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Found 11 results

  1. Hello, I'm attempting to construct a GSSHA model of a low-relief watershed containing a significant number of natural topographic depressions. I'm uncertain about how to build and apply the depression polygon mask within WMS. I have a polygon shapefile of the depressions for this watershed. Can someone either point me in the direction of a tutorial on this process, or provide general steps within the answer to this post? Thanks, David
  2. Hi. I was wondering if anyone could clarify an aspect of the water elevation in the channel when using GSSHA. In the development of the channel input file for GSSHA, firstly stream arcs are generated from the DEM in WMS for GSSHA; then the thalweg profile (vertices) are then assigned elevations and corrected using the Smooth GSSHA Streams dialog box; and finally channel properties (channel depth, bottom width and side slope, and Manning's N) are assigned (using the Feature Objects -> Attributes). Figure 1 (attached) illustrates the cross-section of a river, where the brown line is a 40m resolution DEM that was used as the DEM input to GSSHA, and used to generate the stream network. The orange lines are the actual channel bed derived from field observations, and the blue area is water in the channel. A was the water level in the channel when the cross-section was recorded, When the thalweg profile (at one data point in the form of a vertex for this location) is assigned using the Smooth GSSHA Streams option, the elevation extracted from the data for this location would be A (1m). Then the channel properties are assigned, in this case a trapezoidal channel with a channel depth of 0.5m. This would mean that the streambed elevation would be 1-0.5 = 0.5m. My question is, if the channel depth (CHANNEL_DEPTH) project card is included in the simulation, and the water elevation rises above A, what processes/computation does GSSHA use to calculate the channel depth, considering that what GSSHA thinks is the top of the river channel is reached? Would this only of consideration if the OVERLAND_BACKWATER and/or OVERBANK_FLOW project cards are included in the simulation? Thank you in advance for any information. Hamish Asmath Institute of Marine Affairs, Trinidad and Tobago
  3. For long term simulation in GSSHA, where can we download direct and global radiation? I downloaded other hydrometeorology parameters (Pressure, Sky Cover, Wind Speed and Temperature) from NCDC website ( Relative Humidity was estimated based on dew point and average temperature using this formula: RH: =100*(EXP((17.625*TD)/(243.04+TD))/EXP((17.625*T)/(243.04+T))) Is there any other recommended method for Relative Humidity estimation?
  4. GSSHA needs observed peak and volume flow data to compare calibration runs for a closeness of fit. If an observed hydrograph has multiple peaks for a single event, how will automatic calibration in GSSHA deal with that? Also, does automatic calibration in GSSHA tends to match observed peak and volume only, but not the shape of hydrograph?
  5. Recently I've been experiencing issues trying to implement more soil layers into my model. The model which worked fine with classic G&A redistribution infiltration routine suddenly produces weird results with G&A multilayer routine. The only change I made was switching to multilayer routine and assigning the depth of all layers. No matter what the depth was, disregarding any less permeable second layer I tried to introduce - the model always produces the same hydrograph with the peak as much as 20x higher then before and much faster response to all precipitation pulses. Moreover, when I tried to assign less permeable parameters to all layers, the peaks reached astronomic values, the model responded with NEGATIVE infiltration and the discharge volume reached about 200% of precipitation total. Does anyone has similar experience and/or suggestions, what went wrong? I suspect there's a numeric calculation bug inside :-) Thx Ludek S. CTU Prague
  6. What version of GSSHA does WMS 9.1.8 have?
  7. Attached picture is from the GSSHA long-term runoff simulation summary file. Although the first rainfall event starts on 07/14/2013 at 15:00, the summary file writes Hydrometeorology (hmet) data began on 07/15/2013 at 2:00. Is this delay normal, shouldn't both rainfall and hmet data start on same time? Seaworth06.txt
  8. There is still time to register for the training course "Hydrologic Modelling with GSSHA and WMS" June 18-21, 2013 in Provo, Utah. For more information, see: In this course, we will cover all aspects of GSSHA modeling, from setting up a basic model to setting up and running models with overland and stream boundary conditions. Visit the web page for more information and to register. We hope you can make it to this interesting course. Thanks, Chris
  9. Is there a way to use a HecRAS geometry file or an *.idx cross section database file to populate the cross sections in stream arcs for GSSHA? Thanks!
  10. I was exploring WMS-GSSHA results visualization and I have a question: Is it possible to show aggregated sediment loss on the map for a longterm simulation ? now I can only view one time step at a time , and I was wondering if I can also view sediment lost for example for the whole month ..using color ramp display on the map.
  11. Hello everyone, I am new to WMS. I would like to know if it is possible to use WMS to perform real-time simulations. Both radar and gauge rainfalls are avaialbe every 10 mins. Once models (HMS, RAS, or GSSHA) are set up, I would like to have an automatic process. Thank you