Sydney Water have an excellent on line contact management system where you can submit problems like this, including photos (I attached both of these to my query, number 090102-000020). This pumping station, number 72, is in Concord.
Given that the site is locked, I don't know how Energy Australia are going to get a crew in to clean up this kiosk. This might be a bit of a challenge - getting one authority to talk to another and arrange access.
Last time I lodged a problem like this with Sydney Water, it went walkabout. I got a very nice letter back from the Managing Director explaining the problem, and the site was quickly cleaned up. This time, I am putting a reminder in my diary to follow this up again in 3 weeks time to ensure their system is still not losing things.