There are many ways to get rid of the water in low areas, squeegee, sludge pump, trash pump, wanding until you get it all done.
When I have a job that I know is a lot lower in some areas like this one yearly job where there has a lot spot in the middle of the parking lot where all the water drains to I bring my sludge pump and 100' of discharge hose.
You need to determine what works best for you, the sludge pump uses either 1.25" or 1.5" discharge hose so that takes up a little bit of room on the trailer so I do not keep it there all the time. The pump and 50' is coiled up inside one of the plastic boxes with removable lid that locks down. The other 50' of hose is just coiled up so when I do that job or something similar I bring the extra hose and box.
One of the guys made a version of the sludge pump and it works good and it is small enough that you can keep it on your trailer like in a tool box and use regular garden hose for it, it is a good idea, I was going to make one but have not got around to it yet but I will.