Not much of an answer, but Its something to do with the moon and gravity.
Hope that helps
the moon
High tides, low tides, spring tides (which are maximum high tides) and neap tides (which are the lowest of low tides).
both spring tides and neap tides have a 20% difference from normal tides
Minimum tides are also known as low tides. It's the lowest a tide will get in the cycle of highs and lows.
Semi diurnal tides occur twice a day (2 low tides, 2 high tides) and diurnal tides occur once (1 high tide one low tide) per day.
Fifteen thousand feet.
A neap tide happens during the quarter phase of the moon and they are weak tides. There is a very small difference between high and low tides during this time.
They consider high and low tides in their journey because if it is high tide the water level will be high but if it is low tides the water level is low.
Low tides
Jo mama
tidal range
neap tides are moderate tides at normal rates while spring tides are more extereme ex to high or to low .