To study the rainfall recharge during effective monsoon period an experiment was conducted during 140 days of effective monsoon in the year 1990 at Kalyani, Nadia district, West Bengal, India. The potential recharging capacity of that soil was found to be 7729 cm by continuous supply of water, while the recharge during the period of effective monsoon after 2 days, 1 day and 1½ days of prolonged saturation by rainfall were found to be 17.44 cm, 39.018 cm and 27.703 cm respectively. It was revealed that the rainfall recharge after 1½ days of saturation by rainfall (i.e. 27.703 cm) was nearly 95.18622% of the average estimated from other empirical formulae.

https://www.researchgate.net/publication/340194132_A_new_approach_for_estimation_of_rainfall_recharge_from_prolonged_infiltration_rate_and_effective_monsoon_period_Dhara_P_K_Panda_S_Datta_D_K_1991