Water Levels (high and low tides)

Water Levels (high and low tides) is a Known Occurrence in Salmon Run.

Description
Before a wave begins, the water level in the area will begin to rise or fall. When it rises, this is known as high tide, and when it falls, this is known as low tide. This mimics the real-world phenomenon of tides.

During high tide, the walking area will be more limited. In this small space, it can be easy to be overwhelmed due to multiple factors, including but not limited to the player or their teammates falling into the water and splatting, losing access to walls facing the waters, or just simply being overpowered by so many enemies in a small space.

During low tide, a new area of the shore will be uncovered. When this happens, the egg basket will be in this area and Boss Salmonids will only spawn in there. An additional occurrence known to accompany low tide on occasion is the Cohock Charge, where, during the wave, the only Lesser Salmonid that spawns will be Cohocks. In the event of this occurrence, Ink Cannons are provided to better handle the situation.

The water level is telegraphed by the water-like overlay that appears over the bottom of the screen at the beginning of each wave for 5 seconds. When the overlay just reaches the bottom of the banner showing what weapon the player will be using, the tide is at its normal level. A lower overlay (nearly at the bottom of the screen) indicates a low tide, and a higher overlay (almost to the top of the weapon banner and the bottom of the green countdown) indicates a high tide.

The chance of a wave being at high and low tide is 20% each, while the remaining 60% is mid-tide.

Salmonid Field Guide
The following text is quoted from the Salmonid Field Guide.
 * Low Tide
 * When the tide goes out a large amount of land that is usually underwater will be exposed.
 * Salmonid warriors use this land as a staging ground from which to launch coordinated attacks.
 * During low tide, the egg basket will be near this newly exposed land.
 * High Tide
 * When high tide is in, there'll be much less land available.
 * The egg basket will be in its normal place.
 * Advice from Mr. Grizz
 * During low tide, you gotta get together and move, move, move down to that exposed land, kid!
 * During high tide—I don't care how hard it is—you gotta survive against those Salmonids!
 * Supplementary Information
 * The sudden and irregular changes in the water levels are a rare phenomenon found only in this area.
 * The cause is as yet unknown, and is the subject of much research throughout the academic world.