Coupled modeling approach to assess climate change impacts on groundwater recharge and adaptation in arid areas

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.

Climate Change Impact on Flood Frequency and Source Area in Northern Iran under CMIP5 Scenarios

“…Water 2019, 11,273 10 of 24 results for changes in minimum temperature displayed the lowest variation for all months in RCP 2.6 that was closest to the median. The uncertainty in minimum temperature for RCP 8.5 can be seen for the MIROC-ESM-CHEM.…”

“…For example, urbanization and urban sprawl are likely to increase flood risk. Therefore, assessing the impact of present and future climate also requires estimation of future land use for achieving appropriate adaptation policy [9][10][11]. In this regard, hydrological modeling plays an important role in simulating possible future changes and their impact, hence helping to determine proper watershed management practices [12].…”

“…In view of the above, the potential impact of climate change on flood risk can be assessed using a coupled climate-hydrological model approach [11,[23][24][25]. Therefore, in this study, the Soil and Water Assessment Tool (SWAT) was used to estimate Flood Frequency Index (FFI) in the Talar River Basin located in the south Caspian Sea region.…”

Precipitation Intensity Effects on Groundwater Recharge in the Southwestern United States

“…Because of the episodic nature of recharge in arid environments, small changes in precipitation intensity have been suggested to influence groundwater recharge [26,27]. Recent studies have sought to quantify episodic recharge [28] or identify regional groundwater recharge [10,11,23]. Such evaluations, however, did not identify influences in observed groundwater recharge as a function of precipitation, the primary goal of this study.…”

“…An example illustrating the influence of anthropogenic impacts to natural aquifer discharge rates is the Nubian aquifer in northeast Africa: prior to extensive development, studies documented the natural rate of groundwater depletion of 0.79 km 3 /year [21] to 2.7 km 3 /year [22] while more recent depletion rates of 6.1 km 3 /year have been observed from 2003 to 2013 [11]. Future imbalances of groundwater recharge are expected to occur as a result of variability attributed to climate change, especially in arid regions [9,23].…”