Extreme water surges from floodgate changes

[BlackOak]

Any time I make a change to my floodgates they send a wave up and down stream. This was not a problem before the update as it would not be a big wave and would damp down pretty quickly.
Now the wave that goes upstream causes the flow to stop(or even to reverse) while the regular flow continues to build up water which makes the return wave MUCH stronger than the original. This then hits the damn causing flooding and an even bigger rebound wave, causing an escalating oscillation. I built a water gauge and measured a surge taking the water level from 0.18 up to 1.23. Even opening up the downstream floodgates 100% stopped making a difference as the water built up faster than it could flow forwards.

The water needs to be less viscous and needs to damp down oscillations.

[Hybris]

I have the same problem and for my saves, its gamebracking. My Whole Town goes under water and starves

[Akarin]

Is that really a bug though? thats how water works it has a flow rate and if you raise the gates all the way up so the flow rate is zero or if you only have one gate so flow output is lower then whats being input then backing up and flooding should be expected yes?

[Hybris]

The Waterflow is the same woppen and with closed gates. Among other things, this means that the water level in front of the gate is four blocks higher than behind it. So yeah, I strongly suspect it's a bug.

[Wise Joe]

Originally posted by Akarin:

Is that really a bug though? thats how water works it has a flow rate and if you raise the gates all the way up so the flow rate is zero or if you only have one gate so flow output is lower then whats being input then backing up and flooding should be expected yes?

No, this is not how water works in the real world. What you describe is accurate. But that is not what is happening in game. What is being discussed here is when the water is flowing over all the floodgates. Floodgates the width of the original river bed so that there is not a change in the channel the water is flowing through. Once the water begins flowing over the top of the gate is should stabilize.

The flooding is one issue. That can be mitigated by building up levees to stop the flooding. Bye bye valuable and picturesque riverside real estate for the beavers. Hello ugly looking settlement. However, this flooding is annoying as it causes all downstream riverbanks and canals to alternate between being flooded to almost being dry.

In my opinion, the other annoying issue is that it makes energy generation by water wheels unreliable. In my case I have a battery back up that looks like a yo-yo as it goes up and down due to these surges in flow making my water wheels spin from over 500 energy generation to zero energy generation.

[Wise Joe]

I thought I found a way to cheese the slopping, but unfortunately not.

Playing on the Helix map. Rerouted the water source closest to the starting area to flow down what looks like its old riverbed. It has at least two waterfalls in the riverbed. (Maybe three, I did not count before leaving the game, but for sure it has two.) The last waterfall is from a four-level height into the existing riverbed. Therefore, nothing happening in the original starting area riverbed should have any feedback on the water coming from that rerouted water source. That is just the background.

Originally built dams and did not have slopping issues. Eventually built one level floodgates across the river right above the last waterfall. At first there was no slop and the flow was steady at 1 and the depth was steady.

After the first drought with the floodgates the slopping started. I thought, why not negate the backwash from the floodgates by building a dam across the back channel. So, I built dams right behind the floodgates on the upstream side of the floodgates. That stabilized the slopping so I thought I had found a way to cheese the slop. Until the next drought. After the next drought the slopping began again. Plus, on a one level floodgate, a dam right behind the floodgate kind of negates the reservoir creating purpose of the floodgate as you lose access to .50 water level.

I then took away the floodgates and left just the dam. The slopping got worse when I did that.

With the floodgates the water level would alternate between .66 and .64 and the flow from .4 to .6. It would not flood the lower river until day 4 even though the range of height and flow stayed the same. It would even flood when the flow was .4. On day 10 the flow finally stabilized to .4 cms. (This was with a one level deep river. When I was dealing with a two-level deep river in my other game it would never stabilize between droughts.)

When I took away the floodgates and left just the dam the slopping became even worse. Flow would go from 0 to 1.4 continuing to flash flood the downstream river. That was behavior that did not exist with the dams before I had put in the floodgates. Not sure if that was a residual effect left behind by the floodgates?

Note: When I first loaded the game today to test removing the floodgates all river branches remained steady within a .1 cms change or completely steady until the first drought when the slop began again.

Maybe it has something to do with the water destroying attribute of the floodgates? Which I have been using to cheese mitigating the flooding caused by the slopping. So, thank goodness for the feature right now.

For me this makes the game unplayable. So, I am out unless or until they fix this "known issue", which should be fixed before adding any more "features" to the game.

[BlackOak]

In my newer maps I have not seen this happening. IDK if they have implemented a fix, or if I have changed the way I build to be more resilient. I suspect it was a fix since I haven't seen flow reversals like the ones I reported above

[Wise Joe]

I am still seeing it in my current game on the Helix Mountain.

[wyatt2996]

This still happens even in update 6. wild 1 to 1.5 block oscillations (either 1-1.5 blocks above normal and 1-1.5 blocks lower than normal) that occur 2-3 days after a drought. I've noticed it both on vanilla maps and custom maps. the flow from the dam is very smooth at around 2 cms then as it goes through a series of single height dams, it picks up a surge from somewhere.