Each second flood covers small part of Manhattan (4,4)

'part of manhattan' is the definition.
'east side' can be an answer for 'part' (east side is a kind of part). I am unsure of the 'of manhattan' bit.

'each second flood covers small' is the wordplay.
'each' becomes 'ea' (abbreviation).
'second' becomes 's' (common abbreviation).
'flood' becomes 'tide'.
'covers' is an insertion indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tide' going around 's' is 'tside'.
'ea'+'s'+'tside'='EAST SIDE'

Can you help me to learn more?