I'm trying to model a MINLP problem in pyomo. Is there a better way to do this?

So, I'm fairly new to pyomo and I've been trying to model a problem of water allocation according to this article (https://doi.org/10.1016/0098-1354(80)85005-8) as MINLP. At first the code worked, but the results were not even close to expected, and ever since I introduced the "delta" restriction (sum of split ratios = 1) it's stopped working altogether.

Here's the link to the code, and there's more info on the comments I left. The equations I used are in page 253 of the article and the parameters in pages 255 and 256.

🔴 No definitive solution yet