Culvert banner

Zs culvert
Compatible Modes
Zombie scenario
Nexon logo

Room degree easyRoom degree normalRoom degree hard

Max Player Count


Map Size


Release Date

South Korea
23 February 2012

Taiwan/Hong Kong
6 March 2012

7 March 2012

14 March 2012

12 September 2012

7 November 2012

23 September 2014

26 March 2015


Sewage Treatment Plant





Map Textures


Basement Culvert (zs_culvert) or Groundwater (for Vietnam region and Counter-Strike Nexon: Zombies) is the second Zombie Scenario: Season 2 map in Counter-Strike Online. It is survival-based instead of pursuit-type.


Time after chasing the wounded Dione

Hello. This is Senior Researcher Soy from Aegis Institute. Unfortunately, we've missed a chance to capture Dione. However, it has been badly injured by us. I've received an order from the headquarters to continue the pursuit. We are requested to capture it alive but if that is impossible, we can kill him. Let's do our best, everyone!

LS team found Dione hidden inside the culvert after their continuous pursuit and have tired to capture him. However, Dione noticed it and went hiding into the darkness. At the same time, countless zombies are coming from everywhere to welcome the LS team.


Culvert takes place in a big sewage treatment plant with a very horrible atmosphere. Not only do the players need to kill the zombies all around the sewers, but also need to dodge Dione's rolling from side to side and survive until the last round. Dione will attack occasionally and will become more powerful as time passes. It only starts to attack from Round 5 and above.

Zombies will appear from 4 sewers, same as Lost City.

There are a total of 15 rounds. The time for each round is 3 minutes. So the whole game will take more than 45 minutes, plus freeze time. The time taken also depends on the strength and/or the number of retries by the whole team.

Rounds & Tactics

  • Round 1: Regular Zombies appear.
  • Round 2: Light Zombies and Regular Zombies appear.
  • Round 3: Host Psycho Zombies, Light Zombies and Regular Zombies appear.
  • Round 4: Voodoo Zombies, host Psycho Zombies, Light Zombies, Regular Zombies and Dione appear.
  • Round 5: Voodoo Zombies, host Psycho Zombies, Light Zombies, Regular Zombies, two Juggernauts and Dione appear.
  • Round 6-7: Heavy zombies, Voodoo Zombies, host Psycho Zombies, Light Zombies, Regular Zombies and Dione appear.
  • Round 8-10: Origin Zombies (Heavy, Light and Psycho), Enhanced Zombies (orange), Throw-type Zombies (green) and Siege Type Dione appear.
  • Round 11: Bonus round, Pierrots appear only.
  • Round 12-14: Same as round 8-10.
  • Round 15: Same as round 8-10. Be careful in last minutes, Siege Type Dione comes out with many tentacles.


  • Always run in the same direction to avoid being trapped by the zombies. Players are recommended to run in clockwise direction.
  • Player can 'camp' at the left or right or any of the four pipes to farm health and damage quickly.
  • Lightweight guns are suitable for killing and running from zombies.
  • M79 Saw Off is recommended for running & surviving purposes.
  • Focus on Siege-Type Dione while he's collecting the poison and jump at the right time to avoid being hit.
  • Avoid being hit by Siege Type Dione while he curl up and roll to another spot. You will die instantly if you get a direct hit.
  • In Round 4, Dione will only come rolling at certain directions.
  • In Round 9, Dione will start spitting poison.
  • There is a bug when a player uses Bendita to shoot Dione, he/she can clear the round before the time ends. This bug was fixed in Zombie Scenario Update 2016.


  1. This is Alpha team. We've found Dione. Dr. Soy, please answer me.
  2. Soy: It is Dione. It seem to be injure pretty badly. Capture him alive!
  3. Soy: Ah! Oops! We’ve lost him again.
  4. Soy: It still have the ability to move so fast even it was badly injured. Lets continue in our pursuit.
  5. Soy: What is that? Zombies!
  6. Soy: I think zombies are coming from somewhere connected with the Culvert!
  7. Soy: Give up the pursuit for now. We need to survive this raids first!
  8. Soy: Survive until the backup force from headquarters arrived!
  9. Soy: Look at the big waterway over there! That is Dione!
  10. Soy: Wait a minute. I’ll try to communicate with it.
  11. Soy: Dione is going to attack us. Be careful!
  12. Soy: Ah, what is this sound?
  13. Soy': Dione is right on top of us! It's collecting the poison! Run!
  14. Soy: Dione’s look different. I don’t have a good feeling about it. Please be careful!
  15. This is Alpha team. We can't hold anymore longer from the zombie attack. Where is the backup force?
  16. Soy: The backup force is reaching soon. Please hold on.
  17. Soy: How can this be.. Dione’s outlook has changed completely!
  18. Soy: It looks very dangerous. Be careful!
  19. Soy: Dione has disappeared into the waterway!
  20. Soy: Although with the hostile force, it is a blessing that Alpha team is still alive.
  21. Soy: Combine with the backup force and reform your battle formation. We need to pursue Dione.
  22. Soy: I think we will have an ideal soon if this culvert is connecting to another hideout.


Honor mission

Title Description Task
Gentleman! Do you think you have the tenacity to survive Zombie hoards and Dione inside a dark and narrow Culvert? Love a challenge? Prove to me that you can survive till the end under any type of situations. Note: Easy stage is not included. Survive the Culvert 100 times.


Culvert was released on:

  • South Korea: 23 February 2012.
  • Taiwan/Hongkong: 6 March 2012.
  • China: 7 March 2012.
  • Japan: 14 March 2012.
  • Singapore/Malaysia: 12 September 2012.
  • Indonesia: 7 November 2012.
  • CSN:Z: 23 September 2014.
  • Vietnam: 26 March 2015.



Radio tone

Dione metamorphosis

Dione's metamorphosis

Zombie Scenario Season 2 - Culvert

Zombie Scenario Season 2 - Culvert

CSO Toxicity, Culvert Trailer

CSO Toxicity, Culvert Trailer

CSO SEA Culvert Revisited Get down and dirty again with M32 (QuatermainJr ft

CSO SEA Culvert Revisited Get down and dirty again with M32 (QuatermainJr ft. GlacialSmile)


  • Culvert is a sewer or drain crossing under a road or embankment.
  • Phoenix in classical mythology is a unique bird that lived for five or six centuries in the Arabian desert, after this time burning itself on a funeral pyre and rising from the ashes with renewed youth to live through another cycle. It is also referred as Ababil in classic Arab literature.
  • In this map, Dione had evolved into Siege Type Dione and later escaped to finally evolve into Angra in the next chapter.
  • During initial releases, a strange blood comes out if you attack the center of the map with certain melee weapons. This easter egg also can be performed in Trap, Another Truth and Last Ride (boss arena only).
  • After Zombie Scenario Re:boot, you will meet 2 or 3 Siege Type Diones. Moreover sometimes when both of them are rolling one might get stuck in the dummy animation, but later will disappear.
  • The HP bar for the regular Dione may appear at random, and disappear. Despite Dione is being shot at, the HP bar does not deplete at all unless Bendita is used.
    • Using Bendita as Dione is attacking from the top floor will immediately end the round as soon as Dione leaves its attacking position. This is best used during the later half of the rounds, as demonstrated here.
  • After the 26 March 2015 update, this is the only map in Zombie Scenario which has bonus round, also the only map in Zombie Scenario where the Pierrots still appear.