There is a passage in Ramayana too that mentions Rama being engaged in “forming” the wet region named Pushkara, presumably by creating a fresh water source there, in the midst of a desert (Maru-kantara) that lay to the north of Lavana-sagara, the saltwater-sea.
The verses below describes a terrible drought, as informed by Sage Vishwamitra.
Mbh.12.206 : “Towards the end of Treta and beginning of Dwapara, a frightful drought occurred, extending over twelve years. There was no rain. The planet Vrihaspati (Jupiter) was retrograde and the Moon was at its southernmost point. Not a dew-drop could be seen, what to speak of clouds gathering ? The rivers shrank to being mere narrow streamlets. Everywhere the lakes, wells and springs had gone dry.
“With life having become impossible, the charitable outlets became desolate and dysfunctional. The Brahmanas abstained from sacrifices and stopped reciting the Vedas. They no longer uttered Vashats nor performed other propitiatory rites. Agriculture and cattle-keeping were given up. Markets and shops were abandoned. Stakes for tethering sacrificial animals disappeared… All festivals and recreational occasions came to be unheard of. All over, heaps of bones were visible; and every place resounded with the shrill cries and yells of fierce creatures. The cities and towns of earth became ghost towns.
“Anarchy prevailed; villages and hamlets were burnt down. Some were set upon by robbers, some were taken over by the weapon-bearing, and some were plundered by cruel kings. But, in the end, they all flew away in fear of one another. Temples and places of worship became desolate. The aged were forcibly turned out of their houses. Kine, goats, sheep and buffaloes fought for food and perished in large numbers… Herbs and plants died. The earth was shorn of all her beauty and looked painfully awful, like the trees in a crematorium. In that period of terror, when righteousness was nowhere, men in hunger lost their senses and began to eat one another.”
It is likely that such drought and famine visited the land a number of times … until it turned arid and into a desert.
Mbh.9.49 too mentions a twelve year drought, when Vedic traditions were disrupted. Sage Saraswata is said to have revived the Vedic practice by teaching the Vedas to Brahmanas, who had lost the knowledge through their constant migrations.
Also related : A groundwater civilization – the history of the well