Hi all,

I’m modeling the Colorado River Basin along with its connected regions (California, the Rio Grande, etc.), so it’s a fairly large-scale system. I’ve set up reservoir release rules using minimum environmental flow nodes, which I then linked to each reservoir’s Maximum Hydraulic Outflow (MHO). I used the minimum environmental flow node as the MHO constraint; otherwise, the reservoirs tend to release excess water to meet downstream demands.

When I run the model with the XA solver, I get warning messages stating that the maximum hydraulic outflow was removed due to LP infeasibility. This also results in large spikes in the reservoir release outputs.

To troubleshoot, I installed the 32-bit version of Gurobi 7.5, and copied gurobi75.dll and Gurobi.lic into the WEAP program folder. However, I receive error when running the model.

Has anyone run into a similar issue or found a reliable way to resolve LP infeasibility problems with MHO constraints? Any guidance would be greatly appreciated.

Thanks,
Burcu

Burcu,

Yes, I have run into this as well myself. One alternative I could recommend is to make the priority of the reservoir higher than all the downstream demands, but lower than that of the minimum flow requirement. Then, the reservoir should release according to the minimum flow requirement, but not more.

Hope this works for you.
-Doug

Hi Doug,

That worked — thank you very much for the suggestion!

Best,
Burcu