Boy that does stink. How old is your battery? It looks like you took off after 5 minutes and the battery at that point was at 16.6v or around 95%, 7 minutes later your battery had fallen to 14.7 to 14.6v or 35-40%, still above LVC (low voltage cutoff) so either way you shouldn't have lost control but it looks like the battery really started to fall off at the last 1.5 minutes of flight.
How deep is the water way? I wonder if you might be able to net it if you drag back and forth a few passes or do you have any friends who are divers? At least it wasn't in the Ocean.
Then again, maybe Yuneec will look at the logs and send you a replacement.
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