Natural vs. artificial groundwater recharge, quantification through inverse modeling

Abstract

Abstract. Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady- and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events, the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system, the recharge volume can be increased even for small flood events, while the recharge through the river channel increases only for major flood events.

Traditional irrigation techniques in MENA with focus on Tunisia

“…Nomadic pastoralism and transhumance are adaptations to seasonal variation in water and vegetation availability. To have the summer and winter quarters in two different regions creates balance and is a sustainable use of the arid ecosystem with scarce natural resources (Hashemi et al 2013). The policy of national integration of nomads in order to develop the country economically, however, has forced nomads to settle in the vicinity of villages and towns.…”

“…A government sponsored project designed a floodwater harvesting system to artificially recharge the groundwater and to irrigate the soil. The designed system uses artificial recharge and spate irrigation as a technique to combat desertification and rehabilitate the water resources and rangelands of the region (Hashemi et al 2013).…”

“…CONTACT R. Berndtsson ronny.berndtsson@tvrl.lth.se Hashemi et al 2013). In fact, along with the population growth, water resources for food production are exposed to severe stress and have become an important topic for science and politics as well as for the general public in these countries (Mader et al 2015).…”

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

“…This can, in principal, be due to (1) the recharge parameters assigned in the prediction model and (2) the boundary conditions assigned in the calibration periods. As discussed by Hashemi et al (2013), the river channel exhibits a high infiltration rate in the case of major flood events relative to the artificial recharge area. Yet, the average value of the river bed's recharge rate was transferred to the prediction model; therefore, the river channel was assumed the main recharge contributor in all future scenarios.…”

“…Hydrologic model structure and parameters uncertainty. Uncertainty and model sensitivity analyses regarding the GW recharge model were documented by Hashemi et al (2012Hashemi et al ( , 2013. Regarding the rainfallrunoff model, there is a degree of uncertainty mainly associated with input parameters, as they are collected from an adjacent basin, however, with great similarity to the studied basin.…”