They dread springs becoming dry (9)
I believe the answer is:
dehydrate
'dry' is the definition.
(dehydrating is a kind of drying)
'they dread springs' is the wordplay.
'they dread' anagrams to 'DEHYDRATE'.
Though, I am not clear how the anagram is indicated.
'becoming' acts as a link.
Can you help me to learn more?
(Other definitions for dehydrate that I've seen before include "Remove moisture content from, dry out" , "Drain" , "Remove moisture from, make dry" , "Remove water from" , "Preserve by removing all liquid from" .)