40d Talk:River

I think the image should be edited... the light blue rivers are streams, not brooks. Brooks are actually invisible on the region map, only visible on local. Only a minor issue though, but it can cause confusion. Lightning4 16:49, 16 November 2007 (EST)

River Mechanics

I want to clean up the "other facts" section an make it a little more organized. I recently dammed a river to build the entrance to my fortress in the middle of the river, and discovered several things that the article didn't quite explain (I updated the language to clarify it, but it's still a little disorganized.) Here are the important things:

• River source tiles function essentially like aquifer tiles. Further experimentation should try to see if they have a greater refill rate or not.
• Also like aquifer tiles, river source tiles cannot provide enough pressure to rise above the level they are on.
• A river, like an aquifer, can absorb an unlimited amount of water.

These three facts taken together lead to a significant exploit. If you build a solid wall of pumps pumping against the current, the river can actually be drained back into itself. I did this with a river in a sunken channel, so water draining off to the sides wasn't an issue, but the water drained back into the river within 6 tiles (on a 20 tile wide river.) It therefore follows that very short walls on both sides of the river could easily be built to contain the water until it drains back in on another map. If you don't want to use this exploit, it takes a little more work, but you can use the same basic structure to divert the river into an aquifer if you have one.FlyingBishop 22:44, 15 October 2009 (UTC)

2967067655

The "cave river" in seed 2967067655 is a short segment enclosed in solid rock, that comes from nowhere and "falls away" into open space at both ends - open space that doesn't extend to the level below. Is this typical of 0.27.169.33? If so, I'll have to put all my cave river plans off to a future version. Kidinnu 09:54, 14 November 2007 (EST)

That sounds very strange. The cave rivers I've seen are sourced from a "mysterious area" and usually either continue off the map or fall off the bottom. They also tend to go through several lowerings of their elevation. Are you sure you fully explored it? VengefulDonut 10:03, 14 November 2007 (EST)

I don't know where this should be mentioned, but there is a huge difference on my machine between FPS on maps with brooks and maps with rivers. I've got a 3.4ghz and 2 gig ram, and my FPS on a map with a river drops to 15-20 right off the bat, where it stays in the high 50's until 30-40 dwarves with only a brook. -- unsigned, but written by Gotthard, according to page history.

I added a bit about temporarily draining and permanently damming rivers and linked to a movie I recorded of doing just that. I think there are ways that would be easier on the dwarves and less micromanagey - one way, perhaps, may be to blast a 3-wide section of the river floor, instead of a 1-wide one, and then build floors in the middle column, and then build floodgates on top of those - that should keep the pesky backflow (which made installing the floodgates so arduous) from interfering with the damming. --SL 00:28, 30 November 2007 (EST)

"Cave river"?

Is there anywhere in the game that these are called "cave rivers"? Or is this purely from this discussion?--Albedo 06:33, 30 May 2009 (UTC)

Draining brooks

I made following experiment:

• 1. Built a bridge over brook, the brook flowed from left to right
• 2. Built walls for the bridge
• 3. channeled under right wall
• 4. I then removed floors between walls of the bridge so that walls would fall in the brook

Purpose of this experiment was to drain the river. I made two walls to see what happens when I drop wall on the brook tile, and when I drop walls on brook tile that has been dug out. I was expecting to see my left wall intact on the brook, like if I had built the wall right on top of brook tile. And to see my right wall intact at the bottom of the brook where I had channeled out the brook.

Setting, before removing any parts of the bridge.

█	Z	█	-	1	█	█	█	Z	█	█	0	█	█	█	Z	█	█	1
█	█	█	█	█	█	█	.	.	▲	.	.	█	█	.	.	▼	.	.
█	█	█	█	█	█	█	.	.	.	.	.	█	█	.	.	+	.	.
7	7	7	7	7	█	█	≈	≈	≈	7	~	█	█	.	█	+	█	.
7	7	7	7	7	█	█	≈	≈	~	7	≈	█	█	.	█	+	█	.
7	7	7	7	7	█	█	≈	≈	≈	7	≈	█	█	.	█	+	█	.
7	7	7	7	7	█	█	≈	~	≈	7	≈	█	█	.	█	+	█	.
█	█	█	█	█	█	█	.	.	.	.	.	█	█	.	.	+	.	.
█	█	█	█	█	█	█	.	.	▲	.	.	█	█	.	.	▼	.	.

Both walls fell to the bottom of brook and fell apart into blocks I had used to build the walls. This wasn't such a terrible surprise to me. What was a surprise was that the walls which had fell through walkable brook tiles had "broken" the brook. The game now seems to handle those tiles like they were ending the brook. Water pours in from both ends and simply disappears.

