Water Use and Urban Agriculture: Estimation and Water Saving Scenarios for Residential Kitchen Gardens

Abstract

Abstract During the last years, in the city of Rome (Italy) due to social and economical trends urban agriculture is a growing phenomenon. Residential kitchen gardens in Rome are a custom started in the past, but recently they experienced a strong increase with a concentration in the city fringe. The amount and extension of these cultivated parcels has been inventoried by the Italian Institute of Agricultural Economics (INEA) in 2014 with a methodology based on photointerpretation of the very high resolution imagery provided by Google Earth. The spatial dataset, after field validation, contains around 2,700 polygons with some attributes, among which the agricultural land use (i.e. horticulture, mixed crops, orchards, vineyards and olive groves). The use of water in urban agriculture is a relevant issue both in terms of competition with other uses and in terms of safety for human health. In Rome, residential kitchen gardens may resort to municipal water supply but, due to water costs, the water abstraction from wells (legal and illegal) and canals and rivers (illegal) is common. This paper describes the estimation of the irrigation water demand of the residential kitchen gardens by taking into account various agricultural land use and two different irrigation systems. Estimations are referred to the irrigation season (April-September) by using average climatic data (1950-2000). Parcels irrigation water requirement is also evaluated in terms of sustainability by considering a scenario where rain water is harvested and stored for the irrigation season as a possible alternative or supplement to the current irrigation sources. The proposed approach could be useful for administrators for a preliminary assessment of one of the component of water use in urban areas, and to support water management activities by taking into account the beneficial role of urban agriculture.