Water physics needs some work with floodgates (at least)

17 Sep, '21
Yonish Admin

This is something we're aware of, currently this is working as intended, as water can fluctuate after hitting a wall (or a floodgate in this example) and some small floods can happen, but we're working on a way to make it calm down faster.

17 Sep, '21
DeathClawz

So if I let it go on it'll eventually settle? It's been 5 days already so I'm not sure if I'll last long enough to see that.

It looks like the floodgates fill too high and then release half a meter of water, but somehow it takes awhile to empty the extra half meter upstream while downstream it refills the entire river and then some before it's done upstream. But then downstream empties very fast, and sometimes even goes dry, while upstream is refilling that half meter to dump back in.

I've realized that's hard to read so here's a list:
1. River started low while upstream filled after dry season
2. Upstream fills to 2m even though gate is at 1.5m
3. Upstream slowly drains, downstream fills fast and then floods
4. Upstream hits 1.5m & stops completely, downstream drains fast
5. Upstream fills back to 2m while downstream drains to very low or dry
6. Repeat 2-4 times a day

Youtube finally cooperated after typing all that so you can watch it for yourself: https://youtu.be/EV9JJbGRLSA

18 Sep, '21
Proply

Yea I have coincidentally set up a very similar arrangement on that map with floodgates upstream of the settlement and a dam downstream, and I get the same behavior. It might be working as intended (expected?), but as a player it certainly isn't intuitive.

18 Sep, '21
Bob the beaver

Same issue with exact same map.
I tried many things to dampen out the oscillation and the answer seems be raise the outer 2 floodgates on each side to 2 and have the middle 4 at 1.5
This evens out the water flow back to the middle of the river.

If you raise them to 2 you can flood most of the upper map and fill in the big round area.
If you go all to 2 during dry remember to put them back down again in the model when wet returns.

The river edges doesn’t slow water and if you watch it the water straight lines as much as possible though curves so when it hits a dam it goes over one first then travels across the width and hits the side and pulses back.

Also since the side as all right angle bits it must reflect all over the place,

Could need some drag or speed reduction if near the bank.

19 Sep, '21
Adam J Lloyd

That's weird, I would say try lowering your flood gate to 0 for now. then in dry season raise it. that might help till something changes in game code

20 Sep, '21
Ghengsta23

I'm having the same problem in the same map. The water comes in waves. I have a floodgate system upstream set at 2.5, almost at half of the lenght of the river. I can clearly see the wave coming down stream. Then once it has past the floodgates, the wave continues down the river to a dam with spillways (tried with floodgates too, set at 0.5) located to a lower altitude. Just after that there is my starting district, which has another spillway system just before the lake. Once the wave reaches my first district it floods almost 50-60% of the land. The depth marker located in the small pond near the first district shows fluctuation between 0.3 to 1.14, I'd say 3-4 times a day.
After writing this, I got an idea and tested it. I replaced some spillways in the 2 dams downstream with floodgates completely open to allow a good flow. Still the same problem.
I can provide a save file too.

22 Sep, '21
Edelmiro

I have the same setup in the same map and the same thing happens to me.
Here is my video: https://youtu.be/w27ugdOcckc
I actually opened a bug report earlier today, I didn't find this one while I was looking for duplicates. I suppose it will get merged into this one eventually.
The strangest/buggiest part for me is that the water in the downstream area empties as if it were climbing up the floodgate...

22 Sep, '21
TheFirstHI

Interesting, I have almost the same setup as you but I have floodgates in all three spots, where as you have (referencing your screenshot) flood gates up top, platforms? near the water wheels, and dam at the bottom try adding floodgates next to the platform? also I agree the flood gate is confusing to use at first but once you figure it out it's really good like an adjustable dam. Basically whatever number you set the floodgate at, the water will flow at above that level. so if you put it at 2.5, the water will overflow at around 2.75 height. if you set it at 2 then it will flow at around 2.25 height. I think that's how it works. Anyway just wanted to leave my comment here as I have a similar setup but no wave issue. Hope it helps!

25 Sep, '21
Lion-Rye

your dam is too tall

25 Sep, '21
Kiranos

I like how the water is reacting. I think the waves are a nice effect. Please let it like this for now.

You could reduce the wave effect by putting dam or floodgate at x.5 in your canals or inlets.
When you release water from a higher altitude, if your canal or river below is already kind of full, it will be too much water at the begining and will overflow, you will have to put some levee on the side at first to contain the water until it spreads out along the canal.

