Authors: Stefano Balbi, Sabindra Bhandari, Animesh Gain, Carlo Giupponi

Climate change impacts on the Venice Lagoon Watershed (VLW), an area of 2.038 km2 in the north-eastern part of Italy, are expected to be particularly relevant for agriculture (Salon et al. 2008), given that approximately two-thirds of the total area are devoted to field crops, horticulture and market gardens. Farmer’s irrigation behaviour will increasingly play a crucial role for the sustainability of crop productions and water consumption. Innovative approaches may require substantial private and public investments.
An agent-based model is developed to explore how farmers’ decisions affect future water consumption in the VLW. The model is an “agentized version” of a soil water balance model based on the FAO-56 procedure proposed by Allen et al. (1998). Farming agents take adaptation decisions concerning irrigation management (system, volume, frequency) on the basis of own information about weather conditions. These strategies directly affect the crop and irrigation parameters, which in turn affect future water needs of the area. Agents are based on actual data about income, utilized agricultural surface, age, crop typologies and irrigation systems in place.
A climatic projection representing the IPCC A1B scenario is used to produce future daily data about relative humidity, precipitation, temperature and wind speed with a 1km2 resolution. In order to inform the farmers about the simulated future climatic conditions, two types of climatic services are made available: (1) a bi-weekly agro-meteorological bulletin and (2) the seasonal forecasts. The precision of these services varies according to the selected exogenous information scenario which simulates different conditions, from perfect knowledge to poor forecasts.
The model allows to investigate farmers’ behaviour and the consequent future irrigation water demand for the period 2015 to 2030, under alternative information scenarios. This paper describes the model and the preliminary results integrating diagrams and the ODD protocol (Grimm et al. 2006).