Daily Reading: Srimad Bhagavatam page-60

SB 1.3.14

ṛṣibhir yācito bheje
 navamaṁ pārthivaṁ vapuḥ
dugdhemām oṣadhīr viprās
 tenāyaṁ sa uśattamaḥ

Translation: 

O brāhmaṇas, in the ninth incarnation, the Lord, prayed for by sages, accepted the body of a king [Pṛthu] who cultivated the land to yield various produce, and for that reason the earth was beautiful and attractive.

Purport: 

Before the advent of King Pṛthu, there was great havoc of maladministration due to the vicious life of the previous king, the father of Mahārāja Pṛthu. The intelligent class of men (namely the sages and the brāhmaṇas) not only prayed for the Lord to come down, but also dethroned the previous king. It is the duty of the king to be pious and thus look after the all-around welfare of the citizens. Whenever there is some negligence on the part of the king in discharging his duty, the intelligent class of men must dethrone him. The intelligent class of men, however, do not occupy the royal throne, because they have much more important duties for the welfare of the public. Instead of occupying the royal throne, they prayed for the incarnation of the Lord, and the Lord came as Mahārāja Pṛthu. Real intelligent men, or qualified brāhmaṇas, never aspire for political posts. Mahārāja Pṛthu excavated many produces from the earth, and thus not only did the citizens become happy to have such a good king, but the complete sight of the earth also became beautiful and attractive.

SB 1.3.15

rūpaṁ sa jagṛhe mātsyaṁ
 cākṣuṣodadhi-samplave
nāvy āropya mahī-mayyām
 apād vaivasvataṁ manum

Translation: 

When there was a complete inundation after the period of the Cākṣuṣa Manu and the whole world was deep within water, the Lord accepted the form of a fish and protected Vaivasvata Manu, keeping him up on a boat.

Purport: 

According to Śrīpāda Śrīdhara Svāmī, the original commentator on the Bhāgavatam, there is not always a devastation after the change of every Manu. And yet this inundation after the period of Cākṣuṣa Manu took place in order to show some wonders to Satyavrata. But Śrī Jīva Gosvāmī has given definite proofs from authoritative scriptures (like Viṣṇu-dharmottara, Mārkaṇḍeya Purāṇa, Harivaṁśa, etc.) that there is always a devastation after the end of each and every Manu. Śrīla Viśvanātha Cakravartī has also supported Śrīla Jīva Gosvāmī, and he (Śrī Cakravartī) has also quoted from Bhāgavatāmṛta about this inundation after each Manu. Apart from this, the Lord, in order to show special favor to Satyavrata, a devotee of the Lord, in this particular period, incarnated Himself.