Hi Zahra,Congratulations on reaching the end of your PhD journey! ASCE is offering a resume workshop in another few weeks where you will be able to get feedback on your resume if you would like to submit one. Here is the link! I will be one of the resume coaches and since I also work in the water field, theres even a chance that I will be the one reviewing it!
https://collaborate.asce.org/careerbydesign/events/simple-registration?CalendarEventKey=1a427a4c-e967-49ed-a168-08335705e0d2I don't have any experience I can speak from regarding the value of the GIS certificate. Don't be too quick to discount your programming experience just because it hasn't been in the field of your choosing though. As long as you understand the fundamentals of programming in a certain language, your future employer will likely be more than happy to explain what they would like to see you do with your skills.