The most common and most likely answer to this crossword clue is the 8 letter word TELEMARK
I've seen this crossword clue in Financial Times
T
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More clues leading to the result TELEMARK
Buddy explains!

The straight part
We know that "where hydroplant destroyed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case where hydroplant destroyed = telemark.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TELEMARK mean?
TELEMARK noun- Telemark skiing, a method of skiing using the telemark turn and a binding that only connects the boot to the ski at the toes.
- A telemark turn.
- (ski jumping) A telemark landing.
- To take part in telemark skiing.
- To perform a telemark turn.