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I am having some issues when computing discharge in the latest version of RIVeR (v2.4.2) and I'm wondering whether anyone else has experienced the same.

These issues can be summarized as follows:

  • I am unable to export the ...StationDischarge.txt (when I do there is no data under "Station,Discharge", see Figure 1 below). I am able to export the ...StationVelocity.txt (see Figure 2 below)
  • The discharge and velocity plots don't look correct: the % of total discharges looks too high, and the number of points/bars does not match the number of stations for the cross section, which I think is the main source of the discharge computation problem. (See Figure 3 below).
  • In this example, RIVeR gives a total Q of 5.8 m^3/s, but the comparison FlowTracker measurement was 22.9 m^3/s)
  • If I manually calculate the total discharge, using the StationVelocity.txt data from RIVeR and the same depths and station distances imported into RIVeR, then I compute a total Q of 24.8 m^3/s, which is much closer to the expected value. (See Table 1 below).


Figure 1: no data in ...StationDischarge.txt


Figure 2: ...StationVelocity.txt data


Figure 3. Note the number of data points for discharge and velocity in the plot on the right hand side does not match the number of stations in the cross section (should be 25). the correct number of stations and velocity points do appear in the table and the exported ...StationVelocity.txt file).


Table 1: Manual check of total discharge, using StationVelocity.txt data from RIVeR (Area and Q manually computed using station dis and velocity respectively.

StDepthStationVelocity

()(m)dis (m)(m/s)AreaQ
00

(m^2)(m^3/s)
10.0900.101460.2268980.023021
20.162.521090.04560.8067470.036788
30.265.042170.321731.3109640.421777
40.287.563260.290351.4118080.409918
50.3610.084340.121861.8151810.221198
60.4312.605430.278022.1681330.602784
70.4915.126510.312612.4706630.772354
80.5517.64760.423972.7731941.175751
90.6520.168680.593033.2774111.943603
100.6622.689770.539153.3278321.794201
110.7925.210850.454163.9833141.809062
120.8227.731940.396084.1345791.637624
130.9130.253020.374964.5883751.720457
140.9132.774110.353664.5883751.622725
150.9435.295190.381854.739641.809831
160.8637.816280.309744.3362661.343115
170.940.337360.299964.5379531.361204
181.0342.858450.243065.1934351.262316
191.0845.379530.224645.4455441.223287
201.147.900620.217475.5463871.206173
211.0250.42170.240865.1430131.238746
220.6952.942790.145733.4791040.50701
230.6655.463880.147783.3278320.491787
240.3957.984960.105531.9664460.207519
25060.506050.097300




Total Q = 24.84225
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6 Comments

  1. Hi Liz–curious if this was a problem you had in previous versions of RIVeR?  Or just 2.4.2?  I haven't used 2.4.2 for a full computation of discharge yet, but should be doing so soon.

  2. Hi Heather, I haven't tried other versions yet. Since I was on leave for a year (from March 2018-2019) I jumped quite a few versions in one go.

  3. Hi Liz !

    • I am unable to export the ...StationDischarge.txt (when I do there is no data under "Station,Discharge", see Figure 1 below). I am able to export the ...StationVelocity.txt (see Figure 2 below)

    Interesting... I will have a look thanks for the warning

    • The discharge and velocity plots don't look correct: the % of total discharges looks too high, and the number of points/bars does not match the number of stations for the cross section, which I think is the main source of the discharge computation problem. (See Figure 3 below).

    So on the discharge plot, the y axis on the left side is for the cumulative curve (the black line with dots). It might not be your question but if not I guess that my following comment will.

    About the the number of points/bars and also the next two issues you summarised I think the problem might come from your Stage Vs. Station plot. In the column station I can see numbers (integers) and I can't see all of them but I guess there are 25 of them. In this column you should have the actual distance (in m or ft) from the left bank. I might be wrong but it looks that those numbers are not distances but the station number. I see that the length of your velocity profile goes up to 60.5 but you bathymetry goes only to 25. So if you compute a discharge value over your current bathymetry that is 25 width instead of 60.5 your results will be lower than expected.

    Can you please double check and let me know if my hypothesis is correct ?

    Best !







  4. Thanks Antoine,

    You're right, I had the station numbers and not the distances in the "Station and Stage Table". I've corrected this and you will see the discharge plot makes a lot more sense (at least to me). See Figure below. However, I didn't think this would be a problem because there were distances in my "Station and Velocity Table". I guess I didn't realize in the discharge computation that the distances in both the velocity and stage table are used?

    Unfortunately, the exported StationDischarge CSV file is still missing the Station and Discharge data. Also, the estimated discharge, while slightly higher than before, is still well below what I am expecting.

    Any other ideas?


    Liz

    [Note: I think it would help if the labels were more descriptive, both for the tables and for the plots. "Station" should really be "Station Dist." or just "Dist". Also for the x-axis in the stage, velocity and discharge plots: it would be less confusing to call this Distance from Left bank. I suppose you want to avoid the use of units in any of your labels, to avoid the need to accommodate metric and imperial? (Not having units does make it more confusing though).

  5. Hi Liz

    You're right, I had the station numbers and not the distances in the "Station and Stage Table". I've corrected this and you will see the discharge plot makes a lot more sense (at least to me).

    Good !


    However, I didn't think this would be a problem because there were distances in my "Station and Velocity Table". I guess I didn't realize in the discharge computation that the distances in both the velocity and stage table are used?

    Yes it does because the stations from your bathymetry are not necessary  the same as your velocity profile. Both have to be on the same grid so the discharge can be computed.


    Unfortunately, the exported StationDischarge CSV file is still missing the Station and Discharge data.

    Yes I am going to check this.


    Also, the estimated discharge, while slightly higher than before, is still well below what I am expecting.

    Yo mean lower that the value you calculated in Table 1 ? Is it possible that you have an error of calculation in the column Area ? It looks that you are calculating the area of a rectangle and not a trapezoid. FYI,  RIVeR calculates the area of the trapezoids and multiplicates them respectively by the mean velocity betwenn two stages.


    [Note: I think it would help if the labels were more descriptive, both for the tables and for the plots. "Station" should really be "Station Dist." or just "Dist". Also for the x-axis in the stage, velocity and discharge plots: it would be less confusing to call this Distance from Left bank. I suppose you want to avoid the use of units in any of your labels, to avoid the need to accommodate metric and imperial? (Not having units does make it more confusing though).

    Good idea thanks !


    Best

    Antoine



  6. Problem solved! We discovered that I had an earlier (and problematic) version of the v2.4.2 executable (.exe),  complied on 2019-07-15. So as long as you have the RIVeR_GUI.exe dated 2019-07-18 then these issues go away in v2.4.2.


    Liz