(Bonnet et al 2012), although the presence of the benthic population still requires further confirmation. Thau lagoon is a semi-enclosed system under heavy human pressure, where shellfish farming is one of the most important economical activities, with a production of 15 000 tons of oysters and mussels per year (Mongruel et al 2013). We here provide a qualitative assessment of the distribution and habitat use of the benthic population of Aurelia sp.…”

Reusability of model components for environmental simulation – Case studies for integrated coastal zone management

“…Exceptions, for example, are the simulation tool for water quality management of the Thau Lagoon in France (Mongruel et al, 2013) and the application of the Scheldt nitrogen apportionment model (Vermaat et al, 2012) to estimate off-shore eutrophication (www.iseca.eu). Furthermore, a SAF webgallery has been created for dissemination purposes, making a selection of the models available for downloading (http://www.…”

A Systems Approach Framework for the Transition to Sustainable Development: Potential Value Based on Coastal Experiments

“…Combining macro-economic and dynamicpollution models of the lagoon at the local level provided an effective, integrated assessment of the risk of microbiological contamination and facilitated the evaluation of scenarios with different local development patterns and management strategies (Mongruel et al 2012).…”

“…The governance component of the dynamic contamination model for the lagoon was sufficiently flexible to simulate changes in its monitoring system and in the protocols that lead to administrative decisions. This allowed the pollution impact assessment to distinguish clearly between real contamination, observed contamination, and risk management (Mongruel et al 2012).…”