The result of the tidal force is a stretching and squashing of Earth. This is what causes the two tidal bulges.

Tides - Met Office Tides - Met Office

Engineers have known for at least a century that tides can change locally. In 1899, builders predicted that tides would increase in the river Ems upstream from a weir they planned to construct. (After the weir was built, the tides did increase about as much as they were expecting.)As Earth rotates, the moon's gravity pulls on different parts of our planet. Even though the moon only has about 1/100th the mass of Earth, since it's so close to us, it has enough gravity to move things around. The moon's gravity even pulls on the land, but not enough for anyone to tell (unless they use special, really precise instruments). But those changes also changed the rhythm with which tides ebbed and flowed into the river from the sea. Those shifting tides stirred up sediment from the river bottom and muddied its waters. Over the last 120 years the tidal range – the distance between high and low tide – has quintupled in the Ems estuary. Several cities in the delta, including Guangzhou and Shenzhen, are among the world’s most vulnerable to rising water levels, says De Dominicis. Knowing how high the water levels could rise can help planners build better barriers and other coastal defenses. Changing tides affect coastal residents in many ways. Someone who wants to sail a tall ship under a short bridge has to wait for just the right tidal conditions. Someone who wants to build a riverfront home in an estuary has to know exactly where the high-tide mark is. Someone designing a tidal-energy system needs to know how much energy they can extract from the water flows. And that’s where the study of changing tides can help people prepare for a changing world, Talke says.

Tides - National Geographic Society Cause and Effect: Tides - National Geographic Society

This article originally appeared in Knowable Magazine, and is republished under a Creative Commons licence. I enjoyed this collection of poetry a lot! It’s an especially nice collection to read a few poems from at a time. It’s soothing and intense but didn’t overwhelm me which... I guess could sometimes be a positive and a negative thing.Separated into two parts, the exploration of losing oneself and then the rediscovery in the aftermath of an abusive and toxic relationship. But those changes also changed the rhythm in which tides ebbed and flowed into the river from the sea. Those shifting tides stirred up sediment from the river bottom and muddied its waters. Over the last 120 years the tidal range — the distance between high and low tide — has quintupled in the Ems estuary.