The book remains a comprehensive guide for undergraduate students, covering: Surface Water Hydrology
: He took her to an abandoned well in the backyard. “Estimate the specific yield of this aquifer without any modern equipment.” She lowered a stone, timed the echo, collected a bucket of water, dried it in the sun, and calculated porosity using a kitchen scale and a thermometer. Her answer matched Ramanujam’s hidden data. k subrahmanyam hydrology book pdf updated