Abstract
Abstract. The effect of future climate scenarios on surface and groundwater resources was simulated using a modeling approach for an artificial recharge area in arid southern Iran. Future climate data for the periods of 2010–2030 and 2030–2050 were acquired from the Canadian Global Coupled Model (CGCM 3.1) for scenarios A1B, A2, and B1. These scenarios were adapted to the studied region using the delta-change method. A conceptual rainfall–runoff model (Qbox) was used to simulate runoff in a flash flood prone catchment. The model was calibrated and validated for the period 2002–2011 using daily discharge data. The projected climate variables were used to simulate future runoff. The rainfall–runoff model was then coupled to a calibrated groundwater flow and recharge model (MODFLOW) to simulate future recharge and groundwater hydraulic heads. As a result of the rainfall–runoff modeling, under the B1 scenario the number of floods is projected to slightly increase in the area. This in turn calls for proper management, as this is the only source of fresh water supply in the studied region. The results of the groundwater recharge modeling showed no significant difference between present and future recharge for all scenarios. Owing to that, four abstraction and recharge scenarios were assumed to simulate the groundwater level and recharge amount in the studied aquifer. The results showed that the abstraction scenarios have the most substantial effect on the groundwater level and the continuation of current pumping rate would lead to a groundwater decline by 18 m up to 2050.
Highlights
Groundwater (GW) is the major source of fresh water for humans
It is noted that daily time steps were used in the climate variable and runoff projections, but a monthly time step was used in the GW recharge projection
In the future scenarios, there are no significant changes in the climate variables during the spring and summer seasons relative to the historical climate
Summary
Groundwater (GW) is the major source of fresh water for humans. GW reserves constitute more than 70 % of water supply in arid environments (Rosegrant and Ringler, 2000; Llamas and MartínezSantos, 2005; Siebert et al, 2010; Surinaidu et al, 2013) often being depleted due to over-extraction for irrigated agriculture. Due to climate change, it is anticipated that GW will be increasingly important in arid areas due to extended drought periods (IPCC-TGICA, 2007) that most likely will lead to less surface water availability. As many GW reservoirs are non-renewable on meaningful timescales for human society (Kløve et al, 2014), climate change adaptation through aquifer management is an urgent need to balance and, especially, rehabilitate already depleted aquifers. There are techniques that can be employed to artificially recharge the GW by diverting runoff from a river channel to the designated recharge area, e.g., spreading basin, infiltration pond, or injection well
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