You are here

Home › Forums › W2 Forum › Announcements

Reservoir simulation problem

Wed, 06/07/2006 - 3:13pm — rajendra
I have error message like this Unstable water surface elevation on day 1.667 negative surface layer thickness using minimum timestep at iteration 1442 Segment, Surface layer thickness, m 2 -0.63 3 -0.63 4 -0.63 What is the best and easiest way to get rid of this error message.
Forums: 
Announcements
Wed, 06/28/2006 - 9:33am — nick

Is this a reservoir simulation? How many segments are in the branch? It appears that the segments are dry. Reducing the timestep in the control file can help here.
Tue, 09/10/2013 - 10:39am — Ujwal

I had similar problem and I reduced the min timestep to 0.01 from 0.1 and max to 30 from 600, and timestep fraction to 0.5, it seemed to work but when i tried to re-run after water balance it again showed some error in some random day. It happened again when we tried to run the model with evaporation and precipitation on as: Unstable water surface elevation on day 4371.165 negative surface layer thickness using minimum timestep at iteration 3245443 Segment, Surface layer thickness, m, Flow m3/s, U(KT,I) m/s, ELWS, m 193 5.11 -18558.79 -218.56 34.54 194 6.16 ********** 17898.82 35.59 195 -28.78 ********** 698803.75 0.63 196 6.10 ********** -4356.73 35.50 197 2.77 -2253.82 -27.45 32.17. I have 3 branches with 203 segments and branch 1 has 2-190 active segments. I am running it from Jday 3288 to 6300. Does anyone has any suggestions? Do I need to look for anything else other than timestep? Thanks, Ujwal