Daily Reading Notes

Tides

Day 5

Posted on 2019-03-07

Most tides are slow moving. Even the largest and fastest once take round 6 hours to come in. However, when the conditions are just right, there are exceptions to the rule. These exceptions are called Bores and occur on rivers with just the right shape.

Many rivers get minor waves caused by the tide at their opening towards the ocean, but there are rivers that get hit with giant waves. These rivers have a cone shape opening towards the ocean that causes the wave to accelerate down river. The most famous one is the Qiantang River Bore.

It is a massive wave that come in at over 25 feet during the spring tides. It relentlessly rips through the river for almost 40 miles. Before people understood the cycle of the tide, this bore destroyed entire villages and killed many people.

Even so, like people always do, the residents of this region adapted with the river. They developed tide table, or wave tables in this case, that predated any western tide table by almost a century. Using these tables, they could build houses on one side of the river and move to other when the tide changed direction with the seasons.

It’s amazing how far and quickly necessity can drive progress. Figuring out a complex topic like the tides because of hardship is the ultimate testament to human perseverance.

Tides