Climate Change Adaptation in a Mediterranean Semi-Arid Catchment: Testing Managed Aquifer Recharge and Increased Surface Reservoir Capacity

Abstract

Among different uses of freshwater, irrigation is the most impacting groundwater resource, leading to water table depletion and possible seawater intrusion. The unbalance between the availability of water resources and demand is currently exacerbated and could become worse in the near future in accordance with climate change observations and scenarios provided by Intergovernmental Panel on Climate Change (IPCC). In this context, Increasing Maximum Capacity of the surface reservoir (IMC) and Managed Aquifer Recharge (MAR) are adaptation measures that have the potential to enhance water supply systems resiliency. In this paper, a multiple-users and multiple-resources-Water Supply System (WSS) model is implemented to evaluate the effectiveness of these two adaptation strategies in a context of overexploited groundwater under the RCP 4.5 and the RCP 8.5 IPCC scenarios. The presented a case study that is located in the Puglia, a semi-arid region of South Italy characterized by a conspicuous water demand for irrigation. We observed that, although no significant long-term trend affects the proposed precipitation scenarios, the expected temperature increase highly impacts the WSS resources due to the associated increase of water demand for irrigation purposes. Under the RCP 4.5 the MAR scenario results are more effective than the IMC during long term wet periods (typically 5 years) and successfully compensates the impact on the groundwater resources. Differently, under RCP 8.5, due to more persistent dry periods, both adaptation scenarios fail and groundwater resource become exposed to massive sea water intrusion during the second half of the century. We conclude that the MAR scenario is a suitable adaptation strategy to face the expected future changes in climate, although mitigation actions to reduce green-house gases are strongly required.

Adaptation Strategies for Water Resources: Criteria for Research

“…Furthermore, when studies investigating future adaptation scenarios do not provide elements to manage the uncertainty specifically related to the proposed adaptation solution, exploring uncertainty related to the climatic and impact scenarios (using different IPCC emission scenarios) is strongly recommended. Two examples of complete development of adaptation scenarios, at least as regards the climatic and impact scenarios, are provided by Guyennon et al (2017) and Zhai et al (2017).…”

“…Guyennon et al (2017) face the problems related to the impact of irrigation on groundwater resources: increasing demand or water scarcity caused by climate change are the main drivers leading to groundwater table depletion [9]. In many areas of the world, periodic water shortages caused by temporal imbalances between supply and demand can be faced by storing water during rainy periods for later use during dry periods.…”

“…In particular, the discussion of uncertainty of the provision of implementation guidance to adaptation actions has never been faced. Only two studies [9,11] identify, propose, discuss, and develop an adaptation scenario. Five other studies [10,14,[16][17][18] belong more properly to the category "Climate change impact studies".…”

“…The parties affirmed that "adaptation must be addressed with the same priority as mitigation" [1,2]. Under this framework, the COP invited "all Parties to enhance action on adaptation" [1][2][3][4][5][6][7][8][9][10][11][12][13][14] by "planning, prioritizing and implementing adaptation actions, including projects and programs" [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The Paris agreement (COP21) provided numerous indications and details about adaptation, mainly in Article 7 [2].…”

The Impact of a Check Dam on Groundwater Recharge and Sedimentation in an Ephemeral Stream

“…The sustainability of groundwater bodies is therefore very important, and induced groundwater recharge is one of the main methods for increasing the sustainable yield of a groundwater body [1][2][3]. Especially under climate change conditions, managed aquifer recharge systems could be more effective than increasing surface reservoir capacities [4] and could also be the most economically and socially feasible solution for the integrated management of water resources [5].…”