Basically this could be used to create more tiles for water to pour out of map...

--Athan 13:17, 15 April 2008 (EDT)

Unfound Underwater River

on my old fortress i used to have alot of 'Deceased' creatures like snakemen and lizardmen popping up on the Creatures Menu. Why are they popping up when i can't see the underground river? – unsigned comment by Hoborobo

It's an exploit (I think), wait a season then zoom to a body part of these dead creatures and dig to that location to uncover it. – unsigned comment by LrZeph

Specific Location

It seems like cave rivers (the tiles that actually have water) are only found 1 z-level below the base of a mountain. Is this true? If it is it might be helpful to add that to the page... – unsigned comment by Xonara

Doesn't look like it. My cave river is 19 z-levels above "ground zero".--Maximus 03:14, 25 October 2008 (EDT)

Oh OK, thanks. --Xonara 03:56, 25 October 2008 (EDT)

River Source tiles

On my map a four tile wide river starts at the north edge of the map, winds around then branches into about six one tile wide fingers. The flow is from the fingers out to the north edge. At the tip of each finger is a tile marked "River Source". Some of these are above ground and some are just inside the mountain, one z-level from the surface.
The source looks something like this, I've shortend it a bit, with the water flowing up.

 RRRR                   R   River
 RRRR                   S   River Source
 RRRR
 RRRRR
  RRRRRR
  RRRRRRRR
  RRRRRRRRRR
  RR RRRRRRRRR
  RR RR RRRRRRRR
  RR RR   RRRRRR
  RR  RR   RRR RRR
  RRR  RRR  RR   RRR
  R R  R R  R R    RRR
  R S  R R  S S      RRRS
  S    S R
         S

I haven't seen mention of these River Source tiles before. I mention it because the article says "rivers presumably contain an unlimited amount of water and cannot be drained." Well, now we have a source for all that water. I'm going to dam each of the river sources, should be easier to dam each of the single tile fingers then the river itself, gaining full control over the river. Then I can close off all but one to see what the rate of flow is. I count eight source tiles feeding my four tile wide river.
--Schwern 04:03, 14 December 2008 (EST)

Depends on how much drain you put on the system. Merely falling off the map edge a few dozen tiles away is probably something that a single water source tile can handle. River source tiles do not appear under that name but are on all maps with a river: a row at the side of the map from which the water flows. They also work a lot like aquifer tiles. --Savok 09:50, 14 December 2008 (EST)

River Source tiles also appear for brooks --Calculator

River Sinks

I'd like to redirect my river out a different side of the map... Since it's on a plateau I can easily redirect it to the valley on one edge of a map, but is it confirmed that water reaching the edge of the map will spread off of it? And, if so, how do I efficiently get that water right to the very edge, given that I can't channel (or, I assume build walls) on the last row at the edge of the map? Similarly, I assume I can't channel through the lowest level of the map to make my own chasm, right? Thanks! Freshyq314 20:52, 28 January 2009 (EST)

It is possible to carve fortifications in the map edge. Do this after digging a new river bed, and voila. You directed the river.--Zchris13 01:07, 16 October 2009 (UTC)

Redirecting brooks and rivers

I am currently experimenting with ways to redirect a brook. Using screw pumps turned out to be unfeasible. I'm going with the "punch a hole in the bottom of the river" method. I intend to do this in two places at the same time, just in case water would flow backwards up the river to "water" my tiles. Now, using the "Underground Room" method works well (but takes a lot of digging and timing) because when the room is full, the water will fill up to the next Z-level and start flowing again on its own. The alternative is to use an "infinite outlet" way, like a chasm or fortifications at the edge of the map - but I guess a problem might be creating new floors in the river to replace the ones destroyed. My current bet is to build 4 raisable bridges at the Z-level below the "hole punch" point, surrounding it, and a channel to a chasm. When work is done, raise the bridges, create a nice little reservoir, and the river flows again. 158.143.137.8 21:58, 15 November 2009 (UTC)

Disaster strikes! - firstly, when trying this, make sure that the construction to punch a hole in the brook does not land close to one of the damming bridges on the level below, or the bridge gets destroyed. Secondly, even when the artificial reservoir is filled to 7/7, it does NOT cause the water to rise to the level above and the river to flow again! I am currently experimenting with building floors to replace the holes in the river...158.143.137.20 19:23, 17 November 2009 (UTC)

Also worth looking at is... flooding, and water pressure 127.0.0.1 02:23, 19 February 2010 (UTC)