Investigating the Impressibility of Groundwater Level from Infiltration and Seepage in Water Conveyance Channels (Case Study: Boldaji)

Groundwater is the main source of potable water for more than 1.5 billion people throughout the world, including arid and semi-arid regions like Iran. Literature review showed that there is no use of the dimensional similitude and physical modelling for estimating seepage from channels and its effect on the groundwater, yet. Thus, in order to better understand this phenomenon, the current study aimed at investigating the effects of infiltration and seepage on the groundwater recharge at different water level depths. Numerous studies have been conducted to assess the groundwater recharge, such as Yin et al. (2011) that utilized some methods such as the water table fluctuation method and the Darcian flux and water balance method in China. Similarly, using data from some irrigation projects and piezometric level data, Ochoa et al. (2013) evaluated the effects of seepage on the groundwater recharge in New Mexico. Moreover, Demlie (2015) compared the water balance method and the chloride mass balance method to quantify and investigate the groundwater recharge in Ethiopia. In the current research, the earth channel of Boldaji with loamy soil, located in Borujen city, Chaharmahal and Bakhtiari province, was chosen as the prototype. The dimensions of such a channel were transmitted to laboratory models at soil mechanics lab at Shahrekord University. Using dimensional similitude equations, 9 discharges (40-161 l/s) and 4 water-table depths (0.75, 0.8, 0.85 and 0.9 m from soil surface) were converted to the applicable discharges of the model. The results of the laboratory physical model showed that the infiltrated water raised the groundwater 3.5-11 cm. The values of recharged groundwater were, in turn, calculated by means of water balance method and the results showed no suitable estimates of such a method for the trapezoid and triangle cross-sections.