HEC-HMS Issue

[cveg05]

Hi,
I'm modeling a detention basin in HEC-HMS using the reservoir function. The reservoir has two drainage sub-basins flowing into it. There are three culverts and a spillway acting as the outlet structure. I've entered the reservoir data in the elevation-storage format. For the tailwater conditions I've entered an elevation-discharge rating curve.
The problem I'm having is that when I run the simulation I get several errors which say "ERROR 40243: Could not compute water elevation for reservoir". The simulation will then keep on computing for about five minutes and then finish and give results. The results it calculates seem reasonable but I question their accuracy since I'm getting this error message and the program is obviously having trouble computing the simulation. Also the water elevation in the reservoir never reaches the spillway elevation so the outlet culverts seem adequtely sized.
Any thoughts?

 

[blueoak]

Are you running version 3? I find it gives error messages up front. I had trouble with version 2 about errors like this until runtime.

One thing if you really think it is right may be to check your basins. If you can get these to run you can output the hydrographs and do the stage storage discharge on a spreadhseet. Another trouble shoot is to set up a steady inflow that is just amazingly big. This way you can see if it spills. I would definetly resolve this before you submit the plans. I had an error similar using version 2 and I had not entered a starting elevation for the reservoir. I finally fixed it and had 20% of the capacity I originally thought.

 

[Crystalct1]

I have also found errors in HMS when your elevation-discharge-storage data is incomplete. In other words, when the program went to do the iteration, it ran out of inputted data for the next iteration. The solution is to add one or two more lines of stage-discharge and stage -storage data.

The last line of input should be too big for your meteorologic model rainfall and simulation event.