Legal Definitions - spring tide

Spring Tide

A spring tide refers to the exceptionally high and low tides that occur when the Earth, Moon, and Sun are aligned. This alignment happens twice a month, specifically during the new moon and full moon phases. When these celestial bodies are in line, their combined gravitational pull on the Earth's oceans is at its strongest, resulting in a greater difference between high and low water levels than during other times of the month. This means high tides are higher than average, and low tides are lower than average.

• Example 1: Coastal Flooding Risk

  During a full moon in October, a coastal town known for its low-lying areas issues a flood advisory. Even without significant rainfall or storm surge, the combination of the full moon's gravitational pull and the typical autumn high tides creates an unusually high water level, causing minor flooding in streets closest to the harbor. This scenario illustrates a spring tide because the alignment of the sun, moon, and earth during the full moon phase leads to a higher-than-average high tide, increasing the risk of coastal inundation.

• Example 2: Marina Operations

  A captain planning to dock their sailboat in a shallow marina channel consults a tide chart. They notice that during the upcoming new moon, the predicted low tide is significantly lower than usual, potentially exposing mudflats and making the channel impassable for their keel. To avoid grounding, they adjust their arrival time to coincide with a higher tide. This demonstrates a spring tide because the new moon's alignment with the sun and earth creates an exceptionally low low tide, which impacts navigation and requires careful planning for vessels in shallow waters.

• Example 3: Beachcombing and Marine Life Exposure

  A group of marine biology students visits a rocky intertidal zone during a full moon. They observe that the water has receded much further than usual, exposing a wider array of tide pools and marine organisms, such as sea stars and anemones, that are typically submerged. This allows them to study species usually inaccessible. This situation exemplifies a spring tide because the combined gravitational forces during the full moon result in an extremely low tide, revealing more of the seabed and its inhabitants than on an average day.