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Dan Wagner

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  1. Hello everyone, I'm manually spinning down a FESWMS flo2DH model to a known flood discharge and water surface elevation. Target Q of 40,100 cfs is the inflow (upstream boundary condition is set at this value), and target WS el at the downstream boundary of the model is 905 ft above sea level. The water surface elevation I'm at in the spindown process is about 940 ft. Spindown is going OK and the model seems to be stable. The problem: The reach of floodplain I'm modeling is in a mountainous area and drops about 35 ft in 1.5 miles. The known water surface elevation at the upstream end of the model (from high water marks) is 937 ft above sea level. As I've been spinning down, I've been disabling elements as they've gone dry to help the model stay stable. However, I'm to the point where some elements that span the known water surface elevation at the upstream end of the model are within the wet/dry boundary. So the question is, do I continue to disable these elements? It seems that I should leave the elements enabled, as they will need to be when I start calibrating the model to match the known flood. Or am I in a type of situation where I'm going to have to start tweaking roughness coefficients to keep the water surface high at that end of the model? Anybody have any experience in such a situation? Thanks, Dan
  2. Thanks for the advice Cameron. The terrain I'm modeling has very steep slopes on the edges of the model domain at the location of the total flow string (upstream end of model). Elements have been going dry and I have been disabling them as I've dropped the water surface elevation during spindown (is this what you refer to as "trimming the mesh down in size?"). I'll try making the inflow boundary string smaller, to prevent the error from occurring again. The total flow boundary string originally included all nodes at the upstream end of the model. Regards, Dan
  3. Hello all, First, a little background: I'm manually spinning down a FESWMS model from a bathtub condition to a water surface elevation and flow from a known flood. The nodestrings representing boundary condition cross sections are #1-downstream end (WS elevation), #2-flux line mid-reach, and #3-upstream end (total flow nodestring). I've spun down from a bathtub condition at elevation 975 ft to 960 ft. I've gradually upped the total flow from 5000 cfs to the flood flow (40,100 cfs) and have dropped the Vo from 300 to 150. I've had to start dropping only 1 ft in elevation at a time since 965 ft to keep the model converging (the target WS elevation is 905 ft). I've also been disabling elements that have gone dry after each iteration. I've noted that I receive warnings for the missing elements/nodes along my boundary nodestrings as a result, but FESWMS seems to run OK despite the warnings. OK. Now that I'm at 960 ft, trying to spin down to 959 ft, I'm running into troubles. I have received the error "Total Total conveyance is zero in boundary cross section "1". How does one go about diagnosing this error, i.e., why did it occur, and how to go about proceeding? Any ideas would be appreciated! Thanks, Dan
  4. Todd, thanks for the help. I'll take a look at the post. I might have missed turning off a couple of dry elements. -Dan
  5. Hello all, I have 1 error and 1 warning that keep popping up on me as I try to spin down a river model from bathtub conditions to a known flood's water surface elevation and flow rate. First, the warning message: I keep receiving the following warning message: "Flux line element edge 179-180-181 not found." This message occurs for every iteration. I believe I've traced it to the edge of an element I disabled after it went dry. The downstream edge of the element corresponds with a nodestring representing the downstream end of the model and natural water surface elevation boundary condition, and the three node #s on the edge of the element are 179, 180, and 181. The question is: Will this condition cause instability in the model? Is this something I should address, or ignore? Second, the error: Can anyone explain the meaning of the error message 'Top width zero in flux line 2 "2"'? I've received that a couple of times on runs that crashed. Thanks in advance to anyone who can help. -Dan
  6. Todd, I posted my zipped folder "USGS_dwagner"-as it was loading I realized I had the Mr. Sid background image in there. I canceled the transfer, tried to re-load with just the SMS project and 2d mesh files, but the server wouldn't grant permissions that time. If the files you need are in there, great; if not, the zipped folder can be deleted and I'll re-load without the large Mr. Sid image. Thanks, Dan
  7. Todd- Thanks. I'll upload the files for you in a folder "USGS_dwagner" -Dan
  8. I'm wondering if it's normal for nodestrings that I have set up as weirs to lose the weir properties every time I close SMS and re-open (as in leaving for the day and opening the next morning)? Also have an issue with my SMS project having lost the mesh. When I open the project, the mesh does not open with it, although I've saved both the project and the mesh. Any ideas? Thanks all, Dan
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