A spatial decision support system to evaluate the agronomic and economic feasibility for short rotation forestry irrigated with wastewater in Basilicata region

Energy crops irrigated with non-conventional water resources on large scale could decrease negative impacts from fossil fuel use, at the same time saving potable supplies and reducing pollution in surface water, particularly in water scarcity environments as the Mediterranean basin. Willow and poplar short rotation forestry (SRF) irrigated with wastewater, known as “vegetation filter systems”, are an attractive alternative to conventional forestry and water purification systems for attaining environmental and energy goals set in the European Union and increasing farmers’ income. Energy planning issues are complex problems with multiple decision makers and criteria. Given the spatial nature of the problem, the research proposes a spatial decision support system (SDSS) to evaluate the agronomic and economic feasibility of vegetation filter systems in Basilicata region, southern Italy. Environmental and economic sustainability underlies the development of SDSS, which relies on a multi-criteria evaluation model (MCE) and a range of spatial analysis functions. The MCE model chosen for land suitability analysis is the ordered weighted averaging (OWA) with the use of linguistic quantifiers. The latter has been proven to be more flexible than other MCE methods. Land suitability analysis indicates the poplar as the most suitable species in the region with a suitable surface of 258,512 ha. The poplar suitability map was used as input in the spatial analysis functions useful to quantify the productivity and irrigation needs of the species, the irrigation capacity of the wastewater treatment plants (WWTP), as well as the distances between them and poplar SRF, the key elements in the economic evaluation. The results show that the distance is the main element that influences the feasibility: only 25 out of 163 WWTPs are cost-effective and capable to irrigate 864 ha of SRF. The research demonstrates that there is a great potential for bio-energy development in the region with clear economic advantages, highlighting a wide availability of sites with positive NPV up to 50,876.43 €/ha and payback period content between 5 and 10 years. The realization of vegetation filter systems could create chains with a large number of local actors (farmers, harvest intermediaries, nurseries for the forest material production, etc.), promoting territory and employment development.