Temporary current running through place underground close to dam (7)
I believe the answer is:
interim
'temporary' is the definition.
(similar in meaning)
'current running through place underground close to dam' is the wordplay.
'current' becomes 'in' ('in' can mean current or trendy).
'running through place underground' becomes 'teri' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'close to' suggests the final letters (the 'close' to the word).
The last letter of 'dam' is 'm'.
'in'+'teri'+'m'='INTERIM'
Can you help me to learn more?
(Other definitions for interim that I've seen before include "An intervening period of time" , "not there for ever" , "Stopgap" , ", I'm put in grave situation initially" , "Caretaker" .)