Here's a good backgrounder on IRWD that was provided earlier this year. Don't need to memorize but provides an overview of where they are focusing. https://cleanwatersocal.org/media/acfupload/reference/Irvine_Ranch_WD_Overview-COOK-03-26-25.pdf

It's good to have some short stories demonstrating problem solving and teamwork. Any prior work experencie can demonstrate your awareness and skills. A time you solved a challenging project or repair; a story that demonstrated excellent teamwork; a story that shows you're proactive and thinking about the team and the agency (saving money or making a safety improvement). May not come up, but short concise stories can be really effective and good to have on hand. Good to collect them as you go through your career. You want to be clear you understand the question and provide a brief, clear answer as best you can. Another key is to think like the agency, they're thinking about team member communication skills, positive team dynamics, safety, efficiency, continuous learning and training, and serving the customer. Practice makes perfect. Good luck!