The condition of Lake Balaton, also known as the 'Sea of Hungary', is a high-priority issue for Hungarians, the Government of Hungary and the millions of foreign tourists visiting its unique habitat, shorelines and upland protected areas.
Following many years of water quality problems, a negative water balance induced a water shortage starting in 2000 and lasting for four years. This raised and continues to raise serious sustainability concerns in the Lake Balaton area, Hungary and the region. Because of these trends, the sensitivity of Lake Balaton to climate change and its impacts came to the fore both for policy and scientific reasons. Besides Balaton, there are also many other shallow lakes and reservoirs of significant economic and ecological importance in Hungary, and other regions facing similar vulnerability and adaptation problems, where lessons from this initiative can be applied.
Lake Balaton's uniquely vulnerable situation is the combined result mainly of its very shallow profile, and the fact that through heavy reliance on tourism as a primary source of livelihoods, the socio-economic consequences of ecological deterioration can be severe and immediate. If the frequency of years with negative water balance indeed increases in the future, as indicated by applicable climate change scenarios, Lake Balaton and the coupled socio-economic system are expected to emerge as a highly sensitive and internationally-unique indicator of vulnerability to global change. On a more positive side, it could also serve as a high-profile example of adaptation measures consistent with sustainable development.
Considering this potential, UNEP's Division of Early Warning and Assessment, the Lake Balaton Development Council (LBDC) and the International Institute for Sustainable Development (IISD) launched the “Lake Balaton Integrated Vulnerability Assessment, Early Warning and Adaptation Strategies” project, in 2005.
The overall purpose of the project is to contribute to a better understanding of Lake Balaton’s ecological and socio-economic system vulnerability and resilience arising from multiple forces of global and local change, including land use, demographic, economic and climate change, and build capacity for more effective policy-making and adaptation measures in response.
Within this project GRID-Europe is
· the development of the conceptual framework,
· the conception and population of a geodatabase,
· the elaboration of an Internet MapServer using ESRI ArcIMS technology,
· the identification of indicators and study areas.
In the first step of the project, GRID-Europe developed an Internet MapServer using ESRI ArcIMS technology with the aim to let implementing partners visualize and access available geo-data. In order to facilitate the access and update the meta-information, a web application has been developed on PHP/MySQL and linked to the IMS.
GRID-Europe has been simulating hydrological processes using the ESRI ArcGIS extension SWAT (Soil and Water Assessment Tool) following a set of climatic and land use scenarios. SWAT is a river basin, or watershed, scale physically-based model developed to predict the impact of land management practices on water, sediment and agricultural chemical yields in large, complex watersheds with varying soils, land use and management conditions over long periods of time. The aim of those simulations is to better understand the environmental and socio-economic vulnerability of the Balaton region, related to water quality and quantity towards potential global climatic and land use changes. The output of the scenarios have been integrated in an existing lake model and related to other non-water indicators.
Currently GRID-Europe is in the process of applying scenarios based on the model. Two types of scenarios have been developed: land use and climate. The land use scenarios are based on CORINE Land Cover 2000 and expand or shrink randomly land cover categories within a defined range until 2030 and 2100. A separate land use scenario has been prepared that is the strict application of the “Lake Balaton Act 2000”, the official land use plan.
Climate scenarios are issued from PRUDENCE- DMI models and adapted to the appropriate period (2030, 2100) using the monthly ten-percentiles delta method. A2 (pessimistic) and B2 (optimistic) scenarios have been used. The aim of running the scenarios is to predict how water quality and quantity will evolve as a function of the scenario used and compared to the actual period used as reference. Ultimately the output of the scenarios will be integrated to an existing lake model and related to indicators that are not linked to water.