Canal are best with floodgate at x.5 at the end, with a x.5 floodgate at the beginning.
It will allow a constant smooth flow from your reservoir.
When the drough is coming, close the end floodgate, fill up the canal to max and it will maintain for a lots of days without refilling.

25 Sep, '21
Kiranos

@DeathClawz :
your problem is that your floodgate are too high.
The water behing is higher than the ground where it's flooding, and the ground is close to the dam.
You could try to open only a few floodgates near the wall.
Or better, build more upstream, this dam is not really useful.

27 Sep, '21
Brandon Hicks

+1 splitting rivers for irrigation canals is a nightmare to get proper waterflow on all. physics needs update prob.

28 Sep, '21
Jason

What I've been doing is dropping my floodgates to 0 during the wet season and raising them during droughts. There's still a little bit of flooding, but this takes care of 90% of it. Maybe include that in the tutorial/tooltip though?

01 Oct, '21
UristMcKerman

I think I've figured out. I have exactly the same issue in that very particular spot - which I solved by setting up a second row of floodgates set to 1.0 height (first row is at 1.5). Now I don't see flooings that oftn as I used too.

14 Oct, '21
mjevans

Here is an example to test with.

The slight flooding happens at the far end of the lake reservoir after either: the dry season ends and the output is set to -0.5 from the top (1.5) OR the output side is lower and raised above that value.

An earlier game levee across the river with only two 0.5 (fixed height) dams did not have the sloshing problem even with the flow strong enough to keep the level near the rim until the dry season.

Since I can't attach files as a comment: https://mproj.net/WhyFloodedSloshAfterDrySeason.zip

It's a zip file because I'm positive that can be recognized and unpacked by most, and because the game save is an uncompressed JSON stream. i opened a report about that. https://timberborn.featureupvote.com/suggestions/224707/

1000 characters is far too limiting for a properly detailed bug report.

27 Oct, '21
John H.

Water flow physics still needs a bit of a relook. When you build levees to redirect water and it doesn't change the way that it's flowing there needs to be a relook. The water didn't really change until after a drought came and went. Water should flow differently as each levee is added. It's probably very complex, but would certainly be nice.

06 Nov, '21
Thagusta

I also have a similar problem where I split the river into two parts near the start of the map, with two sets of floodgates for either branch of the river. For some reason, once a flow is established in one branch of the river, very little will go to the other branch and vice versa. I can actually change which branch the water goes to (at random) by fiddling with the floodgate settings (closing them fully and then back to 2.5), but then after a drought, it reverts back...

Sorry if this is too vague. I'd describe it that the water flow follows the path of fast flow too much, even if it should rather flow (from a physics pov) to another place.

09 Dec, '21
Christoph

> I also have a similar problem where I split the river into two parts near the start of the map, with two sets of floodgates for either branch of the river. For some reason, once a flow is established in one branch of the river, very little will go to the other branch and vice versa.

I am experiencing the exact same thing and it's driving me insane. One set of my water wheels always stop :-/

22 Dec, '21
Max DeLiso

I agree that there are issues with the water flow at the moment (as of v0.1.1.0-b735201-sw). It is fairly easy to run into this, (and I did, in game, and then came to report it here); simply blockade the main river with levees and notice that water overflows into the banks (disabling the buildings there). Then, remove the levees and notice that the water remains flooding the areas adjacent to the river (when ideally it should recede once the levee is torn down, imo).

28 Dec, '21
Katotsu

I don't have that issue on that map in that spot, but I also only have one floodgate. I have 3 dams and the rest Levees, the floodgate is just a quick release. It might be a problem with overusing Floodgates in a single spot?

16 Jan, '22
Cyclops

Hi,

I have experienced the same issue until I realised the following:
1. The level for the Floodgates need to be about 0.5 difference between the upper stream and lower stream. If you jump to more than that it will flood. So, if your upper stream floodgates are set to 2 than the immediately next ones down river need to be set to 1.5. If you put it any lower it will create the wave and flood/drain effect constantly.
2. When building a dam you need to make sure that all the sections for it are at 90 degrees. If you use diagonally placed boxes it will still spill water between them.
3. You need to maintain a steady flow of water. If you know that occasionally during the night the water levels will rise than drop your floodgates by at least 0.5 to balance it out with point 1 in mind.

