How to make a big lake in Unity Scene?

My design talents is very poor.But I want to make a big lake with Unity prefabs.What can I use?

 

Are you using a premade water asset? Do you need to be able to go under water as well? My experience with different water systems is they are all implemented very differently. As far as "Unity prefabs", as in from Unity themselves, I believe the last one they put out was the Unity 4 Water prefab included in Standard Assets. But since that prefab hasn't been updated since Unity 4.x, I'd be very surprised if it was working today. You might take a look at available water systems on the Asset Store, and see if one meets your requirements.

 

I looked at whole prefabs related to sea.But I didn't find any prefabs inside my mind.