Parallel drainage pattern. A parallel drainage system is a pattern of rivers caused by steep slopes with some relief. Because of the steep slopes, the streams are swift and straight, with very few tributaries, and all flow in the same direction.
1 In Creative, the player can use spawn eggs to spawn most mobs. 2  When mobs are spawned this way, all normal spawning requirements, such as light level and block type, are ignored. 3  Any entity can be spawned using the /summon command.
Answers. 1  It is good, make sure the ceiling is 5 blocks high or more, also i would recommend making an area about 50x50 to 75x75 so as to make sure they will spawn, also, no water is needed and light level doesn't matter... although it would limit the amount of other mobs spawning. User Info: GoIdenAce.