Welcome to the RAS Solution Forums HEC-RAS Help HEC RAS 1D Error

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • #7546
    Anonymous
    Guest

    hi,
    I am running HEC-RAS 1d model for unsteady flow. i have used SRTM 30m DEM and digitized cross sections at every 3km interval. length of the river is approximately 1200 km and it has five tributaries. at upstream boundary conditions i have given flow hydrographs and at downstream normal depth. i am running model from june to october 2019 but i am getting this error ” Minimum error exceeds allowable tolerance at 01JUN2019 09:00:00″. after reading solution in this forum i have increased HTab parameters to 500 points as i am using 5.0.7 version of HEC-RAS but still it is showing the same error. if i modify particular cross section mentioned in error then it will show error at some other cross section. Even i have tried different combinations of time step interval and simulation time. i have tried from 5 mins to 1 hr. i tried to run for 10 days to 1 month. normal depth also from 0.0001 to 0.1 i tried. but still the same error.
    if i am running each tributaries separately then its running fine. only if i combine all the reaches and try to run then only it is showing error. i thought junctions might be the problem. but i tried everything whatever solution i get from user manual, google but its not helping. i am working on this from last three months.
    If anybody knows anything regarding this problem please help me.

    #12648
    Anonymous
    Guest

    Decrease your time step to lower intervals

    #12649
    Anonymous
    Guest

    that also i tried. i tried with 30 sec also.

    #12650
    Anonymous
    Guest

    Leave your downstream boundary condition alone, calculate it as is the normal process. Add initial conditions to areas where the 1D model may be drying out. If you have large amounts of terrain slope changes as the river moves downstream, add a pilot channel. This will help keep the pilot channel wet

Viewing 4 posts - 1 through 4 (of 4 total)
  • You must be logged in to reply to this topic.