We created the lower section of our gameplay area to be the water level or where water will be. This can be a useful tool as a level designer to designate places that players can't go to if you can't swim. Thankfully, it's also quite easy to add to our level, and due to it being included with Unity, we won't need to go to the Asset Store to get it.
Standard Assets/Environment/Water/Water/Prefabs
folder to then drag and drop the WaterProNighttime
prefab into the scene.250, 90, 250
and give it a Scale of 250, 1, 250
so it covers the entire area. Next, in the Water Script component from the Inspector tab, change Water Mode to Reflective. This will make it so instead of seeing what's underneath the water it will instead reflect what's around us.