Number one, you arnt going to pump that creek. If you think 2,500 gpm pump will keep up your in for a MASSIVE surprise. All you need is a floating sediment break wall out in the water. If you must have a dry work area then your needing to use a portable dam system. Google dam-it-dams, he can ship you a dam to rent. Figure 5k if you need one.
Knock that dirt down behind the wall so its all a gentle slope and gives you good access behind it.
Rip the concrete out with the exc. and use a CTL to bring it up and out.
I cant see that job being more than 2 weeks if that. As long as you have two guys on machines and 3 or 4 laborers.
We estimate around 2-3 weeks. We will have 2-3 laborers working. Just depends on what the insurance decides to do.