Long hose to a soccer pitch? pressure!

Hello all, hopefully you can help.

The situation we are in is as follows.

We have a 150metre hose, of 1/2" diameter that runs from the outside tap of the club house to the soccer pitch adjacent.

Pressure from the outside tap is generally fine, but as you would expect, its not worth talking about when it arrives at the end of a 150 metre hose pipe, at which stage it is to fit on to standard garden sprinklers.

The questions I have are as follows.

(1) We tried to run the tap through a pressure washer, then on to the hose pipe and that helps allot, but I dont think a pressure washer can keep a continous pressure for constant sprinkling. Can anyone give na opinion on that please?

(2) Can anyone suggest what I can put between the outside tap and the long hose pipe that would push water down the hose pipe at an increased constant pressure?


ps: Changing the plumbnig is not an option, and the water supply is generally fine.

Many thanks