LIFE REWAT - sustainable water management in the lower Cornia Valley.

Introduction The availability of water sources for irrigation is diminishing in all parts of the world, and the conflicts between urban and agricultural interests for this water are rising due to the increasing demand of food by a growing population in the next few years. This situation is exacerbated in the Mediterranean basin, where historically climate conditions were characterised by scarce annual rainfall and high summer temperature. In the last years, climate changes rise these issues by worsening of precipitation distribution (i.e. storms frequency and intensity) and increasing of heat wave phenomena (Iglesias and Garrote, 2015). This leads to a decrease of aquifer recharge and increase in fluxes towards the atmosphere by higher evapotranspiration. The Cornia basin is 365 km2 large, and it runs through Livorno, Pisa and Grosseto provinces before flowing into the Tyrrhenian Sea. The Cornia river flows from Metallifere hills at 875 m o.s.l. and it's 50 km long. The hydrologic balance of the basin has been characterized for years by heavy quantitative imbalance, caused by an intensive use of water resource from the civil and agricultural sectors. Large part of the water resource is conveyed to Elba Island using a submarine pipe to supply about 50% of the Island water needs. Basin groundwater has been largely impacted, with head lowering of about 12 m the inland of lower Cornia plain. A volumetric calculation from the 70’s to 2001 estimates about 8 Mm3 total water deficit, with about the 50% built up in 90’s. This change had heavy effects on freshwater systems causing saline intrusion in coastal water bodies, modifying connected ecosystems (particularly coastal wetlands, like SIC/ZPS IT5160010 "Padule Orti Bottagone" and "Parco della Sterpaia") and complete salinization of the hydrogeologic units. Now, a dangerous trend of middle lower salinity is moving towards water potable fields (Bianchini et al., 2005; Pennisi et al., 2006). Based on this, the aim of the REWAT project is to develop a participated strategy for an integrated water resources management at sub-catchment level, as a model of governance for sustainable development of the lower Cornia valley. Project description Life REWAT project (sustainable WATer management in the lower Cornia valley through demand REduction, aquifer Recharge and river Restoration) aims to develop a participated strategy for integrated water resource management at sub­catchment level, as a model of governance for sustainable development of the lower Cornia valley. Within the project, this strategy - adaptive towards Climate Change - is strictly linked to (re)balancing water budget of the complex hydrological system of the lower river Cornia. Means to reach this goal will range from optimization of water consumption (civil and agricultural) to an increase of intentional groundwater recharge (through river morphological restoration and a Managed Aquifer Recharge, MAR, scheme). As far as the lower Cornia valley, the purpose of the project consists of four specific objectives: (i) fostering an integrated knowledge on the hydrological system and related water uses; (ii) raising awareness and proactive involvement of water users on the importance of water saving, river restoration and groundwater banking. These actors are both public and private, individual or organized, and they make up the community which directly or indirectly affects the water budget in the lower Cornia valley; (iii) demonstrating the technical feasibility, the economical advantages and the environmental sustainability of several technical solutions able to increase natural infiltration rates and managed recharge of aquifers, together with effective solutions for water saving; (iv) developing an integrated and participated governance tool for surface and groundwater management at a sub-catchment scale, that will lead to sign a "Water Contract", a pioneer innovative experience in Italy of negotiated agreement involving all the waterbodies (fluvial, groundwater, transitional and coastal) and the related stakeholders. The REWAT project will implement a number of demonstration measures in the lower Cornia valley, both structural (pilot) and non-structural (education and training), which will form the basis for a governance processes. The so-called “Water Contract” will then aim at sharing a long-medium term strategy for sustainable water management in the project area. The five demonstration actions are related to: (1) set up of a Managed Aquifer Recharge (MAR) facility, (2) river restoration of a Cornia river reach, (3) water saving in the civil water supply sector, (4) water saving in agriculture, (5) reduction and sustainable management of storm-water in urban areas. The strategic decision making process aiming at a long term negotiated agreement for water resources management in the lower Cornia basin will result in a voluntary governance tool for the wide scale implementation, in the medium term (post-LIFE), of the good practices developed in this project. Water saving treatment in agriculture. Sub-surface drip-irrigation demonstration action Globe artichoke (Cynara cardunculus L. var. scolymus L. (Fiori)), a perennial horticulture species, covers in Italy a surface of about 50,000 ha. In Tuscany, four varieties represent almost the total artichoke cropping surface. Traditional varieties “Violetto di Toscana” ad “Empolese” are still cultivated along with recent varieties derived from breeding project, “Terom” and “Tema”. In the lower Cornia valley, the artichoke cropping surface is about 600 ha and in order to increase stability and productivity of the crop, about 2000 – 4000 m3 ha-1 yr-1 of irrigation water is required. Drip irrigation systems allow to enhance water use efficiency in artichoke cultivation compared with other low efficiency systems (i.e. furrow and sprinkler) (Leskovar and Xu, 2013). Several studies demonstrated that yield of different crops increases using sub-surface drip-irrigation (SDI) system under high frequency irrigation management (Ayras et al., 1999). The aim of the action is to demonstrate the feasibility of SDI for artichoke cultivation in order to reduce the water consumption for irrigation in lower Cornia valley. The action is located in Venturina (43°01'59.0"N 10°35'12.0"E) and cover a 4 ha surface inside the Stefano Forconi’s farm. The soil is characterized by sandy loam texture, 7.81 pH and 1.72 % of organic matter. Irrigation water is characterized by neutral pH (7.2) and 1363 μS/cm of electrical conductivity. The field test provides the comparison of SDI system respect to surface irrigation and surface drip irrigation. Moreover, deficit irrigation strategy will be investigating, in order to test the possible increasing of water saving in artichoke cultivation. The LIFE REWAT Consortium is led by Consorzio di Bonifica Toscana Costa, a local institution devoted to water management, Scuola Superiore Sant'Anna, a public research university, ASA spa, a water utility, and the governing authority Regione Toscana. References Ayars J.E. Phene C.J. et al. 1999. Subsurface drip irrigation of row crops: A review of 15 years of research at the Water Management Research Laboratory. Agric. Water Manag, 42:1-27. Bianchini G. Pennisi M. et al. 2005. Hydrochemistry of the high-boron groundwaters of the Cornia aquifer (Tuscany, Italy) Geothermics, 34:297-319. Iglesias A. Garrote L. 2015. Adaptation strategies for agricultural water management under climate change in Europe. Agric. Water Manag, 155:113–124. Leskovar D.I. Xu C. 2013. Irrigation strategies and water use efficiency of globe artichoke. Acta Hortic, 983:261-268. Pennisi M. Bianchini G. et al. 2006. Behaviour of boron and strontium isotopes in groundwater-aquifer interactions in the Cornia Plain (Tuscany, Italy) Appl Geochem, 21:1169-1183.