Inputing the single rating curve

Dear Sir,

We have any problem to run the Boss Dambrk Program about the single rating curve position.
The condition of our problem :

1. The first Problem
· There is subcritical and supercritical flow happened in the channel, then we choose " Mixed flow option ".
· After we choose these option, the warning statement show that we should make a single rating curve for the boundary condition.
· But we confuse, in which section the single rating curve should be taken.
· If we took it in the second from the upstream, it might be trouble when the low discharge is running along the channel. Because in the most down stream section the program won't found the minimum elevation.
· But if we took it in the most down stream section, it might be trouble when the low discharge is running along the channel. Because in the up stream section the program not found the minimum elevation.
· The same program we ask you, in which section we must take the stage hydrograph if we choose it. And stage hydrograph we must be taken.

2. The second Problem
We have the condition of three dams, Which each dams have storage, along the one river.
Qustions :
· The each of three dams have an inflow hydrograph. How should we make the true input data ?
· Now we make to try the condition devide :

Condition I : The first dam until the seventh cross section, with option I.
Condition II : The seventh cross section until the second dam, with option II
Condition III : The second dam until the seventeenth cross section, with option I.
Condition IV : The seventeenth cross section until the third dam, etc, with option 14.

In the result we don't find in each dams there are storage, in fact the three dams have storage. How we make to solve our problem for these condition?

Therefore we expect your advice, for which are appreciate it.
Thank you very much,
Sincerely yours,
PT. Indra Karya
Nuny Sundari.

Dear Indra Karya Cabang I :

Note that the Flow Type Parameter data entry is not controlling the specifying the Single Value Rating Control Curve. Rather, this is defined in the data entry directly above it, which is labeled Downstream Water Surface Control. Typically what is selected is Channel Control, which means that normal depth is computed using Mannings Equation. However, there are other options available. You can learn more about these options from our DAMBRK User Manual, or pressing function key <F1> and reviewing this information in the on-line help. Note, however, that all of these boundary conditions apply to the downstream most cross- section.

Also, you can perform a simultaneous routing with all three dams within the same model. Note that several of the example problems that we have provided have more than one dam. If additional flow enters the downstream reservoirs, you can enter that as a lateral inflow hydrograph. The storage effects for the reservoir can be defined within the cross-section geometry with the storage top width data entries. In defining the reservoir, you use multiple cross-sections to define the width of the reservoir, and then define areas of storage in the cross-section geometry description for the reservoir. You would use Option 13 or 14 for multiple dam structures. Note that this explained quite well in our latest BOSS DAMBRK User Manual. You can download this manual from our website as a PDF document.

If you have any additional questions or need any further information, please contact me again.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com