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run-time error

Tue, 12/09/2003 - 8:45pm — bdcequal
I ran the preprocessor just fine with some warnings and no error. However, when I tried to run the actual W2V3 model, it keeps giving me the folloing error message "forrtl severe (157) program exception - access violation" and more lines of unknowns. Can somebody point me to the probable cause of such an error? any help is appreciated, bekele[addsig]
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Installation
Wed, 12/10/2003 - 7:45am — srm

Hi, I am not the indicated person to help you, but I had already a similar problem. I do not remember of which was the problem, but in my case I solved it by confirming all the input files regarding the number of constituents that were been computed and the dates of simulation. And certifyd that i were asking the model to construct correctly the output files in the control file (eg. in the TSR SEG and TSR LAYE etc). It seems that you are asking for the model to make something that go outside the domain of your system. If in the error message appear the lines of the code where the problem occurs, you can check in the source code about what that line of code makes. I don't know if it helps. Hope so! regards, sandra[addsig]
Wed, 12/10/2003 - 9:36am — bdcequal

Sandra, thanks for your help - i'll go through it and see what comes out. take care, bekele[addsig]
Fri, 12/12/2003 - 12:38am — Scott

The preprocessor needs to catch this error - but it doesn't yet. The usual cause for this is that you have specified output segments that are greater than IMX, the maximum number of segments. Check - as mentioned already - the segment #'s for the SNP file. The preprocessor is trying to write the initial condition based on the segment numbers for the SNP file - but these do not exist. Hope that helps, Scott[addsig]
Fri, 12/12/2003 - 10:35am — bdcequal

message deleted [addsig]
Mon, 12/29/2003 - 9:20am — Tom

I think I understand what is going on. You are modeling a river, and you want the model to compute what the flow is at the last segment based on inflows. You will need to set up the downstream flow as a spillway, with the elevation slightly above the bottom elevation of the last segment. Scott, you ought to chime in here as you have more experience with this than I do.[addsig]
Tue, 12/16/2003 - 8:08am — Tom

The model requires that an outlet and an outflow file be specified for all branches that have a downstream flow (DHS= 0) boundary condition. You just need to set the flow to zero. I am a little confused as to how you intend on managing the outflow for the water balance. Does this system have an outflow? If it does, then you can allow the model to compute the outflow by specifying a spillway or gate as the outlet structure, or you can specify the outflow if it is measured. However, be aware that any errors in the inflow specification will not have a chance to be corrected if you allow the model to compute the outflows. In other words, computing the outflows may or may not have anything to do with reality.[addsig]
Fri, 12/19/2003 - 12:05pm — bdcequal

Thanks Tom, My apology for not being very clear in my previous posting. My question was since the CE-QUAL-W2 also simulates mass balance in the system, once inflows were specified I was expecting the model to give me prediction of flow over time period at any specified segment (outlet in my definition), which is the last segment in the most downstream branch in this case. I wanted to check if the model simulates the flowrate over time at the specified segment where I've a measurement as the first hand check. However, there is no real structure at the segment where river flow measurement was taken (i.e., no outlet structure). At the same time, I didn't want to use my measurements as input to the model but for calibration. There is where my question lays - why do I've to specify an imaginery outlet structure? But, I've got the point now - DHS = 0. So, my next question will be what other DHS value do I've to use under such cases where no real structure is available at the segment where measurement is taken? many thanks, BD[addsig]