Translation:I wait at the gracht at a quarter to eight.
I just can't resist attempting a translation with three words rhyming, just like the Dutch sentence. Here goes: "I'll wait at the gracht for our date at a quarter to eight." If you feel like outdoing (?) the Dutch sentence, you could even add one more rhyme: "Don't be late!" Romantic, right? I don't expect it to be accepted by Duolingo, though...
Actually, German tends to have a more harsh pronunciation than Dutch. To Dutch people, German sometimes sounds like someone is trying to speak Dutch whilst being very angry.
I have been told that to Swiss people Dutch sounds like a drunk person trying to speak in Schwizerdütsch.
Perhaps "gracht" is a basic idea about something. A park can be a bench and a garbage can, or something with many benches and swings and those little metal rides mounted on automobile suspension springs on which kids throw themselves around. A meal can be steak and potatoes, or there can be bread and salad and soup and I'm hungry now! So perhaps gracht is just a basic idea, and it's up to the listener to ask for further details.
Actually, rather the other way around! :-) Wikipedia correctly defines canals as "human-made channels for water", a definition that applies to a gracht as well. It's a specific kind of kanaal, 'city-canal' would be a good description, because in the Netherlands they're usually in the city (Utrecht, A'dam, Groningen...). In general, I picture kanalen being outside of the city. Take a look at some pictures: kanaal vs gracht