8-Evaluation of Recharge Rate of Injection Wells and Effect of Artificial Recharging using Surface Runoff on Ground Water Quality

Abstract

The study was conducted on artificial recharging of groundwater through injection well using surface runoff. The mean injection rate at site-I, where injection well was installed below ground water table (saturated zone), was 21.2 m3clay-1 and at site-2, where injection well was installed above water table (vadose zone), it was 8.04 m3day-1. The results from the present study have shown that recharge rate increased with increase in recharge head and the incremental increase was 20 and 8.66 m3day'lm-1 for the well installed in saturated and the vadose zone respectively. It was also found that injection rate was more for the well constructed in the saturated zone than for the injection well that was installed in the vadose zone as, soil formation of the former case consisted of higher proportion of coarse sand mixed with gravel. The laboratorial study of pre and post recharge groundwater samples has shown considerable change in chemical and biological qualities. The EC and pH values decreased at both site. The post recharge Na and K concentrations were observed to be decreased at site-1 but increased at site-2. Similarly MPN (No./I00m1) and COD (ppm) for site-1 and site-2 were found to be 26, 65 and 110 and 175 respectively whereas for pre recharge water samples corresponding values were 0 and 10.