With this approach I have built a massive dam that is kept to almost maximum levels, 3, without any waves. Water is a non issue for me at this point. If required I can provide the save file or screenshot.

12 May, '22
Bartlomiej Szczygiel

It seems to still be a problem.
A simple 1.5m dam (first layer levee, second one: dam; The floodgate is set to 1.5, later replaced with the levee+dam).
A second dam is at the end of the river, one layer.
The water level oscillates between 0.20 to 1.06, and it seems the oscillations are not dampened.

While accidental flooding is great, beavers have to be careful, that infinite cycle may be frustrating to new players (quoting my wife: "WTF, why did you tell me to build that stupid dam. Carrots are wet!". ;-) )

What is even worse, the oscillations come back after a drought! (the second savefile).

It looks like the reason is the part upstream of the dam ( https://www.youtube.com/watch?v=QW3CzgpfN00 ) The water level near the river bend does up and down, and the current between the dam and the river band starts and stops periodically.

It feels quite unnatural. Even considering unrealistic proportions/skewed timescale, those oscillations should decrease in amplitude.

12 May, '22
Bartlomiej Szczygiel

Sorry for the second post, I hit the limit.
Does anyone know the formula the game is using to calculate flow?

13 Nov, '22
Lillie

I agree with this, the only solution I've found so far is to not have all the floodgates at the same height, so I'll have one or two set .5 lower than the rest. That evens out the flow pretty fast, and then I can raise the floodgates back up slowly, preventing the oscillation.

18 Dec, '22
mosc

The issue is the reflective wave needs more damping. Deeper water rippling back upstream works correctly but the oscillation continues without damping. An "upstream wave" should dampen out very quickly. The water physics are pretty reasonable, or at least playable, other than this oscillation. It's interesting the starting map shows it so clearly and the reason is the water volumes involved. The starting map has a relatively narrow channel with a very wide water source. Rivers in Timberborn should not "narrow" as they go away from their source. Another solution is to reduce the width of the water sources on this map but I'm almost glad it is the way it is so the devs can see the oscillation and the need for damping in their water physics.

How would I add damping? If you're computing the water change on a cell and both sides of it are trying to raise it, make sure you don't just add both effects, damp them.

10 Feb, '23
Megz

Still a big issue this, In the attached screenshot I set up some levees to block overspill from the blue area, worked great and had a little flood plain to do aquatic farming, I then wanted to have some control of the onward water as well as keep some water in the flood plain during drought. I popped in the floodgates in the little gap. Perfect I could get the water level just right for the plants to not be water logged or the water to go over and then I had perfect water flow through the gates again allowing water retention lower down.
When drought finishes firstly the water floods the top area, over spilling the levees on the right. So too much water clearly, drop the floodgate from 1.5 down to 1. This clears the overspill but now the lower half floods. Ok I think, it'll subside after the level evens out but it doesn't. It remains between 1.5 to 1.10. This flooded all my fields and killed my town from starvation. no level allows it to go back to the way it was when it was working.

13 Feb, '23
Jcheung Admin

first, not a dev, just a player. take what i have to say with grain of salt.

second, try using fewer dams per span of river to reduce oscillations. on plains specifically (OP image) you want 4 dams or floodgates per span and the rest levee to cut down on the flooding.
it appears that the dams are slightly sticky on their response to water level changes and one dam can cause feedback in another. reducing the number of dams reduces the maximum rate possible, and uses a greater percentage of the capacity in steady state.

13 Feb, '23
Jcheung Admin

for example, on plains (again, chosen because OP) most players end up with 7 or 8 dams going across one span.
that's 15.4-17.6 cms capacity. plains map has a total water generation strength of 8 cms.
when there's a change in water level going downwards, the amount of water the dams will pull will change to that new level with a slight delay... which means that it's pulling more water than it should. then it keeps going until it catches up and then it overshoots a little.
now it's pulling less than it should, and it goes up and up until it catches up and overshoots.
add in a second set of dams and this amplifies the effect until it spills out of bounds.

by reducing the number of dams/floodgates to 4, you reduce the maximum rate to 8.8 cms which gives a possible range of around +/- 0.8cms which usually isn't enough to flood the banks, as compared to +/- 7cms

third, not sure what's going on megz, but i don't think that's related to the original post. try sending in a bug report email.

Comments: 28